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【Objective】 The leaf area index (LAI) is an important trait of plant canopies but challenging to measure accurately at large scales. We studied the feasibility of using multispectral imaging and machine learning to estimate the LAI of spring wheat. 【Method】 The experiment was conducted in a spring wheat field on the Tumochuan Plain in the Yellow River Basin, Inner Mongolia. Images of the spring wheat at the jointing, booting, and grain-filling stages were acquired using a multispectral camera mounted on a DJI P4M UAV. Selected vegetation indices were subjected to principal component analysis (PCA), and the resulting components were used to estimate LAI. We compared six models: multiple linear regression (MLR), decision tree regression (DTR), backpropagation neural network regression (BPNN), gradient boosting decision tree regression (GBDT), support vector machine regression (SVR), and random forest regression (RFR). LAI was calculated separately for each growth stage using different vegetation indices. 【Result】 LAI was significantly correlated with the normalized difference vegetation index (NDVI), modified simple ratio (MSR), ratio vegetation index (RVI), difference vegetation index (DVI), soil-adjusted vegetation index (SAVI), and normalized difference red edge index (NDRE). It showed a weak correlation with the renormalized difference vegetation index (RDVI) during the heading and grain-filling stages, with their correlation coefficients being 0.23 and 0.21, respectively. The BPNN model was most accurate during the jointing stage, with R2, RMSE, and MAE being 0.822, 0.305, and 0.257, respectively. In contrast, the RFR model performed best during the heading, grain-filling, and entire growth periods, with R2 being 0.613, 0.811 and 0.834, RMSE being 0.189, 0.150 and 0.174, and MAE being 0.126, 0.121 and 0.133, respectively. Additionally, the RFR model constructed using data from all three stages was more accurate than models derived from data at individual growth stages. 【Conclusion】 Multispectral data acquired via UAV, combined with machine learning algorithms, can accurately estimate the LAI of spring wheat at various growth stages. Models constructed using data from multiple growth stages are more accurate than those based on a single stage. The models are most accurate for the booting stage and least for the heading stage. Overall, the RFR model provided the most accurate LAI estimates across the three growth stages.

【Objective】 Subsurface drip irrigation is a water-saving technique that involves burying emitters in the soil. Its efficacy depends on irrigation amount. This paper investigates the impact of irrigation amount in subsurface drip irrigation on root growth and water use efficiency of maize cultivated in the Xiliao River Plain, Northeastern China. 【Method】 The experiment was conducted in a maize field in the Keerqin District of Tongliao City, comprising six treatments with its associated irrigation amount being 220 mm (CK), 195 mm (W1), 170 mm (W2), 145 mm (W3), 120 mm (W4), and 95 mm (W5), respectively. For each treatment, we measured root distribution and water use efficiency. 【Result】 The spatial distribution patterns of root dry matter, root length, root surface area, and root diameter in the 0-40 cm soil layer at the maturity stage were similar across all treatments. As the irrigation amount decreased, these root characteristics initially increased and then decreased. The total water consumption of the maize during its growing season decreased with reduced irrigation amount, while the relationship between kernel yield and irrigation amount followed a quadratic pattern. With increasing irrigation amount, water use efficiency initially increased and then declined, with W2 achieving the highest water use efficiency at 2.46 kg/m3. Grain yield showed significant positive correlations with root weight density, root length density, and root surface area density in the 0-20 cm soil layer, and root diameter in the 30-40 cm soil layer. Net benefit increased with reduced irrigation among initially and then declined, with the highest net benefit of 20 098 Yuan/hm2 achieved when the irrigation amount was 170 mm. 【Conclusion】 Subsurface drip irrigation is a water-saving technology, applicable for maize production in Xiliao River Plain in the northeastern China. The optimal irrigation amount was 170 mm.

Objective To conduct hazard vulnerability analysis(HVA) in a blood bank, aimed to identify high-risk events and optimize emergency management measures. Methods The risk event evaluation index system was established by referring to the Kaiser model and the situation of Guangzhou Blood Center, and risk events were ranked by risk matrix and Borda count. Results The top five events with the highest risk values identified by Kaiser model were information system emergencies (39.61%), extreme weather (38.03%), major public sentiment (37.86%), public health events (37.37%) and policy changes (37.24%). The results of risk matrix and Borda count revealed 1 extremely high-risk indicator as information system emergency, 5 high-risk indicators with the highest risk being major public sentiment, 11 medium-risk indicators with the highest risk being major medical disputes and 1 low-risk indicator as external fires. Conclusion Conducting HVA in combination with the actual situation of blood banks can effectively identify high-risk events and provide theoretical basis for improving emergency management measures.

Cerebellar mutism syndrome (CMS) is a prevalent postoperative complication in children following posterior fossa tumor surgery, with a significantly variable incidence rate across different pathological types of tumors, being highest in medulloblastoma (24%-30%). The pathogenesis of CMS remains to be elucidated, but it is believed to be associated with damage to the cerebellocerebral circuits, harm to the fastigial nuclei of cerebellum and periaqueductal gray matter of the midbrain, and alterations in brain networks. Predictive models constructed based on the risk factors of CMS have not yet demonstrated the anticipated stability and have not been widely adopted in clinical settings. Pharmacological treatments are primarily based on clinical experience, yet their efficacy requires further validation, hence there is currently a lack of a clearly effective treatment method; non-pharmacological treatments, such as physical therapy, occupational therapy, and speech therapy, have shown some effect on improving the long - term quality of life. This review summarizes the pathogenesis and therapeutic advances of CMS, and future research should be dedicated to exploring the pathophysiological mechanisms of CMS, constructing more accurate predictive models, devising personalized treatment plans, and enhancing the long-term prognosis for children.

【Objective】 A pre-planting border irrigation in spring coupled with a drip irrigation in summer during crops growth season is an irrigation technique to reduce soil salinity and safeguard crops growth in the salt-affected soils in the Hetao Irrigation District in Inner Mongolia. This paper investigates the impact of different combinations of irrigation amounts in the dual irrigations on changes in soil water and salt, as well as the growth of sunflower. 【Method】 The field experiment compared two spring (S) irrigation amounts: 95 mm and 135 mm, and three summer (W) irrigation amounts: 68, 100 mm and 135 mm. In each treatment, we measured the spatiotemporal changes in soil water and salt, as well as crop growth characteristics. 【Result】 ① The soil water content in the S135W135 treatment was the highest among all treatments during the experimental period, with the average soil water content and saturation being 17.10% and 75.53%, respectively. The coefficient of variation of soil water content in the S95W135 treatment was 22.40%, the lowest among all treatments. ② Depending on the summer irrigation amount, the desalination rate of the 0-80 cm soil layer under S135 and S95 varied from 32.64% to 50.50% and 21.8% to 38.87%, respectively. Although the spring irrigation amounts did not significantly affect immediate post-irrigation salt content, the S135W100 and S95W135 combinations showed deeper leaching depths and higher desalination rates (40.77% and 33.37%, respectively) than other treatments. ③ Aboveground dry matter production was significantly higher in the S95W135 and S135W100 combinations than in other combinations, surpassing the S135W135 combination by 10.55% and 9.94%, respectively. The S135W100 combination achieved the highest water use efficiency at 21.59%, an increase of 13.03% compared to S135W135. 【Conclusion】 Reducing spring irrigation by 30% to 95 mm combined with a summer drip irrigation of 135 mm is the most efficient irrigation scheme for sunflower cultivation in the salt-affected soils in the Hetao Irrigation District.

Granary is an important facility to ensure the safety of grain storage. The granary is a large closed space with dim lighting and poor air circulation. Operations such as fumigation and air conditioning increase personnel safety risks. The identification and analysis of abnormal behaviors of workers through security videos in the granary has become a key safe operations for workers as an important technical guarantee. This paper proposed a video recognition algorithm for abnormal behavior of workers in a granary based on a skeleton sequence multi-algorithm. First, the YOLOv3tiny model was used to quickly detect the human body, combined with Sort to track the motion trajectories of multiple targets, and the human skeleton coordinate sequence and weight information were extracted through the AlphaPose model. Then, based on the real spacial graph (RSG) composed of natural connection nodes of the human skeleton and virtual spacial graph (VSG) constructed by interconnecting the center of gravity of the virtual human body with the head, hands, and feet, the bin was extracted based on the balance of the interaction between the center of gravity of the human body dynamics and the hands and feet. Spatial characteristics of abnormal behavior of internal workers and spatiotemporal characteristics of concatenated temporal convolution (TC). Finally, a virtual-real combining spatial temporal graph convolution network (VR-STGCN) video recognition algorithm for abnormal behavior of granary workers was proposed. At the same time, a hybrid dataset was built, and comparative experiments and analysis were conducted between VR-STGCN and four algorithms such as SSD, PCANet, Two-StreamCNN, and STGCN. The results showed that all indicators of VR-STGCN were better than those of the other four algorithms. VR-STGCN can accurately identify abnormal behaviors such as falling, crawling, and lying down of people in the granary in complex environments such as insufficient light, multiple targets, and long distances. The recognition accuracy reached 97.7%, and the processing speed was 18.67fps, which can analyze the abnormal behavior of workers in real time. The research results could provide a new and efficient technology for the safety of granary workers in complex environments.

The autonomous navigation capability of drones in post disaster mines is a prerequisite for their capability to perform rescue and disaster relief tasks. The autonomous pose estimation technology in unknown three-dimensional space is one of the key technologies for autonomous navigation of drones. At present, vision based pose estimation algorithms are prone to blurred scale and poor positioning performance due to the inability of monocular cameras to directly obtain depth information in three-dimensional space and the susceptibility to underground dim light. However, laser based pose estimation algorithms are prone to errors due to the small viewing angle, uneven scanning patterns, and constraints on the structural characteristics of mining scenes caused by LiDAR. In order to solve the above problems, an autonomous pose estimation algorithm of underground disaster rescue drones based on visual and laser fusion is proposed. Firstly, the monocular camera and LiDAR carried by the underground drone are used to obtain the image data and laser point cloud data of the mine. The ORB feature points are uniformly extracted from each frame of the mine image data. The depth information of the laser point cloud is used to recover the ORB feature points. The visual based drone pose estimation is achieved through inter frame matching of the feature points. Secondly, feature corner points and feature plane points are extracted from each frame of underground laser point cloud data, and laser based drone pose estimation is achieved through inter frame matching of feature points. Thirdly, the visual matching error function and the laser matching error function are placed under the same pose optimization function, and the pose of the underground drone is estimated based on vision and laser fusion. Finally, historical frame data is introduced through visual sliding windows and laser local maps to construct an error function between the historical frame data and the latest estimated pose. The optimization and correction of the drone pose under local constraints are completed through nonlinear optimization of the error function, avoiding the accumulation of estimated pose errors that may lead to trajectory deviation of the drone. The simulation experiments that simulating the complex environment after a mine disaster are conducted. The results show that the average relative translation error and relative rotation error of the pose estimation algorithm based on visual and laser fusion are 0.001 1 m and 0.000 8°, respectively. The average processing time of one frame of data is less than 100 ms. The algorithm does not experience trajectory drift during long-term operation underground. Compared to pose estimation algorithms based solely on vision or laser, the accuracy and stability of this fusion algorithm have been improved, and the real-time performance meets the requirements.

GB/T 3836.1-2021 Explosive atmospheres-Part 1: Equipment-General requirements stipulates that the threshold power of RF equipment in explosive environments shall not exceed 6 W. This regulation limits the application of high-power RF equipment in coal mines. However, existing research on electromagnetic safety in explosive environments lacks comprehensive theoretical analysis and experimental verification. In order to solve the above problems, the electromagnetic wave thermal effect equation is derived. It is analyzed that the controllable parameters affecting the generation of thermal energy from the mixture of gas and coal dust coupled by electromagnetic waves are the electromagnetic wave coupling time, the electric field strength and the electromagnetic wave frequency. Based on the regulation in GB/T 3836.1-2021 that the maximum surface temperature of electrical equipment that may accumulate coal dust cannot exceed 150 ℃, simulation experiments are conducted using the multi physics field simulation software COMSOL to evaluate the thermal safety of gas and coal dust mixtures coupled with electromagnetic waves of different emission powers. The results show that the emission power that meets the safety threshold of electromagnetic wave thermal effect with a temperature not exceeding 150 ℃ is 16.48 W. With the increase of electromagnetic wave emission power, the safe duration of electromagnetic wave thermal effect (the corresponding time period that the thermal energy generated by the mixed gas of electromagnetic wave coupling gas and coal dust not causing the ambient temperature to exceed 150 ℃) gradually decreases. However, as long as the safe duration is maintained, the emission power of electromagnetic waves is not limited.

The use of electrospinning technology to construct edible nano-delivery carriers has been one of the most important way to improve the utilize efficiency of novel localized drugs or food active components. However, it is still challenging to develop nanofibers with natural polymers due to many problems such as the toxicity of organic reagent and difficulty in forming the nanostructure. In this study, natural plant polysaccharide guar gum （guar gum，GG） were selected as the fiber forming substrate to co-load corn starch（starch，ST）, and successfully developed a edible GG/ST composite nanofiber delivery carrier. The results showed that the minimum molecular entanglement concentration of GG as a fiber forming matrix was 1.1 wt%. A series of GG/ST composite solution were prepared (4∶1, 2∶1, 1∶1, and 1∶4). Through static and dynamic rheological testing of GG/ST solution and characterization of fiber microstructure, it was found that the ratio of GG/ST at 2∶1 was the optimal concentration to obtain the uniform and smooth fiber nanostructure. When the ST content is 5w%~10w%, beaded fiber morphology in the structure and unnormal distribution of diameter was observed, and electrospinning process had little effect on the improvement of the fiber structure. This study provide a support for developing edible nano carriers and offered a basis for developing targeted drugs or functional foods in the future.

In order to solve the problem of difficulty in achieving individual scheduling for large-scale electric vehicles entering the grid and the existence of "dimensionality disaster" in cluster scheduling, a hierarchical and partitioned optimization operation model for active distribution network based on vehicle-to-grid(V2G) mode is established. The upper level optimization model schedules the electric vehicle agent (EVA) of electric vehicles, optimizes the charging and discharging power of EVA in each region, and serves as input for the lower level optimization model. Lower level optimization model adjusts various voltage regulation methods. In terms of optimization algorithm, a self adaptive differential evolution biogeography based optimization (SaDE-BBO) algorithm is proposed and simulated in the improved IEEE 33-node distribution system. The results show that under different charging control strategies, the coordinated interaction between V2G mode and various voltage regulation methods has significant advantages in reducing EVA operating costs in various regions, suppressing load fluctuations, and ensuring the safe and economic operation of active distribution networks. Compared with other optimization algorithms, the SaDE-BBO algorithm has better solutions and convergence.

From the perspective of food packaging design, the interaction between packaging and consumer behaviors was explored through the analysis of their demand trends. This review analyzed the performance characteristics of consumer experience at instinct level, behavior level and reflection level between users and packaging, and discussed the design strategies of food packaging at different levels. In view of the multi-dimensional needs of consumers, the emotional responses to products from visual and non-visual sensory experience at the instinct level can be responded and thereby attract their attentions. At the behavioral level, it starts from interesting, humanized and intelligent interaction, prompt and feedback to expand the use function of the product and create a good use experience. On the reflection level, starting from creating interactive experience to stimulate users' creativity. The creation of interactive experience and stimulation of user creativity were focused on to systematically shape deep emotional experience at the reflection level. Integrating user experience into food packaging design effectively and exploring the process of information experience will be a new idea and direction of food packaging design in the future.

Objective: In order to improve freshness preservation quality of the fresh-cut shiitake mushroom. Methods: Carbon quantum dots were synthesized from dragon fruit peel and ethylenediamine, and characterized for stability and toxicity. Fresh-cut shiitake mushrooms were studied, and stored at 4 ℃ for 10 d after coating with 0.0, 1.5, 3.0 and 4.5 mL/100 mL carbon quantum dots-chitosan （N-CDs/CH） for preservation treatment. During the period of preservation, the weight loss, color difference, soluble solids and polyphenol oxidase were measured every 24 h to evaluate the preservation effect of the composite films. Results: The synthesized N-CDs had the typical characteristics, which had good fluorescence stability, hydroxyl and amino groups on outer surface, and no cytotoxicity. After fresh-cut shiitake mushrooms were treated with different concentrations of N-CDs/CH until the 10th day of storage, 4.5 mL/100 mL N-CDs/CH coating group had weight loss of 3.31%, coloration of 10.32, soluble solids of 4%, and polyphenol oxidase （PPO） activity of 104.65 U/(kg·s), all of which were significantly better than the blank group and other treatment groups （P＜0.05）. Conclusion: The preservation effect at the 4.5 mL/100 mL of N-CDs/CH coating was significantly better than that of blank and others （P＜0.05）. N-CDs/CH coating inhibited water loss and PPO activity, improved color and enhanced the preservation quality of fresh-cut shiitake mushroom.

In order to effectively solve the problems of many units involved in the war, complex command relations and large information flow in the future naval fleet battle, a set of reliable communication system is needed. Two-way multi-relay communication system have higher spectrum utilization and network throughput, and it is a research hotspot in the field of collaborative communication. This paper systematically studies the general model of two-way multi-relay communication system, optimizes the distributed relay selection scheme based on the existing research. Through simulation comparison with the optimal received SNR relay selection scheme, the optimized system channel capacity and outage probability are relatively close, and they are improved by simulation comparison with the existing distributed relay selection scheme.

A rapid method for the detection of rapeseed polyphenols (Canolol) in rapeseed oil was studied. A normal phase high performance liquid chromatography (NP-HPLC) method for the determination of Canolol was established. The Canolol in rapeseed oil were determined by using hexane to isopropanol (volume ratio 96∶4) as the mobile phase with the flow rate of 0.8 mL/min, column temperature of 30 ℃, fluorescence detector with excitation wavelength of 298 nm and emission wavelength of 325 nm. The linear correlation coefficient was above 0.999, and the recovery rate was between 96% and 110%. The detection limit of the instrument was 15 ng/mL, and the precision was better than 3%. The method has the advantages of simple operation, short analysis time, high accuracy and less environmental pollution. The optimized detection method was used to determine the rapeseed oil samples from 90 different varieties of rapeseed in different regions of China. The content of Canolol ranged from 190 mg/kg to 2 246 mg/kg. At the same time, different types of vegetable oils randomly purchased from the market were tested. The results showed that Canolol was a unique component in rapeseed oil by processing of heated screw-pressing.

Objective To construct and validate a prognosis prediction model and a risk stratification tool for more precise and individualized evaluation of prognosis for patients following resection of esophageal squamous cell carcinoma (ESCC), and provide real-world evidence for informing optimal decision-making about adjuvant therapy. Methods The comprehensive clinical data and follow-up data were collected from consecutive patients with ESCC in the Anyang Cancer Hospital (Anyang center) from May 31, 2011 to July 31, 2018, and in the Cancer Hospital of Shantou University Medical College (Shantou center) from August 1, 2009 to December 31, 2018. Patients from the Anyang center formed the training cohort, and a two-phase selection based on backward stepwise multivariable Cox proportional hazard regression and minimization of AIC was used to construct prediction model for overall survival (OS). Bootstrap with 1 000 resamples was used for internal validation, and cohort from the Shantou center was used for external validation. Furthermore, a risk stratification tool was constructed according to the tertiles of the total points derived from nomogram in the training cohort. Results A total of 4 171 eligible patients were included in the training cohort, and 1 895 patients were included in the validation cohort. The final model incorporated nine variables: age, sex, primary tumor location, T stage, N stage, number of lymph nodes harvested, tumor size, adjuvant treatment, and preoperative hemoglobin level. A significant interaction was observed between N stage and adjuvant treatment (P < 0.001), which means that N+ stage patients were likely to benefit from addition of adjuvant therapy as opposed to surgery alone, but adjuvant therapy did not improve OS for N0 stage patients. The C-index of the model was 0.728 (95% CI: 0.713-0.742) in the training cohort, 0.722 (95% CI: 0.711-0.739) after bootstrapping, and 0.679 (95% CI: 0.662-0.697) in the external validation cohort. Calibration plots demonstrated favorable agreement between model prediction and actual observation for 1-, 3- and 5-year OS. In both training and validation cohorts, this model outperformed the seventh edition of the AJCC TNM (tumor, lymph node, and metastasis) staging system in terms of the accuracy of prognostic prediction (P < 0.05). Moreover, within each TNM staging group, this model achieved ideal risk stratification. Conclusions The prediction model constructed in this study may provide individualized survival prediction for patients with resected ESCC in China. This study also demonstrated that the N stage may be a fundamental determinant in planning postoperative adjuvant therapy for ESCC patients.

In order to meet the development needs of economic and efficient in oilfield distribution network,and to realize the goal of low carbon more quickly,the investment decision-making method of energy-saving measures optimization is proposed. Firstly,the loading behaviors of pumps is analyzed,an calculation model for special line loss of oilfield distribution network based on load superposition characteristics is proposed,which is corrected according to the actual load of oilfield. Next, according to different energy-saving models and the GM(1,1)gray prediction model,the optimization investment decision model of oilfield distribution network is established. Then,based on the characteristics of oilfield energy-saving measures,the direct comparison objective method and the taboo search method are respectively selected to solve the solution of the different oilfield scale. Finally,a 30-node 6 kV distribution network line in an oilfield is taken as an example for simulation verification. The results show that the energy-saving and loss reduction scheme of oilfield distribution network obtained by the investment decision-making method in this paper has high cost performance and can effectively improve the voltage at the end of the line.

Aiming at the problem of coal and gas outburst in the process of coal mining in China, this paper first summarizes the research progress of coal and gas outburst mechanism, and points out that the research on outburst mechanism of tectonic belt is of great significance by summarizing the shortcomings of existing theoretical models. Then, the influence of geological structure on three key factors of coal and gas outburst is analyzed, that is, geological structure has a control effect on the distribution of in-situ stress and gas occurrence in coal seams, and tectonic movement can change the microstructure of coal, thus changing the physical and mechanical properties of coal; the coal and gas outburst process in the structural belt is summarized and divided into four stages: preparation, initiation, development and termination. The preparation stage includes two parts: tectonic movement and mining operation. Finally, based on the shortcomings of the existing research results, the direction of coal and gas outburst to be further studied is put forward from the perspective of geological structure.

This paper introduces the working principle of electronic nose via two key elements including gas sensor array and signal processing. The applications of electronic nose in adulteration identification and quality analysis of edible oil, dairy products, beverage, meat, spices, and other foods are reviewed. The operations and analytical principle of electronic nose for food adulteration are clarified, and the successful applications of electronic nose as well as the shortcomings are discussed.

Objective: In order to study the optimal enzymatic hydrolysis process conditions of corneum galli gigerii endothelium, and analyze the amino acid composition, molecular weight distribution and antioxidant activity of the enzymatic hydrolysate. Methods: With the yield of polypeptide and the degree of hydrolysis as indicators, the orthogonal experiment was used to optimize the enzymatic hydrolysis conditions of corneum galli gigerii endothelium. Amino acid analyzer and high-performance gel permeation chromatography were used to determine the amino acid composition and molecular weight distribution of the enzymatic hydrolysate of corneum galli gigerii endothelium. The clear ability of corneum galli gigerii endothelium to DPPH free radicals and ABTS+ radical were also investigated. Results: The results showed that the optimal enzymatic hydrolysis conditions of corneum galli gigerii endothelium were as follows: co-enzymatic hydrolysis with neutral protease and alkaline protease, enzymatic hydrolysis temperature at 60 ℃, enzymatic hydrolysis for 9 h at pH 11, and cooking time for 6 h. Under the control of these conditions, the yield of polypeptide was 75.68%, and the degree of hydrolysis was 14.43%. The ratio of the essential amino acid to the non-essential amino acid of the enzymatic hydrolysate was 58.56%, which has high nutritional value. The proportion of enzymatic hydrolysate with a relative molecular mass of ＜1 000 Da accounts for 90.2%, which was easy to be digested and absorbed. When the concentration of the enzymatic hydrolysate was 1.5 mg/mL, the scavenging rate of ABTS+ free radicals reached 94.19%. Conclusion: Using the optimal enzymatic hydrolysis process strategy, the yield of corneum galli gigerii endothelium polypeptide is as high as 75.68%, and it has good antioxidant activity.

Objective To investigate the characteristics of temporal lobe epilepsy (TLE) executive function and its correlation with neuropsychological tests. Methods A total of 25 patients with TLE [including 8 patients with left TLE (LTLE) and 17 patients with right TLE (RTLE)] and 15 healthy controls with matched sex, age and education level admitted to Tianjin Medical University General Hospital and China Resources & WISCO General Hospital from June 2017 to December 2018 were enrolled. Neuropsychological tests [including Mini-Mental State Examination (MMSE), Hamilton Anxiety Rating Scale (HAMA), Beck Depression Inventory (BDI)] and executive function tests [including digital working memory, verbal working memory, Stroop Color-Word Test (SCWT), Trail Making Test-A and B (TMT-A and TMT-B), and Verbal Fluency Test (VFT)] were performed. Pearson correlation analysis and partial correlation analysis were used to explore the correlation between executive function and various factors, and multiple linear stepwise regression analysis was used to verify the linear quantitative relationship between executive function and various factors. Results MMSE score (P = 0.003), digital working memory score (P = 0.000), verbal working memory score (P = 0.000), color response time (P = 0.001), word response time (P = 0.001), color word response time (P = 0.001), TMT-A time (P = 0.010), TMT-B time (P = 0.009) and the number of VFT (P = 0.000) of LTLE group, RTLE group and control group were significantly different. MMSE score (P = 0.013, 0.029), digital working memory score (P = 0.000, 0.000), verbal working memory score (P = 0.000, 0.000) and the number of VFT (P = 0.000, 0.000) in LTLE group and RTLE group were lower than those in control group. Color response time (P = 0.047, 0.000), word response time (P = 0.002, 0.006) and color word response time (P = 0.024, 0.001) were longer than those in control group, but TMT-A time (P = 0.004) and TMT-B time (P = 0.002) in RTLE group were longer than those in control group. There were no significant differences in executive function scores between LTLE group and RTLE group (P > 0.05, for all). Correlation analysis showed that digital working memory score, color response time, vocabulary response time and attention transfer time were positively correlated with MMSE score, HAMA score, BDI score, age, education level, seizure frequency, type of antiepileptic drugs (P < 0.05 or P < 0.01). TMT-A time and TMT-B time were positively correlated with MMSE score, HAMA score, age, education level, seizure frequency, type of anti-epileptic drugs (P < 0.05 or P < 0.01). There was a positive correlation between color word response time and word fluency with HAMA score, age and education level (P < 0.05 or P < 0.01). Multiple linear stepwise regression analysis showed that there was a linear regression relationship between digital working memory score and seizure frequency (standardized partial regression coefficient = 0.998, P = 0.001) and type of antiepileptic drugs (standardized partial regression coefficient = -1.634, P = 0.006). There was a linear regression relationship between verbal working memory score and HAMA score (standardized partial regression coefficient = -0.089, P = 0.035), a linear regression relationship between color response time and education level (standardized partial regression coefficient = -0.097, P = 0.002), a linear regression relationship between vocabulary response time (standardized partial regression coefficient = -0.121, P = 0.004), color word response time (standardized partial regression coefficient = -0.243, P = 0.002), TMT-A time (standardized partial regression coefficient = -5.984, P = 0.002), TMT-B time (standardized partial regression coefficient = -17.376, P = 0.000), attention transfer time (standardized partial regression coefficient = -12.413, P = 0.000) and MMSE score had linear regression relationship. Vocabulary fluency and age (standardized partial regression coefficient = 0.327, P = 0.032), education level (standardized partial regression coefficient = 1.976, P = 0.001), HAMA score (standardized partial regression coefficient = -0.431, P = 0.008) had a linear regression relationship. Conclusions Executive function (working memory, inhibitory control and cognitive flexibility) was impaired in patients with TLE, but there was no significant difference in executive function between RTLE and LTLE. The older the age and the lower the education level, the more severe the overall cognitive dysfunction, the more significant decline in executive function.

When the metal structures distributed in the underground roadway are in the near-field of the large loop transmitting antenna, they will couple the electromagnetic wave energy of the large loop transmitting antenna. Once the metal structure has a breakpoint and friction occurs, it may produce friction discharge spark and ignite gas. This poses a threat to the safety of coal mine. In order to solve this problem, the safety of electromagnetic wave energy of underground metal structure near-field coupled large loop transmitting antenna is analyzed from two aspects of near-field coupling risk coefficient and safe distance. By establishing the equivalent circuit of electromagnetic wave energy of metal structure near-field coupled large loop transmitting antenna, the expressions of near-field coupling risk coefficient and safe distance between metal structure and large loop transmitting antenna are derived. The influence of the radius of the large loop transmitting antenna, the radius of the equivalent receiving coil of the metal structure, the friction discharge spark load and the distance between the metal structure and the large loop transmitting antenna on the near-field coupling risk coefficient and the safe distance are analyzed. The simulation results show that the near-field coupling risk coefficient increases slightly at first and then decreases slightly or increases all the time with the increase of the radius of the large loop transmitting antenna. Under certain conditions, the friction discharge spark load can make the near-field coupling risk coefficient reach the peak value. When the radius of the large loop transmitting antenna is greater than or equal to the radius of the equivalent receiving coil of the metal structure, the near-field coupling risk coefficient at the peak value may exceed the critical value 0.46 of the near-field coupling risk coefficient. This may cause danger. When the radius of the large loop transmitting antenna is smaller than the radius of equivalent receiving coil of the metal structure, the near-field coupling risk coefficient at the peak value is less than the critical value 0.46 in most cases. This will not cause danger in most cases. Under certain conditions, the radius of the large loop transmitting antenna can make the near-field coupling risk coefficient reach the peak value. The near-field coupling risk coefficient at the peak value first increases and then decreases with the increase of the radius of equivalent receiving coil of the metal structure. It is more likely to exceed the critical value 0.46 of the near-field coupling risk coefficient, which is likely to cause danger in the gas environment. The safe distance increases with the increase of the radius of the large loop transmitting antenna. The safety of the electromagnetic wave energy on the friction discharge spark load decreases with the increase of the radius of the large loop transmitting antenna. When the radius of the large loop transmitting antenna is greater than or equal to the radius of the equivalent receiving coil of the metal structure, the safe distance increases with the increase of the radius of the equivalent receiving coil of the metal structure. The safety of the electromagnetic wave energy on the friction discharge spark load decreases with the increase of the radius of the equivalent receiving coil of the metal structure. When the radius of the large loop transmitting antenna is smaller than the radius of the equivalent receiving coil of the metal structure, the safe distance first increases slowly and then decreases with the increase of the radius of the equivalent receiving coil of the metal structure. The safety of the electromagnetic wave energy on the friction discharge spark load first decreases and then increases with the increase of the radius of the equivalent receiving coil of the metal structure.

The posture detection of underground personnel can provide effective information for disaster warning and accident rescue. The postures of the underground personnel are complex and diverse and they are time series data. The existing human posture detection methods are difficult to process continuous related posture data. And the real-time performance is poor due to the complex algorithm and the need to configure an independent computer. In order to solve the above problems, a human posture detection method in coal mine based on improved long short term memory network(LSTM) is proposed. The pressure sensor and angle sensor are used to obtain the posture data of underground personnel, such as foot pressure, waist and leg angle, etc. The portable edge operation decision unit carried by the personnel can discriminate the posture. It can realize the real-time detection of five postures of underground personnel, such as standing, walking, bending, squatting (sitting) and lying down. In order to reduce the dimension of the original sampled data of human posture and improve the compute efficiency, LSTM is improved. The long short term memory sparse autoencoder(LSTMSA) is designed. The characteristics of the original sampled data is extracted by the sparse autoencoder(SA) to reduce the dimension, and then the human posture is detected by the LSTM. Human posture data are collected in the laboratory environment, and LSTMSA, LSTM and recursive neural network(RNN) are trained and tested respectively. The results show that under the same experimental settings and sampling data, the accuracy of LSTMSA for five kinds of human posture detection reaches more than 90%, which is close to LSTM and greater than RNN. The computing time of LSTMSA is shortened by more than 50% compared with LSTM, which meets the real-time requirements of human posture detection in coal mine.

Based on the industrial application of fly ash, a new method of using fly ash instead of sand as the main raw material for wall grouting of coal mine roadway is proposed. The effect of fly ash instead of sand on the compressive strength of shotcrete was studied, and the activation of fly ash shotcrete with Na2SO4, NaOH and Na2SiO3 were studied. The results show that the compressive strength of the grouting material is lower than that of the traditional grouting material when the fly ash completely replaces the sand, which can not meet the requirement of field application, the problem of compressive strength of fly ash shotcrete can be effectively solved by adding proper amount of alkaline activator, and when the content of Na2SO4 is 3%, the increase of compressive strength of fly ash shotcrete is the best.

The existing research only analyzes the rock burst appearance characteristics under specific conditions, lacks research on the rock burst appearance induced by coal pillar under the condition of thick and hard roof. In order to solve this problem, taking I010203 working face of a mine in Xinjiang as the research object, the paper analyzes the characteristics and causes of working face rock burst under the condition of thick and hard roof multi-seam mining by means of field monitoring and numerical simulation. By analyzing the spatial distribution law of microseismic and large energy events monitored on site, the distribution characteristics of support pressure, and the distribution characteristics of surrounding rock stress during the mining of the working face simulated by numerical simulation, this paper obtained the following results. The stress concentration and the microseismic event density in the transport roadway area of the working face are higher than those in the return air roadway area. And the stress concentration and microseismic event density in the roof and coal seam area are higher than those in the floor area. Based on the above results, the causes of coal pillar rock burst appearance in the mining process of I010203 working face are analyzed by using rock burst caused by dynamic and static combined load theory. ① It is easy to produce lateral overhanging roof above the coal pillar in the transport roadway section. The sudden breaking of the long overhanging roof generates a large amount of dynamic loads. At the same time, a large amount of static loads accumulate on the coal pillars and the roof during the mining process. When the superposition of the two exceeds the critical load, it may cause the rock burst appearance of the working face or a large energy event. The mining process of the I010203 working face mainly includes the main controlling factors such as coal pillar concentrated stress, overlying roof and surrounding rock supporting stress. Therefore, it is easy to produce coal pillar type and thick hard roof caving type rock burst appearance. ② When the mining position of the working face gradually approaches the boundary of the ‘knife shape’ goaf, the boundary stress is transferred downward to the I010203 working face, which leads to the further increase of the rock burst risk of the I010203 working face.

【Objective】 Hetao Irrigation District relies on Yellow River water for irrigation, but excessive use of the river water had resulted in soil salinity. Jointly using groundwater and river water has been postulated as a feasible mitigation technology, and the purpose of this paper is to present the results of a study on how to achieve optimal use of groundwater and surface water. 【Method】 A three-dimensional groundwater model for the region was calibrated and verified using MODFLOW based on measured groundwater depths and other datasets. We then applied the model to four typical well-canal combination areas in four sub-districts: Wulanbuhe, Jiefangzha, Yongji and Yichang. 44 scenarios with four different well-irrigation areas and 11 kinds of canal-well combination ratios were considered. For each scenario, we predicted how the groundwater depth changed with the well-canal combination ratio and well-irrigation area. 【Result】 ①The three-dimensional groundwater model correctly captured physical properties of the aquifers and soils and reproduced the observed change in groundwater depth at different scenarios. ②When the ratio of well-irrigated to canal- irrigated areas was the same, the average groundwater depth in Jiefangzha and Wulanbuhe was the shallowest followed by Yongji, with that in Yichang the deepest. Isograms of groundwater depth in areas with well-canal irrigation in Wulanbuhe was the densest, followed by Yichang, with Yongji and Jiefangzha the sparsest. ③When the well-irrigated area was constant, the average groundwater depth decreased asymptotically as the canal-well combination ratio increased. 【Conclusion】 The suitable canal-well combination ratio and well-irrigation area for controlling groundwater depth not exceeding 3 m varied with the sub-districts due to their difference in hydrogeological conditions. The well-irrigation areas in Wulanbuhe, Jiefangzha, Yongji and Yichang should not exceed 12.25 km2, 12.25 km2, 9 km2 and 6.25 km2 respectively, with their associated ratio of canal-irrigated area to well- irrigation area not exceeding 2.5, 2.5, 3.0 and 3.3 respectively.

【Background】 The wide distribution of saline and alkali soils in Ordos of Inner Mongolia is a main abiotic factor hindering crop growth. Their remediation is a prerequisite for developing sustainable agriculture in this region. Subsurface drain is a technology widely used to alleviate salt accumulation and enhance salt leaching. 【Objective】 The objective of this paper is to experimentally study the effects of subsurface drain on salt dynamics in soils heavily affected by salinity and alkalinity. 【Method】 The experiment was conducted from May to October 2015 at Dalat Banner, with the drains spaced 18 m apart and buried in a depth varying from 1.2 m to 1.5 m; the depth of the drainage ditches was 1.8~2.0 m. In each treatment, we measured soil salt distribution up to 1.0 m deep, the change in groundwater table and salinity, as well as the quality of the irrigation water and drainage water, salt ion data and their relationship. 【Result】 ①Spatial variation of salt in the top 0~100 cm soil was moderate with a coefficient of variation of 25%~75%; the majority of salt was accumulated in regions proximal to the soil surface. ②The drains dropped the groundwater table by 50~60 cm and reduced soil salinity by approximately 10%, compared with data measured before experiment. ③At the end of the experiment, the main salt ions in the soil were K++Na+, SO42- and Cl-, while in the groundwater they were K++Na+, Cl- and HCO3-. ④Irrigating using the Yellow river water increased HCO3- in soil by 56% and the decreased of other salt ions, with SO42-, K++Na+ and Cl- reduced by 36%, 34% and 31% respectively. Leaching of the irrigation water increased ion contents in both drainage water and groundwater, especially the drainage water whose salinity was 3.43 times that of groundwater. 【Conclusion】 Subsurface drains can control the groundwater depth and reduce soil salt content; it facilitates leaching of SO42-, K++Na+ and Cl- from the soil. However, care should be taken to avoid an increase in HCO3- and its consequence for soil alkalization when irrigating with the Yellow river water.

Objective To compare the disinfection effect of hydrogen peroxide low temperature plasma sterilization and traditional lens disinfection on rigid gas permeable contact lens (RGP), so as to improve the clinical management procedure of RGP trial lens. Methods A total of 90 RGP trial lenses used by patients in our hospital from April to August 2020 were collected and randomly divided into 3 groups. Group A was treated with modified hydrogen peroxide low temperature plasma sterilizing method (n=30); group B was disinfected with conventional conditioning solution (n=30); and group C was sterilized with anti-bacterial case made of polymer injection material (n=30). The preserving solution of the 3 groups was respectively cultured for 5 d and then tested with the automatic microbial culture system of American Simmer TREK 528, and a comparison of the sterilization effect was made among the groups. The test was performed once a month for 3 months. Moreover, patients' ocular surface condition was examined with a slit lamp, and the comfort level after wearing was evaluated through questionnaire survey. Results The bacteria culture of group A was negative with the sterilization effect of 100.0%, while abnormal bacteria were detected 2 cases in group B and 1 case in group C, with the disinfection rates of 97.7% and 98.9%, respectively, though there was no statistical difference among the 3 disinfection methods. In addition, the results of corneal examination and comfort questionnaire survey showed no statistical difference among the groups as well. Conclusion Hydrogen peroxide low-temperature plasma sterilization has a thorough disinfection effect with a safe and simple procedure, and is worth popularizing.

Most of the existing research on the influencing factors of coal electrical parameters are carried out under fixed frequency or low frequency and high temperature conditions. There is a lack of research on the influencing factors of coal electrical parameters under ultra-wideband frequency and normal temperature conditions. Therefore, there are certain limitations in the research on the influencing factors of coal electrical parameters. To address this problem, in order to study the influence of coal electrical parameters on the selection of ultra-wideband radar wave mine detection frequency band under different conditions, the Concept-80 ultra-wideband dielectric spectrum test system is applied. The system is set to detect the relative permittivity, electrical conductivity and loss angle tangent values of coals with different metamorphic degrees (lignite, long-flame coal and lean coal) at 0-80 ℃ and 500-1 000 MHz detection frequency and analyze their variation laws. The analysis results show that the relative permittivity of coal increases with the increase of coal metamorphic degrees, and the electrical conductivity and loss angle tangent values of coals decrease with the increase of coal metamorphic degrees. The relative permittivity of coal samples with different metamorphic degrees decreases, then increases and decreases again with the increase of detection frequency, and the relative permittivity is positively correlated with temperature. The electrical conductivity is positively correlated with both detection frequency and temperature. The loss angle tangent value is positively correlated with temperature. However, the detection frequency does not reflect the variation of loss angle tangent value well. Based on the variation law of three electrical parameters at different temperatures and detection frequencies, and the comprehensive comparison of influence of three electrical parameters on the transmission of ultra-wideband radar waves in coal, it is pointed out that the frequency of 550-650 MHz performs best when using 500-1 000 MHz ultra-wideband radar waves to penetrate the coal body for detection at 0-80 ℃, and the detection frequency should decrease as the temperature increases. The conclusion of this study can provide a reference for the selection of ultra-wideband radar wave mine detection frequency band under different conditions.

In order to prevent spontaneous combustion in goaf caused by long withdrawal period of spontaneous combustion working face in rock burst mine, by analyzing the characteristics of fire prevention and extinguishing during the withdrawal period of working face in thick coal seam prone to spontaneous combustion under rock burst condition, an accurate control technology of air leakage in multi-layer goaf is proposed, which is based on the measures of ground fissure plugging, air leakage plugging in pressure regulating chamber, O-ring plugging and pressure regulating of ventilation system. An accurate control technology of oxidation zone width in goaf by means of full-section curtain nitrogen injection technology in goaf is proposed. An accurate temperature control technology combining drilling grouting in non-coal caving area in goaf and buried pipe grouting in coal caving area in goaf is proposed. And the three-dimensional prevention and control system of “wind control-oxygen reduction-temperature suppression” was constructed and applied. The results show that in the past three months of the withdrawal of the working face, the temperature of the goaf is always maintained below 27 ℃, and there is no natural fire sign. The technical system can effectively guarantee the long-term withdrawal safety of the working face.

Due to the existence of obstacles, none-line-of-sight(NLOS) propagation is common in localization scenes like mines, which causes refraction, reflection, diffraction and scattering of localization signals, leads to the increase of ranging error, and further influences accuracy of object localization. The influence of NLOS propagation on localization methods is analyzed including TOA(Time of Arrival), TDOA(Time Difference of Arrival), AOA(Angle of Arrival), RSSI(Received Signal Strength Indication), etc. Then existing literatures are reviewed from four aspects: identification of NLOS propagation, suppression of NLOS propagation error, utilization of NLOS propagation and localization method design in NLOS scenes. For the identification of NLOS propagation, the residual test method, error statistics method, energy detection method, neural network algorithm and geometry relation method are focused on. For the suppression of NLOS propagation error, the filtering-based method, semi-parametric-based method, energy detection-based method and database-based method are mainly analyzed. For the utilization of NLOS propagation, the method of improving robustness of localization system and the one based on error learning and matching are summarized emphatically. For the localization method design in NLOS scenes, the literatures are reviewed from two situations: the LOS/NLOS mixed scenes and only NLOS scenes. The new research directions of NLOS propagation in object localization are discussed, which are improving localization accuracy by using multiple technologies together, improving localization accuracy in NLOS scenes through new technologies and realizing cooperative localization among different systems by introducing extra information of other information systems.

Recycling is the most effective way to dispose of waste polymer materials. It can not only reduce the harm of polymer materials to the natural environment, but also achieve the purpose of saving cost and turning waste into treasure. A self-made melt differential electrospinning device was used to recover the degraded polypropylene (PP) non-woven fabric as a raw material, and the special powder for recycling and degrading PP non-woven fabric after acid treatment and adding different plasticizers with a mass fraction of 10%. A blend of materials of sodium stearate, acetyl tributyl citrate (ATBC), and dioctyl adipate (DOA) was spun, and a nanofiber membrane was prepared at 300 ℃. The optimum degradation time of PP nonwoven fabric spinning and the effect of adding different plasticizers on the morphology, oil absorption performance and reusability of PP-degraded non-woven fabric nanofibers were investigated. Studies have shown that the addition of plasticizer ATBC works best. When the spinning voltage is 40 kV, the spinning distance is 70 mm, the spinning temperature is 300 ℃, and the ATBC mass fraction is 10%, the fiber diameter is as fine as 1.13 μm. The fiber membrane oil absorption ratio is 115.4 g/g, and the oil retention ratio is 70.3 g/g, which are 4 times and 3 times that of the initially commercially available PP nonwoven fabric, and has good reusability.

Based on conventional weather data, automatic weather station data, and the observation of Yueyang Doppler radar, a waterspout occurred in Bianshan waters of East Dongting Lake (Bianshan waterspout for short) on 13 August 2017 is analyzed. Results show that the cold and warm airflows converge in the East Dongting Lake area when the upper East Asian trough forces the cold air southward, and the subtropical high guides the southwestern warm moist flow northward. The quasi stationary front over the north central Hunan Province is northeast to southwest, forming an "S" curve, which is favorable for the convergence of frontal instability energy to the East Dongting Lake area. The special geographical environment is easy to trigger canyon effect, which often leads to increased wind speed and humidity. The strong divergence in front of the upper trough, the deep low-pressure shear from northeast to southwest in the middle and lower layers, strong cyclonic convergence in the boundary layer, and the special topography jointly form a strong convergent upwelling flow field. When three meso-gamma-scale low eddies on the ground move northward to Bianshan waters, influenced by combined effects of the above flow field and the front and back vortices, the second vortex strengthens rapidly and forms a waterspout. The meteorological factors such as wind speed, wind direction, air pressure and visibility recorded by the lighthouse automatic meteorological station in the lake center change significantly when the waterspout passes, while precipitation is only 0.2 mm. Yueyang Doppler radar shows that the centroid of heavy precipitation is low to the north of strong convergence zone, where shear of strong wind is moderate and the radial wind speed over the shear is low. Yueyang Doppler radar wind profiles show that mesocyclone at the height of 0.6 km and the convergent flow fields near the ground at the height of 0.3 km are superimposed when the waterspout formed at 0905 BT. Waterspouts in the southern convergence zone have no storm tracking information, mesocyclones or tornado-type vortices. However, heavy precipitation accompanied by strong subsidence and convergence at the middle and low altitudes often produce both rising and subsidence currents, which are obviously unfavorable for the formation and development of waterspouts that need huge upward pumping. Comparing and analyzing waterspout processes of the Shengjin Lake in Anhui Province and the Dongting Lake in Hunan Province, it is concluded that the funnel-shaped strong lift suction caused by large-scale divergence at high altitude and the deep low-pressure shear from northeast to southwest in the middle and lower layers, and the intense convergence of cyclones and surface cyclones in the boundary layer are the main causes of the waterspout formation.

This paper reviews the novel azimuthal multi-angle spaceborne Synthetic Aperture Radar (SAR) technique. First, the development status and trend of SAR satellites are analyzed, and their observation capacities are compared considering different aspects. Furthermore, the novel azimuthal multi-angle observation SAR imaging modes are presented based on the application requirements, and the imaging mechanism is analyzed in detail. Moreover, the advantages of the azimuthal multi-angle observation spaceborne SAR system for obtaining full scattering information, geometry information, and motion information of ground targets are analyzed. Detailed conclusions are provided, and experiment results are presented. Finally, the azimuthal multiangle observation spaceborne SAR technique is summarized, and its prospects are highlighted.

The Internet engineering task force (IETF) is developing an IPv6-based low-power industrial Internet of things (IIoT) protocol stack called 6TiSCH, which is mainly used in complex industrial process control and automation. The network layer of the protocol stack adopts an IPv6 protocol, enabling the massive Internet of things (IoT) nodes to seamlessly access the Internet. The link layer adopts IEEE802.15.4e TSCH protocol, which can enable low-power and highly reliable wireless mesh networks. The OpenWSN open source project provides a complete implementation of the protocol stack code. This paper systematically summarizes the standards, key technologies and platforms of the IETF 6TiSCH IIoT. First of all, this paper provides a detailed description of its development process and current situation. Next, this paper analyzes the CoAP application layer protocol, UDP transport layer protocol, IPv6 network layer protocol, IEEE802.15.4e link layer protocol and its physical layer standard protocol in turn. Furthermore, this paper summarizes its key technologies such as high-precision time synchronization, resource scheduling and security, and conducts an in-depth analysis of its implementation platform. Finally, a perspective of the future work in this research area is discussed.

In this paper, Semi-digestion-inductively coupled plasma mass spectrometry method was employed to detect concentration of Ca, Fe, Cu, Pb, Zn, Cd, Mn, Mg and As in rapeseed samples simultaneously.The condition of semi-digestion and inductively coupled plasma mass spectrometry was optimized.Sample pretreatment was compared between semi-digestion and microwave digestion by t-test verification.The results show no significant difference between our method and the microwave digestion method mentioned in GB 5009.268.The relative standard deviation of our method is between 2.5% and 14.5%.The detection limit of 9 elements is between 0.001～0.14 mg/kg.The method has been applied to the determination of nine metal elements in rapeseed samples with satisfactory results.

The development course of grain and oil standard system in China, and the composition and characteristics of current standard system were introduced. The main problems existing in standard and standardization were analyzed.Some suggestions were put forward to improve standardization of grain and oil in China.

High-quality rice with moisture content of 13.5%was tested at 35 ℃,40 ℃and 45 ℃storage with nitrogen,compared with the control group without nitrogen.The degree of yellowing of high-quality rice and the quality change during the process of yellowing were researched by detecting yellowness index,fatty acid value,brown rice rate and head rice yield.The results showed that high temperature can cause yellowing of high quality rice.The higher the temperature,the higher the yellowness index,the deeper the yellowing degree.After storage at 35 ℃,40 ℃and 45 ℃for 45 days,yellowness index with nitrogen was 1.2,2.2 and 3.0 lower than that without nitrogen,which indicated that nitrogen gas regulation can effectively reduce the yellowness index.In the process of high-quality rice yellowing,the temperature was proportional to the fatty acid value,but inversely proportional to brown rice rate and head rice yield.After 45 days of storage,the difference of quality of the rice between nitrogen group and control group was most obviously,in which the fatty acid value of the nitrogen group was 7 mgKOH/100g lower than that of the control group,the brown rice rate was 0.20% higher and the head rice yield was 16.05% higher,which indicated that nitrogen gas can inhibit fatty acidsformation in high-quality rice,and decrease ofthe head rice yield,while have a little affection on brown rice rate.Therefore,in thepractical storage of high-quality rice,high temperature should be avoided as much as possible.If it is unavoidable,storage with nitrogen can be selected to postpone the yellowing and quality deterioration of high-quality rice.

Degradable polylactide (PLA) nanofibers can be prepared by solvent free melt electrospinning technology which is promising,challenging and green. The nanofiber membrane prepared by this method have high porosities and strong adsorption capacities,and thus are useful for treating the environmental pollution efficiently. The organic montmorillonite(OMMT) was introduced into PLA, and the PLA/OMMT nanofiber membrane were prepared at 260℃ by using a self-made melt differential electrospinning device. The effect of OMMT content of PLA nanofiber membrane on the morphology,the oil absorption property,the air filtration performance and the degradability was investigated, and the optimum OMMT content was obtained. The research shows that the thermal stability of PLA is increased and the crystallinity of PLA is decreased significantly after adding OMMT. When the OMMT content is 2%,the diameter of the fiber reaches 450nm. The oil absorption rate of the nanofiber membrane is 133.5g/g which is 4-5 times higher than that of commercially available PP non-wovens,and the oil holding rate is 84.2g/g. Moreover,the nanofiber membrane has good reuse performance. The air filtration efficiency of the nanofiber membrane for dust particles(≥ 0.3μm) is 99.31%,reaching the European standard H11 filtration class. The degradation of PLA/OMMT nanofiber membrane is improved comparing with the pure PLA, which reduces the second pollution and accords with the requirements of industrial green environmental protection.

Since the discovery of the unique physical, chemical and biological characteristics of ultrathin twodimensional (2D) nanomaterials, related research has grown exponentially in the fields of material science and biomedicine. Graphene, as the typical example, develops rapidly in the field of tumor therapy because of good water solubility and large surface area. Black phosphorus is regarded as a new super material because of its excellent photoelectric properties and larger surface area. In this review, we summarize the state-ofart progress on the ultrathin 2D nanomaterials as well as combining with ultrasound-related biomedical technology for cancer therapy and diagnosis.

Underground monitoring and control system is usually fixed and has limited range, so it is difficult to fully meet dynamic monitoring requirements of underground safety production. Moreover, due to limited wireless communication distance, underground single unmanned aerial vehicle has weak monitoring ability. For the above problems, an underground unmanned aerial vehicles cluster system for monitoring was proposed. The key technologies of the system implementation were introduced in detail such as cooperative control for flying and avoidance, data chain networking, creation of mine roadway environment maps, attitude and position estimation for unmanned aerial vehicles, moving obstacle detection and path planning. Ground dispatching center issues dispatching orders to the underground unmanned aerial vehicles cluster through gateway node set up in underground monitoring sub-station, and the underground unmanned aerial vehicles formation fly with 'one' shaped queue along underground roadway. After entering the target area, the unmanned aerial vehicles can monitor the underground target area through the video sensors and environmental monitoring sensors on board, and transmit the monitoring video information and environmental parameters to the underground monitoring sub-station through the cooperation of multiple unmanned aerial vehicles, so as to realize autonomous and dynamic monitoring of the underground target area. The unmanned aerial vehicles cluster system has advantages of wide coverage and strong monitoring capability,through collaborative control, which can effectively improve monitoring efficiency. In addition, it can also solve the problem of limited wireless communication distance of single platform of underground unmanned aerial vehicle by means of wireless multi-hop, which is conducive to transmission of monitoring and control information.

BACKGROUND Diethylenetriaminepentaacetic acid (DTPA) dissolution and reprecipitation (DDARP) method is used frequently to eliminate encapsulated nitrate during barite precipitation. However, the effect of DDARP on barite precipitated from different kinds of natural water is rarely reported, particularly it is not clear whether the DDARP method plays a role in eliminating the effect of organic matter on barite from organic-rich water samples. OBJECTIVES To obtain more accurate sulfate oxygen isotope values, using the modified DDARP method and identify the factors affecting the oxygen isotope values of barite from natural water samples. METHODS Element Analyzer (EA) coupled with Isotope Ratio Mass Spectrometry (IRMS) was used to determine the oxygen isotope values of original and purified barite. RESULTS After purification, oxygen isotope values of high grade barite reagent show little variations, indicating that purification of high grade barite reagent is not needed and it can be directly used as the laboratory standard. However, oxygen isotope values of barite from Yellow River water have large variations from 0.6 to 1.0 with an average of 0.8‰, indicating that it is necessary to purify natural water barite. The differences in oxygen isotope values between original and purified barite from natural water samples vary from -0.4‰ to +1.9‰, and the average differences of oxygen isotope values are 0.7‰, 0.2‰, 0.3‰, -0.3‰, 0.1‰ and 1.4‰ for dissolved detergent, groundwater, river water, sewage, dissolved fertilizer, and rainwater, respectively. The large positive differences of oxygen isotope values (from +0.5‰ to +1.9‰) between original and purified barite is found in rainwater samples due to nitrate encapsulated in barite, which is related to the high molar ratio of nitrate to sulfate in rainwater (from 0.2 to 1.9 with an average of 0.7). The negative differences of oxygen isotope values (from -0.2‰ to 0.4‰) are observed in sewage with respect to the organic matter encapsulated in barite from organic-rich sewage, suggesting that the purification method can remove organic interference. CONCLUSIONS The modified DDARP method works well in eliminating nitrate and organic matter encapsulated in barite. It can be used to purify barite to obtain more accurate oxygen isotope values of sulfate in natural water samples. The proposed method can be used as a standard purification method for water body sulfate oxygen isotope determination.

Traditional spaceborne Synthetic Aperture Radar (SAR) can acquire three-dimensional (3D) images by using multi-baseline SAR data, which solves the problem of layover in two-dimensional (2D) SAR image, however, there is still a problem of insufficient information acquisition caused by occlusion. Considering this, a 3D imaging algorithm for multi-azimuth-angle multi-baseline spaceborne SAR is proposed in this paper; this algorithm not only solves the problem of layover, but also reduces the occlusion area by fusing the 3D point clouds obtained under different azimuth angles and improves the information acquisition ability of spaceborne SAR. First, the observation model of multi-azimuth-angle multi-baseline spaceborne SAR is established, and it shows that the mathematical signal models of the multi-baseline SAR in the squint mode and broadside mode are the same, which provides theoretical support for the direct application of broadside 3D imaging algorithm to the 3D processing of squint mode. On this basis, the 3D imaging algorithm and processing flow of multiazimuth-angle multi-baseline spaceborne SAR are presented. Finally, the effectivenesses of the squint 3D imaging method and 3D point clouds fusion method are verified by point targets simulation experiment with 45° azimuth angle and helicopter simulation experiments with 45° and –45° azimuth angles, respectively.

The operating temperature of advanced aeroturbine engine increases rapidly for higher working efficiency. Thermal barrier coatings (TBCs) with high temperature capability and thermal insulation effect are required. In this work, a novel multilayer TBCs consisting of rare-earth element doped YSZ and YSZ sublayers were designed and fabricated. The influence of microstructure to the phase structure, thermal conductivity and infrared reflectivity of the coatings were investigated. The results show that a preferred orientation of (200) is yielded in the coating. With the increase of layers, the thermal conductivity of the coating decreases and the infrared reflectivity increases respectively. The multilayer coating with 200 sublayers exhibits a thermal conductivity of 1.1-1.16 W/m·K, 11% lower than that of the conventional single layer coating. The infrared reflectivity of the coating reaches as high as 48%-55%.

Based on the micro-electro-mechanical systems（MEMS） technology,the chip structure of a two-axis force sensor with comb structure was designed.Silicon force sensitive structure converted the faint mechanical signals into measurable electrical signals.After finite element model was established,the structure and electrical properties of the sensor were analyzed.The corresponding relation between the mechanical signals and the electrical signal was obtained.The mode analysis and harmonic response analysis were performed for the model.The natural frequency of the structure and the harmonic response frequency both are verified that far away from the operating frequency of the system.The work stability and measurement accuracy of the chip are guaranteed.The resolutions of force and moment of the sensor chip are 2.85 μm and 0.0382 μN·m,respectively.The linearity of the signal conversion reached 0.999 6 and 0.999 9.The first and second order modal natural frequency is783.28 Hz and 1 294.3 Hz and harmonic response frequency is 770 Hz.Simulation results meet the requirement of performance specification.

According to the new demand for grain and oil quality inspection put forward by the current economic development of grain industry.In order to obtain the real,detailed and accurate basic data,the sampling information technology is proposed to set the characteristic mark for the data,the traceability mechanism of quality inspection is constructed,and the direction of using traceability information of quality inspection to serve the economic development of grain industry is proposed.

Aiming at the problem that the national network customer telephone voice recognition has poor recognition of core words in specific fields, this paper proposes a method based on HCLG domain weight enhancement and domain word correction, which can add domain words in real time and quickly, to dynamically optimize the language model and improve speech recognition. The model and algorithm are optimized in the various fields of the telephone voice consultation, maintenance, complaints, etc. of the State Grid Customer Service Center. The speech recognition results have been greatly improved.

According to multimedia information collection requirements and characteristics of confined band space in coal mine tunnel and limited energy of sensor nodes, a wireless multimedia sensor network (WMSN) system model of coal mine was built, and an energy balancing routing method for coal mine WMSN was proposed, which included a position and residual energy based hierarchy clustering in virtual grids (PREHCVG) algorithm and an energy and distance based ant colony routing (EDACR) algorithm. In the method, PREHCVG algorithm divides nodes into different virtual grid for cluster management based on communication radius of the nodes in the network, and selects cluster head nodes according to residual energy and location information of the nodes. EDACR algorithm selects routing nodes from cluster head nodes and alternative cluster head nodes according to residual energy and distance information of the nodes. The simulation results show that the energy balancing routing method for coal mine WMSN can effectively balance energy consumption of WMSN nodes, reduce the number of energy-exhausted nodes and prolong life cycle of WMSN compared to traditional LEACH algorithm.

Most sulfate and sulfide ores are composed of low electrical magnetic materials. In the process of combustion, the sulfur in sulfate and sulfide ores cannot be released completely, because it is difficult to produce a large enough electromagnetic induction eddy current. Thus, the results are lower than real values when the sulfur in sulfate and sulfide ores is determined by High Frequency Infrared Carbon-Sulfur Spectrometer. In this study, the barite and pyrite samples are diluted with silicon dioxide to acquire different contents of sulfur. By optimizing the sample weight and flux types, determination of sulfur by High Frequency Infrared Carbon-Sulfur Spectrometer was developed. Results show that the sample weight is 0.07 g when the content of sulfur is higher than 2% whereas sample weight is 0.1 g when the sulfur content is below 2%. Furthermore, the sulfur in barite and pyrite can be released completely into the infrared absorption area when adding 0.4 g of tin grain, 0.4 g of iron grain, and 0.5 g of tungsten grain to the sample. The recovery of sulfur can reach 95.8%-104.2%(barite) and 95.3%-105.1%(pyrite), which is far higher than the recovery of 83.3%-91.1% and 91.5-97.5% for the conventional analysis of sulfur by Infrared Carbon-Sulfur Spectrometer. This method precision is less than 5% and can determine the accurate content of sulfur.

The looseness or fall off of the clamp is one of the important factors for the failure of spacer bar. The research on the clamp strength is very important. Based on ANSYS finite element analysis software,non-linear emulation analysis is carried out. A reinforced spacer clamps was chosen as the object,using Mooney-Rivlin rubber constitutive model,simulating clamp for pre-clamping the wire by using pre-rigid displacement and simulating non-uniformloading conditions such as wire icing and winding by applying the tension along the line and rotarytorque load. Compared with experiment result,it shows that the strength and gripping performance of the new clamp satisfies the requirement of DL/T1098-2009,and the clamprubber spacer plays a role in reducing wear and protection. At the same time,the correctness of finite element model of spacer bar clamp is verified. It also provides useful reference for the clamp structure improvements,and lays the foundation for wind-resistant simulation analysis of high-voltage transmission line system.

Based on the analysis of converter slagging and limestone slagging,the key point of smelting control and the operation strategies during the entire limestone steelmaking process were proposed in this paper,combined with the research of the double-slagging process by lime. According to the production practice in Shijiazhuang Iron and Steel Company,the entire limestone steelmaking of special steel was conducted. In the results,the average C content of the molten steel after converter tapping is 0.16%,and the average P content is 0.011%,which meet the requirements of special steel production. Compared with the entire lime steelmaking,the cost of entire limestone steelmaking is reduced by ￥2.32 per ton molten steel. The results of the industrial experiment show that the entire limestone steelmaking can make good economic benefits,and has some promotional values.