Search

The objective of the current study is to investigate the formation mechanism of rail corrugation. According to the actual wheel-rail motion relationship, that is, considering the influence of the angle of attack (AoA), a single degree of freedom friction pair model considering different friction attributes was established. The system stick-slip oscillation characteristics under different friction attributes were analyzed by using the model, so as to explore the generation reason of corrugation. Meantime, combined with the parameter analysis of the power system, the corresponding control measures for the stick-slip oscillation were put forward to slow down the formation and development of corrugation. The results show that the lateral and vertical dynamics play important role on its stick-slip oscillation characteristics. The corrugation formation on the metro small radius curve is related to the unstable stick-slip oscillation induced by the negative slope friction creep property of wheel-rail interface. The parameter analysis illustrates that the unstable stick-slip oscillation can be effectively controlled by increasing the damping coefficient, increasing the modal stiffness, appropriately reducing the static vertical force of the contact interface and increasing the lateral velocity (AoA) within a certain range. Practically, knowing the formation mechanism of rail corrugation is conducive to understanding the evolution process of rail corrugation; meantime, by referring to the results of parameter analysis, the active control of stick-slip oscillations can be realized, thereby controlling the growth of rail corrugation.

This study proposes a layout scheme for external staggered roadway and builds a mechanical model for unconventional coal pillars with staggered positions as a solution to the waste of resources caused by the large coal pillar size between the sections of 1301 fully mechanized top coal caving face and the difficulty in supporting the roadway in Xinjulong Coal Mine. We analyzed the stress environment and characteristics of the extreme equilibrium zone of unconventional coal pillars using the limit equilibrium theory. For the bottom roadway, the reasonable horizontal staggered distance in the lower section is set at 3.0 meters after considering its stress environment at different horizontal offset conditions and the distribution of elastic strain energy density of the section coal pillars. Meanwhile, we proposed a joint support scheme for adjacent roadways between sections. We simulated and verified the original support scheme and the joint support scheme in actual geological conditions during the mining stage of the continuous working face. Results show that the joint support scheme for adjacent roadways between sections outperforms the original support scheme. The peak stress of the joint support scheme reduced from 80 MPa to 64 MPa, with a reduction rate of 20 %, indicating that the it is more effective in controlling the surrounding rock of the roadway. Moreover, the unit reserved area of coal pillars in the section was 111.5 m2, which is a 34.4 % reduction from 170 m2 in the original support scheme. This study offers implications for reducing the reserved size of coal pillars in fewer sections and improving the coal recovery rate.

The production wastewater of a circuit board enterprise comes from the printing plate washing wastewater,developing and post-developing cleaning wastewater, deinking cleaning wastewater, etching cleaning wastewater, pre-treatment cleaning wastewater, intermediate treatment cleaning wastewater, and OSP antioxidant cleaning wastewater. The produced wastewater in this project was divided into high-concentration organic wastewater, etching cleaning wastewater, and general cleaning wastewater for separate pretreatment, and then converged for biochemical treatment and advanced treatment. The results showed that the COD, BOD5, NH3-N, and SS of the discharged wastewater after treatment were ≤95 mg/L, ≤22.4 mg/L, ≤11.3 mg/L, and ≤78 mg/L, respectively, which reached the indirect emission limit of the “Electronic Process Water Pollutant Emission Standards”(GB 39731—2020) and the second-stage secondary emission standard of the “Water Pollutant Emission Limits”(DB 44/26—2001) in Guangdong Province. The COD, BOD5, NH3-N, and conductivity of the reclaimed water were ≤27 mg/L, ≤8.14 mg/L, ≤2.4 mg/L, and ≤843 μS/cm. After meeting the process and product water standards of “Recycling of Urban Sewage for Industrial Water Quality”(GB/T 19923—2005), it could be reused for etching, deinking, and other production processes. The direct operating cost of wastewater treatment in this project was 10.54 yuan/ton of water, and the cost of reclaimed water treatment was 2.72 yuan per ton of water.

[Objective] In order to grasp the current situation and spatial variability pattern of black soil layer thickness in the typical black soil region within a small watershed, and realize dynamic monitoring of black soil layer thickness in such areas. [Methods] This study selected a small watershed of Heshan Farm in Nenjiang City, Heilongjiang Province. Soil sampling points were uniformly distributed at intervals of 100 meters, and undisturbed soil samples were collected from surface to parent material using soil augers to determine the thickness of the black soil layer. Meanwhile, terrain and land use data were extracted based on UAV aerial photography data. The study analyzed the thickness of black soil layer in the small watershed and its influencing factors. [Results] Among the 295 sampling points in the small watershed, the thickness of black soil layer varied from 0 to 160 cm, with an average of 44.1 cm. “Popihuang” (black soil layer thickness ≤20 cm) accounted for 17.63%, thin black soil (60 cm) accounted for 20.34%. Thick layer black soil was primarily distributed in the lower slopes, in the vicinity of gullies, and other gently sloping areas of the watershed, while thin layer black soil was predominantly found in steep slopes and areas with sandy gravel parent material, and medium layer black soil was predominant in other regions. Terrain indices such as topographic position index, curvature, slope exhibited significant correlations with the black soil layer thickness. The thickness of black soil layers in cultivated land was significantly lower compared to grassland and forest land. [Conclusion] The thickness of black soil layer exhibits significant spatial heterogeneity within the small watershed, which is primarily influenced by terrain characteristic, parent material and landuse. The research findings can be used as one of the bases for dynamic monitoring of regional black soil layer thickness, and can provide data support for the formulation of soil and water conservation measures in small watershed.

[Objective] To realize rapid detection of green tea species identification. [Methods] A rapid detection method based on the combination of electronic tongue and electronic nose combined with CNN-Transformer composite model was proposed. The electronic tongue and electronic nose were used to collect the fingerprint information of taste and smell for five different kinds of green tea. The one-dimensional electronic tongue and electronic nose signals were transformed into two-dimensional time-frequency maps using the short-time Fourier transform （STFT）, which fully revealed the distribution characteristics of the signal energy in the time-frequency domain. A CNN-Transformer combination model was proposed to realize the fusion of the electronic tongue and the electronic nose information and pattern recognition. The model adopted selective kernel convolution and normalized attention in designing convolution module to replace the convolution layer of the traditional CNN to achieve the dynamic extraction of local features from the time-frequency map of the signal. The multi-head self-attention mechanism in the Transformer encoder was used to extract the global temporal information in the features of the electronic tongue and the electronic nose and achieve the weighted fusion of their features. Finally, classification recognition was carried out by the fully connected layer. [Results] The information fusion method based on electronic tongue and electronic nose could effectively extract the deep features of the taste and smell signals from green tea samples and provide richer fused feature representations for the model to achieve highly accurate recognition of different species, with a test set accuracy, precision, recall and F1-Score of 99.00%, 99.05%, 99.00%, and 99.00%, respectively. [Conclusion] This study provides a low-cost, fast and efficient detection method for green tea species recognition.

ObjectiveTo provide the basis for formulating relevant prevention and control measures， the etiological characteristics of foodborne diarrhea cases in Anhui Province from 2017 to 2021 were analyzed.MethodsThis cross-sectional study method was conducted from 2017 to 2021 and included data from diarrhea cases in 22 foodborne disease etiology-monitoring hospitals， Anhui Province. Anal swabs or feces were taken from all cases of diarrhea and the samples were tested for etiology as required. Data were processed with χ2 trend test or χ2 trend test.ResultsA total of 15 484 specimens were collected from 2017 to 2021， and the total detection rate of pathogens was 23.75% （3 678/15 484）. The detection rate of Norovirus， Salmonella， diarrheagenic Escherichia coli， Vibrio parahaemolyticus， and Shigella were 10.01% （1 550/15 484）， 6.16% （954/15 484）， 6.10% （944/15 484）， 1.66% （257/15 484）， and 1.00% （155/15 484）， respectively. The detection rate of pathogens in different years （χ2trend=11.249， P

Abstract Background In the context of esophageal cancers, lymph nodes located along the left recurrent laryngeal nerve (RLN) exhibit significant involvement, posing significant challenges for lymphadenectomy. The objective of this study is to assess the safety and efficacy of a novel technique for lymphadenectomy called "elastic suspension of left RLN" method, comparing it with the conventional approach. Methods Between January 2016 and June 2020, a total of 393 patients who underwent minimally invasive esophagectomy with gastroplasty and cervical esophagogastric anastomosis were enrolled in the study. Among them, 291 patients underwent the "elastic suspension of left RLN" method, while 102 patients underwent the conventional method. We compared the number of harvested lymph nodes along the left RLN and assessed postoperative complications between these two groups. Additionally, the overall survival (OS) rate was calculated and analyzed for the entire cohort. Results In comparison to the conventional group, the elastic suspension group exhibited a higher yield of harvested lymph nodes along the left RLN (5.36 vs 3.07, P

The high pressure difference between the inlet and outlet of the air preheater in coal-fired power plants has always been a problem that plagues the operation of the power plant. If the pressure difference of the air preheater can be predicted in advance and adjusted in time, it will be beneficial to the safe operation of the power plant. Based on the distributed control system (DCS) big data of a 660 MW coal-fired boiler, the BP neural network and support vector regression (SVR) methods were used to model the pressure difference between the inlet and outlet of air preheater in the power plant.Comparing the prediction results of the two models, it is found that the BP neural network model is more suitable for the prediction of the pressure difference between the inlet and outlet of the air preheater under the background of big data. Aiming at the inherent shortcomings of BP neural network model such as local optimization and slow convergence speed, the particle swarm optimization (PSO) was used to improve it, and a PSO-BP neural network model was proposed. The results show that the PSO-BP neural network model has the best comprehensive performance, the highest accuracy in predicting the change in the pressure difference between the inlet and outlet of the air preheater, and the strongest generalization ability.

ObjectiveTo analyze the clinical efficacy and prognostic influencing factors of neuro-endoscopic minimally invasive surgery for hypertensive intracerebral hemorrhage （HICH）. MethodsA total of 100 patients with HICH admitted to Handan First Hospital from January 2020 to December 2021 were randomly divided into control group （n=50） and observation group （n=50）. The control group underwent small bone window craniotomy for hematoma debridement, and the observation group underwent neuro-endoscopic minimally invasive surgery. The hematoma clearance, National Institutes of Health Stroke Scale （NIHSS）, Activity of Daily Living (ADL) and prognosis were compared between two groups. According to the prognosis, patients in observation group were divided into good prognosis sub-group （n=37） and poor prognosis sub-group （n=13）, and the influencing factors were analyzed. ResultsThe intraoperative blood loss and postoperative residual hematoma in observation group were less than those in control group, and the hematoma clearance rate was higher than that in control group （P＜0.05）. One month after operation, the good prognosis rate of observation group was higher than that of control group （74.00%vs48.00%, χ2=7.104, P＜0.05）. The preoperative MAP ［(122.57±7.88) mmHgvs(130.26±8.97) mmHg, t=2.921, PConclusionNeuro-endoscopic minimally invasive surgery for HICH patients can help to clear hematoma, restore nerve function and improve prognosis. And preoperative MAP, hematoma volume, GCS, and NIHSS are associated with prognosis.

In order to study the waterproof performance of elastic rubber gasket in shield tunnel lining joints, an innovative sensitivity analysis method is proposed by combining the Monte Carlo method with the stochastic finite element method (FEM) in this paper. The sensitivity values of the waterproof performance respecting to elastic rubber gaskets are obtained via the ANSYS Probabilistic Design System (PDS) module, in which the parameters of material hardness, coordinates of the hole center, apertures are selected as random input variables. Meantime, the extent of the tolerance effect of the random parameters on the waterproof performance is explored.

The current research achievements in the construction of intelligent fully mechanized caving face lack systematic implementation case for a specific fully mechanized caving face. In order to solve this problem, The 81309 intelligent fully mechanized caving face of Baode Coal Mine, CHN Energy Shendong Coal Group Co.,Ltd. is taken as the research background. Based on the configuration of hydraulic support electro-hydraulic control system and fully mechanized mining automation system, the key technologies such as equipment upgrading and transformation, limited transparent mining model building, intelligent coal drawing process decision-making, optimization of coal gangue recognition method, and multi-mode fusion integrated control are introduced in detail. ① The localization upgrading and transformation of the electric control system of the shearer is carried out. The inertial navigation system is installed. The optical fiber composite cable/5G communication is supported to realize efficient and stable transmission of attitude and control data of shearer. The equipment train can be pulled and moved by 1 - 2 persons by adopting step-type self-shift equipment train and pipe and cable expansion device. ② The iterative correction on the geological model in the data source of the intelligent planning center is carried out. The limited transparent mining geological model is formed through a series of conversions and multi-source heterogeneous data fusion. ③ In view of the sequential coal caving mode of 'one cut, one caving and two rounds' in the 81309 working face, 10 intelligent fully mechanized caving mining stages and the corresponding actions and time of shearer, fully mechanized caving hydraulic support, front and rear scraper conveyor are constructed. The automatic mining and drawing in the middle and automatic mining in the triangle coal area are realized. ④ The intelligent coal gangue recognition system of fully mechanized caving is built by combining the vibration coal gangue recognition and video coal gangue recognition technology. ⑤ With the SAM-type fully mechanized mining automation control system as the hub, an intelligent centralized control system is constructed by integrating the electro-hydraulic control of hydraulic support, video monitoring, electric control of shearer and centralized control of pump stations of three machines. The intelligent fully mechanized caving face with adaptation in all links of 'mining, support, recognition, caving and transportation' based on transparent mining has been initially built. The debugging results show that the middle part of 81309 fully mechanized caving face can realize the automatic control of 4 coal cutters in a single shift. The hydraulic support can realize the functions of the automatic following machine and pulling frame, linkage receiving and extension guard / expansion beam, and automatic pushing and sliding. The intelligent centralized control system can start and stop the production system with one key, and monitor the equipment operation data in real-time.

The exploration of biomarkers predicting response to immune checkpoint inhibitors in microsatellite stability colorectal cancer can enable more patients to benefit from immunotherapy. Tumor mutational burden (TMB), POLE/POLD1 mutation, CMS classifications, MGMT methylation, and other indicators own the potential and value of predicting response to immune checkpoint inhibitors in microsatellite stability colorectal cancer. In this paper, we reviewed the related research on predictive biomarkers of immune checkpoint inhibitors in microsatellite stability colorectal cancer, provide a reference for the best treatment strategy for microsatellite stability colorectal cancer.

Taking point-line meshing gears and involute gears as the research object, a simulation model of two kinds of meshing gears is established, the meshing characteristics of point-line meshing gears and involute gears in transmission error, tooth surface load distribution, tooth surface sliding speed distribution, tooth surface contact stress distribution, tooth root bending stress distribution, meshing contact trace analysis are comprehensively compared and analyzed. It is obtained that the point-line meshing gear is obviously better than the involute gear in the above meshing characteristics, which provides a theoretical basis for a more comprehensive understanding of point-line meshing gear transmission and has a certain theoretical value for its popularization and application.

The detection of external fire in coal mines and the reliable identification of initial fire are of great significance for improving the level of coal mine fire detection. It is also an important direction of intelligent mine construction in the future. In order to improve the speed, precision and real-time of coal mine external fire detection, a coal mine external fire detection method based on edge intelligence is proposed. The feature scale of the backbone network of the YOLOv5s model is improved. The model can fully learn the shallow features and improve the small target detection performance. At the same time, an adaptive attention module is added on the basis of the original feature pyramid network (FPN) to improve the detection precision of the model. There are problems of image detection error and missed detection caused by poor light conditions, more dust and camera shooting angle in the underground mine. In order to solve the above problems, the YOLOv5s-as model is constructed by using multi-sensor auxiliary detection and weighting fusion identification of video detection information and multi-sensor detection information through dynamic weighting algorithm. The YOLOv5s-as model is transplanted to the intelligent edge processor, and lightweight processing is carried out to realize the deployment of edge intelligent devices. The experimental results show that the reasoning time of the YOLOv5s-as model is slightly longer than that of the YOLOv5s-a model without sensor information fusion reasoning, but mean value of average precision when the intersection over union is 0.5 (mAP@0.5) is increased by 7.24%. Compared with the YOLOv5s model before transplantation, the mAP@0.5 of the YOLOv5s-as model transplanted to the intelligent edge processor and subjected to lightweight processing increased by 15.04%. For small target fire sources, SSD 300, SSD 512 and YOLOv5s models cannot identify them. The YOLOv5s-a and YOLOv5s-as models can detect small target fire sources with good adaptability. When using the edge processing method, the response period of YOLOv5s as model is 238 ms, which is 38.66% shorter than the centralized processing method.

Abstract Background Previous studies have shown that the Kyoto classification of gastritis can accurately predict H. pylori infection status on conventional gastroscopy. The aim of this study was to test whether the Kyoto classification of gastritis applies well to magnetic controlled capsule endoscopy (MCCE). Methods We consecutively recruited 227 participants who underwent both MCCE and urea breath tests (UBTs). Two physicians who were blinded to the UBT results independently made the diagnosis of H. pylori infection status according to 10 findings listed in the Kyoto classification of gastritis after reviewing MCCE images. We also developed 2 predictive models to assess H. pylori infection status by combining these 10 findings. Results The MCCE’s overall diagnostic accuracy for H. pylori infection status was 80.2%. The sensitivity, specificity and diagnostic odds ratio (DOR) for current infection were 89.4%, 90.1% and 77.1, respectively. Major specific findings were mucosal swelling and spotty redness for current infection, regular arrangement of collecting venules (RAC), streak redness, fundic gland polyp (FGP) for noninfection, and map-like redness for past-infection. In the two prediction models, the area under the curve (AUC) values for predicting noninfection and current infection were 84.7 and 84.9, respectively. Conclusions The Kyoto classification of gastritis applied well to MCCE. H. pylori infection status could be accurately assessed on MCCE according to the Kyoto classification of gastritis.

This meta-analysis investigated the effect of physical exercise (PE) on the levels of oxidative biomarkers in randomized controlled trials (RCTs) involving healthy subjects. We searched five databases for articles until May 1, 2023. A random-effect meta-analysis, subgroup analysis, meta-regressions as well as trim and fill method were conducted using STATA 11.0, involving ten articles. According to the results of the meta-analysis, PE had no significant effect on superoxide dismutase (SOD), glutathione peroxidase, and catalase levels. PE induced significant increase in total antioxidant status (standardized mean difference [SMD] 1.53, 95% CI 0.73–2.32), and PE could significantly reduce the level of malondialdehyde (MDA) (SMD −1.11, 95% CI −2.15 to −0.06). Sensitivity analyses and subgroup analyses showed that male participants, body mass index (BMI)

Objective To assess the efficacy of the trans-cervical and trans-hiatal esophagectomy versus thoracoscopic esophagectomy in patients with esophageal carcinoma. Methods A total of 80 esophageal carcinoma patients undergoing surgical treatment in our hospital from September 2018 to October 2020 were enrolled in this study, and they were divided into observation group (n=40) and control group (n=40). The patients out of the observation group underwent the trans-cervical and trans-hiatal esophagectomy, and those from the control group underwent the thoracoscopic esophagectomy. The preoperative, intraoperative and postoperative data were analyzed between the 2 groups, regarding intraoperative blood loss, number of dissected mediastinal lymph nodes, operation time, number of lymph nodes in left para-recurrent laryngeal nerve (para-RLN) or right para-RLN, length of staying in intensive care unit (ICU), postoperative pain score, length of postoperative stay, PO2/fraction of inspiration O2 (PO2/FIO2), pulmonary infection, and lymphatic metastasis. Results The operation was successfully performed in all 80 patients. The patients in the observation group had shorter operation time (200 vs 235 min, Z=-3.700, P < 0.001) and larger number of dissected mediastinal lymph nodes in left para-RLN (25.0% vs 2.5%, Z=2.568, P=0.010) than those in the control group. Significant differences were observed in the pain scores of postoperative day 1 (0% vs 17.5%, Z=-4.292, P < 0.001) and day 3 (12.5% vs 37.5%, Z=-3.363, P < 0.001), postoperative 48-h PO2/FIO2 (290 vs 255 min, Z=3.747, P < 0.001), length of postoperative stay (7 d vs 8 d, Z=-2.119, P=0.034), and incidence of postoperative pulmonary infection (χ2=4.114, P=0.043) between the 2 groups. Conclusion Trans-cervical and trans-cervical esophagectomy is a good approach in treatment of esophageal carcinoma, and may provide an option to the patients who cannot suffer from the thoracotomy.

【Objective】 Green roof has been increasingly used in new buildings not only as a compensation to the lost habitat in urbanization but also as a strategy to mitigate urban flooding. One issue in green roof maintenance is irrigation, which is expensive and difficult to manage. This paper studied the efficacy of microfiber capillary wick as an irrigation system for green roofs. 【Method】 Four plexiglass platforms were set up on a roof. From the top to the bottom, each consisted of a planting layer, a substrate layer, a water storage layer and a base layer to prevent exfiltration. Microfiber capillary wick (MCW) in different patterns - steering wheel (MCWI), spiral annular rings (MCWII) and straight capillary (MCWIII) - were placed in the plexiglass platforms for irrigation; irrigation without wick was taken as the control. In each platform, we measured the change in soil moisture content from 25 May to 30 August 2017. We also calculated the change in irrigation uniformity coefficient (UC) of each system. 【Result】 Based on the mean SMC, the systems are ranked in the order: MCWII < MCWI < MCWIII. The average SMC in the three treatments was 46.7% higher than that in the control. Using MCW can keep the soil water content more than 5% during 97.8% of the experimental period, compared to 2/3 in the control. The Christiansen irrigation uniformity coefficient (CUC) of MCWI and MCWIII was approximately the same, while the CUC of MCWII at radius of 25 cm, 20 cm, 15 cm, 10 cm, and 5 cm was 1.6%, 4.2%, 4.8%, 4.3% and 9.3% higher than that of MCWI, respectively. Daily irrigation variable coefficient (CV) of MCWI and MCW II was approximately 6%, while the CV of MCWIII was more than 10%. 【Conclusion】 MCWII worked best by increasing SMC and relieving drought stress. The results presented in this work have wide implications for developing water-saving irrigation technologies for green roofs.

C12H17N9O8, orthorhombic, Pna21 (no. 33), a = 11.376(4) Å, b = 7.966(2) Å, c = 19.076(6) Å, V = 1728.6(9) Å3, Z = 4, Rgt(F) = 0.0373, wRref(F2) = 0.0908, T = 296 K.

In order to ensure the normal use of a junction section of a modern tram, this paper mainly studied a trackside concrete reinforcement scheme. Firstly, the entire non-reinforcement system model with a small radius curve composed of rail, fastener, fastener cover, flexible material, asphalt layer and track slab was established using the ABAQUS finite element software, and the stress distribution and deformation state of the asphalt layers of the non-reinforcement system model under the social vehicle load were analyzed. Then, the whole system model of the concrete reinforcement scheme was founded, and the stress and deformation of the asphalt layers under the same load were investigated. Finally, the calculation results of the concrete reinforcement model were com-pared with those of the non-reinforcement model, and the reinforcement effect was studied. The results show that the concrete reinforcement scheme significantly reduces the stress and deformation of the asphalt layers and improves the stress distribution and deformation state of the asphalt layers.

In order to solve the problems of video image distortion caused by uneven light distribution and low accuracy of fire identification in coal mines, an intelligent identification method of mine fire video images is proposed. The method uses YOLOv5 as the identification model and uses K-means algorithm to improve the traditional dark channel image defogging algorithm to defog the collected flame images and improve the identification accuracy of mine fire video images. In order to reduce the impact of static background on fire identification, the fusion algorithm of frame difference method and Gaussian mixture model is used to extract the characteristics of the dynamically evolved flame images, and the morphological processing algorithm is used to eliminate the gaps in the images so as to obtain more complete flame target images. The fire video image data set is annotated and input to the YOLOv5 algorithm model for training and testing. The results show that the average accuracy of the intelligent identification method of mine fire video images based on YOLOv5 is 92% with a loss function of 0.6, which is 9.6%, 13.5% and 4.9% higher than that of the traditional algorithms, Alexnet, VGG16 and Inceptionv3 respectively, indicating that this method has fast detection speed and high accuracy, and can improve the accuracy of mine fire identification effectively.

【Background】 Lime concretion black soil is widely distributed in central China including Henan and Anhui provinces. Apart from its low fertility, it is also hard and less porous for roots to penetrate. These combine to hinder crop growth and comprise crop yield. Traditional remediation methods including deep tillage to loosen the soil are effective but are tedious and laborious. As an alternative, soil conditioners have been increasingly used over the past years to improve the properties of the black soil to sustain its productivity. 【Objective】 The objective of this paper is to compare the effectiveness of different soil conditioners in improving soil properties and the consequence for crop growth and yield. 【Method】 We took summer maize as an example and the soil was plowed using conventional tillage after maize harvest but before winter wheat was drilled. There were three treatments: rotary tillage + application of root promoter (RT+RP), rotary tillage + application of soil remediating agent (RT+RA), rotary tillage + soil improvement agent (RT+SI). Traditional deep tillage was taken as the control (CK). In each treatment, we measured the changes in soil properties and fertility, enzyme activity, as we as the resistance of the maize against lodging and the eventual yield. 【Result】 Compared to CK, all treatments increased soil water content and reduced soil bulk density although the change varied with treatments; they also boosted the activity of soil enzymes including urease, sucrase and neutral phosphatase, and improved the contents of available P, ammonium N and nitrate N in the soils, as well as plant height and stem diameter. All improvements and increases were at significant level (p

The direct roof subsidence of retracement channel is of utmost importanie to the withdrawal of equipment in the final mining stage.Based on the basic roof fracture position, a mechanical model of the direct roof deflection of the withdrawal channel after penetration was established.The expression of the supporting stress was simplified to the n-th parabolic function of x fitted to it.The value of n varies with the fracture position, the expression of the direct roof subsidence at the center line of the roof of the retreat channel was derived.The basic roof fracture position d of 312 working face was about 12 m, at this time n was taken as 4, and the direct roof subsidence was about 105 mm.On the basis of theoretical calculations, the factors affecting the direct roof subsidence were analyzed.The results showed: The direct roof subsidence increases with the increase of the basic roof fracture location, coal seam depth, stress concentration coefficient and the span of the retreat channel, and decreases with the increase of the direct roof thickness and elastic modulus.The influence of other factors is not significant.Under the condition of ensuring the equipment withdrawal space, the span of the withdrawal channel should be reduced as much as possible to control the direct subsidence of the withdrawal channel.

The measurement of dissolved oxygen content in water is of great significance to aquaculture. However, the dissolved oxygen sensors on the market in China are expensive, and are difficult to maintain continuous online measurement and update parts, so they cannot be widely applied in real production and play expected role in the aquaculture Internet of things(IoT). Based on the principle of fluorescence quenching, a low cost and easy maintenance of dissolved oxygen sensor was developed in this work based on the relationship between the concentration of dissolved oxygen in water and the phase difference of fluorescence signal. The self-made oxygen-sensitive membrane was used to generate red fluorescence which being excited by blue light, and the fluorescence life was regulated by the concentration of dissolved oxygen. Photoelectric conversion circuit with optical signal sensing device was designed to sense optical signal. The STM32F103 microprocessor was used as the main control chip, and the lower computer program was programmed to generate the excitation light pulse. The phase-sensitive detection principle and fast Fourier transform (FFT) were used to calculate the phase difference between the excitation light and the reference light, which was converted into the concentration of dissolved oxygen and realized the measurement of dissolved oxygen. The fluorescence detection part and the main control part of the system were designed as detachable independent modules, and shield lines were used to plug and pull directly, so as to facilitate replacement and maintenance and realize online remote measurement. The testing results showed that, the measurement range of the sensor was 0-20 mg/L, system time delay was less than 2 s, and the life time of the oxygen sensitive membrane would be about 1 year. The dissolved oxygen sensor has the characteristics of convenient measurement, stable result output, low cost and small volume, which will lay a good foundation for the development and marketization of low-cost dissolved oxygen sensors in aquaculture industry of China.

Aiming at the serious damage caused by the stress concentration in the isolated working face for a long time in the underground transportation roadway, the mining treatment of the isolated working face is carried out to reduce its influence on the stress concentration of the surrounding rock of the roadway.This paper compares and analyzes the stress transfer law of roof and floor of isolated working face before and after mining, and probes into the law of roof supporting pressure of isolated working face and the vertical distance between underlying transportation roadway and isolated working face floor by numerical simulation.It found that with the increase of the distance from the floor to the floor, the stress concentration of the surrounding rock of the roadway shows a decreasing trend.When the isolated island face is mined, the stress of the floor is obviously released.The stress concentration factor of surrounding rock of floor roadway is reduced by 52%~60%, and the shear failure of surrounding rock of floor roadway presents X failure, which provides theoretical basis for the optimization of surrounding rock support in subsequent roadway.

Based on vehicle-track coupled dynamics and Archard wear models,the influence of different axle loads,friction coefficients and running speeds on the rail wear characteristics of small radius curve section in metro were analyzed and discussed.The results indicated that the left rail wear concentrated on the shoulder and the right rail wear concentrated on the middle of the rail head,and the cumulative wear amplitude of the left rail was greater than that of the right rail. When the axle load increases,both the left and right rail wear increases. When the friction coefficient increases,both the left and right rail wear increases. When the speed increases,the left rail wear increases and the right rail wear tends to decrease. Relative to the speed of 80 km/h,the left rail wear tends to develop towards the shoulder at 40 km/h,the middle of the rail head at 60 km/h,and the right rail wear is basically unchanged. Through analysis of the prediction of rail profile,it can be concluded that the left rail wear concentrates on the middle and shoulder of rail head. The wear on the shoulder is relatively large,and the maximum value is located at the rail transverse position 18. 506 mm,reaching 0. 820 mm. The right rail wear appears to varying degrees. The wear on the middle of the rail head is relatively large,and the maximum value is located at the rail transverse position 2. 082 mm,reaching 0. 170 mm.

We employ real-time spectral measurements to investigate the transitions from the stable mode locking to period doubling and long-period pulsations. We highlight the role of self-phase modulation as a general mechanism triggering period-2 bifurcations. We analyze the new frequencies generated during the sequence of bifurcations and report an entrainment where the period of the long oscillation locks to multiples of the cavity roundtrip time.

This article discusses a model of a robotic platform that can be used for the proximal probing of biological objects in an ecologically balanced zone. The proximal probing is for scanning deciduous and fertile parts of biological objects with a hyperspectral camera at a distance of no more than a few meters. It allows for the obtention of information about the presence of phyto-diseases of tissues and also about the degree of ripeness and other parameters of the internal quality of the fruit. In this article, we report the methods and approaches used to detect fruits in the crown of a tree and also to identify their diseases such as scab and decay with an accuracy of at least 87%. For the autonomous movement of the platform in an ecologically balanced area, visual and inertial navigation is based on a Zed 2i stereo camera. This allows for the moving of biological objects in accordance with a given route indicated on the 2D map. The analysis of the information received from this platform allows for the building of maps of the presence of phyto-deseases in an ecologically balanced zone, and decisions are promptly made regarding the implementation of technical and protective measures that ensure high-quality products.

[Introduction] The design of transmission pole and tower has a significant impact on the project cost and the surrounding environment. Exploring the design method and economic index of 220 kV single circuit composite tower is of positive significance to the optimization of transmission lines. [Method] Firstly, the recommended scheme was obtained by comparing different tower forms, composite cross-section forms and cross-section arrangement. Then the linear and non-linear analysis of tower was carried out by ANSYS software to understand the difference between the two analysis methods. Then found out the relevant information, calculated the cost of common and composite pole towers, and explored their economy. [Result] Compared with Cathead Tower, Wine Cup Tower and Top Pyramid Tower, it is more reasonable to apply composite crossbars in Top Pyramid Tower; ring section has the advantages of larger moment of inertia, higher bearing capacity and convenient processing and connection; 220 kV straight tower can reasonably choose more economical structural layout form on the premise of satisfying safety, and it is recommended to choose three-pull-one-press layout scheme through ANSYS simulation analysis shows that the linear analysis has enough accuracy and can be designed by linear analysis. When selecting composite crossbar, the related factors such as tower cost, installation cost, relocation compensation and so on should be taken into consideration, and the technical and economic comparison on the engineering quantity should be made, so as to obtain a more reasonable scheme. [Conclusion] The research results are of universal significance and can provide some technical support for the design of composite tower in the future.

This paper study mainly on the reasonable haulage roadway position of successive panel between two adjoint panels .Relying on a mine for the project background,by the theoretical analysis,three zones in the vertical direction of the solid coal side were given:Solid coal stress zone along one side of the goaf,transitional zone and elastic zone along the floor.According to the principle of roadway layout,the roadway should be arranged vertically in the elastic zone along the floor and horizontally in the low-stress region of the limit equilibrium zone.The reasonable staggered horizontal distance between adjacent roadways for this project background was found to be 2 m by theoretical analysis and FLAC3D numerical simulation.In the engineering application,combined support was applied on the haulage roadway,and the deformation of the surrounding rock in the roof,floor and sides of the haulage roadway was effectively controlled according to the actual field test.