Search

Artificial zeolite was used as an adsorbent to treat sewage with low C/N from an expressway service area. The effect of zeolite dosage on nitrogen removal from sewage was investigated. The factors affecting the adsorption effect of NH3-N by artificial zeolite were discussed by orthogonal experiments. The mechanism of NH3-N removal by artificial zeolite was discussed by means of adsorption kinetics and thermodynamics, specific surface area analysis (BET) and scanning electron microscopy (SEM). The results showed that artificial zeolite could significantly remove NH3-N and TN in sewage in a short time, and could effectively increase the C/N of sewage. After 24 h reaction, 40 g/L artificial zeolite could reduce NH3-N and TN in sewage to (13.45±0.39) mg/L and (19.23±0.21) mg/L, with the removal rates of (91.14±0.32)% and (87.12±0.10)%, respectively. Meanwhile, the C/N increased from 1.30±0.01 to 5.47±0.07. The orthogonal experiments showed that the effect of various factors on nitrogen removal of artificial zeolite was as follows: zeolite dosage>aeration volume>initial concentration of NH3-N. The adsorption process of NH3-N by artificial zeolite conformed to the quasi-secondary reaction kinetic model (R2=0.990), and the adsorption was a heat-absorbing process. The efficient removal of NH3-N by artificial zeolite was mainly due to its large specific surface area (493.23 m2/g) and its mesoporous pores with a wide distribution range. After adsorption, the particles on zeolite surface became smooth, compact and reduced in number.

AIM: To evaluate the therapeutic effect of emedastine difumarate eye drops combined with fluorometholone eye drops on allergic conjunctivitis.METHODS: Retrospective study. A total of 115 patients(230 eyes)with allergic conjunctivitis who received treatment from June 2020 to August 2022 were selected, and they were divided into the observation group(56 cases, 112 eyes)and the control group(59 cases, 118 eyes)according to whether to use fluorometholone eye drops combined with the conventional use of emedastine difumarate eye drops. The clinical symptoms and signs, tear film break-up time(BUT), corneal fluorescein staining score and complications of the two groups were observed before treatment and at 4 wk after treatment.RESULTS: After treatment, the scores of eye symptoms and signs in the two groups were decreased, and the observation group was lower than the control group(P0.05).CONCLUSION: With high therapeutic safety and effectiveness, the combination of emedastine difumarate eye drops and fluorometholone eye drops in the treatment of allergic conjunctivitis can significantly reduce the patient's symptom and sign scores, prolong BUT, promote a decrease in corneal fluorescein staining scores, improve efficacy, and do not increase the risk of complications.

Objective On December 18, 2023, an MS 6.2 earthquake occurred in Jishishan County, Gansu Province, China. Coseismic geological hazards induced by the earthquake crucially threatened the safety of personnel and property. Existing research is mainly concentrated in the vicinity of active faults and the concentrated distribution area of hidden danger points. Moreover, no special susceptibility assessment studies have been carried out on coseismic geological hazards in the administrative area of Jishishan County, making it challenging to meet the needs of the county's post-disaster recovery and reconstruction planning. Hence, the development laws of coseismic geological hazards must be summarized and analyzed crucially, and county susceptibility must be analyzed in time to support post-earthquake recovery and reconstruction. Methods The development characteristics of coseismic geological hazards are analyzed and summarized through emergency investigations, field surveys, and result analysis. Using the newly added and exacerbated coseismic hazard points identified during post-earthquake investigations as analysis samples, influencing factors were selected using the Pearson correlation coefficient and random forest Gini coefficient analysis methods. Then, a machine learning-random forest model was applied to assess the susceptibility of coseismic geological hazards in Jishishan County. Results In analyzing the development characteristics of coseismic geological hazards, we identified 134 instances of increased and exacerbated hazards in Jishishan County. Overall, the degree of development of these hazards was relatively low, with primarily small-scale occurrences. These hazards were categorized into three main types and eight sub-categories: ① Collapse (including cut slope loess collapse, high loess collapse, and high rock collapse); ② Landslide (encompassing loess landslide, secondary sand/mudstone landslide, and potential landslide); and ③ Debris flow (comprising gully debris flow and slope debris flow). In terms of factor selection, 15 influencing factors were screened. Regarding the susceptibility assessment results, the AUC value of the susceptibility assessment results of coseismic geological hazards in most Jishishan counties was 0.961, and the results showed that the areas of extremely high susceptibility accounted for approximately 8.67 %, mainly distributed in Hulinjia, Xuhujia, Liugoujia, and other townships. The statistical results of the proportion of susceptibility zones in 17 townships in Jishishan County showed that the top three townships with the largest proportions of extremely high-susceptibility areas are Hulinjia (24.67%), Xuhujia (21.24%), and Biezang (20.94%). Conclusion (1) Most coseismic geological hazards in Jishishan are distributed in the loess hilly area, with few occurrences in the Jishishan area and the right bank terrace of the Yellow River. (2) The influence of elevation and peak ground acceleration (PGA) on hazard occurrence is notably greater than that of other factors, playing a predominant role in developing coseismic geological hazards. (3) Utilizing the random forest model, the susceptibility assessment of coseismic geological hazards in Jishishan County demonstrates high accuracy, with hidden danger points clustered in highly susceptible areas. This alignment between susceptibility assessment results and the spatial distribution of hidden dangers underscores the reliability of the assessment outcomes. Significance In addition to identifying existing hidden danger points, this study offers predictive insights into slope deformation and potential landslides significantly affected by seismic cracking. The assessment results exhibit high accuracy and reliability, offering valuable geological safety support for post-disaster recovery and reconstruction planning in the county.

Sebacic acid wastewater is a typical industrial wastewater that is difficult to degrade, and the high sulfate rich in sebacic acid water is easy to be reduced to hydrogen sulfide release, leading to environmental pollution. The micro-oxygen biochemical coupling biological contact oxidation process was applied to treat sebacic acid wastewater, and the treatment characteristics of refractory industrial wastewater was investigated. The results showed that when the influent load gradually tended to be stable with COD of 4 500-5 500 mg/L and volatile phenol of 150-200 mg/L, the effluent COD was less than 400 mg/L and the volatile phenol was less than 0.5 mg/L after treating by micro-oxygen biochemical and biological contact oxidation process. The mass concentration of sulfide in effluent was lower than 0.2 mg/L, indicating that H2S was not easily produced in micro-oxygen biochemical and biological contact oxidation process. During the construction and start-up stage of the micro-oxygen section, the turbidity of the effluent decreased with the increase of DO concentration. The turbidity removal rate of the system was maintained between 70% and 90% when the overall process ran continuously and stably, indicating that the overall process played an important role in reducing the turbidity of the effluent. MLSS of 6 000-8 000 mg/L and SVI of 100-150 mL/g in the system indicated that sludge settling ability was good. The stability evaluation of the system showed that the system had strong ability to withstand load shock and salinity change, it could be widely used in the treatment of refractory industrial wastewater.

Pig farm biogas slurry is high in color and turbidity with high content of nitrogen and phosphorus. The use of microalgae-bacteria symbiosis can simultaneously and efficiently remove carbon，nitrogen and phosphorus，save energy and reduce consumption，and recover resources，meeting the needs of the new era for wastewater treatment. In this study，the three parameters of light intensity，aeration intensity and the proportion of microalgae and bacteria were optimized from the perspectives of pollutant removal and microbial growth. It was found that the amount of aeration had the greatest impact on nitrogen removal，while the three parameters had little impact on carbon and phosphorus removal. After weighted evaluation，the sequence of three factors followed aeration amount>light intensity>inoculation proportion，and the optimal parameter combination is light intensity at 550 μmol/（m2·s），aeration rate at 0.2 L/min，microalgae-bacteria inoculation ratio at 1∶1. The concentrations of TP，COD，TN and NH4+-N in the group with the best comprehensive score were 0.48，219.2，125.2，64 mg/L respectively，and the removal rates were 95.46%，88.58%，61.58% and 80.21% respectively. The particle size of microalgae-bacteria flocs in each group increased，and decreased with the increase of the microalgae-bacteria proportion.

A novel any cell to any cell equalization circuit topology with small column, low weight, low cost, and high efficiency is proposed for serial-connected batteries, especially suitable for unmanned aerial vehicles, satellites, and other fields with strict requirements on size, weight, reliability, and safety. To solve the problems of high switching losses in equalization circuits and low reliability of complex control schemes. A half-bridge circuit to convert the DC voltage of the battery into AC voltage is employed, and the energy is exchanged autonomously via the bus. At the same time, LC resonant circuit is used to achieve zero-current switching of the MOSFET, thus reduces greatly the switching losses. The working principle is analyzed by theoretical derivation, and the parameters of the circuit are optimized through circuit simulation. Furthermore, experiments which support six cells equalization are carried out to verify the feasibility and advantage of this topology. This equalization uses a bus-type architecture to improve equalization efficiency and topological flexibility making it even more valuable in the industrial and aerospace fields.

Abstract Recently, natural photosensitizers, such as berberine, curcumin, riboflavin, and emodin, have received more and more attention in photodynamic therapy. Tanshinone I (TanI) is extracted from a traditional Chinese herb Danshen, and exhibits many physiological functions including antitumor. TanI is a photoactive phytocompounds, but no work was tried to investigate its potential photodynamic effect. This study evaluated the cytotoxicity induced by the photodynamic effect of TanI. The photochemical reactions of TanI were firstly investigated by laser flash photolysis. Then breast cancer cell line MDA-MB-231 was chosen as a model and the photodynamic effect of TanI on cancer cell was evaluated by MTT assay and flow cytometry. The results showed that TanI could be photoexcited by its UV–Vis absorption light to produce 3TanI* which was quickly quenched by O2. MTT assay showed that the photodynamic effect of TanI resulted in more obvious inhibitive effect on cell survival and cell migration. Besides, the photodynamic effect of TanI could induce cell apoptosis and necrosis, lead to cell cycle arrest in G2, increase intracellular ROS, and decrease the cellular Δψm. It can be concluded that the photodynamic effect of TanI can obviously enhance the cytotoxicity of TanI on MDA-MB-231 cells in vitro, which indicated that TanI might serve as a natural photosensitizer.

The purpose of this study was to identify whether liquid fruit waxes could be added with bleached shellac. The compounds of bleached shellac from different sources were analyzed by targeted metabolomics based on liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) combined with liquid chromatography with evaporative light scattering detection. Twelve target compounds were selected by multivariate statistical analysis including unsupervised principal component analysis (PCA) and supervised partial least squares discriminant analysis (PLS-DA). According to variable importance in the projection (VIP) value, five differential compounds and seven shared compounds were identified. Finally, the viability of this method in the detection of commercial liquid fruit wax products was verified using the shared compounds as biomarkers. These results showed that chromatography combined with mass spectrometry can identify whether bleached shellac could be added in liquid fruit wax.

Abstract Background The traditional Chinese dentistry classroom teaching model focuses on the instruction of knowledge details, but less on the frameworks and learners’ motivation. Here, we introduced a combination of mind mapping and PBL instruction (MBL)into the prosthodontics course for Chinese dental students. This study aimed to evaluate the effectiveness and efficiency of MBL in prosthodontics and make observations from the students’ perspectives, based on their response with the learning process. Methods We prospectively enrolled 56 fourth-year undergraduates of stomatology, and these participants were randomly allocated into either the combined mind map teaching group (MBL) or the problem-based learning group (PBL) to attend the prosthodontics course. An anonymous questionnaire was also administered to both groups to evaluate the students’ perceptions and experiences, using closed and open-ended items. Data were analyzed using descriptive statistics and thematic analysis. Results The students’ responses to closed items indicate their experience in PBL and MBL to be positive, including increased motivation, improved memory of knowledge, enhanced discipline connection and raised teamwork, with fairly higher ratings for the MBL group. However, the tutor-guided competence scores including the memory and framework part, were significantly higher for MBL group than PBL group (two-way ANOVA, p

Along with the limited conventional energy sources and the increasingly prominent environmental problems, new energy sources characterized by “environmental protection” and “renewable” are gradually gaining the attention of many countries in the world. In order to accelerate the development of new energy, countries have introduced control strategies for the new energy industry, but the effect is that the seeds are widely planted and thinly sown. This paper constructs a control strategy for new energy trend based on Eviews econometric model through sliding average model calculation, multiple linear regression prediction, statistics of total new energy, new energy usage and new energy market share calculation. The strategy was also experimented, and the experiments analyzed and predicted the development of new energy in the world and China under the new energy trend. The results show that under the Eviews econometric model, the share of world new energy consumption in the total energy consumption market increases from 25% to 80%, while in China the new energy represented by natural gas grows from 698 million cubic meters to 9,671 million cubic meters, a full 70.76%, and with the development of the economy new energy consumption will rise from 5 billion to 11 billion.

In order to meet the design requirements of the end-actuator of the drill pipe loading and unloading robot in coal mines, a hydraulic permanent magnet drill pipe grabbing device was developed. The structural characteristics and the process flow of the drill pipe loading and unloading robot are analyzed, and the method of mechanical clamping and positioning after magnetic suction is proposed to solve the grasping problem of the drill pipe which were tightly stacked in the drill pipe bin and the end compliance problem of the robot; the transmission clearance of the device is eliminated and the precise positioning of the drill pipe is realized. The rationality of the selection of key technical parameters of the device is verified by theoretical calculation. The test results show that the gripping force of the grasping device meets the design and use requirements; the robot in different technological processes can work within the rated load range. However, the use of magnetic force to realize the pick and place of the drill pipe requires special attention to ensure that the surface of the drill pipe is clean.

In order to solve the problems of dust pollution, poor lubrication of screw motor and overtemperature in the hole during air directional drilling in broken soft coal seams, an intelligent multifunctional dust removal system was developed for the first time, with a rated processing capacity of 32 m3/min orifice dust collector system to solve the problem of dust pollution during construction; the oil mist automatic lubrication system of air screw motor is developed, which realizes long-distance transmission of lubricating medium and continuous lubrication of screw motor, and ensures the service life of motor; an automatic emergency cooling system has been set up, which can automatically judge the abnormal temperature in the hole and take cooling measures independently to eliminate the risk of combustion of coal seam during drilling by real-time monitoring and calculation of the inlet air temperature and the return air temperature in the hole. Meanwhile, an air pressure and temperature monitoring and warning system is built to monitor the pressure air flow timely. The successful development of the multifunctional auxiliary system has solved the key problems of air directional drilling and laid a foundation for the promotion and application of the air directional drilling technology in broken soft coal seams and the “one hole and two elimination” gas control mode.

When the air directional drilling technology is used for drilling construction, whether the screw motor can be well lubricated is a key factor affecting its life. This paper introduces two kinds of key equipment supporting the hole-outside lubrication technology, and details their working principles. Combined with the use of the equipment, the shortcomings of the hole-outside lubrication technology are analyzed. The bottom-hole lubrication technology of the screw motor is proposed pertinently, and the advantages of the technology are analyzed. A special bottom-hole lubricating drill rod for air screw motor is developed, which can be installed at the front end of the screw motor. The lubrication distance is no longer affected by the drilling depth, which improves the lubrication effect and reduces the waste of lubricating oil.

Aiming at the low accuracy with unbalanced data sets in existing bearing fault diagnosis methods, we proposed a bearing fault diagnosis method based on importance weighted auto-encoder（IWAE） in unbalanced data sets. It was trained by minority samples, and the generated samples were added into original data sets to obtain balanced data sets. Then, deep learning method was used as diagnose network, and the balanced data sets were fed into it as input, so as to adaptively learn fault characteristics and realize fault classification. A large number of qualitative experiments showed that when the imbalance rate was 1∶7, the method could correctly classify the balanced samples, and the accuracy rate was 98.90%. Based on various imbalance ratios, the proposed method had better convergence and generalization than other existing models.

The operation environment along the long-distance oil and gas pipelines is complex, and the abnormal external load during pipeline operation may lead to local stress concentration, which will increase the operation risk of pipeline.The coercivity-based stress measurement method is a new technology to evaluate the safety margin and prevent the safety accidents of pipeline. Herein, the magnetic properties of ferromagnetic materials, such as atomic magnetic moment, domain structure and hysteresis loop, were explored in depth. The mechanism of mechanical and magnetic coupling in coercivitybased stress measurement was clarified. The existing expressions of relationship between coercivity and stress in uniaxial stress state were introduced. The model of relationship between coercivity and stress in biaxial stress state was deduced.Besides, experiments were performed to verify the relationship between coercivity and stress of X80 pipeline steel in the uniaxial and biaxial stress states. The experimental results show that there is a good linear relationship between the coercivity and stress of X80 pipeline steel in uniaxial stress state, the coercivity is related to the biaxial stress in the biaxial stress state, and the laws are consistent with the models derived herein. The research result provides a theoretical and experimental basis for the field application of coercivity-based stress measurement method, which is proved to be capable of accurately measuring the stress of X80 pipeline steel, and it is a reliable method to evaluate the safety margin of in-service pipeline.

This study synthesized NaA zeolite by alkali melting-hydrothermal method based on fly ash as raw material. The effects of hydrothermal temperature, hydrothermal time, alkali concentration and alkali/FA mass ratio on the preparation of zeolites were investigated by single factor experiments, and the performance of the prepared zeolites was evaluated by water adsorption capacity and Cation Exchange Capacity (CEC) value.Results show that it is beneficial to the synthesis of NaA zeolite under hydrothermal temperature of 100 ℃, hydrothermal time of 5 h, NaOH concentration of 2.73 mol/L, and alkali/FA mass ratio of 2.8, in which the highest CEC value can reach 374.63 mg/g. The adsorption of Pb(Ⅱ) in liquid phase was studied by using the synthetic NaA zeolite. The adsorption capacity was up to 471.51 mg/g with 1 g/L dosage of zeolite, at pH 6.2 and 25 ℃ of adsorption temperature and the adsorption time was 60 min.The adsorption data of Pb(Ⅱ) by NaA zeolite was fitted better with Langmuir model, and the saturated adsorption capacity of Pb(Ⅱ) could reach to 580.18 mg/g.

To study the combustion phenomenon of square hollow fire sources in ship cabins, PyroSim software was used to establish numerical models of different inner and outer edge lengths of the same fire source area. FDS software was used to numerically simulate fire temperature and smoke spread, observe and record the flame and smoke spread characteristics in cabins under different working conditions, and analyze the temperature distribution of flame plumes and the temperature field characteristics inside the cabin. The results indicate that: During the combustion process of a square hollow fire source in a ship’s cabin, a typical flame convergence phenomenon occurs, and the flame temperature of the fire source combustion first increases significantly and then gradually stabilizes. The smaller the inner edge length of a square hollow, the higher the combustion temperature of the fire source, the faster the heating rate, the more obvious the phenomenon of fire convergence, and the more intense the flame combustion. As the inner edge length increases, the influence of flame combustion at the center of the square decreases, and the peak temperature of the flame decreases with a smaller amplitude and tends to concentrate.

Objective To summarize the clinical application of micro-double-port endoscopic thoracic sympathectomy in treatment of primary palmar hyperhidrosis. Methods Clinical data of 25 patients with primary palmar hyperhidrosis undergoing sympathectomy in our department from April 2021 to March 2022 were collected and retrospectively analyzed. They were 9 males and 16 females, at an age of 23.0±5.1 (15, 35) years. During the operation, two 0.5-cm incisions were made at the anterior axillary line and the mid-axillary line of the 3rd or 4th intercostal space, then two 5-mm trocars were placed, and a 5-mm needle-type thoracoscope was used to establish an artificial pneumothorax. R3 and R4 thoracic sympathetic chains were transected. Results All 25 patients successfully received the operation and were discharged upon recovery. One patient developed a small amount of pneumothorax on the right side after operation, and re-examination with chest X-ray filming showed that the pneumothorax was absorbed in 12 d after operation. The symptoms of hyperhidrosis on the hands all disappeared, and hand temperature was increased as expected. The operation time was 23.2±4.7 min, the intraoperative blood loss was 4.2±2.3 mL, the postoperative hospital stay was 0.6±0.4 d, and the postoperative pain score was 1.0±0.6. The treatment effective rate was 100%, and the satisfaction of outcome was 100%. Fifteen patients had mild compensatory hyperhidrosis postoperatively. Conclusion In treatment of primary palmar hyperhidrosis, micro-double-port endoscopic thoracic sympathectomy is characterized by small incision, safe and easy operation, short operation time and postoperative hospital stay, and no obvious pain and more satisfying outcomes.

Carpesium (Family – Compositae) is a genus with 24 species of mainly perennial herbs. Several species of this genus have served as folk medicine in China and Korea for their antipyretic, anti-inflammatory, analgesic, antifungal, antibacterial, and cytotoxic activity properties. Chemical constituents are mostly sesquiterpenes, diterpenes, glycosides, and several other types of compounds. This article summarizes the literature on the isolated and identified constituents from various Carpesium species and their various biological activities.

Objective To compare and explore the histopathological and ultrastructural characteristics of the olfactory bulb in 6- and 12-month-old APP/PS1 double-transgenic mice and their spatial learning and memory ability, as well as the effects of memantine intervention.Methods Three-month-old SPF male APP/PS1 mice were randomly divided into 6- and 12-month-old model groups (named 6-APP/PS1 group and 12-APP/PS1 group, respectively) and memantine (MEM) groups (named 6-MEM group and 12-MEM group, respectively, the dose of MEM was 2.60 mg/kg/d), with 10 mice in each group. Age-matched C57BL/6 mice were used as the blank controls. The mice in the MEM groups were continuously administered MEM (from 3 months and 9 months, respectively) by gavage for 3 months, and the mice in the non-MEM group received equal volume of pure water for 3 months. The Morris water maze test was used to assess spatial learning and memory ability of those mice at 6 months and 12 months of age. After hematoxylin-eosin staining, the pathological morphology of the olfactory bulb was observed under an optical microscope, and the ultrastructure of the olfactory bulb was observed under a transmission electron microscope.Results The results of the water maze test revealed that the crossing numbers and the time spent in the target quadrant were significantly decreased in the 6-APP/PS1 and 12-APP/PS1 groups compared with the blank control group of the same age (all P < 0.05), whereas the 12-APP/PS1 group showed a more significant decrease than the 6-APP/PS1 group (both P < 0.05). Compared with the non-MEM group, the two parameters of the MEM treatment groups increased significantly (all P < 0.05). Histopathological observation showed that, compared with the age-matched blank group, the nerve cells in the olfactory bulb had no obvious atrophy and deformation, and the number of mitral cells was significantly reduced in the 6-APP/PS1 group (P < 0.05), while the nerve cells in the olfactory bulb were atrophic and deformed, and the number of periglomerular cells and mitral cells were significantly reduced in the 12-APP/PS1 group (all P < 0.05). Compared with the non-MEM group, the number of mitral cells were significantly increased in the 6-APP/PS1 group (P < 0.05), but there was no significant difference in the number of periglomerular cells and mitral cells in the 12-MEM group (all P > 0.05). Ultrastructural observation showed that, compared with the blank control group, the synaptic structure was swollen in the 6-APP/PS1 and 12-APP/PS1 groups, the thickness of the postsynaptic density was reduced and the number of asymmetric synapses decreased in the 6-APP/PS1 group, while the thickness of the postsynaptic density and the number of asymmetric synapses could not be observed clearly in the 12-APP/PS1 group. Compared with the non-MEM group, the synaptic swelling in the 6-MEM group was significantly improved, the thickness of the postsynaptic density and the number of asymmetric synapses increased, but the synaptic swelling in the 12-MEM group was not significantly improved, and the thickness of the postsynaptic density and the number of asymmetric synapses could not be observed.Conclusion Changes in the pathology and synaptic ultrastructural morphology of the olfactory bulbs in the APP/PS1 mice correlated with age, accompanied by behavioral alterations. MEM intervention not only improved spatial memory ability in the APP/PS1 mice, but also increased the number of mitral cells and alleviated the damage to the synaptic structure in the 6-APP/PS1 group, with significant improvement in early intervention.

Exceeding the limit of underground hydrogen sulfide not only harms operators, but also damages underground equipment.The concentration of hydrogen sulfide in water in a coal mine roadway in Shanxi is 228.19 mg/m3, and 45.64 mg/m3in the air, rendering it a high hydrogen sulfide coal mine.The method of coal seam drilling and alkali injection is used to control hydrogen sulfide.In order to determine the optimal parameters of alkali injection, this paper uses COMSOL Multiphysics software to carry out single-hole and double-hole alkali injection numerical simulations on the process and effect of coal seam alkali injection to treat hydrogen sulfide.The simulation results of single-hole and double-hole alkali injection show that: the farther away from the drilling center, the lower the alkali injection pressure on the coal seam.The longer the alkali injection time, the larger the diffusion range of the alkali solution.And the diffusion speed of the alkali solution gradually decreases as the diffusion range becomes larger.When the distance of double-hole alkali injection is too close, the cross-flow will cause the diffusion range of the alkali solution to become smaller at the same time.The optimal simulation scheme is as follows: the hole distance is 10 m, the pressure is 8 MPa, and the alkali injection time is 48 h.After alkali injection at the 13103 working face, a 28 d on-site data monitoring was carried out.The maximum hydrogen sulfide concentration in the return air flow was 9.13 mg/m3, which did not exceed the limit during the mining, indicating that the optimal alkali injection parameters can guide the coal seam alkali injection work.

Based on the positive quadratic function method, the rich nonautonomous solutions of a generalized (2+1)-dimensional variable-coefficient breaking soliton equation with different wave structures are given. In this case, due to the influence of nonlinearity and dispersion, the characteristics, amplitude and velocity of nonautonomous wave will change with time. The breather wave and the interaction among lump wave, solitary wave and periodic wave solutions are studied. For different choices of arbitrary functions in these solutions, the corresponding dynamic properties are demonstrated.

Kadomtsev–Petviashvili equation is used for describing the long water wave and small amplitude surface wave with weak nonlinearity, weak dispersion, and weak perturbation in fluid mechanics. Based on the modified symbolic computation approach, the multiple rogue wave solutions of a generalized (3+1)-dimensional variable-coefficient Kadomtsev–Petviashvili equation are investigated. When the variable coefficient selects different functions, the dynamic properties of the derived solutions are displayed and analyzed by different three-dimensional graphics and contour graphics.

Vertical silos have become the first choice for large silos to store grain due to their large capacity and small footprint. However, the problem of grain accumulation and small volume in star silos has not been well resolved. Based on the midas Gen2019 software, this paper expands the capacity of the silos for a comprehensive terminal project in a port area, and connects the silos with short walls to form a new silo layout. Through the overall finite element simulation analysis of 7 kinds of grain load conditions, the internal force distribution law of the short wall and the adjacent warehouse wall is studied. and the design control conditions are found, which provides a reference for the silo design of similar type of layout.

For any positive integer n and a set of positive integers mi{m}_{i}, i=1,2,…,n+1i=1,2,\ldots ,n+1, we construct a class of quadratic eigenparameter-dependent boundary Sturm-Liouville problems with n transmission conditions, which have at most ∑i=1n+1mi+n+5{\sum }_{i=1}^{n+1}{m}_{i}+n+5 eigenvalues. The key to this analysis is still the division of intervals and an iterative construction of the characteristic function. Further, some examples are given for a simple explanation.

In this article, we investigate the time-periodic pulse electroosmotic flow (EOF) of Jeffreys fluids through a microannulus. By using the Laplace transform method, the velocity expression of the pulse EOF is derived. The effect of some variables on the time it takes for the fluid to go from a static state to a flowing state is analyzed. We find that increasing the relaxation time λ¯1{\bar{\lambda }}_{\text{1}} and decreasing the inner and outer radius ratio α\alpha will result in longer time for the fluid to reach the flowing state, but the retardation time λ¯2{\bar{\lambda }}_{\text{2}} and the inner and outer zeta potential ratio β\beta have little effect on it. The impact of some related parameters on the pulse EOF velocity for different inner and outer radius ratios (α\alpha ) is discussed in detail. The results show that for a smaller inner and outer radius ratio α\alpha , the velocity amplitude increases with the relaxation time λ¯1{\bar{\lambda }}_{\text{1}} and decreases with the retardation time λ¯2{\bar{\lambda }}_{\text{2}}. As the inner and outer radius ratio α\alpha increases, the effect of relaxation time λ¯1{\bar{\lambda }}_{\text{1}} on velocity amplitude gradually weakens or even becomes insignificant, and the effect of the retardation time λ¯2{\bar{\lambda }}_{\text{2}} on the velocity amplitude remains unchanged. Moreover, the velocity amplitude will decrease with the increase in the inner and outer radius ratio α\alpha and its change range will expand from the electric double layer near the annular wall to the entire flow region.

【Objective】 Nutrient uptake and its use efficiency by crops are modulated by many biotic and abiotic factors, and the objective of this paper is to investigate their change in response to planting density and irrigations amount in attempts to provide a guidance to help improve water use efficiency and reduce fertilizer usage without compromising crop yield. 【Method】 The experiment was conducted in a field in an arid warm valley in Yunnan province, with onion used as the model plant. We compared three irrigation amounts: 7 000 m3/hm2(I1), 4 550 m3/hm2 (I2) and 3 300 m3/hm2 (I3), and two planting densities: 21 200 plants/hm2 (D1) and 118 800 plants/hm2(D2). In each treatment, we measured the biomass and bolting percentage of the onion, its nutrient absorption and utilization, harvest traits, as well as water use efficiency (WUE). 【Result】 Irrigation amount had a significant effect on WUE, nutrient absorption and utilization efficiency. Compared with other irrigation treatments, I1 increased the uptake of P, K and Mg by the crop, but the use efficiencies of these minerals in I3 were the highest. Planting density also significantly affected biomass, bolting percentage, nutrient absorption and utilization efficiency of the crop. Compared with D2, D1 increased the uptake efficiency of N, P and Mg by the crop, whilst their utilization efficiency was higher in the D2. It was found D2 significantly increased the biomass but reduced the bolting percentage of the crop. We found irrigation amount and planting density interactively affected biomass, bolting percentage, WUE, nutrient absorption and utilization efficiency, harvest traits, absorption efficiency of N, P, K, Ca and Mg, with most of these entities peaking in I1+D1. The principal component analysis gave the highest score to I3+D2 followed by I1+D1. 【Conclusion】 Comparison of various combinations of irrigation amounts and planting densities revealed that I3+D2 was optimal for growing onion in the arid warming valley studied in this work.

Aiming at the problems of faults, precipitation, weak layers and other factors inducing the deformation and instability of the end slope of the open-pit mine, taking the north slope of Dongming Open-pit Mine as the engineering practice background, the method of combining numerical simulation theory and limit equilibrium analysis is used. The influence of the weak layer of the north side slope on the deformation and displacement law of the slope rock and soil, and at the same time, combined with the limit equilibrium analysis method to control the stability of the north side slope, two schemes are proposed, namely, slope cutting and load reduction + pressure reduction. Through analysis and research, and based on the calculation results of Geo-slope and engineering geological conditions, the plan of slope cutting and load reduction + presser foot is finally adopted, which provides a reference for safe and efficient production during actual mining.

Machine reading comprehension (MRC) is a research field driven by datasets. The task of MRC is to make the machine correctly answer relevant questions on the basis of understanding the natural language text. But limited by datasets, most of the machine reading comprehension tasks are single-turn question answering, and there is no dependency between question answering pairs. Conversational question answering (ConvQA) is the human-computer process that enables the machine to carry out continuous topics when it helps human to obtain information. In recent years, with the development of MRC datasets and deep neural networks, researchers combine machine reading com-prehension and conversational question answering to form a new more complex field, conversational machine com-prehension (CMC). This has greatly boosted the field of MRC. This paper summarizes the latest research progress of CMC in recent years from three aspects. Firstly, it describes the definition of CMC task, the challenges and the characteristics of the datasets. Then, it summarizes the research progress and the current architecture of the latest models, and focuses on the relevant technical methods used in conversational history embedding and conversational reasoning. Finally, this paper analyzes the current model of CMC, and prospects the future research hotspots and methods of CMC.

Objective To evaluate the diagnostic efficacy of mDIXON Quant for vertebral metastasis. Methods We retrospectively analyzed MRI images of 152 patients with clinically diagnosed malignant tumors and vertebral metastases. Scanning sequence included T1WI, STIR, mDIXON Quant and enhanced T1WI. We compared the diagnostic efficiency between T1WI and FF images for vertebral metastases. FF values between normal vertebral body and vertebral metastases were quantitatively compared, and the diagnostic efficacy of FF value was evaluated by ROC curve. Results The sensitivity, false positive rate, false negative rate, negative predictive value and accuracy of FF images in the diagnosis of vertebral metastases were all higher than those of T1WI images. The FF value of vertebral metastasis was significantly lower than that of normal vertebral body (Z=-21.792, P < 0.05), and the area under ROC curve was 0.987 and the cutoff value was 9.87%. The diagnostic sensitivity and specificity of vertebral metastasis were 99.6% and 92.0%. Conclusion mDIXON Quant can quantitatively determine the fat content of vertebral metastasis and has a high diagnostic efficiency for vertebral metastases.

Appropriate biomimetic scaffolds created via 3D bioprinting are promising methods for treating damaged menisci. However, given the unique anatomical structure and complex stress environment of the meniscus, many studies have adopted various techniques to take full advantage of different materials, such as the printing combined with infusion, or electrospining, to chase the biomimetic meniscus, which makes the process complicated to some extent. Some researchers have tried to tackle the challenges only by 3D biopringting, while its alternative materials and models have been constrained. In this study, based on a multilayer biomimetic strategy, we optimized the preparation of meniscus-derived bioink, gelatin methacrylate (GelMA)/meniscal extracellular matrix (MECM), to take printability and cytocompatibility into account together. Subsequently, a customized 3D bioprinting system featuring a dual nozzle + multitemperature printing was used to integrate the advantages of polycaprolactone (PCL) and meniscal fibrocartilage chondrocytes (MFCs)-laden GelMA/MECM bioink to complete the biomimetic meniscal scaffold, which had the best biomimetic features in terms of morphology and components. Furthermore, cell viability, mechanics, biodegradation and tissue formation in vivo were performed to ensure that the scaffold had sufficient feasibility and functionality, thereby providing a reliable basis for its application in tissue engineering.

Inflammation-mediated lung injury in severe cases of infection with SARS-CoV-2, the aetiological agent of Coronavirus disease 2019 (COVID-19), can lead to respiratory failure and death, and therapies that block or ameliorate lung injury-associated inflammatory “cytokine storms” and progression to acute respiratory distress syndrome (ARDS) are urgently needed. Therapeutic use of corticosteroids for this purpose has been controversial because of conflicting reports on their efficacy and immunosuppressive behaviour. The WHO has strongly recommended treating critical COVID-19 patients with systemic corticosteroid therapy, but recommends against corticosteroid therapy in non-severe COVID-19 disease because of a lack of strong evidence on its efficacy. This retrospective case report describing the successful treatment of a non-severe COVID-19 case in Changchun, China, by judicious administration of corticosteroids using a personalized therapeutic approach was recorded to strengthen the evidence base showing how corticosteroid use in non-severe COVID-19 cases can be safe and efficacious. Alongside supportive care and lopinavir/ritonavir antiviral drugs, a low dosage of methylprednisolone was administered over a short period to attenuate lung inflammation. Regular chest CT scans guided dosage reduction in response to lesion absorption and improved lung condition. Judicious use of corticosteroids safely attenuated disease progression and facilitated rapid and complete recovery.