bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Antioxidant Enzyme Activity of Pioneer Plants in Karst Areas of the Northwest Guangxi
Authors: Qin Yongrong , Wang Weiping , Li Qiqian , Huang Jiangbin , Huang Zhenqiu , Liang Wenzhong , Liu Xuhui
Published: August 2020

The selection of pioneer species is one of the key technologies for ecological restoration in Karst Rocky desertification areas. The purpose of this study is to explore the relationship between antioxidant enzyme activities of different pioneer plants in Karst Rocky desertification areas and their living conditions, environmental adaptability and other ecological factors, so as to screen out excellent species with good ecological and economic benefits and provide a theoretical basis for ecological restoration in Karst Rocky desertification areas. In this study, the pioneer plant samples were collected from the karst area of the Northwest Guangxi and their SOD, POD, CAT, GSH, APX and other antioxidant enzymes activities were determined and compared. Our results showed that the antioxidant enzyme activities of different plants were significantly various due to the influence of themselves and various external factors. The plant species with high antioxidant enzyme activities often had better soil ecological restoration effect. The activity of antioxidant enzymes in pioneer plants was closely related to soil organic matter, soil enzyme activity and other physical and chemical indexes. Antioxidant enzyme activity of plants in Karst regions may be a critical indicator for species selection for ecological restoration of Karst Rocky desertification.
Application of excess sludge extract from sewage treatment plant in garden flower planting
Authors: Cui Lifang , Yang Cheng , Yang Aiai , Sun Yan , Meng Fanfei , Yuan Ju , Yuan Huaguan , Ye Shasha
Published: August 2020

In order to explore the application effect of excess sludge extract from sewage treatment plant in garden flower planting, the extracts prepared from excess sludge and its fertilizer efficiency were evaluated and its effects on plant height, stem diameter, flower yield and diameter and plant weight of Impatiens balsamina were studied by pot experiments, which provided reference for the resource utilization of excess sludge. The results showed that the initial solution content of amino acid in excess sludge extract was 3.6%, and the total amount of microelement was 66.46 ppm. It was fully soluble, slightly alkaline, and the harmful elements As, Cd, and Pb did not exceed the content of the standard. Although the total amount of amino acids and microelement was lower than the standards of amino acid-containing foliar fertilizers in China, it can meet the requirement of foliar fertilizer dilution in the market and can be used as amino acid foliar fertilizer after dilution. The appropriate concentration of excess sludge extract can promote the growth of Impatiens balsamina significantly, and the application effect was close to or better than some foliar fertilizer products in the market. The best concentration was 600 times diluted excess sludge extract. If the excess sludge extract is further prepared into amino acid foliar fertilizer, the effect will be better, it can be applied in garden flower planting, and can provide a new way for the resource utilization of excess sludge in sewage treatment plant.
Evaluation of ecological restoration effect of rare plant Rhododendron chrysanthum population in Changbai Mountain Area
Authors: Zhao Ying , Yin Hang , Qin Liwu , Chen Qinghong , Huang Liya , Jia Xiang , Liu Lijie , Dai Yuhong , Zu Weizhong , Jin Hui
Published: August 2020

In order to study the population viability and restoration effect of Rhododendron chrysanthum population after restoration, an ecological evaluation method based on analytic hierarchy process and fuzzy comprehensive evaluation was proposed. The ecological evaluation index system was established with the help of analytic hierarchy process (AHP) and the index weight was determined. The fuzzy comprehensive evaluation method was used to evaluate the restoration effect of Rhododendron chrysanthum population from three aspects: target layer, criterion layer and index layer. The results showed that this method could effectively evaluate the ecological effect of Rhododendron chrysanthum population after restoration, in which 33% of the restoration effect of Rhododendron chrysanthum population might be “very good” and 67% might be “good”. According to the principle of maximum membership degree, the comprehensive evaluation of the restoration effect of Rhododendron chrysanthum population in the experimental area was excellent.
Study on the Effect of Constructed Wetland in Treating Rural Domestic Sewage
Authors: Zhong Wei , Zhang Yue
Published: August 2020

With the progress of modern science and technology, people’s living standard is getting higher and higher. The free discharge of production and domestic sewage has caused more and more serious water pollution. The focus of sewage treatment is generally in the city, the rural sewage treatment is often neglected. According to the results of the first national pollution census, the discharge of pollutants in rural areas has a serious impact on the water environment, with COD, nitrogen and phosphorus accounting for 43.7%, 57.2% and 67.4% of the total. China produces about 80 billion tons of rural sewage every year. In rural sewage, 90% of domestic sewage is directly discharged without effective treatment, causing serious water pollution, and sewage treatment is urgent. In this paper, the situation of sewage treatment in rural A of Fujian Province is analyzed, and a constructed wetland is designed according to the actual situation. The constructed wetland has the advantages of simple sewage treatment and maintenance, low operating cost and relatively small consumption. It can also save land resources, can be widely transported to sewage treatment, and can better protect the water environment and aquatic ecosystem.
General situation and utilization potential of wild plant resources in Changbai Mountain Reserve
Authors: Yin Hang , Jin Hui , Jia Xiang , Liya Huang , Chen Qinghong , Liu Lijie , Zhang Dewen , Dai Yuhong , Xiao Ying , Zhao Ying
Published: August 2020

According to the field investigation of Changbai Mountain Nature Reserve, the wild plant resources in this region were investigated in detail. Combined with the investigation of wild plant resource types, the utilization potential of wild plant resources was analyzed and evaluated in order to provide reference for the development and utilization of wild plant resources in Changbai Mountain. The results showed that the vascular plants in Changbai Mountain Nature Reserve consist of 6 classes, 47 orders, 124families, 515 genera and 1550 species. There were about 1244 species of plants that could be used as resources, among which, medicinal plant resources ranked first, a total of 1083 species, accounting for 87.06%. From the perspective of market value of resources, 1244 species of wild vascular plants in the reserve were graded, and 276 species of resource plants with high value and great significance, which were rated as 4 and 5 points, were screened out. According to the evaluation level of resource utilization potential, There were 48 species of first level, 87 species of second level, 103 species of third level, 32 species of fourth level and 6 species of fifth level. Finally, some suggestions on the protection, development and utilization of wild resources in Changbai Mountain Nature Reserve were provided.
Construction of soil environment information management platform based on ArcGIS
Authors: Lv Zhulin
Published: August 2020

With the development of industry and agriculture, the problem of soil environmental pollution is gradually exposed. Strengthening soil environmental management is an effective way to prevent and control pollution. Through consulting data and on-the-spot investigation, to identify and analyze the types of soil pollution in a certain area. To grasp the situation of soil pollution in this area preliminarily, and identify the degree of soil pollution and characteristic pollutants of soil risk sources through investigation of key pollution enterprises. At the same time, the technological process of chemical plant and coking plant as well as the discharge of the Three Wastes are analyzed. To find out the main pollution factors of the region and make an accurate evaluation of the pollution situation, use ArcGIS to analyze, basic framework of the construction of soil environment information management platform, provide the framework foundation for the construction of the platform, put forward reasonable suggestions for the regional soil restoration work, and provide scientific guidance for the prevention and control of soil pollution and the use of agricultural land in the region.
Pilot-scale Study on Removal of Pollutants in Tannery Wastewater and Sludge Reduction by Biological Synergist Effect
Authors: Zou Xiaofeng , Ma Fang , Yu Jun , Su Qiang , Gai Lihong , Zhao Wei , Ma Kun , Wang Jianguo , Tan Xin , Sun Fengmei , Xiao Shuxin
Published: August 2020

The characteristics of tannery wastewater are complex composition, high suspended substance (SS) and heavy sludge load. Adding the functional bacteria agent into the Aerobic system and Sludge digestion tank can improve the biological system activity and reduce sludge discharge. The pilot-scale study results show that: The removal of CODcr and NH3-N was improved after biological synergy. The average removal rate of CODcr was 90.1% and the average removal rate of NH3-N was 97.4%, both of which were higher than the control group. The excess sludge reduction of the system could reach 75.16%, and the effect of sludge reduction was obvious in the experimental group. After biological synergy, the number of bacteria in aerobic pool increased significantly, and the microbial flora migrated in a better direction.
Analysis on the Influence of the Climate Changes on the Global Vegetation
Authors: Chen Guangyu
Published: August 2020

An overview of the impact of climate change on vegetation is presented in this paper. With the rapid development of industries and technologies around the world, the concentration of carbon dioxide and other contaminants in the atmosphere has increased significantly. CO2 is one of the main gases responsible for global warming. Data show the global mean temperature rose by 1.15 Celsius degree in 2019 compared with the period of pre-industrial average (1800-1900). Air warmed faster than sea water based on historical data. According to the existing reseach, the Northern Hemisphere is warming faster than the Southern Hemisphere, and the warming speed of the entire Arctic is the most in the world. As a result, vegetation has to adapt to the change in temperature by its phenology. Temperature stress, water stress, phenological changes, and changes in sunshine and light intensity are the main factors that impact distribution and combination of forests.
A Study on the Effect of the Modified Bioretention Pond to Remove Nitrogen Pollution from Rainwater Runoff
Authors: Li Peiqiang , Chen Youyuan , Sun Ping , Zhao Xinyue , Li Jie
Published: August 2020

The bioretention pond plays an important role in controlling stormwater runoff pollution. However, the removal efficiency of the traditional bioretention pond is unstable. In this study, we used NaOH (2 mol′L−1) to modify Enteromorpha prolifera biochar (BC), preparing alkali-modified biochar (KBC). We tried to study the removal capacity of biochar as a kind of bioretention filter and optimization of operating conditions of the bioretention pond. The results showed that: (1) When modified biochar was used as the filler medium, the maximum removal rate of TN, NH4
+-N, NO3
--N, NO2
--N in effluent were 59.1%, 79.0%, 54.3%, and 76.7%, respectively; In short, the average removal rate of experimental columns added with primitive biochar increased by 1%-12%. (2) The hydraulic retention time and setting of the saturation region had a clear influence on removing nitrogen from rainwater runoff in the bioretention pond. When TL=2 h, Ds=10 cm, the average removal rates of NH4
+-N, NO3
--N, NO2
--N in effluent reached 80%, 60%, and 70%, respectively.
Dynamic flashback induced by sound wave in a premixed bluff-body stabilized flame
Authors: Chang Liuyong , Cao Zhang , Xu Lijun
Published: August 2020

Flashback is a critical issue for premixed flame, because it can result in increased pollutant emissions and serious mechanical damage. In this study, the sound wave is used to induce velocity fluctuation which further induces the flashback. The structure of the dynamic flashback induced by sound wave in a premixed bluff-body flame is studied using a high-speed camera. The sound pressure level is fixed at 94 dB and the sound frequency is set at 10 Hz, 30 Hz and 60 Hz, respectively. The flame images show that the transient structure of flashback can be obtained clearly by the high speed camera and the structure of flashback at different sound frequency is different. This indicates that the oscillation frequency of the instable flame affects the structure of flashback seriously.
Energy Efficiency Pre-assessment on the Reactor Cabin Air Conditioning Cold and Hot Water System of Floating Reactor
Authors: Wen Enlong , Dong Changqing , Xian Chunmei , Gui Ting , Liao Cong , Fang Zhen , Kun Huang , Hu Chuntao
Published: August 2020

The character of the Reactor cabin air conditioning cold and hot water system is analyzed, which is supported by a demonstration project of floating reactor, combined with environment conditions and requirements of standing wave sea area. On the basis of ensuring the stability and reliability of the system, the energy consumption of the system can be effectively reduced by using natural seawater and self high temperature steam absence as cold and heat sources, and the purpose of energy conservation and environmental protection can be achieved. Then, the conclusion is finally drawn: the system has good economic and environmental benefits, after the energy efficiency of the optimized system being pre-evaluated under the refrigeration conditions from Apial to November, including energy saving assessment and environment assessment.
Simulation study on the influence of cofferdam on the leakage of liquid ammonia storage tank
Authors: Zhan Xingxing , Liu Hongtao , Han Xuefeng
Published: August 2020

This paper mainly researches the influence of cofferdam on the leakage liquid and gas diffusion after the liquid ammonia storage tank leaks. In the experiment, different leak-diffusion models were constructed for comparative analysis, and the fluid mechanics model was used for numerical simulation. At the same time, the calculation domain size was determined according to the blocking rate principle, and a physical model was established for simulation analysis. The experimental results show that the reasonable setting of the cofferdam can effectively reduce the diffusion distance of ammonia gas in the downwind direction and the concentration of the ammonia gas in the downwind direction after the leakage of the liquid ammonia storage tank, and is of great significance for reducing casualties and accident losses.
Study on photocatalytic degradation of CEES by ZIF-8, NTU-9 and MOF-525
Authors: Liu Yi
Published: August 2020

We studied the photocatalytic degradation of 2-chloroethyl ethyl sulfide (CEES) by three kinds of MOFs (ZIF-8, NTU-9 and MOF-525). Among the three kinds of MOFs, NTU-9 and MOF-525 can selectively photocatalytic oxidize CEES to 2-chloroethyl ethyl sulfoxide (CEESO). And MOF-525 showed higher catalytic activity.
The Luminescence Mechanism of Glycitein
Authors: Li GuangJun , Ma Kun
Published: August 2020

Amyloid β-peptide is a well-known therapeutic target for Alzheimer’s disease. Many studies have focused on the design and synthesis of effective fluorescent probes. Glycitein has been reported inhibit amyloid-β peptide aggregation, and solution of glycitein alone can give a maximum fluorescence emission at 465nm with excitation at 350nm. Density functional theory (DFT) and time-dependent density functional theory (TDDFT) have been used to interpret the fluorescence luminescence mechanism of glycitein. Glycitein’s fluorescence luminescence mechanism was the intramolecular charge transfer. The result of this study maybe useful to find the further potent fluorescent probes for alzheimer’s early clinical diagnosis.
Improving the absorption rate of thin-film solar cells by composite structures
Authors: Xiao Liang , Zhu Qunzhi
Published: August 2020

In order to improve the absorption rate of polycrystalline silicon thin film cells, an inverted pyramid structure was constructed and the metal nanoparticles were dispersed in the inverted pyramid structure. The absorption rate of the designed composite structure was improved by utilizing the LSPR effect generated by the metal particles, and the change of the absorption rate under different conditions was studied by changing the type, volume fraction and H/P ratio of the periodic structure in the composite structure. By using FDTD software to simulate, this paper finds that the designed inverted pyramid structure has a maximum absorption rate of 20% in the 0.4∼0.55um band. In the composite structure, the dispersed Ag nanoparticles have the best absorption rate in the 0.55∼0.8um band; The volume fraction of the particles in the inverted pyramid structure is found to increase slowly with the increase of volume fraction in a certain band. By changing the ratio of the depth of the inverted pyramid structure to the length of the period, it is found that as the ratio increases, the whole absorption rate will increase to some extent.
Research on the Evaluation Index of Grid Enterprises’ Innovation Index Based on the Same Industry Benchmark
Authors: Chang Yan , Meng Weixuan
Published: August 2020

Based on the in-depth analysis and construction of the technology innovation index and evaluation system that meet the characteristics of power grid enterprises, this paper studies the key technical issues involved in the technology innovation index system of different types of units, such as indicator dimension, indicator type, indicator application, indicator management, application technology route and evaluation results. By constructing an evaluation index system for the technology innovation index of power grid companies, this paper proposes a linkage strategy between the index and technology innovation management, promptly discovers the gaps, diagnoses the cause of the problem, formulates effective countermeasures, provides effective technical support and systematic decision-making basis.
Development status of Anti-corrosion Technology for Power Transmission Tower’s Steel Structure
Authors: Li Xinmei , Zhang Zhongwen , Du Baoslmai , Li Wen , Suo Shuai
Published: August 2020

Higher requirements have been brought forward on the reliability and service life of power transmission tower’s steel structure along with the growing of power generation capacity. This paper analyzes types of corrosion of power transmission tower’s steel structure and the status of research on corrosion and summarizes categories of protective coating for steel and iron materials. Hot-dip galvanizing still remains as the main anti-corrosion method for power transmission tower’s steel structure in China, while the promotion and application of cold spray technology, cold zinc-spraying anti-corrosion technology and weathering resistant steel provide more options of anti-corrosion technologies for power transmission tower. The engineering practice proves that cold zinc-spraying anti-corrosion technology has achieved superior application effects in on-site reinforcement and repair of power transmission tower.
Research and Application on the Key Technology of Ecological Route Selection in the Mountain Area of Northern Guangdong Province
Authors: Zhaoming  , Kaicheng Hua , Zhaoming Wang
Published: August 2020

Based on the express way from Huizhou to Qingyuan section in Guangdong province, this study used the “3S” technology to collect the eco-environmental factors in the mountain area of northern Guangdong province. By quantified analysis, various eco-environmental indexes were assigned and standardized. In addition, the analytic hierarchy process was used to set up the weight of respective index factor, as well as to establish the regional ecological evaluation criteria system of the mountain area in northern Guangdong province. It consisted of two primary criteria and ten secondary criteria. As a result, this method was proved to be an available method on route planning for highways in different areas, which was worthy of promotion and utilization.
Research on battery control method based on matrix rectifier
Authors: Qiu Huidong , Wang Zhao , Cao Qianlei
Published: August 2020

In this paper, a battery control method based on matrix rectifier is developed. The matrix rectifier is used to control the current of the input battery. Compared with the ordinary rectifier, it can greatly reduce the disturbance caused by the grid side and internal parameters and ensure the performance of the battery at all charging stages. In addition to stability, this control method can also compensate reactive power factor, and has better dynamic controllability.
Research Progress of Tap Water Treatment Process
Authors: Wang Yian , Wang Chao , Wang Xinshuai , Qin Hui , Lin Hua , Chhuon Kong , Chen Qi
Published: August 2020

With the rapid decrease of available water resources, to satisfy the needs of human life, it is urgent to treat and purify the water resources of waterworks so that the purified water can satisfy people’s needs. This article mainly elaborates on the current research progress of tap water treatment technology and advanced treatment technology. Provide some basis for the application of social enterprises and scientific research workers.
Design and Application of Automatic Monitoring System based on Static Force Level in Construction of Shield-bored Underneath Metro
Authors: Zhao Wei , Wei Yongbin
Published: August 2020

When metro shield passes through existing operating lines, it is necessary to carry out automatic monitoring of existing lines. In this paper, taking the construction of Changsha Metro Line 4 under the shield of the existing Metro Line 2 as an example, the static level is set up in the construction affected area to monitor the vertical displacement of the track bed automatically. According to the actual situation of the site, a complete set of automatic monitoring system is designed, and a detailed site implementation scheme is formulated. Finally, the deformation data is analysed, and the characteristics of the whole system are summarized.
An Empirical Study on the Exploration of Factors Influencing Customer Satisfaction in Logistics Distribution Service
Authors: Lang Guoling
Published: August 2020

In order to solve the problem of lacking quantitative description method for customer satisfaction of logistics distribution service, based on the China Customer Satisfaction Index model, the three core influencing factors named perceived service quality, expected service quality and brand image were respectively set up with second-level measurement indicators, to explore its impact on customer satisfaction and loyalty, and then construct a customer satisfaction evaluation model for logistics distribution service. The second-order structural equation model is used to analyze the quantitative relationship among the influencing factors, between satisfaction and loyalty, and the effect of each influencing factor on the customer satisfaction of logistics distribution service. Finally, the model is applied to the case analysis of residents in the main urban area of Chongqing. The results show that the perceived service quality (0.63***) and perceived service cost (-0.40***) have the most significant impact on the customer satisfaction of logistics distribution service. Customer satisfaction plays a decisive role in customer loyalty (0.78***).
Experimental study on rock cross-cut coal uncovering with ultra-high pressure hydraulic slotting
Authors: Li Chengcheng
Published: August 2020

In view of the coal seam with low permeability, high gas content, high gas pressure and high outburst risk, the rock cross-cut coal uncovering is carried out, and the Xinji No.1 Coal Mine in Anhui Province is selected as the engineering background. The experimental study on the rock cross-cut coal uncovering by the ultra-high pressure hydraulic slotted crosscut is carried out, and the amount of slag discharged by the hydraulic slotting and the initial velocity of gas emission are investigated. The results show that after the ultra-high pressure hydraulic slotting measures are adopted, the equivalent radius of the uncovering area of the crosscut of coal seam group is increased by 31.9 times, the average initial velocity of gas emission is increased by 3.5 times, the amount of drilling work is reduced by 47%, and the coal is discharged by the slotting. The chip rate is more than 3 ‰ and the coal uncovering time is shortened by 50%. Based on this, the paper tests the effect of the measures in the area of rock cross-cut coal uncovering. The maximum residual gas content is 4.4m3/t, and the maximum residual gas pressure is 0.16MPa. The practice shows that the hydraulic slotting measures can greatly reduce the residual gas pressure (content) of the coal seam. Therefore, the ultra-high pressure hydraulic slotting technology can be used as an effective means for rock cross-cut coal uncovering in high gas and low permeability coal seam, and it can provide important reference and reference for similar conditions.
Research on hydraulic permeability enhancement technology of high, medium and low pressure coal seam with deep well and high ground stress
Authors: Huang Jun , Yi Enbing
Published: August 2020

Aiming at the problem of poor gas extraction, long outburst time and low pre-drainage efficiency in the drilling zone of the floor tunnel through the drilling, the problem of mining excavation replacement is severely restricted. Dingji Coal Mine has carried out ultra-high pressure, medium pressure, and low pressure hydraulic cutting coal seam enhanced permeability gas extraction technology tests. Through continuous exploration and summary, it has achieved remarkable results, maximized extraction, and accumulated rich hydraulic coal Through experience. The results show that: the high-pressure hydraulic coal seam anti-reflection pre-draining unit has a maximum extraction pure volume of 3.1m3/min, the single-hole average extraction pure volume is 0.008m3/min; the medium-pressure hydraulic coal seam anti-reflection pre-extraction unit has a maximum extraction pure volume of 2.2 m3/min, single-hole average extraction pure volume is 0.005m3/min; low-pressure hydraulic coal seam permeability enhancement unit extraction pure volume is maximum 1.3m3/min, single-hole average extraction pure volume is 0.002m3/min. 1351(1)Yunshun’s gas pre-drainage rate reached 65.2% after adopting high-pressure hydraulic coal seam penetration enhancement measures. Through statistical analysis of the anti-burst prediction index during coal tunnel footage, the sensitive index is relatively small, and the effect of pre-draining outburst is better. The lane enters 200m per month. The permeability enhancement technology of hydraulic coal seam has a significant effect on the pre-drainage of gas in high ground pressure outburst coal seam. It provides an effective method for improving the gas pre-drainage and outburst work, which is worthy of in-depth promotion and application.
Frequency Optimization of a Splash Shield Based on Topology Optimization and Reverse Engineering
Authors: Ma Changliang , Chen Yuhao , Wu Lin , Zhang Yue , Yang Li
Published: August 2020

Natural frequency optimization and structure redesign of a bicycle splash shield are completed with the combination of reverse engineering and topology optimization. Based on reverse engineering, the three-dimensional model of the splash shield is established. The maximum first natural frequency is taken as the design objective, the maximum acceleration response and minimum volume are taken as constraints, and the material density is taken as design variable. The variable density method is used to realize the optimization of the splash shield. The results show that: the first natural frequency increased by about 5 times under all constraints after optimization; the combination of optimization design and reverse engineering technology is an effective method of structural design.
A comparative study of machine learning based modeling methods for Lithium-ion battery
Authors: Wang Peng , Fan Jie , Ou Yang , Li Zhe , Wang Yi , Deng Bo , Zhang Yuanwei , Gao Zihao
Published: August 2020

A suitable battery model plays an important role in assisting accurate state estimation for power battery used in electric vehicles. This paper compares the applications of four commonly used machine learning methods (decision tree, k-nearest neighbour, support vector machine and neural network) in lithium-ion battery modeling. The adaptability on working condition, temperature and degradation of above four modeling methods are analysed in detail. Results show that neural network performs best when working condition changes. All the models basically have the same performance on adaptability to temperature. The battery dynamic characteristics change significantly in the aging process and it is necessary to include battery test data under different degradation levels into training sets as to obtain a model that can predict the voltage response accurately in various aging states.
A Simple Hydrothermal Synthesis of Flower-like Titanium Dioxide Microparticles and Their Application in Organic Waste Removal
Authors: Fan Xiaoxu , Wei Aili , Du Juan , Chen Song
Published: August 2020

In this paper, the flower-like titanium dioxide microparticles (F-Ti MPs) were synthesized by a simple treatment of titanium dioxide nanoparticles (Ti NPs) in the NaOH solution via a hydrothermal method. Size and morphology of the resultant samples were characterized with a scanning electron microscopy (SEM) and a transmission electron microscopy (TEM). The results showed that F-Ti MPs had a hierarchical and flower-like morphology with the diameter around 3-5 μm and constructed by numerous nanowires. When incubated with the solution of methylene blue (MB, model organic pollutant), F-Ti MPs showed much stronger adsorption capacity to remove MB from water than Ti NPs.
Isolation and identification of Bacillus subtilisstrain T-3from Soybean and its antagonism against severalcommonpathogenic fungi
Authors: Wang Youmin , Jiang Linhong , Liu Ji , Lu Qiyu , Zheng Qi , Guo Qiliang , Tu Caihong , Zhang Zhengzhou
Published: August 2020

An antagonistic bacteriastrain was isolated and purified from soybean using Alternaria alternataasindicator. There sultsofmorpho logical identification and 16S rDNA sequencing analysis showed the antagonistic bacteria belongs to Bacillus subtilis. The culture solution of this strain showed an inhibition rate of 73.19% against A. alternata. The strain also showed strong antagonistic action againstBotrytis cinerea, Fusarium graminearum, Lasiodiplodiatheobromae, Botrytis erythraea, Mucor circinelloidesand Aspergillus niger.
Study and Practice of stabilized injection technologies in injection well life cycle
Authors: Yan Yu , Guo Shuzhao , Cai Qingqin , Yang Taiwei , Yang Yang , Du Yuqiao
Published: August 2020

The technologies to steady pressure and injection rate and that to reduce pressure and increase injection rate are along with multiple stages of secondary and tertiary oil recovery. The ongoing injection process will subject most wells to pressure rise, reduced injection volume, fouling and plugging of reservoir, and corrosion of tubing string. In this paper, a portfolio of feasible measures can be provided for the steady injection in injection well life cycle by taking a closer look at cleaning & anti-swelling & anti-migrating technology, interlayer pressure influence balancing technology, slow releasing solid acid unpowered acidizing technology, low damage & low reaction rate acidizing technology, and degrading & acidizing technology for polymer injection wells.
Theory of the thickness dependence of the charge density wave transition in 1 T-TiTe2
Authors: Sky Zhou Jianqiang , Bianco Raffaello , Monacelli Lorenzo , Errea Ion , Mauri Francesco , Calandra Matteo
Published: August 2020

Most metallic transition metal dichalcogenides undergo charge density wave (CDW) instabilities with similar or identical ordering vectors in bulk and in single layer, albeit with different critical temperatures. Metallic 1 T-TiTe2 is a remarkable exception as it shows no evidence of charge density wave formation in bulk, but it displays a stable 2 × 2 reconstruction in single-layer form. The mechanism for this 3D-2D crossover of the transition is still unclear, although strain from the substrate and the exchange interaction have been pointed out as possible formation mechanisms. Here, by performing non-perturbative anharmonic calculations with gradient corrected and hybrid functionals, we explain the thickness behaviour of the transition in 1 T-TiTe. We demonstrate that the CDW in single-layer TiTe2 occurs from the interplay of non-perturbative anharmonicity and an exchange enhancement of the electron-phonon interaction, larger in the single layer than in the bulk. Finally, we study the electronic and structural properties of the single-layer CDW phase and provide a complete description of its electronic structure, phonon dispersion as well as infrared and Raman active phonon modes.
Effect of heat treatment on the microstructure and properties of in-situ Mg2Si reinforced hypereutectic Al-18%Si matrix composites
Authors: Xu Kai , Wang Jianjun , Zhang Shuquan
Published: August 2020

The in situ preparation of particle reinforced metal matrix composites (PRMMCs) can prevent the particle surface from pollution, improve the wettability of particles and matrix metals, and reduce the production cost of composites. In this paper, in situ Mg2Si reinforced hypereutectic Al-18%Si matrix composites were prepared by adding an appropriate amount of magnesium. However, the Mg2Si enhanced phase often has developed dendrites, which are easy to cause stress concentration and cut apart the matrix, resulting in the decrease of the mechanical properties of the material. Therefore, in this study, necessary solution treatment and aging treatment were carried out, and the effect of heat treatment on the microstructure and properties of the prepared composites was discussed. The results showed that the in situ Mg2Si reinforced Al-18%Si matrix composites with an ideal microstructure could be prepared by adding 4% Mg. After solution treatment at 545 °C for 8 h and aging treatment at 170 ± 2 °C for 8 h, the coarse dendrites of Mg2Si were broke and granulated, which improved the strength, hardness and wear resistance of the composites. Compared with the common as cast hypereutectic Al-18%Si alloy, the hardness and the strength of the prepared composites were increased by 30% and 46%, respectively. Besides, the granulation process of the in situ Mg2Si phase was explained with the Gibbs-Thomson theorem in this paper.
One-step hydrothermal preparation and characterization of ZnO–TiO2 nanocomposites for photocatalytic activity
Authors: Sun Yan , Gao Yue , Zhao Binshan , Xu Sheng , Luo Chunhui , Zhao Qiang
Published: August 2020

ZnO–TiO2 nanowire composites with different Zn/Ti molar ratios were prepared by one-step hydrothermal process. The crystal structure, surface morphology and chemical state of the samples were characterized by XRD, SEM, TEM and XPS. The effect of ZnO content on the photocatalytic performance was investigated by degradation of Rhodamine B dye under xenon lamp illumination. The XRD result indicated that Zn/Ti molar ratio significantly affected the crystallinity and phase composition of ZnO–TiO2 composites. SEM images showed that ZnO nanoparticles of smaller size were dispersed on the surface of TiO2 nanowires and aggregated in the TiO2 framework. The optimal Zn/Ti molar ratio of 5% was obtained with highest photocatalytic activity, which could be attributed to the superior charge separation ability.
Improving the generative performance of chemical autoencoders through transfer learning
Authors: Iovanac Nicolae C , Savoie Brett M
Published: August 2020

Generative models are a sub-class of machine learning models that are capable of generating new samples with a target set of properties. In chemical and materials applications, these new samples might be drug targets, novel semiconductors, or catalysts constrained to exhibit an application-specific set of properties. Given their potential to yield high-value targets from otherwise intractable design spaces, generative models are currently under intense study with respect to how predictions can be improved through changes in model architecture and data representation. Here we explore the potential of multi-task transfer learning as a complementary approach to improving the validity and property specificity of molecules generated by such models. We have compared baseline generative models trained on a single property prediction task against models trained on additional ancillary prediction tasks and observe a generic positive impact on the validity and specificity of the multi-task models. In particular, we observe that the validity of generated structures is strongly affected by whether or not the models have chemical property data, as opposed to only syntactic structural data, supplied during learning. We demonstrate this effect in both interpolative and extrapolative scenarios (i.e., where the generative targets are poorly represented in training data) for models trained to generate high energy structures and models trained to generated structures with targeted bandgaps within certain ranges. In both instances, the inclusion of additional chemical property data improves the ability of models to generate valid, unique structures with increased property specificity. This approach requires only minor alterations to existing generative models, in many cases leveraging prediction frameworks already native to these models. Additionally, the transfer learning strategy is complementary to ongoing efforts to improve model architectures and data representation and can foreseeably be stacked on top of these developments.
Associations of Occupational Styrene Exposure With Risk of Encephalopathy and Unspecified Dementia: A Long-Term Follow-up Study of Workers in the Reinforced Plastics Industry
Authors: Iversen Inge Brosbøl , Mohr Mette Skovgaard , Vestergaard Jesper Medom , Stokholm Zara Ann , Kolstad Henrik Albert
Published: August 2020

Exposure to industrial solvents has been associated with encephalopathy. Styrene is a neurotoxic industrial solvent, and we investigated the long-term risk of encephalopathy and unspecified dementia following styrene exposure. We followed 72,465 workers in the reinforced plastics industry in Denmark (1977–2011) and identified incident cases of encephalopathy (n = 228) and unspecified dementia (n = 565) in national registers. Individual styrene exposure levels were modeled from information on occupation, measurements of work place styrene levels, product, process, and years of employment. Adjusted analyses were performed using a discrete survival function. A positive trend for encephalopathy (P < 0.01) and a negative trend for unspecified dementia (P = 0.03) were seen with cumulative styrene exposure accrued during the recent period of up to 15 years. For unspecified dementia and the combination of unspecified dementia and encephalopathy, a positive trend was indicated when applying a 30-year exposure lag (P = 0.13 and P = 0.07). The risk patterns seen following recent exposure probably reflect diagnostic criteria for encephalopathy requiring recent industrial solvent exposure and referral bias rather than association with styrene exposure, while the increasing risk observed for unspecified dementia and the combination of encephalopathy and unspecified dementia following distant exposure indicates an increased risk of dementia following styrene exposure with a long latency period.
Associations of Endometriosis and Hormone Therapy With Risk of Hyperlipidemia
Authors: Chang Cherry Yin-Yi , Muo Chih-Hsin , Yeh Yi-Chun , Lu Chung-Yen , Lin William Wu-Chou , Chen Pei-Chun
Published: August 2020

Using claims data from the universal health insurance program of Taiwan, we conducted a retrospective cohort study to investigate whether endometriosis and hormone therapy are associated with the risk of developing hyperlipidemia. We selected 9,155 women aged 20–55 years with endometriosis diagnosed during the period 2000–2013 and 212,641 women without endometriosis with a median follow-up time of 7 years. Among patients with endometriosis, 86% of cases were identified on the basis of diagnosis codes with an ultrasound claim, and 14% were defined by diagnostic laparoscopy or surgical treatments. In a Cox proportional hazards model, the adjusted hazard ratio was 1.30 (95% confidence interval (CI): 1.19, 1.41) for all women, 1.04 (95% CI: 0.81, 1.32) for women under 35 years of age, 1.17 (95% CI: 1.03, 1.32) for women aged 35–44 years, and 1.34 (95% CI: 1.18, 1.52) for women aged 45–54 years. Hysterectomy and/or bilateral oophorectomy accounted for 46.9% of the association between endometriosis and hyperlipidemia, and hormone therapy accounted for 21.6%. Among women with endometriosis, the marginal structural model approach adjusting for time-varying hysterectomy/bilateral oophorectomy showed no association between use of hormone medications and risk of hyperlipidemia. We concluded that women with endometriosis are at increased risk of hyperlipidemia; use of hormone therapy by these women was not independently associated with the development of hyperlipidemia.
Adjusting Coronavirus Prevalence Estimates for Laboratory Test Kit Error
Authors: Sempos Christopher T , Tian Lu
Published: August 2020

Testing representative populations to determine the prevalence or the percentage of the population with active severe acute respiratory syndrome coronavirus 2 infection and/or antibodies to infection is being recommended as essential for making public policy decisions to ease restrictions or to continue enforcing national, state, and local government rules to shelter in place. However, all laboratory tests are imperfect and have estimates of sensitivity and specificity less than 100%—in some cases, considerably less than 100%. That error will lead to biased prevalence estimates. If the true prevalence is low, possibly in the range of 1%–5%, then testing error will lead to a constant background of bias that most likely will be larger, and possibly much larger, than the true prevalence itself. As a result, what is needed is a method for adjusting prevalence estimates for testing error. Methods are outlined in this article for adjusting prevalence estimates for testing error both prospectively in studies being planned and retrospectively in studies that have been conducted. If used, these methods also would help harmonize study results within countries and worldwide. Adjustment can lead to more accurate prevalence estimates and to better policy decisions. However, adjustment will not improve the accuracy of an individual test.
Neurogenic Orthostatic Hypotension. Lessons From Synucleinopathies
Authors: Idiaquez Juan Francisco , Idiaquez Juan , Casar Juan Carlos , Biaggioni Italo
Published: August 2020

Maintenance of upright blood pressure critically depends on the autonomic nervous system and its failure leads to neurogenic orthostatic hypotension (NOH). The most severe cases are seen in neurodegenerative disorders caused by abnormal α-synuclein deposits: multiple system atrophy (MSA), Parkinson’s disease, Lewy body dementia, and pure autonomic failure (PAF). The development of novel treatments for NOH derives from research in these disorders. We provide a brief review of their underlying pathophysiology relevant to understand the rationale behind treatment options for NOH. The goal of treatment is not to normalize blood pressure but rather to improve quality of life and prevent syncope and falls by reducing symptoms of cerebral hypoperfusion. Patients not able to recognize NOH symptoms are at a higher risk for falls. The first step in the management of NOH is to educate patients on how to avoid high-risk situations and providers to identify medications that trigger or worsen NOH. Conservative countermeasures, including diet and compression garments, should always precede pharmacologic therapies. Volume expanders (fludrocortisone and desmopressin) should be used with caution. Drugs that enhance residual sympathetic tone (pyridostigmine and atomoxetine) are more effective in patients with mild disease and in MSA patients with spared postganglionic fibers. Norepinephrine replacement therapy (midodrine and droxidopa) is more effective in patients with neurodegeneration of peripheral noradrenergic fibers like PAF. NOH is often associated with other cardiovascular diseases, most notably supine hypertension, and treatment should be adapted to their presence.
Environmentally driven escalation of host egg rejection decimates success of an avian brood parasite
Authors: Eadie John M , Lyon Bruce E
Published: August 2020

The black-headed duck (Heteronetta atricapilla) of South America is the only known avian obligate brood parasite with precocial offspring. In Argentina, it relies on two species of coots as primary hosts, which typically reject 35–65% of duck eggs. We show that environmentally driven increases in host egg rejection behavior lead to substantial reductions in the reproductive success of the brood parasite. Episodes of flooding and vegetation loss caused dramatic shifts in host egg-rejection behavior, resulting in rejection (85–95%) of almost all duck eggs. Coots respond to fluctuating water levels by building up their nest, raising their own eggs but leaving duck eggs behind. Coots can apparently recognize parasitic duck eggs, but large-scale rejection is triggered only when hosts must actively make a choice. We use a simple population model to illustrate the unique demographic challenges that black-headed ducks face with their parasitic lifestyle and to explore the potential impact of environmentally induced escalation of egg rejection. Using the best available estimates for key vital rates, we show that obligate parasitism may provide a demographically precarious existence for black-headed ducks, even under benign environmental conditions. Environmentally mediated increases in egg rejection rates by hosts could impact significantly the viability of this enigmatic species of brood parasitic duck. Our results demonstrate that egg rejection rates are not fixed properties of host populations or individuals but are strongly influenced by social and ecological factors. Shifts in these environmental drivers could have important and unforeseen demographic consequences for brood parasites.