bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Interstage-Turbine Mixing Cycle on Engine Performance
Authors: Sun Jingchuan , Xu Guoqiang , Wen Jie
Published: October 2020

The optimization of the Brayton cycle has gained an increasing worldwide attention, in order to improve the specific thrust for achieving super cruise. This paper proposes a novel Interstage-Turbine Mixing (ITM) cycle, which guide vanes and rotor blades of turbine would be used as mixing chambers in the expansion process, and presents an analytical methodology by which ITM can be simulated at actual state. The motivation and the working principle of the ITM cycle are explained in detail. In this paper, the variable components method is used to establish the simulation program of the turbine stage mixing cycle. Then parametric cycle studies are performed with the variation of mixing ratio, bypass ratio and fan pressure ratio respectively. The interrelationships between cycle parameters and their effects on cycle performance are discussed. The results show that the mixing ratio of engine with the maximum specific thrust is 0.923, the mixing ratio with the maximum specific fuel consumption is 0.613, the mixing ratio with the best comprehensive performance is 1.127. The above conclusions are independent of the bypass ratio and fan pressure ratio. The predicted engine performance shows that the ITM cycle concept exhibits a competitive specific thrust with respect to engine in the state of non-afterburning, and might be a promising propulsion system for super-cruise air-breathing flying vehicles.
Characteristics and Typical Problems Analysis of Laizhou 1000MW Double Reheat Tower Boiler
Authors: Xu Chunxing
Published: October 2020

The boilers of no. 3 and no. 4 units of laizhou power plant phase II project are 1000MW ultra-supercritical pressure double reheat tower boilers. The units 3 and 4 have been puted into operation in august and november 2019 respectively, and several typical problems of tower boiler are encountered during boiler commissioning. This paper mainly introduces the characteristics of the boiler and some typical problems and their solutions encountered during commissioning.
The Application of Sneak Circuit Analysis on Chemical and Volume Control System
Authors: Gong Zi-Li , Wang Xiaoyan , Yu shengzhi
Published: October 2020

In the chemical and volume control system (RCV) of nuclear power plant pipelines are very complex, there are many valve control nodes. These make the probabilistic risk of unexpected situation rather high in design and running. In order to increase the reliability and safety of the system in design and running, the sneak circuit analysis technology is applied in gas and liquid pipelines of RCV to find latent path and temporal sequence in design and running. Improvements and advices are given to avoid these latent risks in design and running.
Carbon Aerogels Preparation With Kaolin addition
Authors: Xu Yuelong , Ren Bin , Liu Zhenfa
Published: October 2020

Wet gels (WGs) have been obtained from the polymerization of phloroglucinol (P), resorcinol (R) and formaldehyde (F) using sodium carbonate (C) as catalyst with kaolin (KL) addition. Carbon aerogels (CAs) have been gotten through the carbonization of WGs. The porous texture properties of as - prepared samples are investigated using the surface-area analyzer. The crystal structure of CAs are studied by X-ray diffraction (XRD) and the degree of graphitization are obtained through a Raman spectrometer. Meanwhile scanning electron microscopy (SEM) are executed to observe the morphology of different samples. When the addition of 5 wt%, the samples exhibit the high specific surface area (SSA), up to 855m2 g–1, with a concentrated pore size disdribution (PSD) of 30 nm.
INFLUENCE of ELECTRIC FIELD on STRUCTURE and PROPERTIES of TERNARY CARBONATE MOLTEN SALT
Authors: Zhu Chuang , Gong Li
Published: October 2020

Molten salt is one of the important heat storage materials in the field of solar thermal utilization, and nanoparticles can improve partial thermal properties of molten salt. To investigate whether nanoparticles with charge can affect the structure of molten salt ions, the micro electric field of nanoparticles was replaced by applied electric field and the liquid Li2CO3- Na2CO3-K2CO3 was solidified in the electric field. DSC was used to determine the phase change temperatures and latent heat, and thermal stability was analyzed by TG curve. At last, the microstructures of molten salt were analyzed by SEM. Results show that the applied electric field can reduce the starting and ending temperatures of the carbonate by about 10°C as well as the latent heat. The mass loss rates of molten salt samples at the positive and negative plates are 1.44% and 0.81% respectively at 700°, and these samples have higher thermal stability than normal molten salt. The applied electric field can produce new microstructure of molten salt near positive and negative plates.
Application of surfactant in oilfield development
Authors: Cui Shizhang , Wang Pengzhen , Zheng Zhiwei , Zhang Xu
Published: October 2020

With the rapid growth of the global economy, China’s economy is also rapid development, and the demand for crude oil in various countries is geometric multiple growth, domestic demand far exceeds the progress of domestic mining. The security of the domestic economy will suffer as crude oil prices rise. The increase of mining rate should be strengthened on the domestic baseline, using physical, biological and chemical technology support, three mining. The recovery of crude oil was increased to 80.0%-85.0% with high-dose polymer and surfactant.
Growth and metabolism of an aerobic thermophilic Geobacillus strain under simulated composite extreme reservoir conditions
Authors: Wang Junqi , Kong Xiangping
Published: October 2020

The growth and metabolism of an aerobic thermophilic Geobacillus strain DM-2 under simulated composite extreme conditions of the Ng3, Gudao Block, Shengli Oilfield (China) with sufficient oxygen and nutrition were investigated. The experimental device for simultaneously simulating the temperature, pressure, salinity, porosity, permeability, fluid characteristics and development status of the target reservoir was designed, where the air assisted flooding technology was used. Particularly, the oxygen demand was estimated according to biotic and abiotic oxygen consumption. Despite the relatively lower rates of microbial growth and metabolism, the strain was able to grow under these conditions with the cell density increased from 106 to 108 cellsmL−1, and CH3COO− produced at the concentration of about 400 mg ⋅ L−1. Aerobic microorganisms, such as Geobacillus sp., may be promising candidates for microbial enhanced oil recovery and oily sewage treatment technology.
A New Type of Gelled Foam Plugging Agent with Resistance to Temperature, Salt and Dilution
Authors: Li Yuan , Dai Caili , Wu Yining , Wang Ruoyu
Published: October 2020

The conventional foam plugging agent is susceptible to factors such as dilution of formation water, high temperature and high salinity, which usually shortens its effective period and undermine its application. Based on conventional foam plugging agents, an anti-dilution gelled foam plugging agent suitable for oil reservoirs with high temperature and high salinity is proposed in this paper. The research results show that the density of the gelled foam plugging agent (0.6∼0.9 g/cm3) is controllable and easy to prepare, and it can be stabilized at 130° and 2.2 × 105mg/L mineralization for at least 72 h. The indoor physical simulation experiments show that the plugging rate of gelled foam plugging agent is more than 98%, and the plugging effect is obvious, showing a good channeling plugging capability.
Comparison of Cyclosporin A and Tacrolimus in the Field of Organ Transplantation
Authors: Wen Ruixuan
Published: October 2020

Organ rejection occurs when a patient’s immune system recognizes transplanted organ as foreign, initiating immune responses that ultimately destroys the transplant. Since organ transplantation is offered only after all the other treatments have failed, the rejection is hence fatal and requires immediate medical treatment. As a solution, immunosuppressive drugs are widely used to treat organ rejection. Calcineurin inhibitors (CNIs), a kind of non-depleting agents including but not limited to Cyclosporin A (CsA) and Tacrolimus (FK506), prevent T- cell activity intracellularly through inhibiting cytokine expression and T-cell proliferation. By comparing the structure, mechanism and application of Cyclosporin A and Tacrolimus, not only organ rejection can be better understood, the two immunosuppressant can be better evaluated and studied.
Isolation and Identification of Lactic Acid Bacteria from Koumiss in Xinjiang, China
Authors: Zhou Haiyan , Wu Linrong , Hu Pan , Zhao Xin , Liu Bihui
Published: October 2020

Koumiss is a traditional fermented drink in Xinjiang, which is rich in microorganisms. In this study, seven strains of lactic acid bacteria were isolated and identified from Xinjiang homemade koumiss by traditional separation culture method, Gram staining method and 16s rDNA sequencing analysis. The observation of colonial morphology showed that seven isolates mostly round milky white with convex surfaces, and the results of gram staining showed that all seven isolates were gram-positive. The isolates were considered to be Enterococcus sp., Streptococcus gallolyticus, Lactobacillus fermentum, Lactobacillus delbrueckii subsp. Bulgaricus, Lactobacillus fermentum, Bacillus cereus and Enterococcus durans separately through 16s rDNA sequencing analysis. These results can provide scientific basis for the diversity of lactic acid bacteria in dairy products in Xinjiang, and provide theoretical support for the development of lactic acid bacteria food.
The Isolation and Identification of Lactobacillus from Naturally Fermented Yoghurt
Authors: Wu Ya , Wu Dongdong , Liu Danyan , Chen Juling , Zhao Xin
Published: October 2020

Lactic acid bacteria were isolated from natural fermented yoghurt by traditional isolation and culture method, and identified by gram staining and 16S rDNA sequencing analysis. The results showed that 5 strains of lactic acid bacteria were obtained, which were X22-1, X22- 2, X22-3, X22-4 and X40-1. After 16S rDNA sequencing, X22-1, X22-3, X40-1 were Lactobacillus fermentans, X22-2 and X22-4 were Lactobacillus delbrueckii subsp. Bulgaricus.
The Study on Extraction Technology of Flavonoids from Tribute Citru Peel
Authors: Wu Ya , Hu Chengming , Chen Xinxing , Su Xiaofei , Zhao Xin
Published: October 2020

Tribute Citru peel is rich in various natural products. Total flavonoids from Tribute Citru peel were extracted by solvent extraction method and the content of total flavonoids was determined by UV spectrophotometer with rutin as standard. The effects of reflux time, solidliquid ratio, ethanol concentration and temperature on the extraction of flavonoids were investigated. The optimum condition determined by orthogonal test was that Tribute Citru peel and 80% ethanol were mixed in the solid-liquid ratio of 1:20, then heated for 4h at 90 °C. Under this condition, the extraction rate yield of flavonoids reached 1.43%.
Hydrogen sulfide biological removal efficiency by vermicompost horizontal biofilter
Authors: Tian Weiping , Chen Xuemin , Zhou Peng , Fu Xiaoyong
Published: October 2020

To efficiently treat hydrogen sulfide (H2S) from contaminated air, we designed a fixed carrier horizontal biofilter. The biofilter system was packed with vermicompost as baffle plate. The inlet concentration and the thickness of media on the removal efficiency were studied. Furthermore, a final product analysis and the macro-kinetics of bio-degradation were also evaluated. The results showed that the horizontal biofilter can be started quickly, favorable removal efficiencies of H2S were proved and reached nearly100% when the inlet concentration lower than 350 mg m−3. The thickness of vermicompost affected the H2S removal efficiency. It was found that the nutrient elements of vermicompost increased, especially the sulfur increased significantly. In addition, in kinetic analysis, the semi-saturation constant and maximum removal rate of H2S were calculated to be 417.1 mg m−3 and 1428.6 g m−3 d−1. The results presented in this study the horizontal vermicompost biofilter was effective for removing H2S contaminated air, and will be valuable for further research and engineering applications.
Enhancement of antioxidant effect of pitaya by lactic acid bacteria fermentation
Authors: Gan Yi , Long Xingyao , Zhou Xianrong , Mu Jianfei , Zhao Xin
Published: October 2020

Pitaya has received a great deal of consumer interest for its large amount of micronutritions. This study investigated the changes of total phenols and total flavonoids of fermented pitaya, as well as the antioxidant abilities. The results showed that fermentation could significantly increase the counts of water-soluble phenols and flavonoids. After being fermented for 24h, the DPPH free radical, hydroxyl radical and superoxide anion scavenging ability raised significantly. Reducing power of fermented pitaya also increased remarkably. Thus, fermentation could increase the antioxidant ability of pitaya, and could be a potential process for pitaya products.
Water Susceptibility and Raveling Resistance of Polyurethane Mixture
Authors: Zhong Ke , Zhang Meng , Sun Mingzhi , Sun Shengkai , Wang Xue
Published: October 2020

The amount of different rubber particles has a certain influence on the water stability and raveling resistance of polyurethane mixture. The more rubber particles are, the better the water stability and raveling resistance. Different grades have a certain influence on the water stability and raveling resistance. The addition of fine aggregate is conducive to improving the water stability of polyurethane mixture. Different kinds of polyurethane binders can change the polyurethane Water stability and raveling resistance of the mixture.
Study on Extraction Process of Polyphenols from Actinidia
Authors: Yanping Wang , Yanyan Liu
Published: October 2020

To study the optimum extraction conditions of polyphenols in actinidia. The extraction rate of polyphenols was used as the inspection index. Single factor test and orthogonal experiment were used to study the effect of the type and volume fraction of organic solvents, extraction temperature, extraction time and solid-liquid ratio on the extraction rate of polyphenols from kiwifruit. [Result] The optimum extraction process was as follows: methanol volume fraction was 60%, extraction time was 30 min, extraction temperature was 60 °C, solid-liquid ratio was 1:3, the extraction rate of polyphenols in kiwifruit was 35.7%.The process is stable and feasible, which can provide basis for the development and application of polyphenols in kiwifruit.
The improvement effect of LiF on stability of Li anode in PVDF-HFP gel polymer electrolyte
Authors: Yang Lei , Guo Xingming , Yao Ying , Zhang Cunzhong
Published: October 2020

The porous composite polymer membranes, based on poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) polymer matrix and lithium fluoride (LiF) inorganic additive, were prepared by phase inversion method and gel polymer electrolytes (GPEs) were obtained by immersing membranes into liquid electrolyte. GPEs containing LiF additive exhibited a high ionic conductivity of 1.10 × 10−3 S cm−1 and a high lithium ion transference number of 0.65 because of the lower crystallinity degree of GPEs. Moreover, we disclosed distinct merits including enhanced migration of Li+ and suppressed Li-ion concentration gradient in GPE near the surface of Li electrode. These merits ameliorated electrochemical performance of Li metal anode by retarding Li dendrite. LiF-GPEs effectively improved the cyclability and rate performance of symmetrical Li cells in a wide current densities rage. Pairing with LiFePO4 cathode, full cells containing LiF-GPEs showed excellent rate performance and cycling stability. This work effectively demonstrates that LiF-GPEs could suppress lithium dendrite by boosting electrochemical characters of mass transfer, and kinetic parameters.
Effects of Ultra-high Pressure Treatment on Aroma Components of Braised Mandarin Fish
Authors: Weiping Tao , Shiyi Wang , Wei Jiang
Published: October 2020

Ultra-high pressure technology is a new type of non-thermal food processing technology, which has the characteristics of low temperature, high quality, fast uniformity, energy saving and no pollution for food sterilization and inactivation of enzymes[1], at the same time, it is the best processing method that can keep the natural color, aroma, taste and nutrition of the food in the prior art. In this study, the effects of ultra-high pressure treatment on the aroma components of braised mandarin fish were studied. According to the experimental results, more alkanes were detected and accounted for a large proportion, which was the main substance affecting the flavor of mandarin fish.
Study on microbial diversity of fresh-cut potatoes in different storage periods
Authors: Kong Xiangzheng , Chang Xiguang , Feng Xiaoguang , Han Guicheng , Chen Xiangning
Published: October 2020

In order to extend the shelf life of fresh-cut potatoes, maintain their edible quality, and clarify the flora succession rules in fresh-cut potatoes during storage (4 ° C), this experiment uses PE film natural packaging, and high-throughput sequencing was used to study the On day 0, day 7, and day 14, the microbial diversity was high. The results showed that the dominant bacteria in the samples stored on days 0, 7, and 14 were mainly Pseudomonas, Pantoea, Erwinia, Bucher Buchnera. There is basically no difference in the diversity of microorganisms during different storage periods, but the abundance changes.
Novel gelatin/polyacrylonitrile thin film nanofibrous composite membranes with high filtration performance
Authors: Shen Ke , Wang Xuefen
Published: October 2020

High performance thin film nanofibrous composite (TFNC) membrane consisting of a thin gelatin (GE) selective skin layer and a polyacrylonitrile (PAN) nanofibrous substrate was fabricated in this work. Ultrathin GE nanofibers were electrospun and deposited onto the PAN nanofibrous supporting membranes and followed by moistening treatment and hot-pressing treatment. The moistened electrospun GE nanofibers would be melted and pressed into an integrated selective skin layer on the porous PAN nanofibrous membranes. The treated GE/PAN double-layer membranes were then chemically cross-linked by glutaraldehyde (GA). The depositing time of GE nanofibers was optimized to achieve a thin and integrated GE separating layer. The optimized GE/PAN TFNC membrane exhibited high flux (182.1 L m−2 h−1) and rejection (98.3%) in BSA test at 0.3 MPa. In addition, the GE/PAN composite membrane possessed great mechanical stabilities.
Performance test of self - made fast film detection all-in-one machine under different pressure
Authors: Guo Linyuan , Feng Shichun , Rong Yan , Peng Yunyan , Jin Dong
Published: October 2020

Ultrafiltration membrane can remove colloid, virus and large molecules of organic matter, but it does not have the ability to remove small molecules of organic matter and ionic pollutants, and the nanofiltration membrane can effectively remove organic matter and inorganic salts and other pollutants. However, the research and application of nanofiltration advanced water treatment technology are still few in China. In this experiment, ultrafiltration membrane was combined with nanofiltration membrane to make a rapid detection instrument. The instrument was used to test key performance indicators such as desalination rate and water flux under different pressures, which proved that the instrument could quickly detect related indicators of the membrane and its efficiency could be doubled.
Iron-cobalt bimetallic selenide as effective and durable catalyst for HER and OER
Authors: Zhou Yu , Yue Qin
Published: October 2020

As a way of energy conversion with zero carbon emission, water splitting plays a crucial role in the green and efficient energy utilization. Reasonable design of suitable catalysts for hydrogen evolution reaction and oxygen evolution reaction is conducive to the wideranging application of water splitting. Double metallic composite is superior to single-metal and non-metal materials due to the unique electronic configuration. In this work, we synthesized a Fe-Co-Se catalyst on carbon cloth (Fe-Co-Se/CC) for HER and OER. Fe-Co- Se/CC shows an overpotential of 131 mV@10 mA cm−2, 177 mV@100 mA cm−2 and 215 mV@500 mA cm−2 in 1.0 M HClO4 for HER and 300 mV@100 mA cm−2, 365 mV@500 mA cm−2 and 416 mV@1000 mA cm−2 in 1.0 M KOH for OER. Fe-Co-Se/CC also exhibits excellent stability in HER and OER measurements. This work demonstrates that Fe-Co-Se/CC is a promising candidate catalyst for water splitting.
The effects of four cadmium tolerant plant straws on the growth and cadmium content of jujube seedlings
Authors: Huang Zhenglian , Deng Qunxian
Published: October 2020

To study the effects of four cadmium-tolerant plant straws on the growth and cadmium content of Zizyphus acidojujuba seedlings, Zizyphus acidojujuba seedlings were planted in cadmium-contaminated soil (5mg ⋅ kg−1) with cadmium-tolerant plants straws such as Ranunculus sieboldii, Clinopodium confine, Plantago asistica and Mazus pumilus through pot experiments. Results showed that the biomass, photosynthetic pigment content, peroxidase (POD) activity and soluble protein content of Zizyphus acidojujuba seedlings could be improved by applying four kinds of plant straws with cadmium tolerance to cadmium-contaminated soil. At the same time, the catalase (CAT) activity in cadmium-contaminated soil was increased, the growth of Zizyphus acidojujuba seedlings was promoted, and the cadmium content in root and overground parts of Zizyphus acidojujuba seedlings was reduced. The cadmium transfer coefficient of Zizyphus acidojujuba seedlings could be increased by only applying the straw of the Clinopodium confine, while the cadmium transfer coefficient of Zizyphus acidojujuba seedlings could be reduced by all the other straw treatments Therefore, the four kinds of cadmium-tolerant plant straws are all suitable for the restoration of cadmium-polluted Zizyphus acidojujuba gardens, among which the Ranunculus sieboldii, Plantago asistica and Mazus pumilus straws are better.
The impermeability effect of soil air on the ponding infiltration experiment of soil column
Authors: Guo Qinghua
Published: October 2020

The agricultural flood irrigation in Jingyang South Platform, Shaanxi Province caused the rise of groundwater level, which induced a large number of loess landslides. The study of water movement in unsaturated loess under irrigation is the premise of revealing the mechanism of loess landslide. In this paper, the changes of matric suction, volume moisture content and air pressure with time at different depths of unsaturated undisturbed loess are measured by indoor soil column water infiltration test. Air pressure at each point of the soil rises to about 98 Pa in a short time after the test beginning, and keeps small fluctuation up and down during the test. At the end of the experiment, the air pressure at each point of the soil returns to zero in a short time after the upper water accumulation is eliminated. During the test, the change of infiltration rate has a significant corresponding relationship with the exhaust phenomenon at the top of the soil column, and the air resistance significantly reduces the infiltration rate of water.
Research on Displacement Failure Characteristics of Deep Roadway Surrounding Rock
Authors: Wang ZHonghua
Published: October 2020

In order to explore the displacement failure characteristics of deep roadway surrounding rock, the surrounding rock stress field model of the uniform stress field in the circular tunnel is simplified. It analyzes the stress evolution features of deep coal rock and discusses the mechanism of zonal disintegration. It observes the deep displacement surrounding rock of Qujiang mine n the depth of 1000m, the displacement shows that the wave crests and troughs appears alternately; wave crest position for damage area, trough part for non-damage zone. The surrounding rock of roadway exists zonal disintegration phenomenon, each roadway section is a total of four fracture zones. Due to different positions of roadway section tunnel excavation time rheological effect, the longer the tunnel is excavated, the more serious the surrounding rock is damaged.
Analysis of the index change laws of the B and C strips of Block A after well pattern infilling
Authors: Li Guoyi
Published: October 2020

After entering the ultra-high water cut stage, it is more and more difficult to tap the remaining oil potential, especially in the B and C strips because of the prominent contradictions between injection and production. It is difficult to adjust a injection well and get a good effect of well stimulation, so oil recovery is low. The index change laws are analyzed and summarized in two test areas of well pattern infilling, which can be used as a reference for the well pattern infilling and efficient development in the B and C strips.
A Hybrid Foresting Model for the Wind Energy based on Small World Optimization Algorithm and BP Neural Network
Authors: Li Chuyao , Zhang Runfeng
Published: October 2020

Wind energy is a clean and pollution-free renewable energy source, but it has the characteristics of randomness and intermittentness. Therefore, it is of great economic significance and practical value to study the high-precision wind power prediction model for accurately predict the power generation of wind farms. This paper use the small world optimization algorithm (SWOA) to optimize the selection of the weights and threshold of the BP neural network, so that it has the advantages of small errors and global optimization. Then we proposes an improved BP neural network model based on the small world optimization algorithm. Afterwards, the model was applied to wind power prediction in actual wind fields. The experiment results show that SWOA can quickly and accurately find the global optimal solution of the parameters of the BP neural network model, which can further improve the SWOA-BP model to obtain better prediction performance.
Study on Mechanical Property and Blocking Test of Multistage Resin Composite Ductile Cement Slurry System
Authors: Yan Xuanqi , Hao Huijun , Liu Shasha , Yan Haijun , Xie Gang , Jing Jizhe , Wei Aijun
Published: October 2020

In view of the traditional inorganic cement-based material hydration shrinkage caused by the impact of performance defects range of application, applying the principle of doping dispersion and compact packing, a multistage resin composite ductile cement slurry system with different temperatures was constructed. The compatibility, thickening and mechanical evaluation tests were carried out to optimize the resin type, doping amount and method. The results show that the thickening of the composite system is controllable, and the addition of resin is beneficial to improve the elastic deformation, whereas easy to pile up if adding extra amounts, and the compressive strength reduced. At the same time, adding resin first is beneficial to disperse in the cement gap. Compared with cement-based materials, the compressive strength increased 7% to 13%, the elastic modulus decreased 10% to 15%, and the deformation capacity increased 14% to 22%. Field test shows that it has good sealing performance and remarkable effect of oil increasing and dewatering, which provides a new technical means for controlling casing leakage and ensuring its normal production.
Carbon Aerogels With Kaolin Addition For Supercapacitors Application
Authors: Xu Yuelong , Ren Bin , Wang Shasha , Liu Zhenfa
Published: October 2020

Carbon aerogels with excellent electrochemical properties and 3D porous structure are prepared from the reaction of phloroglucinol (P), resorcinol (R) and formaldehyde (F) under ascorbic acid (VC) catalyzing with kaolin (KL) addition. Because of the double-layer capacitance behavior, CAs have been used as supercapacitors for energy storage. The reaction mechanism of the wet aerogels formation is analyzed. Meanwhile, the chemical environments of CAs surface is systematically investigated using X-ray photoelectron spectroscopy (XPS). The cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) measurements and electrochemical impedance spectroscopy (EIS) are adopted to studied the excellent electrochemical properties of different samples. The specific capacitance (SC) is up to 162 F g−1, and 97% of initial capacitance is retained over 1000 cycles at a current density of 1.0 A g−1.
Experimental comparison of ultrasonic properties of shaft lining concrete and surrounding rock in Xincheng Gold Mine
Authors: Xu Yan , Zhou Xiaoming
Published: October 2020

Based on the design of the wall rock and concrete lining of the new main shaft in Xincheng gold mine and the ultrasonic test as the main research method, the ultrasonic performance characteristics and influencing factors of the surrounding rock specimen and concrete specimen of the new main shaft are compared. It is concluded that the mechanical properties of rock specimens of metal mine surrounding rock are better than those of concrete lining. The complete surrounding rock segment of concrete lining does not play the role of rigid support. The two cube specimens have a significant influence on the attenuation of longitudinal wave. It is suggested to convert the cube specimen with a side length of 150mm into or directly use the cylinder specimen with a diameter of 50mm and a height of 100mm when determining the indoor ultrasonic parameters of rock and concrete in the shaft wall design of ultra-deep shafts of metal ore. The research results are of great significance to the design of shaft lining in mines.
Research on thermal response of pool fire of oil tank based on PyroSim
Authors: Zhang Qibo , Zhang Huguo , Lu Shouqing , Zhang Ran , Chen Yao
Published: October 2020

This paper presents a numerical investigation aimed at studying the thermal response of adjacent tank caused by different fire conditions. The analysis involves two-step procedure:(1) PyroSim model to obtain the temperature and the inclination variation of the large pool-fire flame, to determine the ultimate temperature distributions of the target tank, and to compare the ultimate temperature and the fuel ignition temperature, thus to determine the target tank is safety or not,(2) There are three kinds of semi-empirical models for describing the radiation e.g.(i) point source,(ii) Shokri-Beyler and (iii) Mudan models, to determine thermal radiation flux of the target tank. The analysis considered the influence of two parameters: (i) seven kinds of wind, (ii) five kinds of distances between the tanks. The paper compares three kinds of semi-empirical models and PyroSim model, so PyroSim model is more fit for relationships between thermal radiation flux. The simulation results show that the maximum temperature of the target tank is the connection between the wall and the top of the tank; the target tanks have failure risk within 0.3D and 0.6D tank distances and the tank spacing greater than or equal to 0.9D have no failure risk.
Research on New Flexible Bridge Pier Anti-collision Technology
Authors: Jiang Peng-fei , Wang Peng-fei , Cao Hong-fei , Wang Fei
Published: October 2020

With the increase of ship traffic flow, ship size and ship tonnage have increased significantly, while the original anti-collision design of many bridges built in early China has not met the protection requirements, resulting in the increase of the risk of bridge collision by ships. Ship collision with bridges can not only cause huge economic losses, but also result in fatal accidents, leaving a huge hidden danger to the safety of bridges. In this paper, the advanced safety protection concept of ship, bridge and device triple protection is introduced, and a new flexible pier anti-collision technology is used, the additional pile isolation type flexible anti-collision device is proposed.The LS-DYNA dynamic numerical simulation software is used to analyze the dynamic behavior of the ship collision avoidance device. The results show that the anti-collision device using flexible components can store large deformation energy in the process of ship collision. Compared with the theoretical calculation of ship impact force, the ship impact force is significantly reduced after the installation of the new flexible protective device. The flexible anti-collision device proposed in this paper can provide a reliable design for bridge anti-collision.
Application of artificial intelligence bird recognition technology in airport bird strike prevention safety management
Authors: Guo Bin , Du Wenjia , Cheng Lan , Liang Jing , Wang Lu
Published: October 2020

Bird strike prevention is an important part of airport safety production management. For bird identification technology in airport bird strike prevention business, this paper summarizes various research results of using artificial intelligence for bird recognition, and analyses the pros and cons of different types of application of the technology in the actual airport bird control business. Also, the bird identification technology in the current airport bird prevention and control technology is prospected.
Research on behavior safety evaluation of subway construction personnel based on improved AHP-FCE method
Authors: Chen Xin , Chen Dawei , Heng Kong , Fei Guo
Published: October 2020

This paper studies the behavior safety evaluation of subway construction personnel. According to expert interviews, accident case analysis and references, the behavior safety evaluation system of subway construction personnel is constructed, including 6 first-class indicators and 20 second-class indicators. The improved AHP method, entropy weight method and difference coefficient linear weighting method is used to calculate the subjective and objective combination weights of each evaluation index, and FCE method is used to evaluate the behavior safety status of the construction personnel of a subway project. The results show that: (1)The evaluation model is scientific and reasonable, and has strong operability; (2) The behavior safety status of subway construction personnel is greatly affected by knowledge and skills, safety atmosphere and management factors. Among them, safety attitude, safe operation skills, exemplary role of team leaders, safety initiative participation, safety education and training, and safety leadership are of great importance. Strengthening their management will effectively improve the level of behavior safety management and put forward new management ideas for the project management idea.
Research on sensitive index and critical value of local prediction for coal roadway insteep seam
Authors: Wang ZHonghua , Sun Luanluan
Published: October 2020

In response to the prediction of the local outburst danger of steeply inclined coal seams, it tested the initial gas emission rate of coal ΔP, the firmness coefficient f of coal, and the gas desorption characteristics K1-P in laboratory. Using the methods of historical data analysis, on-site inspection and on-site expansion verification, it was determined that the drill cuttings volume index S and drill cuttings gas desorption index Δh2 are the sensitive indexes and critical values for the coal roadway prediction in Qingshan Coal Mine. The application effect is good, which provides reference for mines with similar conditions.
Research and Application of Optimizing Pre-drainage Hole Layout along Seam
Authors: Houquan Zhou , Qianqian Ma
Published: October 2020

In order to solve the problem of the unsatisfactory pre-drainage effect of bedding holes, based on the theory of elastoplastic mechanics, the distribution of elastoplastic zone around the borehole and its influencing factors were analyzed, and it was found that the three-dimensional arrangement of the boreholes can increase the hole circumference of the drilled network Plastic zone volume, effective drilling length of borehole, coal seam permeability and gas drainage efficiency. Engineering application was carried out at the 3215working face of Wangpo Coal Mine. Three test schemes of dense parallel drilling, plane cross drilling and three-dimensional cross drilling were used, and the effect of extraction was investigated for comparative analysis. The test shows that the extraction efficiency of the three-dimensional cross-drilled hole is high, and the attenuation coefficient is small. Under the same amount of drilling, the extraction capacity of the three-dimensional cross-drilled hole is 1.7 times and 1.3 times that of the dense parallel drilling and plane cross-drilled hole. The drainage efficiency of three-dimensional cross drilling is 69% and 26% higher than that of dense parallel drilling and plane cross drilling, respectively.
Experimental Study on Membrane Fouling and Cleaning in Hydrolytic Acidification -Membrane - Sequencing Batch Reactors Process
Authors: Gao Yulan , Yang Jie , Song Xinwei , Shen Dongmei , Wang Wanfen , Liu Kai , Jiang Jichao
Published: October 2020

The process of hydrolytic acidification (HA) - membrane (M) - sequencing batch reactors (SBR) was used to deal with mixed municipal wastewater and landfill leachate. The system operated continuously for 90 days, and the changes of membrane filtration resistance and membrane cleaning were investigated. The results showed that the membrane fouling rate developed slowly during the continuous operation of the system, and the tota membrane filtration resistance increased from the initial 2.82 × 1012m−1 to 11.4 × 1012 m−1. In addition, it was found that the reversible membrane fouling was the main part of the membrane-sequencing batch filter, which accounted for 47.35% of the total filtration resistance, by observing the surface of the membrane module before and after cleaning test. What’s more, hydraulic cleaning could effectively remove the sludge and granular sediments deposited on the membrane surface, and the total resistance of membrane filtration decreased from 293.84% to 176.45%. However, by further soaking membrane components with 5%o NaClO and 5%o HCl solutions, the membrane filtration performance would be fully restored, and the total membrane filtration resistance would be restored to 104.35% of the initial state.
Safety evaluation of chemical production based on AHP-fuzzy comprehensive evaluation method
Authors: Cui Liyuan , Zhang Yansong , Jin Hu , Ma Xu
Published: October 2020

In order to prevent fire and explosion accidents in the production process of chemical companies and ensure the production safety of chemical companies, taking the styrene production process of a chemical company as an example, according to the production characteristics of chemical companies and the hazardous factors in production, combined with industry expert opinions, 17 safety evaluation indexes affecting the safety in production of chemical enterprises are analyzed and summarized from the aspects of human, machine, material, environment and management, the second level safety evaluation index system is established, and AHP-fuzzy comprehensive evaluation method is used for production. The safety evaluation of the process showed that the production status of the chemical enterprise was relatively dangerous. The danger mainly came from management and materials. The enterprise did a good job in terms of human, machin and environment. This evaluation method can objectively and accurately evaluate the risk of chemical production, help companies find the key prevention direction of accidents, strengthen safety supervision, and prevent the occurrence of fire and explosion accidents. It provides a reference for the application of AHP-fuzzy comprehensive evaluation method in chemical engineering evaluation in the future.
Analyzing drought conditions using NDVI in Coke, Texas
Authors: Yuan Xingyu
Published: October 2020

In this research, drought in Coke County, Texas is analyzed using Normalized Difference Vegetation Index (NDVI) derived from remotely sensed Landsat data. Shrub, crop, and evergreen are focused to analyze their response to a drought event. The study reveals that pre-drought NDVI in 2009 is found to be higher than post-drought NDVI in 2011. The dominant vegetation, shrub, is most affected by drought, and the crop is least affected by drought. The study of dominant vegetation type can be used to monitor and study the severity and status of local drought.
Research on Strength Test Technology of Bogie Frames
Authors: Cao Yu
Published: October 2020

The bogie frames play a vital role in the reliable operation of rolling stocks. In order to more effectively test the performance of the bogie frames’ strength, a test plan of bogie frames’ static tests and fatigue tests is designed according to related standards which is carried out by calculating the load and applying the load spectrum and combined with Goodman diagram to evaluate the structural performance of bogie frames. The research on the strength test technology of bogie frames provides an important guarantee for the operation safety of the railway system.
Predicting in BIM Labour Cost with a hybrid approach Simple Linear Regression and Random Forest
Authors: Wang Jun Ze , Zhang Jie
Published: October 2020

In most cases, BIM labour cost can only be calculated through the proportion of the gross floor area according to the practical projects, which always brings unpredictable risks to project managers since this simple method of linear regression contains a high risk of estimating error in construction phases. Therefore, this study will develop a new hybrid methodology which combines the Random Forest and Simple Linear Regression for eliminating the error of prediction on BIM labour cost in construction phases. A case study will be conducted to illustrate the prediction results through four completed projects, including two steel structure and two reinforced concrete projects.
Summary of regional innovation ecosystem research
Authors: Li Jian-bo , Zhang Rui
Published: October 2020

With the dramatic change of the world innovation environment, the innovation model is moving from the traditional innovation paradigm 1.0 (linear paradigm) and interactive innovation paradigm 2.0 (innovation system) to the era of innovation paradigm 3.0, that is, the innovation ecosystem. Innovation ecosystem is related to national economic development and international competitiveness, in the current economic situation is a very important part of the industry and scholars. By searching the relevant literature on the innovation ecosystem at home and abroad in the past five years, this paper summarizes the relevant research results around the concept, theory and research methods of the innovation ecosystem at the regional level, summarizes the current research deficiencies, and looks forward to the future research direction and focus, with a view to providing reference and enlightenment for the relevant research in China.
Diagnostic accuracy of the 4AT for delirium detection in older adults: systematic review and meta-analysis
Authors: Tieges Zoë , Maclullich Alasdair M J , Anand Atul , Brookes Claire , Cassarino Marica , O’connor Margaret , Ryan Damien , Saller Thomas , Arora Rakesh C , Chang Yue , Agarwal Kathryn , Taffet George , Quinn Terence , Shenkin Susan D , Galvin Rose
Published: October 2020

Objective

Detection of delirium in hospitalised older adults is recommended in national and international guidelines. The 4 ‘A’s Test (4AT) is a short (<2 minutes) instrument for delirium detection that is used internationally as a standard tool in clinical practice. We performed a systematic review and meta-analysis of diagnostic test accuracy of the 4AT for delirium detection.

Methods

We searched MEDLINE, EMBASE, PsycINFO, CINAHL, clinicaltrials.gov and the Cochrane Central Register of Controlled Trials, from 2011 (year of 4AT release on the website www.the4AT.com) until 21 December 2019. Inclusion criteria were: older adults (≥65 years); diagnostic accuracy study of the 4AT index test when compared to delirium reference standard (standard diagnostic criteria or validated tool). Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Pooled estimates of sensitivity and specificity were generated from a bivariate random effects model.

Results

Seventeen studies (3,702 observations) were included. Settings were acute medicine, surgery, a care home and the emergency department. Three studies assessed performance of the 4AT in stroke. The overall prevalence of delirium was 24.2% (95% CI 17.8–32.1%; range 10.5–61.9%). The pooled sensitivity was 0.88 (95% CI 0.80–0.93) and the pooled specificity was 0.88 (95% CI 0.82–0.92). Excluding the stroke studies, the pooled sensitivity was 0.86 (95% CI 0.77–0.92) and the pooled specificity was 0.89 (95% CI 0.83–0.93). The methodological quality of studies varied but was moderate to good overall.

Conclusions

The 4AT shows good diagnostic test accuracy for delirium in the 17 available studies. These findings support its use in routine clinical practice in delirium detection.

PROSPERO Registration number

CRD42019133702.
Deep-DRM: a computational method for identifying disease-related metabolites based on graph deep learning approaches
Authors: Zhao Tianyi , Hu Yang , Cheng Liang
Published: October 2020

Motivation: The functional changes of the genes, RNAs and proteins will eventually be reflected in the metabolic level. Increasing number of researchers have researched mechanism, biomarkers and targeted drugs by metabolites. However, compared with our knowledge about genes, RNAs, and proteins, we still know few about diseases-related metabolites. All the few existed methods for identifying diseases-related metabolites ignore the chemical structure of metabolites, fail to recognize the association pattern between metabolites and diseases, and fail to apply to isolated diseases and metabolites. Results: In this study, we present a graph deep learning based method, named Deep-DRM, for identifying diseases-related metabolites. First, chemical structures of metabolites were used to calculate similarities of metabolites. The similarities of diseases were obtained based on their functional gene network and semantic associations. Therefore, both metabolites and diseases network could be built. Next, Graph Convolutional Network (GCN) was applied to encode the features of metabolites and diseases, respectively. Then, the dimension of these features was reduced by Principal components analysis (PCA) with retainment 99% information. Finally, Deep neural network was built for identifying true metabolite-disease pairs (MDPs) based on these features. The 10-cross validations on three testing setups showed outstanding AUC (0.952) and AUPR (0.939) of Deep-DRM compared with previous methods and similar approaches. Ten of top 15 predicted associations between diseases and metabolites got support by other studies, which suggests that Deep-DRM is an efficient method to identify MDPs. Contact: liangcheng@hrbmu.edu.cn. Availability and implementation: https://github.com/zty2009/GPDNN-for-Identify-ing-Disease-related-Metabolites.
Deep-joint-learning analysis model of single cell transcriptome and open chromatin accessibility data
Authors: Zuo Chunman , Chen Luonan
Published: October 2020

Simultaneous profiling transcriptomic and chromatin accessibility information in the same individual cells offers an unprecedented resolution to understand cell states. However, computationally effective methods for the integration of these inherent sparse and heterogeneous data are lacking. Here, we present a single-cell multimodal variational autoencoder model, which combines three types of joint-learning strategies with a probabilistic Gaussian Mixture Model to learn the joint latent features that accurately represent these multilayer profiles. Studies on both simulated datasets and real datasets demonstrate that it has more preferable capability (i) dissecting cellular heterogeneity in the joint-learning space, (ii) denoising and imputing data and (iii) constructing the association between multilayer omics data, which can be used for understanding transcriptional regulatory mechanisms.