bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Properties of Branched Polymer Based on Modified Chitosan for Enhanced Oil Recovery
Authors: Liu Yanqin , Lai Nanjun
Published: June 2019

In this study, chitosan and polyamide-amine(PAMAM) were utilized to prepare a branched polymer based on modified chitosan (HPDCS) for enhanced oil recovery(EOR). The structure of the product was confirmed by FT-IR, 1HNMR and SEM. Compared with hydrolyzed polyacrylamide (HPAM), HPDCS exhibited better thickening properties and shear resistance due to its special branched structure and the flexible molecular chains can be deformed through the pore throat of the porous medium, which can avoid serious damage to the molecular chains. After a 45-hour reaction period with biological enzyme, the apparent viscosity of the HPDCS solution decreased significantly, and the viscosity retention rate was only 67.7%, indicating that the introduction of chitosan in the polymer could improve the biodegradability of polymers to a certain extent. Based on sandpacked tube displacement experiments, the HPDCS could build high resistance factor and residual resistance factor in the corresponding porous medium which indicated that the HPDCS performed excellent mobility control ability. Besides, compared with HPAM, the HPDCS solution of 2000 mg/L showed better oil recovery of 24.12% in the corresponding porous medium, which demonstrated that the branched polymer has a more outstanding EOR ability.
The analysis of collision risk effect among different aircraft combinations by parallel runways spacing
Authors: Pang K , Cai L C , Qiao Y , Chen D F
Published: June 2019

International Civil Aviation Organization (ICAO) has stipulated the spacing of parallel runways, but it hasn’t considered different aircraft categories classified by speed. So there is no provision as a reference for the safety runway spacing corresponding to different aircraft speed combinations. This paper studied the safety spacing of parallel runways based on aircraft categories classified by speed in the ICAO regulations with the aim of providing more reasonable planning for the parallel runway configuration suited for different aircraft speed combinations. The improved simulation model is established. The innovations are mainly reflected in the following two aspects. First, based on the established evasion solution to the hazardous scenario in PLB(Parallel Landing Blunder) model, this paper added a new solution that the deviating aircraft (blunderer) corrects its course returning to the designated approach course (i.e., the course correction solution). Second, when adopting the evasion solution, this paper revised the simulated evasion maneuver command according to Doc. 8168 of ICAO, because it could better reflect the pilot’s real response. According to the simulation results, it is concluded that when the combinations consists of the same aircraft category, both A-A and B-B combinations can conduct simultaneous independent parallel instrument approaches (SIPIA) to the parallel runways with the spacing of 835m. When the combinations consist of different aircraft categories, the paper emphatically studied the A-E combinations with the largest difference of approach speed. In the case of A-E combinations, with 1035 m runway spacing, the collision risk of SIPIA is relatively high.
Improvement of the UV-induced Reduction Efficiency of Nitrate by Manganese (II) chloride based on Sequential Injection Analysis
Authors: Zhang Y M , Shi Q , Sun Z L , Wang Y , Zou Y , Wang Q , Liu Y
Published: June 2019

The traditional method of reducing nitrate by ultraviolet radiation was improved in this study. Manganous (II) Chloride (MnCl2) was added on the basis of original reagent to improve the efficiency of nitrate reduction by Ultraviolet radiation (UV), and the optimum reaction conditions of improved UV reduction method were discussed. It was found that the best UV-reduced reduction efficiency of nitrate obtained at the concentration of 1.0 g/L photoreduction DTPA, the concentration of Tris was 1.0 g/L with 8.0 of pH in the presence of 0.8g/L MnCl2 with 2 min UV radiation. The reduction efficiency increased by about 25.00% compared with the traditional analysis method, reached to 88.24%. The linear relationship of the established method was good at the range of 0-500μg/L, and the detection limit was 2.17μg/L. The average concentration of nitrate in the coastal seawater was 8.89μg/L and the relative standard deviation was 0.23%. We added the standard solution of NO3-N with the concentrations of 100μg/L and 300μg/L to the seawater samples, respectively, with the recovery of standard addition among 99.90%~100.34%. The established method improved the UV reduction efficiency of nitrate and got high reproducibility and good accuracy which can be used to monitor nitrate content by in-situ analyzer.
Suitability evaluation of rural tourism based on AHP and fuzzy evaluation method
Authors: Xing Yunheng , Li Sheng , Liao Jianjun , Wang Zhiyuan , Wu Bo
Published: June 2019

In order to study the suitability of rural tourism development and prevent the blind development of rural tourism, we have identified 12 evaluation indicators of natural resources and human resources from three aspects: tourism resources, current development intensity and village development potential. Using AHP and fuzzy evaluation method to quantitatively analyze the various elements of rural tourism development, and evaluate the suitability of village development tourism industry.
Study on dynamic stress-strain response law of frozen saline soil
Authors: Zhao Futang , Chang Lijun , Zhang Wuyu , Kou Guangyun , Liu Haoyang
Published: June 2019

The subgrade saline soil in a certain area of western Qinghai province was studied, based on the British GDS dynamic triaxial test system, the dynamic triaxial test under laboratory test was carried out to study variation dynamic stress-strain and dynamic shear modulus under the different temperature, frequency and confining pressure. The test results show that the dynamic stress-strain relationship is significantly affected by temperature change under cyclic dynamic load, followed by frequency and confining pressure. Under the same strain amplitude, the lower the temperature, the larger the dynamic shear modulus. When frequency and confining pressure increase, dynamic shear modulus also increases. Whereas, the influence of confining pressure on the dynamic shear modulus is more obvious, and the backbone curve development trend is steeper. Both maximum dynamic shear modulus and final shear stress amplitude increase with the frequency increases when temperature and confining pressure remain unchanged. Meantime, the maximum dynamic shear modulus curve is a convex shape, and the final shear stress amplitude curve is a convex shape at positive temperature,while which a concave shape at negative temperature. At constant frequency and confining pressure, the maximum dynamic shear modulus and final shear stress amplitude increase with the decrease of temperature. Curves of change trend are slower above 0°C, and steeper below 0°C.
Modeling and Simulation of Evacuation Based on Bat Algorithm
Authors: Yu Tongtong , Wang Jian , Chen Xiaowei
Published: June 2019

The safe and orderly evacuation of crowds is a hot topic at home and abroad. To solve the problem of low evacuation efficiency of evacuation model based on PSO, this paper constructed a crowd evacuation model based on Bat Algorithm (BA). This model selected the new swarm intelligence algorithm Bat Algorithm and comprehensively considered obstacle avoidance. Specifically, firstly, the principle of BA and its feasibility for evacuation was introduced. Then, BA was used to update the crowd movement, the obstacle avoidance mechanism was established by using the cost function, and the crowd evacuation model based on BA was constructed. Finally, the evacuation path, evacuation efficiency and degree of chaos of this model and PSO-based evacuation model were compared and analyzed. The degree of chaos is represented by the value of evacuation entropy. Simulation results show that this model can effectively improve the evacuation efficiency and reduce the degree of chaos in the evacuation process.
Numerical Simulation of Fracture Propagation in Low Permeability Reservoir
Authors: ZOU Zuxu , Liu Jianjun , PEI Guihong , Chen Jiwen
Published: June 2019

In order to reveal fracture propagation law of low permeability oil reservoir, using RFPA software, a series of simulation models were built. Through numerical simulation, the maximum shear stress, the minimum main stress and pore pressure changes under different water injection pressure were got. The results shown that the process of fracture extension can be divided into three stages: the front stage, the microcrack stage and the rupture stage, the water injection pressure at 25 ~ 30MPa is the best result. The founding provides important theoretical guidance for low permeability reservoir reconstruction and optimization of well layout in the process of waterflood development.
Beijing and New York City: A comparison of building energy efficiency policies
Authors: Zhang Li , Wang Yonghui
Published: June 2019

Building energy efficiency is an important measure for reducing carbon emissions, and it plays a key role in the energy saving strategies all over the world. There is a growing global appeal to improve building energy efficiency due to the pursuit of sustainable development. Reducing building energy consumption and improving building energy efficiency are the main tasks of energy conservation work in China and the United States. We chose Beijing and New York City to highlight the current building energy efficiency policies in two cities. We then examine the differences between them. In New York City, there are more financial incentives, funding channels, participants, and public data available than in Beijing. Using the lesson learned from our investigation of New York City, we make recommendations for the development of Beijing’s policies. To overcome barriers to creating energy-efficient buildings, Beijing should increase energy efficiency awareness, innovate with flexible and feasible incentive policies, and improve data disclosure policies.
Effects of carbon dioxide dilution and composition on tip opening and OH radical distribution in laminar non-premixed Bunsen flame
Authors: Wang Zhonghua , Tang Qiang , Yang Zhongqing , Li Keliang
Published: June 2019

Effects of CO2 dilution and composition on tip opening and flame OH radical distribution in laminar non-premixed Bunsen flame were investigated by using planar laser induced fluorescence (PLIF) technique. Experiments were conducted at different component fractions diluted with CO2 at 20%, 25%, and 30%. The syngas were produced by biomass catalytic gasifying. Stretch rates were calculated and combined with OH-PLIF images and simulation. We conducted kinetic simulation to analyze the production of OH radical. Results show that as VH2 increases and hydrogen slightly increases, the effect of mass diffusion is enhanced, in addition, the value of stretch rate decreases, and the tip opening becomes further obvious. The profile of OH radical distribution also becomes broad. Finally, the total production rates of OH radicals increases with a rate less than 7.5%. Hence, the maximum value of OH radical counts is reduced by 33.33%, 27.92%, and 23.09%. Nonetheless, with the increasing addition of CO2, the effect of mass diffusion is weakened; besides, chemical reaction residence time increases, and the value of stretch rate increases; the tip opening is less obvious. Although the distribution area of OH was narrowed, its production decreased and the relative concentration of all OH radical decreased.
Research on standards and regulations of the operation of wastewater treatment plants
Authors: Xiaoxin Zhang , Jin Huang , Ling Lin , Shuming Liu , Yueping Wang , Xinheng Zhang
Published: June 2019

This paper summarizes the regulations related to operation of wastewater treatment plant at home and abroad, analyses the system, quantity and type distribution of the standards related to operation of wastewater treatment plant (WWTP) at home and abroad, and provides theoretical basis for research and development of operation effect evaluation criteria for Chinese WWTP by studying the contents and demands of standards related to operation effect evaluation of WWTP at home and abroad.
Influence of Product Modularity on Performance of Old Buildings’ Promotion and Transformation Projects
Authors: Cao Yayun , He Weiyi
Published: June 2019

Old buildings’ function promotion and transformation in cities is a new way to effectively improve people’s livelihood and vigorously stimulate domestic demand. However, government, as the sponsor of old buildings’ promotion and transformation projects, experiences a policy dilemma that exactly how to respond to the masses’ individual demands rapidly while taking the efficiency of supply into account. This article focuses on that if the modularity theory, which is applicable to private sector, can solve dis-economies of scale caused by customized supply in public sector. Through a case study in Tianjin, we find functional module partition mode and structural module partition mode, the main considerations of modular design, can make an influence on decision flexibility, whose intention is function configuration; and then, decision flexibility influence project performance by allocating optional space and speed.
Elastoplastic analysis of anchored tunnel under seepage
Authors: Gu Shuancheng , Li Xiaodong , Hu Xiaokai , Wang Bin , Wang Yaping
Published: June 2019

In order to study the stress and displacement distribution of surrounding rock of full-length bonded anchor support tunnel under seepage. The surrounding rock is regarded as a uniform and continuous porous medium. The supporting reaction force and seepage force of the surrounding rock are converted into the axisymmetric radial volume force of the circular tunnel and act on the stress field. Considering the reinforcement of the surrounding rock parameters by the bolt, the mechanical model is established. The elastoplastic analysis method is used to derive the analytical solution of the stress and displacement elasticity of the surrounding rock and plastic analytical solution based on Mohr-Coulomb yield criterion, which can be used to obtain the expression of the radius of the plastic zone of the tunnel and the displacement of the wall. Finally, the calculation results of this paper are compared with the numerical simulation analysis. The results show that the influence of the seepage on the plastic zone range and the wall displacement is more serious. The length and pretension of the bolt are inversely related to the plastic zone range and the displacement of the wall. The bolt row spacing is positively correlated with the plastic zone range and the displacement of the wall. Under the same conditions, considering the seepage requires the anchor to provide greater support. In order to avoid the instability of tunnel caused by seepage, the length of the bolt can be reasonably increased, the bolt spacing can be reduced, and the bolt pretension can be increased.
Study on Qualitative Evaluation Index System of VFM in PPP Project
Authors: Sun Chunling , Li Nannan , Zhang Yupeng
Published: June 2019

With the vigorous development of PPP mode in China, the qualitative evaluation of value for money (VFM) has become an important support for the decision-making of PPP project. As the evaluation system of VFM is still not mature enough in China, it needs to be further improved. On the basis of the "Guide to VFM evaluation in PPP Project (trial)", to get further supplement and enrich the indicators of qualitative evaluation of PPP projects, and giving the specific judgment criterion, the expert investigation method and hierarchical analysis method are used to determine the weight of evaluation indexes, and then a qualitative evaluation model of VFM evaluation with strong operability and reasonable evaluation would be constructed. Finally, the model which is constructed in this paper would be tested by engineering projects so as to make the qualitative evaluation method scientific and feasible for PPP model.
Study on the properties of composite mineral admixture material for rapid repair
Authors: Du Tianling , liu Ying
Published: June 2019

In this paper, the active mineral admixture was used to prepare the quick repair material that meets the requirements of 24h service. The development of the late strength, the shrinkage performance and wear resistance of the 60days were studied. The experimental results show that the composite mineral admixture is used to prepare the material for rapid repair, not only the early strength is high, but also the later strength is steadily increasing, and the dry age of 60 days is reduced, and the wear resistance is good. The use of industrial waste has certain economic and social benefits.
Evaluation of intergranular corrosion susceptibility of Super304H steel after being aged at 600°C
Authors: Zhong-wen ZHANG , Xiulian LI , Xin-mei LI , Yong ZOU , Bao-shuai DU , Shuai SUO , Wen LI
Published: June 2019

The susceptibility to intergranular corrosion of as-received and 600°C aging-treated new austenite heat-resistance Super304H steel was investigated by double loop electrochemical potentiodynamic (EPR) test. Experimental results indicated that the as-received Super304H steel possesses lower tendency of intergranaular corrosion. With the increase of aging time, intergranular corrosion susceptibility of Super304H steel increases. Intergranular corrosion of Super304H steel occurs due to the precipitation of Cr23C6 along grain boundaries. At the initial stage of aging, the rapid precipitating behavior of Cr23C6 leads to the rapid increase of intergranlar corrosion susceptibility. The amount of Cr23C6 precipitates increases with the extension of aging time, and the intergranular corrosion susceptibility of Super304H steel increases accordingly. The extent of intergranular corrosion change is related to the precipitating rate of Cr23C6. ()
Brief Introduction of Engineering Property for Coarse Grained Soil
Authors: Liu Mengshi , Shi Xiaowang
Published: June 2019

Coarse grained soil has been widely used in engineering construction for their excellent physical and mechanical properties. This paper presents the influence factors of shear strength, static and dynamic deformation characteristic of coarse grained soil, and finds that the dynamic property of coarse grained soil under cyclic load would be an important research direction.
Determination of Mountain Flood Warning Index Based on Distributed Hydrological Model
Authors: Hu Yu-bin
Published: June 2019

Mountain flood in small watershed comes unexpectedly, and the determination ofwater index is hard. Combined with the actual situation of Miaoxia Watershed, this paper proposes a design of flood calculation method based on HEC-HMS distributed model, and determines mountain flood warning index by using the method of water level backstepping discharge. The result calculated by this paper’s method has little difference compared with those using rational formula or instantaneous unit hydrograph, and the determination of the warning index is basically reasonable. The applied results shows that the determination of mountain flood warning index based on distributed hydrological model is simple and feasible, which is consultative for mountain flood warning index selection.
Effect of Active Admixture and Air Entraining Agent on Frost Resistance of Volcanic Scoria Thermal Insulation Plastering Mortar
Authors: Liguang Xiao , Genzhuang Li
Published: June 2019

The effects of fly ash, slag powder, diatomite and air entraining agent on the mechanical properties and freeze-thaw resistance of volcanic scoria thermal insulation plastering mortar were studied by orthogonal test. The test results showed that the thermal insulation plastering mortar achieves the best performance when the replacement rate of fly ash was 20%, the substitution rate of slag micropowder and diatomite is 10%, and the amount of air entraining agent is 0.1%. Compared with the ordinary thermal insulation plastering mortar, the 28d compressive strength is increased by 17.8%, the strength loss rate was reduced by 34.5% and the quality loss rate was reduced by 43.3%. Observing the microstructure of the thermal insulation plastering mortar by SEM, active admixture is beneficial to improving the structure of the hydration product and improving the compactness of the thermal insulation mortar.
The Normal Dynamic Stiffness Model of Joint Interfaces Based on Fractal Theory
Authors: Liu Wenwei , Wang Yuanhang , Li Xiaobing , Yang Jianfeng , Dong Chengju
Published: June 2019

To solve the problem of the poor dynamic performance of the machine due to low stiffness of joint interfaces, a theoretical normal dynamic stiffness model of joint interfaces based on fractal theory was proposed. An improved three-dimensional WM fractal function was used to characterize the contact surface, the vibration differential equation of the sphere-plane dynamic contact was established, the linearized stiffness of asperities in elastic deformation and elastoplastic deformation regime are derived respectively, and the normal dynamic stiffness model of the joint interfaces was established. At the same time, the relationship between the dynamic stiffness and the static stiffness of the joint interfaces was established. The analysis results show that, the dynamic stiffness of the joint was approximately equal to the static stiffness when the excitation frequency was much smaller than the natural frequency, and the dynamic stiffness was much larger than the static stiffness when the excitation frequency is much larger than the natural frequency, there also existed a resonant frequency that minimizes the dynamic stiffness.
Behavior of combined fly ash/GBFS-based geopolymer concrete after exposed to elevated temperature
Authors: Junru Ren , Huiguo Chen , Ruixi Dai , Tao Sun
Published: June 2019

Geopolymer is an emerging cementitious material characterized by better mechanical performance and more environmentally sustainable properties than ordinary Portland cement (OPC). Previous work mainly highlighted thermal behavior of metakaolin or fly ash-based geopolymers. This paper provides experimental data of geopolymer concrete manufactured with granulated blast furnace slag (GBFS) and fly ash after high temperature exposures of 400°C, 600°C, 800°C and 1 000°C in terms of ISO834. Residual compressive strength and splitting strength, as well as the effects of standing time were examined and compared with equivalent OPC concrete findings. The results revealed that both kinds of strength improved about 14% and 9% after being exposed to 400°C, and the reduction was less than OPC concrete. Additionally, the residual compressive strength after different exposures evolved variously with prolonging of standing time. On the basis of the results, the empirical equations of residual compressive strength and splitting strength of GC are established.
Finite Element Study on Mechanical Performances of Multi-Span Metal Faced Sandwich Panels under Temperature Actions
Authors: Tang Zhirong , Zha Xiaoxiong , Wang Baolin
Published: June 2019

Metal faced sandwich panel is composed of two relatively high strength metal faces and a relatively thick and lightweight insulated core. Under the continuous action of temperature such as strong sunlight, the multi-span metal faced sandwich panels can be destroyed. In this paper, the finite element (FE) software ABAQUS was used to study the stress and deformation of these sandwich panels under temperature action. The FE results show that the compressive stress in the mid-span region of the metal panel is larger and it gradually decreased from the middle to the two sides. The deformation at the centre of side span of sandwich panels is larger. The support constraints at the bottom of the sandwich panel have a great influence on the temperature stress. The fixed sandwich panel is more likely to occur wrinkle failure than the hinged one. To reduce the effects of temperature, two effective methods are proposed. The method increasing the density of the core material can increase the buckling stress and improve the bearing capacity against temperature action. The other method reducing the length of each segment of the sandwich panel can effectively release the temperature stress and reduce the negative effects of temperature.
Study on the Influence of the Height of Steel Beam on Creep Effects of Composite Beams
Authors: Zhang Shengping , Chen Xu , Lai Yingliang
Published: June 2019

The height of steel beam is an important parameter in the disign of structure. The effects of increasing the steel height of composite beam are quiet different from that of the pure steel beam because of composite and creep effects. To reveal the influences of this critical prarameter Rüsch constitutive equation of creep is used to obtain the exact results. With the increase of the steel height and after a limiting value is reached, the rate of the increase of the whole section stiffness becomes smaller, the rate of the increase of the compression zone of steel web becomes larger, yet the axial force and redistributed moment of concrete slab become almost constant. The deflection increases almost linearly and keeps a large slope with the increase of the steel height. Local buckling risk of the web must be considered.
Research on Information Integration of Construction Project Management Based on BIM
Authors: Gao Xiong , Wu Yansheng , Li Yan
Published: June 2019

The application of BIM play a crucial role to improve the current situation, and it has attracted increasingly attention from ACE (Architecture, Engineering, and Construction) industry participants, which improves the quality of project management and the ability of processing, integration and sharing information. The paper puts forward the framework of information integrated management mode based on BIM technology generally and based on the conceptual model of integrated information management system.The work still needed to complete is to develop BIM platform of integrated information management system based on Cloud technology and Internet of things at the later stage.
Experimental Study on Flexural Behavior of RC Beams Strengthened by External Prestressing
Authors: Cheng Yinglei , Xu Xinsheng
Published: June 2019

The efficient external prestressing reinforcement technology has the characteristics of simple construction, clear force transmission and convenient changing of cables, and has become a hot spot in the research of concrete structure reinforcement. In this paper, the external prestressed steel members are taken as the research object, and the two test beams are subjected to two-point loading test. The load-deflection curve is drawn. The ultimate bearing capacity, crack morphology and deflection of bending reinforced RC beams adopted external prestressing technology were compared and evaluated based on the experimental and theory analyzation. The experimental results show that the efficient external prestressing reinforcement technology can significantly improve the performance of concrete members and can be applied to structural reinforcement.
Second-order Effect Finite Element Analysis of Stainless Steel Frame Structure
Authors: Liao Rensheng , Zhang Zheng
Published: June 2019

Stainless steel has strong corrosion resistance and durability, which ensures the structural safety and durability, and has a good application prospect. Experiments on stainless steel have shown that the stress-strain nonlinearity of stainless steel is remarkable, which is different from that of ordinary steel. At present, the technical specifications for stainless steel structures do not specify the analysis of the internal force of stainless steel frames. By comparing the design specifications of steel structures and using finite element analysis method to analyze the internal forces of stainless steel frames, it is concluded that the approximate second-order analysis method in the design specifications of stainless steel frames can not be used, and the second-order analysis of internal forces of stainless steel frames should be carried out in consideration of material nonlinearity.
Identification of flowers of Musa nana Lour., flowers of Musa basjoo Sieb. et Zucc and flowers of Musa balbisiana Colla by HPLC fingerprinting
Authors: Zhang Lingling , Liang Yuqing , Zhang Peng , Yang Liubo , Li Xiaofen , Wang Xiangpei , Wu Hongmei
Published: June 2019

Objective: HPLC fingerprint identification method of flowers of Musa nana Lour., flowers of Musa basjoo Sieb. et Zucc and flowers of Musa balbisiana Colla were established, and the chromatogram similarities difference of three kinds of flowers were compared, in order to provide reference for variety identification, resource development and utilization of flowers of Musaceae medicinal materials. Methods: The separation was performed on a Diamonsil C18 column (4.6mm×250mm, 5μm) at 30°C. A binary gradient elution system was composed of acetonitrile and water containing 0.05% phosphoric acid and the flow rate was 0.8mL/min. The detection wavelength was 280nm. The HPLC fingerprint of 17 batches of flowers of Musaceae medicinal materials were determined and the similarities were evaluated. Results: The experimental results showed that the samples from flowers of same varieties showed high similarities, and had more common peaks. Flowers of Musa nana Lour., are compared with flowers of Musa basjoo Sieb. et Zuccr and flowers of Musa balbisiana Colla, whose similarities were less than 0.430 with few common peaks. However, the comparison between flowers of Musa basjoo Sieb. et Zuccr and flowers of Musa balbisiana Colla showed high similarities with more common peaks. The similarities of 17 batches of flowers of Musaceae medicinal materials were between 0.187 and 0.984 with few common peaks, indicating the significant difference of three kinds of flowers. Conclusion: The proposed method is simple, highly reproducible and suitable for the identification of flowers of Musaceae medicinal materials.
Research on the Theory and System for Testing Thermal Conductivity of Materials
Authors: Wang Chunyu , Yang Shifeng , Liu Chunqia
Published: June 2019

Thermal conductivity is one of important indexes of material’s quality evaluation. This material’s thermal conductivity detection system was designed and made based on the least square support vector machine algorithm. The system hardware was made mainly by microcontroller ATmega64, the temperature detection circuit and heating and refrigeration circuit. The system software was based on virtual instrument development platform of Labwindows/CVI and the least square support vector machine algorithm, which has data collection and processing, and the results display and control functions. Application shows that this system has advantages of reliable operation, precise temperature control and high thermal conductivity detection accuracy.
Establishment of a New Analysis Method for Trace Nitrogen Trifluoride in Helium detection by Gas Chromatography
Authors: Yin Qiang , Chen Ling , Ye Lifang , Jia Xiangrui , Mao Yuanwen , Zhou Yang , Zhou Jinyan , Huang Yanjie
Published: June 2019

In this experiment, a method for the determination of trace nitrogen trifluoride in helium (NF3/He) by gas chromatography (GC) was established. First, a series of NF3/He gas standard substance with accurate concentration was prepared by gravimetric method. And then, we had analyzed for the trace nitrogen and oxygen impurities in NF3, and the specific property experiment was used to verify that the impurity did not affect the measured value of the component. However, the analytical calibration curve of NF3 was nonlinear in the concentration range from 1 to 1000 μmol⋅mol−1. Nonlinear curves were transformed into linear curves by a linear power method, and the formula for the uncertainty of the fitting curve was calculated. Moreover, the consistency and uncertainty of the blind test results were evaluated. The results show that the method has high precision; the nitrogen or oxygen impurity has no effect on the specificity of the method; consistentcy of blind sample test result is well. Furthermore, it may be an ideal method for the research on the trace NF3 in helium.
Numerical simulation of elimination of white smoke in coal-fired power plants with WFGD system
Authors: Zhang Yixue , Liu Junyu , Luan Tao
Published: June 2019

White smoke discharged from chimney in coal-fired power plants always includes residual sulfide which can cause corrosive damage to buildings and environment around. In most coal-fired power plants, there are three major measures to eliminate white smoke: direct heating, condensing and heating, mixing with dry flue gas at high temperature. Main studies on white smoke elimination treat diffusion process as simple mixing of smoke and atmosphere, which has large deviation from reality. By 3D-modeling and numerical simulation, accurate data of white smoke elimination process is obtained. Simulation results indicate that humidity and temperature of atmosphere as well as smoke gas temperature are influential factors to the formation of white smoke. A fitting formula of atmosphere temperature, smoke gas discharge temperature and humidity has analyzed from simulation results, which provides exact data reference for practical white smoke elimination in coal-fired power plants.
Research on Operation Optimization of Integrated Energy System
Authors: Niu Honghai , Yu Fan , Li Bing , Chen Jun
Published: June 2019

The increasingly severe energy-saving situation and the need for sustainable development have brought the construction of integrated energy systems to a new level. The integrated energy system integrates multiple energy systems such as power supply, heating supply, and cooling supply. It is an inevitable trend in the development of modern energy systems to fully utilize the energy-saving potential of integrated energy systems through multi-energy complementary coordination and optimization. In this paper, an integrated energy system optimization scheduling model including a combined cooling, heating and power unit(CCHP) is proposed, and the optimal operation strategy of the integrated energy system under multi-season load demand is studied. The research results show that the integrated energy system can meet the requirements of energy security, stability and efficient supply under different seasonal conditions, and can significantly reduce energy operation costs.
Luminescent properties of a novel green phosphor CePO4-6LaPO4:Tb3+
Authors: Liu Ru , Wang Xigui
Published: June 2019

6LaPO4-CePO4:Tb3+ phosphors were synthesized by coprecipitation-high temperature solid phase methods. The structure and luminescence properties of phosphors were tested and analyzed by XRD, IR and fluorescence spectroscopy. The XRD pattern showed that the phosphors were LaPO4 and CePO4 of monoclinic; the FT-IR spectrum showed the same results as the XRD results; the fluorescence spectrum showed that the phosphors emitted green light at 544 nm, which corresponded to the transitions 5D4-7F5 of Tb3+.
A Geometry Elements Based Speed Prediction Model for Interchange Ramps of Mountainous Motorways
Authors: Jun Xie Hua Chai
Published: June 2019

The geometric design of motorways in the mountainous area is the top priority of the interchange planning and design. Reasonable ramp geometric design can not only reduce the cost and difficulties of construction of the interchange, but also improve the driving conditions, ensure traffic safety and improve the comfort of driving. Based on the development of foreign geometric alignment design practice, this paper analyze the continuous travel performance of vehicles on mountainous interchange ramps, and then proposes a highway geometric elements design method based on operating speed for practitioners to predict operating speed on ramps. The method will allow the auditors and the designers to proceed operating speed prediction for varied vehicle types for mountainous interchange ramps, which is also expected to give the auditors a good way to evaluate the consistency between driver’s expectation and the geometric design of the ramps.
Research on Performance Evaluation in PPPs in Sewage Treatment
Authors: Jiaoyue Long , Chuan Chen , Yan Tengteng , Yan Ziju , Zhang Muqian
Published: June 2019

Reasonable performance evaluation is one of the critical successful factors of PPP practices. For the sewage treatment PPP projects, the performance evaluation of "Emphasis on construction, neglect operation" has not been effectively improved. The value-for-money effect was lower than expected. Based on this background, this paper intends to take the XX Sewage Treatment PPP project as the research object, which will focuses on the analysis on the system of performance evaluation and summarize present problems of the system, then redesigns the performance evaluation system. At last, this paper measures the redesigned system, and provides some suggestions that contribute to the design performance evaluation system in PPP projects in sewage treatment.
Electrochemical impedance spectroscopy characteristics of steel corrosion in seawater sea-sand concrete
Authors: Wang Wei , Qian Liang , Zhang Yu , Zhang Yong-sheng
Published: June 2019

In this paper, the electrochemical mechanism and regularity of corrosion of steel bars in seawater sea-sand concrete under different chloride ion erosion styles are studied. Electrochemical impedance spectroscopy (EIS) was used to electrochemically test of steel bars in seawater sea-sand concrete (SSC). By means of analyzing the AC impedance spectra of the steel bars in specimens under two conditions, the conclusions can be gotten that in the EIS diagram of the steel bar in the rust state, the added capacitance arc in medium frequency range is related to pitting corrosion of the steel surface; The chloride ion carried by the aggregate and water decreased the concrete resistivity and transfer resistance of rebar and the anodic oxidation was easier to be carried out. In the equivalent circuit model, the constant phase element (CPE) is taken to replace the capacitor simulation in the equivalent circuit in order to simulate charge and discharge behavior of the electric double layer.
Simultaneous determination of multiple elements of tea garden soil using inductively coupled plasma mass spectrometry
Authors: Gan Z T , Yao T , She X S , Zhang P Q , Wang S Q , Wang Y , Tan Y Y , Qi N
Published: June 2019

Established a method of simultaneous determination of multiple elements of tea garden soil, the inductively coupled plasma mass spectrometry (ICP-MS) was used to test. The soil samples were decomposed by the fully automatic microwave with hydrogen nitrate (HNO3) and hydrofluoric acid (HF). The kinetic energy discrimination (KED) mode, the correction equation and the internal standard method were adopted to eliminate matrix effect interference within the testing process by ICP-MS. Moreover, contents of twenty-six soil elements were calculated with the corresponding standard curve at different content levels of standard solution. The results indicated that the curves of twenty-six elements which the contents were in the range of 0∼200μg/L were all approximately linear with correlation coefficients (R
2)> 0.990. The ranges of the limits of detection (LOD), the limits of quantification (LOQ) and the average recoveries (AR) of twenty-six soil elements were 0.0038∼3.6198μg/L, 0.0127∼12.0660μg/L and 84.04 %∼121 %, respectively, and the relative standard deviations (RSDs) were less than 7 %. The RSDs of standard substances of soil composition analysis were all < 5 % with ICP-MS in our experiments.
Multistage Control of Weak Microgrid with Power Quality Improvement Based on APF
Authors: Zhang Hong yang , Shi Zhen tang , Du Hong yong
Published: June 2019

The power quality of weak microgrid is sensitive due to the nonlinear loads and power electronic devices are applied, and the adjusting automatically compensation function of equipment self is inadequate and ineffective. For this, the control characteristic of active power filter(APF)is studied, and the droop control is analyzed in weak microgrid especially under the isolated island, and the principles of parameter adjustment are proposed. Then the multistage control algorithm of weak microgrid is proposed that improve the power quality and reliability based on APF, the algorithm is that the APF execute multistage filtering process according to the characteristics of harmonic and the other source are designed under droop control scheme, and the constraint condition which considering the THD of load current makes it contributing for the stability and reliability between APF and sources. Further, the mutual influence between multistage control algorithm and transition loads shedding considering different degrees of importance are discussed so that the scheme achieve a higher reliability. Finally, the effectiveness of the control algorithm proposed that taking oil field microgrid as an example in this paper is demonstrated through simulation and analyses.
Study on energy consumption of multi-trains tracking on long heavy down grade of high-speed railway
Authors: Chen Y , Guo H G , Ai Y P , He H
Published: June 2019

For the characteristics of high-speed train tracking operation on long heavy down grade of High-speed Railway, a cellular automaton dynamiccs model is proposed to simulate the energy consumption of multi-train tracking operation on long heavy down grade based on the NaSch model. Through numerical simulation, this paper studies the influence of different long slope value on the energy consumption of high-speed railway traffic flow. The simulation results show that the energy consumption model can accurately reflect the energy consumption of multi-train tracking operation on long heavy down grade. At the same time, the phenomenon of traffic waves that sometimes go and sometimes stop is reproduced. According to the simulation results, it can be concluded that the total energy consumption of multi-train tracking flow decreases gradually with the increase of slope value. The simulation results show that the energy consumption of starting, accelerating and decelerating of high-speed trains will decrease with the decrease of slope value. The results provide a scientific theoretical basis for efficient operation and energy-saving operation of high-speed railway. It has some guiding significance.
Connectedness Study on the Main Financial Institutions by Metal Mining Listed Companies from Perspective of Complex Networks
Authors: Ding Yun
Published: June 2019

This paper studies the network model of the relationship between metal mining listed companies by co-holding financial institutions as the node, and adopts the complex network theory analysis method to carry out the centrality calculation of the network model. The aim is to analyze the impact of main financial institutions in equity financing of China’s metal mining listed companies on the relationship between listed companies in the metal mining industry. According to the research, it is found that the overall network relationship characteristics of metal mining listed companies, the status of each company in the network and the interrelationship of each company. Meanwhile it can help metal mining listed companies to make correct decision-makings, effectively promote enterprises improvement and development.
Protection Scheme of Multi-terminal Flexible DC Distribution Network Based on Current-Limiting Inductor Voltage
Authors: Shangguan Xin , Qin Wenping , Wang Cheng , Niu Yuan
Published: June 2019

The rapid development of power electronic devices has promoted the rapid development of multi-terminal flexible DC distribution networks, indicating the direction of DC technology and urban power distribution systems. However, there are several technical problems in multi-terminal flexible DC distribution network that still need to be solved. In relay protection, the main difficulty faced by DC distribution network is the rapid and reliable identification of DC faults. This paper proposes a multi-terminal flexible DC distribution network protection scheme based on current-limiting inductor. First, the system configuration of the multi-terminal flexible DC distribution network is introduced. Then, the DC-side fault characteristic of the flexible DC distribution network are analysed. Based on this, a protection scheme based on current-limiting inductor voltage is proposed. Next, a complete protection scheme is designed. Finally, the proposed protection scheme is verified by real time digital simulator (RTDS). The simulation results show that the scheme is not affected by the fault resistance and fault distance.
Simulation Analysis of Propylene Storage Tank leakage Based on ALOHA Software
Authors: Yang Rili , Gai Ke , Yang Fengfeng , Zhang Guangsheng , Sun Ning , Feng Biyang , Zhu Xiulan
Published: June 2019

Hazardous chemical leakage accidents occur frequently, and once it appears, it will create a great effect. If a more accurate risk assessment impact area can be made in advance, the preventions and controls will play an invaluable role. A propylene storage tank in an industrial park was taken to identify the lying accidents and the risk ranks with the method of Preliminary Risk Analysis. It was found that the propylene poisoning accident and the steam cloud explosion accident have a great threat to the surrounding. With the inputs of relevant parameters, ALOHA software was used to simulate each accident, and the propylene poisoning accident and the vapour cloud explosion accident threat areas were obtained. The simulation provides effective information for the prevention and control of leakage accidents in the propylene storage tank leaking, and provides a scientific guideline for its ordinary safety management.
Ring-shaped DC Distribution Network Protection Scheme Research Based-on Voltage Prediction
Authors: Chang Xiao , Wang Cheng , Liu Yizhao , Zhang Min , Fan Rui , Shang Guanxin
Published: June 2019

In this paper, it researches the DC-ring distribution network protection scheme. Firstly, it analyzes the fault characteristics of the voltage source converter (VSC) during the DC line-to-ground. Secondly, it proposes a DC distribution network protection scheme based-on local measurement. The quadratic time-varying function is utilized to predict the line-side voltage in case of failure. The difference between the predicted voltage and the measured voltage on the line side in case of failure is utilized as the primary protective action criterion. Under voltage protection is utilized as backup protection in DC ring distribution network to guarantee safety and stability in case of failure. And the overcurrent protection is utilized as the startup criterion. The additional criteria are added to the further distinction between internal faults and external faults to prevent protection malfunction. The loop DC-distribution network protection scheme simulation based-on real-time digital simulator (RTDS) has verified the feasibility and effectiveness of the proposed scheme.
Deformation and Reinforcement Monitoring Analysis of Tail Water Outlet Slope in a Hydropower Station
Authors: Zhang Xu , Zhou Shaowu , Zhang Cheng , Gong Weiqiang , Qiao Yu
Published: June 2019

The slope stability situation surrounding the dam site area is very important to each correlative department during constructing hydroelectric power station. So it is important to enforce the high slope rock deformation monitoring, and to process and analyze the measuring data timely. Surface displacement of different height of slope were tracked and monitored based on the field investigation of a hydroelectric power station in Jinsha river. Deformation and the static stability of high slope were analyzed by utilizing rock deformation monitoring data. Taking the left-bank tailrace outlet slope of underground power station for example, we analyzed the slope stability by numerical simulation to obtain the characteristics of deformation and failure of slope. The time and space deformation distribution regularity of rock mass were summarized, the deformation, stress and failure of the studied slope were simulated. The results intuitively show the displacement distribution characteristics and slope plastic failure.