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A decoupled method to identify affecting mechanism of crosswind on performance of a natural draft dry

Weiliang WANG, Junfu LYU, Hai ZHANG, Qing LIU, Guangxi YUE, Weidou NI

《能源前沿（英文）》 2020年 第14卷 第2期   页码 318-327 doi: 10.1007/s11708-019-0627-x

摘要： The natural draft dry cooling tower (NDDCT) has been increasingly used for cooling in power generation in arid area. As crosswind affects the performance of a NDDCT in a complicated way, and the basic affecting mechanism is unclear, attempts have been made to improve the performance of a NDDCT based on limited experiences. This paper introduces a decoupled method to study the complicated crosswind effects on the inlet and outlet of a NDDCT separately by computational fluid dynamics (CFD) modeling and hot state experiments. Accordingly, the basic affecting mechanism of crosswind on the NDDCT performance is identified. Crosswind changes the inlet flow field of a NDDCT and induces mainstream vortices inside the tower, so as to degrade the ventilation. Besides, low crosswind deflects the upward plume at the outlet to further degrade the ventilation, while high crosswind induces the low pressure area at the outlet to reduce the ventilation degradation.

关键词： affecting mechanism     crosswind     decoupled method     mainstream vortices     natural draft dry cooling tower (NDDCT)     degradation    

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New medical risks affecting obstetrics after implementation of the two-child policy in China

null

《医学前沿（英文）》 2017年 第11卷 第4期   页码 570-575 doi: 10.1007/s11684-017-0552-5

摘要：

China recently instituted a two-child policy in response to its aging population, declining workforce and demographic dividend, and the need to develop asocial economy. Additionally, women generally delay having a second child because of the overwhelming pressure in their lives. With the improvements in assisted fertility technologies in recent years, the number of elderly women attempting to bear children has increased. The quality of woman’s eggs and a man’s sperm declined dramatically with increasing age, leading to an increased risk of pregnancy-related complications among older women. Therefore, the types of fertility problems experienced by elderly females must be provided with considerable attention by obstetricians. This commentary article focuses on the medical problems faced by older second-child pregnant women. This work discusses their increased rates of infertility, spontaneous abortion, fetal malformation, gestational diabetes, cesarean section, placenta previa, postpartum hemorrhage, postpartum depression, and hypertensive disorders, which complicate pregnancy.

关键词： two-child policy     birth defects     cesarean delivery     placenta previa    

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Factors affecting the distribution of microplastics in soils of China

《环境科学与工程前沿（英文）》 2023年 第17卷 第9期 doi: 10.1007/s11783-023-1710-4

摘要：

● Microplastic (MP) abundance in soil of China was highly heterogeneous.

关键词： Microplastic distribution     Microplastic heterogeneity     Effecting factors     Agriculture     Socio-economic factors    

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Factors affecting the seismic behavior of segmental precast bridge columns

Haitham DAWOOD,Mohamed ELGAWADY,Joshua HEWES

《结构与土木工程前沿（英文）》 2014年 第8卷 第4期   页码 388-398 doi: 10.1007/s11709-014-0264-8

摘要： This manuscript discusses the design parameters that potentially affect the lateral seismic response of segmental precast post-tensioned bridge piers. The piers consist of precast circular cross section segments stacked one on top of the other with concentric tendons passing through ducts made in the segments during casting. The bottommost segments of the piers were encased in steel tubes to enhance ductility and minimize damage. An FE model was used to investigate different design parameters and how they influence the lateral force – displacement response of the piers. Design parameters investigated included the initial post-tensioning stress as a percentage of the tendon yield stress, the applied axial stresses on concrete due to post-tensioning, pier aspect ratios, construction details, steel tube thicknesses, and internal mild steel rebar added as energy dissipaters. Based on the data presented, an initial tendon stress in the range of 40%-60% of its yield stress and initial axial stress on concrete of approximately 20% of the concrete’s characteristic strength is appropriate for most typical designs. These design values will prevent tendon yielding until lateral drift angle reaches approximately 4.5%. Changing the steel tube thickness, height, or a combination of both proved to be an effective parameter that may be used to reach a target performance level at a specific seismic zone.

关键词： finite element analysis     concrete     precast units     bridges    

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Investigation of the parameters affecting the behavior of RC beams strengthened with FRP

Kadir SENGUN; Guray ARSLAN

《结构与土木工程前沿（英文）》 2022年 第16卷 第6期   页码 729-743 doi: 10.1007/s11709-022-0854-9

摘要： Three-point bending tests were carried out on nineteen Reinforced Concrete (RC) beams strengthened with FRP in the form of completely wrapping. The strip width to spacing ratios, FRP type, shear span to effective depth ratios, the number of FRP layers in shear, and the effect of stirrups spacing were the parameters investigated in the experimental study. The FRP contribution to strength on beams having the same strip width to spacing ratios could be affected by the shear span to effective depth ratios and stirrups spacing. The FRP contributions to strength were less on beams with stirrups in comparison to the tested beams without stirrups. Strengthening RC beams using FRP could change the failure modes of the beams compared to the reference beam. In addition to the experimental study, a number of equations used to predict the FRP contribution to the shear strength of the strengthened RC beams were assessed by using a limited number of beams available in the literature. The effective FRP strain is predicted by using test results, and this prediction is used to calculate the FRP contribution to shear strength in ACI 440.2R (2017) equation. Based on the statistical values of the data, the proposed equation has the lowest coefficient of variation (COV) value than the other equations.

关键词： carbon     glass     strengthening     shear strength     reinforced concrete beam     fiber reinforced polymer    

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Study on affecting factors of collaborative product development based on collaboration hierarchy model

ZHANG Xiaodong, LI Yingzi, ZHANG Zhiqiang

《机械工程前沿（英文）》 2007年 第2卷 第2期   页码 210-213 doi: 10.1007/s11465-007-0036-4

摘要： Aiming at the levels of collaborative degree in web-based product development, a collaboration hierarchy model of this product development is developed in this paper. Based on the model, the affecting factors on collaboration levels are analyzed systematically from many aspects, such as technology, organization and business. A gap analysis method is studied in detail, and is applied in a real project. The application shows that it can solve the diverse problems of collaborative product development effectively, and help enterprises find out the critical factors that affect the collaboration.

关键词： development     web-based     business     collaborative     collaboration hierarchy    

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Factors affecting photocatalytic performance through the evolution of the properties due to the phase

《能源前沿（英文）》 2022年 第16卷 第3期   页码 471-482 doi: 10.1007/s11708-021-0778-4

摘要： The phase transition process of a photocatalytic system from NaBiO3·2H2O to BiO2–x has been investigated to understand the important factors that affect photocatalytic performance in a composite system. It is found that a proper amount of BiO2–x on the surface of NaBiO3·2H2O could effectively suppress the electron/hole recombination and increase the exposed reactive sites for photocatalytic reaction. A fully covered BiO2–x on NaBiO3·2H2O results in a dramatical decrease of photocatalytic degradation of dye. An over long hydrothermal process can result in BiO2–x with reduced oxygen vacancies, which degrades the photocatalytic activity. Furthermore, the photocatalytic reduction ability of CO2 conversion has been investigated, indicating that the surface activity to different reactants also directly affects the catalytic performance. The investigation of the gradient phase transition process presents a clear guidance to construct a desired photocatalytic system, in addition to selecting gradient materials with suitable bandgap structure and a morphology with different fraction and distribution of each component. The defect evolution of each component during construction of a composite is also an important factor that should be optimized and considered in making a composite to achieve high photocatalytic efficiency.

关键词： composite construction     distribution     BiO2–x     evolution of defects    

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Factors affecting simultaneous nitrification and denitrification in an SBBR treating domestic wastewater

LI Jun, GU Guowei, PENG Yongzhen, WEI Su

《环境科学与工程前沿（英文）》 2007年 第1卷 第2期   页码 246-250 doi: 10.1007/s11783-007-0042-0

摘要： An aerobic sequencing batch biofilm reactor (SBBR) packed with Bauer rings was used to treat real domestic wastewater for simultaneous nitrification and denitrification. The SBBR is advantageous for creating an anoxic condition, and the biofilm can absorb and store carbon for good nitrification and denitrification. An average concentration of oxygen ranging from 0.8 to 4.0 mg/L was proved very efficient for nitrification and denitrification. Volumetric loads of TN dropped dramatically and effluent TN concentration increased quickly when the concentration of average dissolved oxygen was more than 4.0 mg/L. The efficiency of simultaneous nitrification and denitrification (SND) increased with increasing thickness of the biofilm. The influent concentration hardly affected the TN removal efficiency, but the effluent TN increased with increasing influent concentration. It is suggested that a subsequence for denitrification be added or influent amount be decreased to meet effluent quality requirements. At optimum operating parameters, the TN removal efficiency of 74% 82% could be achieved.
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Factors affecting production of nonaqueous peracetic acid in tubular packed reactors

ZHANG Tengyun, FAN Hongbo, ZHONG Li, CHUANG Karl

《化学科学与工程前沿（英文）》 2008年 第2卷 第2期   页码 196-203 doi: 10.1007/s11705-008-0037-9

摘要： The synthesis of nonaqueous peracetic acid in acetone by acetaldehyde oxidation was carried out in a tubular packed reactor. The influencing factors of the reacting system including packing material, oxygen carrier, and reactor configuration were investigated. The results show that porous materials are inappropriate for peracetic acid synthesis and only non porous material with appropriate surface area can provide good peracetic acid selectivity and yield. Among the six kinds of packing material investigated, SA-5118 is the best one. As oxidizing gas, pure oxygen is superior to air. The optimum length-to-inner diameter ratio of the reactor is about 40. Under the proper reaction conditions, the highest peracetic acid yield of 84.15% and the highest selectivity of 93.34% can be achieved which indicates that the novel reacting system is effective and economical for nonaqueous peracetic acid production.
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Changes in major factors affecting the ecosystem health of the Weihe River in Shaanxi Province, China

Qi LI, Jinxi SONG, Anlei WEI, Bo ZHANG

《环境科学与工程前沿（英文）》 2013年 第7卷 第6期   页码 875-885 doi: 10.1007/s11783-013-0568-2

摘要： Maintenance of the ecosystem health of a river is of great importance for local sustainable development. On the basis of both qualitative and quantitative analysis of the influence of natural variations and human activities on the ecosystem function of the Weihe River, the changes in major factors affecting its ecosystem health are determined, which include: 1) Deficiency of environment flow: since the 1960s, the incoming stream flow shows an obvious decreasing tendency. Even in the low flow period, 80% of the water in the stream is impounded by dams for agriculture irrigation in the Baoji district. As a result, the water flow maintained in the stream for environmental use is very limited. 2) Deterioration of water quality: the concentrations of typical pollutants like Chemical Oxygen Demand (COD) and NH -N are higher than their maximum values of the Chinese environmental quality standard. Very few fish species can survive in the River. 3) Deformation of water channels: the continuous channel sedimentation has resulted in the decrease in stream gradient, shrinkage of riverbed and the decline in the capability for flood discharge. 4) Loss of riparian vegetation: most riparian land has been occupied by urban construction activities, which have caused the loss of riparian vegetation and biodiversity and further weakened flood control and water purification functions.

关键词： influencing factors     ecosystem health     ecological and environmental functions     the Weihe River     Shaanxi Province    

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Improvement of sludge dewaterability with modified cinder via affecting EPS

Weichao Ma, Lei Zhao, Huiling Liu, Qianliang Liu, Jun Ma

《环境科学与工程前沿（英文）》 2017年 第11卷 第6期 doi: 10.1007/s11783-017-0967-x

摘要： The relationship between the improvement of sludge dewaterability and variation of organic matters has been studied in the process of sludge pre-conditioning with modified cinder, especially for extracellular polymeric substances (EPS) in the sludge. During the conditioning process, the decreases of total organic carbon (TOC) and soluble chemical oxygen demand (SCOD) were obviously in the supernatant especially for the acid modified cinder (ACMC), which could be attributed to the processes of adsorption and sweeping. The reduction of polysaccharide and protein in supernatant indicated that ACMC might adsorb EPS so that the tightly bound EPS (TB-EPS) decreased in sludge. In the case of ACMC addition with 24 g·L , SRF of the sludge decreased from 7.85 × 1012 m·kg to 2.06 × 1012 m·kg , and the filter cake moisture decreased from 85% to 60%. The reconstruction of “floc mass” was confirmed as the main sludge conditioning mechanism. ACMC promoted the dewatering performance through the charge neutralization and adsorption bridging with the negative EPS, and provided firm and dense structure for sludge floc as skeleton builder. The passages for water quick transmitting were built to avoid collapsing during the high-pressure process.

关键词： Sludge conditioning     Acid or alkali modified cinder     TB-EPS     Floc mass     Floc reconstruction    

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Treatment, residual chlorine and season as factors affecting variability of trihalomethanes in small

Roberta DYCK,Geneviève COOL,Manuel RODRIGUEZ,Rehan SADIQ

《环境科学与工程前沿（英文）》 2015年 第9卷 第1期   页码 171-179 doi: 10.1007/s11783-014-0750-1

摘要： Seasonal variability in source water can lead to challenges for drinking water providers related to operational optimization and process control in treatment facilities. The objective of this study is to investigate seasonal variability of water quality in municipal small water systems (<3000 residents) supplied by surface waters. Residual chlorine and trihalomethanes (THM) were measured over seven years (2003–2009). Comparisons are made within each system over time, as well as between systems according to the type of their treatment technologies. THM concentrations are generally higher in the summer and autumn. The seasonal variability was generally more pronounced in systems using chlorination plus additional treatment. Chloroform, total THM (TTHM) and residual chlorine concentrations were generally lower in systems using chlorination plus additional treatment. Conversely, brominated THM concentrations were higher in systems using additional treatment. Residual chlorine was highest in the winter and lowest in the spring and summer. Seasonal variations were most pronounced for residual chlorine in systems with additional treatment. There was generally poor correlation between THM concentrations and concentrations of residual chlorine. Further study with these data will be beneficial in finding determinants and indicators for both quantity and variability of disinfection byproducts and other water quality parameters.

关键词： drinking water     residual chlorine     seasonal variability     small municipal systems     treatment technologies     trihalomethanes    

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Factors affecting early embryonic development in cattle: relevance for bovine cloning

Yanna DANG, Kun ZHANG

《农业科学与工程前沿（英文）》 2019年 第6卷 第1期   页码 33-41 doi: 10.15302/J-FASE-2018228

摘要：

Female infertility represents a major challenge for improving the production efficiency in the dairy industry. Historically, fertility has declined whereas milk yield has increased tremendously due to intensive genetic selection. evidence reveals about 60% pregnancy loss takes place during the first month following fertilization. Meanwhile, early embryo development is significant for somatic cell nuclear transfer in cattle as a large proportion of cloned embryos fail to develop beyond peri-implantation stage. Oocyte quality is of utmost importance for the early embryo to develop to term for both fertilized and cloned embryos. Epigenetic reprogramming is a key process occurring after fertilization and critical roles of epigenetic modifiers during preimplantation development are now clear. Incomplete epigenetic reprogramming is believed to be a major limitation to cloning efficiency. Treatment of cloned embryos with epigenetic modifying drugs (e.g., Trichostatin A) could greatly improve cloning efficiency in both mice and cattle. Recently, the rapid progress in high-throughput sequencing technologies has enabled detailed deciphering of the molecular mechanisms underlying these events. The robust efficiency of genomic editing tools also presents an alternative approach to the functional annotation of genes critical to early development.

关键词： bovine cloning     embryo development     somatic cell nuclear transfer     X-inactive specific transcript    

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Factors affecting the formation of zeolite seed layers and the effects of seed layers on the growth of

ZHANG Xiongfu, WANG Jinqu, LIU Hai′ou, WANG Anjie

《化学科学与工程前沿（英文）》 2007年 第1卷 第2期   页码 172-177 doi: 10.1007/s11705-007-0032-6

摘要： The present study investigates the formation of silicalite-1 seed layers on a porous carbon support of 0.5 μm pore size and α-A1O supports with different pore sizes (0.1 μm and 4 μm) via the slip-casting technique. The effects of support property, seed size and solvent on the formation of seed layers were investigated in detail. The growth of silicalite-1 membranes on different seeded supports by hydrothermal synthesis was also evaluated. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) characterizations indicate that a continuous seed layer can be obtained on the smooth support of 0.1 μm pore size by using any seed of 100 nm, 600 nm or 2.2 μm in size, whereas, on the coarse supports with either 0.5 μm or 4 μm pore size, a continuous seed layer cannot be formed using the above seed sizes and the same seeding time. At a longer contact time, a seed layer can also be formed using 100 nm seed on the supports with larger pore size. However, the layer is not uniform and smooth. For a hydrophobic porous carbon support, seeding ethanol suspension, which has weak polarity, favors the formation of a continuous seed layer. The seed layers and membranes grown from the smaller seed are more uniform and continuous and possess smoother surfaces than those from the larger seed. The seed layer and respective grown membrane formed from nanosized seed (100 nm) are the most uniform and compact. With this method of seeded secondary synthesis of zeolite membranes, the quality of a membrane mainly depends on the quality of the seed layer.

关键词： silicalite-1     α-A1O     growth     seeding ethanol     quality    

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Presentation of machine learning methods to determine the most important factors affecting road traffic

Hamid MIRZAHOSSEIN; Milad SASHURPOUR; Seyed Mohsen HOSSEINIAN; Vahid Najafi Moghaddam GILANI

《结构与土木工程前沿（英文）》 2022年 第16卷 第5期   页码 657-666 doi: 10.1007/s11709-022-0827-z

摘要： The purpose of this research was to develop statistical and intelligent models for predicting the severity of road traffic accidents (RTAs) on rural roads. Multiple Logistic Regression (MLR) was used to predict the likelihood of RTAs. For more accurate prediction, Multi-Layer Perceptron (MLP) and Radius Basis Function (RBF) neural networks were applied. Results indicated that in MLR, the model obtained from the backward method with the correct percent of 84.7% and R2 value of 0.893 was the best method for predicting the likelihood of RTAs. Also, MLR showed that the variables of not paying attention to the front not paying attention to the frontroad ahead, followed byand then vehicle-motorcycle/bike accidents were the greatest problems. Among the models, MLP had a better performance, so that the prediction accuracy of MLR, MLP, and RBF were 84.7%, 96.7%, and 92.1%, respectively. MLP model, due to higher accuracy, showed that the variable of reason of accident had the highest effect on the prediction of accidents, and considering MLR results, the variables of not paying attention to the front and then vehicle-motorcycle/bike accidents had the most influence on the occurrence of accidents. Therefore, motorcyclists and cyclists are more prone to accidents, and appropriate solutions should be adopted to enhance their safety.

关键词： safety     rural accidents     multiple logistic regression     artificial neural networks    

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标题 作者 时间 类型 操作

A decoupled method to identify affecting mechanism of crosswind on performance of a natural draft dry

Weiliang WANG, Junfu LYU, Hai ZHANG, Qing LIU, Guangxi YUE, Weidou NI

期刊论文

New medical risks affecting obstetrics after implementation of the two-child policy in China

null

期刊论文

Factors affecting the distribution of microplastics in soils of China

期刊论文

Factors affecting the seismic behavior of segmental precast bridge columns

Haitham DAWOOD,Mohamed ELGAWADY,Joshua HEWES

期刊论文

Investigation of the parameters affecting the behavior of RC beams strengthened with FRP

Kadir SENGUN; Guray ARSLAN

期刊论文

Study on affecting factors of collaborative product development based on collaboration hierarchy model

ZHANG Xiaodong, LI Yingzi, ZHANG Zhiqiang

期刊论文

Factors affecting photocatalytic performance through the evolution of the properties due to the phase

期刊论文

Factors affecting simultaneous nitrification and denitrification in an SBBR treating domestic wastewater

LI Jun, GU Guowei, PENG Yongzhen, WEI Su

期刊论文

Factors affecting production of nonaqueous peracetic acid in tubular packed reactors

ZHANG Tengyun, FAN Hongbo, ZHONG Li, CHUANG Karl

期刊论文

Changes in major factors affecting the ecosystem health of the Weihe River in Shaanxi Province, China

Qi LI, Jinxi SONG, Anlei WEI, Bo ZHANG

期刊论文

Improvement of sludge dewaterability with modified cinder via affecting EPS

Weichao Ma, Lei Zhao, Huiling Liu, Qianliang Liu, Jun Ma

期刊论文

Treatment, residual chlorine and season as factors affecting variability of trihalomethanes in small

Roberta DYCK,Geneviève COOL,Manuel RODRIGUEZ,Rehan SADIQ

期刊论文

Factors affecting early embryonic development in cattle: relevance for bovine cloning

Yanna DANG, Kun ZHANG

期刊论文

Factors affecting the formation of zeolite seed layers and the effects of seed layers on the growth of

ZHANG Xiongfu, WANG Jinqu, LIU Hai′ou, WANG Anjie

期刊论文

Presentation of machine learning methods to determine the most important factors affecting road traffic

Hamid MIRZAHOSSEIN; Milad SASHURPOUR; Seyed Mohsen HOSSEINIAN; Vahid Najafi Moghaddam GILANI

期刊论文