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Effects of rotor structure on performance of small size axial flow fans

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Journal of Thermal Science 2011年第3期20卷 205-210页

作者： Pin Liu Yingzi Jin yanping wang Laboratory of Fluid Transmission and Application Zhejiang Sci-Tech University Hangzhou 310018 China

Small size axial flow fans are used as a cooling component for computers,electronic equipment and other electronic *** the increasing power of electrical equipment,the demand for lower noise and higher ventilation of cooling fan is also *** methods of improving ventilation by raising the fan's rotation speed causes a decrease in efficiency and an increase in *** this paper,different structures of fans were simulated,and as a result,the counter-rotating fan can achieve higher pressure,efficiency and facilitate ventilation in a smaller ***,some other conclusions are as follows:(1) Higher pressure rise can be obtained by a counter-rotating fan than by the two-stage rotor fan in the same axial ***,the counter-rotating fan has a broader work scope.(2) The main noise type of the counter-rotating fan is rotating noise;the small peak pulse caused by vortex noise mainly due to the eddy current produced by small eddies.(3) When the distance of counter-rotating fans is smaller than 2 times the chord,the greater distance the greater total pressure of the circum-averages and along the axial direction,the total pressure begin to decline until the distance is three times the chord,so there is an optimal distance between *** simulation results are of important significance to the quantitative analysis and optimization design of the counter-rotating fan.

关键词： axial flow fan counter-rotating eddy current noise

Rhizosphere bacterial communities and soil nutrient conditions reveal sexual dimorphism of Populus deltoides

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Journal of Forestry Research 2023年第3期34卷 761-771页

作者： Qiliang Zhu Kun Yan Yufeng Dong yanping wang Taishan Forest Ecosystem Research Station of State Forestry Administration College of ForestryShandong Agricultural UniversityTai’an 271018People’s Republic of China Shandong Academy of Forest Jinan 250014People’s Republic of China

Sexual dimorphism of plants shapes the diff erent morphology and physiology between males and ***,it is still unclear whether it infl uences belowground ecological *** this study,rhizosphere soil of male and female Populus deltoides and bulk soil were collected from an 18-year plantation(male and female trees mix-planted)and grouped into three soil *** carbon(C),nitrogen(N)and phosphorus(P)levels were determined,and soil bacterial communities were analyzed by high-throughput *** results showed the less total carbon and total organic carbon,the more nutrients(available phosphorus,nitrate nitrogen and ammonium nitrogen)available in the rhizosphere soils of female poplars than soils of ***,α-diversity indices of the rhizosphere bacterial communities under male plants were signifi-cantly *** component analysis showed that the bacterial communities were signifi cantly diff erent between the male and female soil ***,the bacterial co-occurrence network in soil under male trees had more nodes and edges than under *** analysis showed the more functional bacteria taxa related to biofi lm formation and antioxidation under *** results indicate that soils under male poplars had more diverse and more complex co-occurrence networks of the rhizosphere bacterial community than soils under female trees,implying that male poplars might have better environmental *** study provides insight into the diff erent soil-microbe interactions of dioecious *** details about the infl uencing mechanism of sexual dimorphism on rhizosphere soil bacterial communities need to be further studied.

关键词： Dioecious poplar Rhizosphere bacterial community High-throughput sequencing Bacterial function prediction

Nestedness of waterbird assemblages in the subsidence wetlands recently created by underground coal mining

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Current Zoology 2019年第2期65卷 155-163页

作者： Chunlin LI Binbin ZHAO yanping wang School of Resources and Environmental Engineering Anhui University Hefei 230601 China Jiangsu Key Laboratory for Biodiversity and Biotechnology College of Life Sciences Nanjing Normal University Nanjing 210023 China College of Life Sciences Zhejiang University Hangzhou 310058 China

Nestedness has been a research focus in fields of island biogeography and community ecology in recent decades. Although nestedness of faunal assemblages has been investigated in natural wetlands, it remains largely unknown whether and why waterbird communities in artificial wetlands follow n ested patter ns. We exami ned the existence of n ested ness and un derlyi ng drivers in waterbird comm un ities in subside nee wetlands that are recently created by large-scale un derground coal mining in the North China Plain. Twelve point-count surveys for waterbirds were undertaken approximately every 2 weeks in 55 subside nee wetla nds from September 2016 to April 2017. We used the metric WNODF to estimate nestedness of the assemblages. Partial Spearman rank correlations were performed to examine the association between the nestedness and habitat variables (wetland area, landscape connectivity, wetland age, and habitat diversity) as well as life-history traits (body size, clutch size, dispersal ratio, geographical range size, and migrant status) related to species exti notion risk and colon izati on rate. Waterbird assemblages in the subside nee wetla nds were significantly nested. After controlling for other independent variables, the magnitude of nestedness was significantly and negatively correlated with wetland area and species trait linked to extinction risk (i.e., geographical range size). Our results indicate that selective extinction may be the main driver of the nestedness of waterbird assemblages in our study system. However, the nestedness was not due to passive sampling, selective colonization, or habitat diversity. From a conservation viewpoint, both large wetlands and waterbirds with a small geographic range should be protected to maximize the preserved species richness.

关键词： geographical range size nested pattern selective extinction waterbirds WNODF

Comprehensive Parameter for Analyzing Condensation in Pneumatic System

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Chinese Journal of Mechanical Engineering 2010年第5期23卷 641-646页

作者： JIN Yingzi LI Yi wang yanping wang Jie ZHU Zuchao Zhejiang Province Key Laboratory of Textile Machinery Zhejiang Sci- Tech University Hangzhou 310018 China The State Key Lab of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China

The condensation in pneumatic system is a complex physical phenomenon dependant upon status variation and phase transitions,which are related to the parameters of the compressed air,atmospheric conditions and the dimensions of the pneumatic *** to now,general research method for this problem is to calculate the status variation and movement quantity by numerical simulation and experiment *** comprehensive parameters composed of several different effect factors are rarely used to study the *** composed components and the working conditions of each cylinder are different,a large number of experiments and complex calculations are necessary to determine the ***,the transferability of the determined results is *** this paper,the charging and discharging systems of serials cylinder with different structure parameters are *** condensation of the systems is observed and the effects of the structure parameters on condensation are *** changing trends of relative humidity,natural frequency and average speed against the structural parameters of the components during discharge of the pneumatic systems are *** comprehensive parameters used to analyze and determine condensation composed by structure parameters of components are proposed,namely,the ratio of the effective area of the discharge tube and the container volume,the square root of the effective area of the discharge tube divided by the product of the container volume and the length of the discharge tube,and the discharge dimensionless *** experimental results show that these comprehensive parameters can be used to quantitatively determine whether internal,external or zero condensation occurs in a pneumatic system,and can be also used to quantitatively analyze the experimental data of condensation in pneumatic systems *** the same time,the effect factors are too much and the effect relationships are very complex,which

关键词： pneumatic system condensation comprehensive parameter structure parameter

A New Logarithmic Family of Distributions: Properties and Applications

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Computers, Materials & Continua 2021年第1期66卷 919-929页

作者： yanping wang Zhengqiang Feng Almaspoor Zahra Central South University Business School ChangshaChina Hunan International Business Vocational College ChangshaChina Department of Statistics Yazd UniversityYazdIran

In recent years,there has been an increased interest among the researchers to propose new families of distributions to provide the best fit to lifetime data with monotonic(increasing,decreasing,constant)and non-monotonic(unimodal,modified unimodal,bathtub)hazard *** further carry this area of research and propose a new family of lifetime distributions called a new logarithmic family via the T-X family *** the proposed family,explicit expressions for some mathematical properties along with the estimation of parameters through Maximum likelihood method are discussed.A sub-model,called a new logarithmic Weibull distribution is taken *** proposed model is very flexible and can be used to model data with increasing,decreasing,modified unimodal or bathtub shaped hazard *** maximum likelihood estimators of the model parameters are *** assess the behavior of the maximum likelihood estimators,a comprehensive Monte Carlo simulation study has been carried ***,the potentiality of the new model is shown via analyzing two real data sets taken from reliability engineering and biomedical *** comparison of the proposed model is made with the other well-known competitors such as(i)the three parameters exponentiated Weibull and Marshall–Olkin Weibull distributions and(ii)a four-parameter beta Weibull *** practical applications show that the proposed model performs much better than the competitive models and can be used as a good candidate model to analyze data in engineering,medical sciences and other related fields.

关键词： Weibull distribution moments order statistic residual life function maximum likelihood estimation

The influence of urban park characteristics on bird diversity in Nanjing, China

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Avian Research 2020年第4期11卷 475-483页

作者： Xueru Yang Xinwei Tan Chuanwu Chen yanping wang Jiangsu Key Laboratory for Biodiversity and Biotechnology College of Life SciencesNanjing Normal UniversityNanjing 210023China

Background:Habitat loss,fragmentation and decrease of habitat quality caused by urbanization have led to a dramatic decline in biodiversity *** highly urbanized areas,parks have become“islands”or habitat fragments for *** an important indicator group of urban ecosystem health,the response of birds to urbanization has attracted the global attention of *** the key factors affecting bird diversity in urbanized environment is crucial to the protection of biodiversity in urban ***:We used the line-transect method to survey birds in 37 urban parks in Nanjing,*** also measured a number of park characteristics(area,isolation,shape index,environmental noise,distance to city center,and habitat diversity)that are commonly assumed to influence bird *** then used the information-theoretic multi-model inference approach to determine which park characteristics had significant impacts on bird species ***:We found that park area,habitat diversity and the distance to city center were the best positive predictors of bird species richness in Nanjing urban *** contrast,park isolation,park shape and environmental noise had little or no influence on bird ***:Our study highlights the importance of park area,habitat diversity and the distance to city center in determining bird diversity in Nanjing city ***,from a conservation viewpoint,we recommend that large parks with complex and diverse habitats far away from the city center should be retained or constructed to increase bird diversity in urban design and planning.

关键词： Biodiversity conservation Bird diversity Habitat diversity Park area Species richness Urbanization Urban parks

Generalized pseudopolar format algorithm for radar imaging with highly suboptimal aperture length

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Science China(Information Sciences) 2015年第4期58卷 63-77页

作者： HAN KuoYe wang yanping CHANG XiangKe TAN WeiXian HONG Wen Science and Technology on Microwave Imaging Laboratory (MITL) Institute of ElectronicsChinese Academy of Sciences (IECAS) University of Chinese Academy of Sciences (UCAS) Institute of Computational Mathematics and Scientific Engineering Computing Chinese Academy of Sciences (ICMSEC CAS)

Different from conventional spaceborne or airborne synthetic aperture radar(SAR) with optimal aperture length, an imaging radar with highly suboptimal aperture length acquires the data in short bursts by a geometry spreading over a large range. A polarlike or pseudopolar format grid is introduced to sample data close to the resolution, which presents the design of a separable kernel for efficient FFT *** proposed imaging algorithm formulates the reflectivity image of the target scene as an interpolation-free double image series expansion with two usual approximation-induced phase error terms being taken into account,whereby more generalized application scenarios with high frequency, large bandwidth or larger aperture length for imaging a target scene located within either the far-field or the near-field of the radar aperture are processable with high accuracy. In addition, convergence acceleration methods in computational mathematics are introduced to accelerate the convergence of the image series expansion, so as to make the algorithm more efficient. The proposed algorithm has been validated both qualitatively and quantitatively with an extensive collection of numerical simulations and field measurements of ground-based SAR(GB-SAR) data set.

关键词： pseudopolar format ε-algorithm convergence acceleration suboptimal imaging radar imaging synthetic aperture radar(SAR)

Energy convergence effect and jet phenomenon of shock-heavy spherical bubble interaction

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Science China(Physics,Mechanics & Astronomy) 2015年第12期58卷 180-186页

作者： ZOU LiYong ZHAI ZhiGang LIU JinHong wang yanping LIU CangLi Laboratory for Shock Wave and Detonation Physics Institute of Fluid Physics China Academy of Engineering Physics Department of Applied Mathematics and Theoretical Physics Centre for Mathematical Sciences University of Cambridge Advanced Propulsion Laboratory Department of Modern Mechanics University of Science and Technology of China

We present computational results on the evolution of the shock-accelerated heavy bubbles surrounded by nitrogen with the Atwood number At = 0.497–0.677 and the emphasis is on the jet phenomenon caused by the shock focusing. The multi-fluid Eulerian equation is solved by a finite volume method based on MUSCL-Hancock approach. Based on the numerical schlieren and the distributions of density and pressure, it is found that there are three typical jet structures(outward jet, no jet, inward jet) for different combinations of gas mixture inside the bubble which determine the position of shock focusing relative to the downstream pole of the heavy bubble(upstream of the pole, at the pole, downstream the pole). Compared with the inward jet, the velocity of outward jet is obviously larger. As At increases, the moment of jet formation is postponed, and the maximal values and magnifications of pressure and density increase distinctly. Therefore, the energy convergence effects are heavily enhanced with the increase of bubble gas density.

关键词： shock-heavy bubble interaction energy convergence jet

Insights into the electrochemical degradation of sulfamethoxazole and its metabolite by Ti/SnO_(2)-Sb/Er-PbO_(2) anode

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Chinese Chemical Letters 2020年第10期31卷 2673-2677页

作者： yanping wang Chengzhi Zhou Jinhua Wu Junfeng Niu School of Environment and Energy South China University of TechnologyGuangzhou 510006China Research Center for Eco-Environmental Engineering Dongguan University of TechnologyDongguan 523808China

Electrochemical degradation of sulfamethoxazole(SMX)and its metabolite acetyl-sulfamethoxazole(AcSMX)by Ti/SnO_(2)-Sb/Er-PbO_(2) were *** indicated that the electrochemical degradation of SMX and Ac-SMX followed pseudo-first-order *** rate constants of SMX and Ac-SMX were 0.268 and 0.072 min-1 at optimal curre nt density of 10 and 14 mA/cm^(2),*** products of SMX and Ac-SMX were identified and the possible degradation pathways,including the cleavage of S-N bond,opening ring of isoxazole and nitration of amino group,were *** organic carbon removal of SMX was nearly 63.2%after 3 h electrochemical degradation.22.4%nitrogen of SMX was trans formed to NO_(3)-,and 98.8%sulfur of SMX was released as SO_(4)2-.According to quantitative structureactivity relationship model,toxicities of SMX and Ac-SMX to aquatic organisms significantly decreased after electrochemical *** energy consumption for 90%SMX and Ac-SMX degradation was determined to be 0.58-8.97 and 6.88-44.19 Wh/L at different experimental conditions,*** with parent compound SMX,the metabolite Ac-SMX is more refractory and toxic,which emphasizes the importance of taking its metabolites into account when investigating the disposal of pharmaceuticals from wastewater.

关键词： Electrochemical degradation Sulfamethoxazole and metabolite Degradation mechanism Quantitative structure-activity relationship