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Failure Analysis of Aviation Torsional Springs

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Chinese Journal of Aeronautics 2011年第4期24卷 527-532页

作者： hou weiguo ZHANG Weifang LIU Xiao WANG Zongren DING Meili School of Reliability and System Engineering Beihang University Beijing 100191 China

Cracks and fractures occur during the assembly process to a type of torsional springs used in the aviation mechanism. Besides visual examination, other experimental techniques used for the investigation are： 1） fracture characteristics, damage morphology and fractography by scanning electron microscopy （SEM）, 2） spectrum analysis of covering, 3） metallographic observation of cracks and 4） hydrogen content testing. The results are obtained through the analysis of manufacture process and experimental data. Since no changes of microstructure are found, failures are irrelevant to the material. The cracks and fractures initiate on the inner surface, cracks initiate before the cadmium plating and after the winding. No obvious stress corrosion cracks are found near the crack source region. The opening direction of cracks is consistent with the residual tensile stress of the spring inner surface, and the springs are easy to contact hydrogen media between the spring winding and the cadmium plating. The cracks are caused by hydrogen-induced delayed cracking under the action of the residual tensile stress and hydrogen.

关键词： springs failure residual stress hydrogen-induced delayed cracking

Distinguishing ectomycorrhizal and saprophytic fungi using carbon and nitrogen isotopic compositions

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Geoscience Frontiers 2012年第3期3卷 351-356页

作者： weiguo hou Bin Lian Hailiang Dong Hongchen Jiang Xingliang Wu State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences Beijing 100083 China State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China Department of Geology and Environmental Earth Science Miami University Oxford OH 45056 USA Guizhou Academy of Sciences Guiyang 550001 China

Ectomycorrhizal fungi, a group of widespread symbiotic fungi with plant, obtain carbon source from trees and improve plant mineral nutrient uptake with their widespread hyphal network. Ectomycorrhizal fungi can be used as inoculants to improve the survival rates of plantation. Saprophytic fungi use the nutrition from the debris of plant or animals, and it is difficult to distinguish the saprophytic and ectomycorrhizal fungi by morphological and anatomic methods. In this research, the differences of stable carbon and nitrogen isotopic compositions of these fungi were analyzed. The results showed that the abundances of 13C of were higher than those of ectomycorrhizal fungi and the abundances of 15N of saprophytic fungi were lower than those of ectomycorrhizal fungi. Such differences of stable carbon and nitrogen isotopic compositions between ectomycorrhizal fungi and saprophytic fungi can be ascribed to their different nutrition sources and ecological functions. These results collectively indicate that stable carbon and nitrogen isotopic compositions are an effective proxy for distinguishing between ectomycorrhizal and saprophytic fungi.

关键词： Ectomycorrhizal fungi Saprophytic fungi Stable isotopiccompositions Ecological function

The mechanism of barrier river reaches in the middle and lower Yangtze River

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Journal of Geographical Sciences 2017年第10期27卷 1249-1267页

作者： YOU Xingying TANG Jinwu ZHANG Xiaofeng hou weiguo YANG Yunping SUN Zhaohua WENG Zhaohui State Key Laboratory of Water Resource and Hydropower Engineering Science Wuhan University Wuhan 430072 China Hubei Provincial Water Resources and Hydropower Planning Survey and Design Institute Wuhan 430064 China Changjiang Institute of Survey Planning Design and Research Wuhan 430010 China Key Laboratory of Engineering Sediment Tianjin Research Institute for Water Transport Engineering Ministry of Transport Tianjin 300456 China

Alluvial channel has always adjusted itself to the equilibrium state of sediment transport after it was artificially or naturally disturbed. How to maintain the equilibrium state of sediment transport and keep the river regime stable has always been the concerns of fluvial geomorphologists. The channel in the middle and lower reaches of the Yangtze River is characterized by the staggered distribution of the bifurcated river and the single-thread river. The change of river regime is more violently in the bifurcated river than in the single-thread river. Whether the adjustment of the river regime in the bifurcated river can pass through the single-thread river and propagate to the downstream reaches affects the stabilities of the overall river regime. Studies show that the barrier river reach can block the upstream channel adjustment from propagating to the downstream reaches; therefore, it plays a key role in stabilizing the river regime. This study investigates 34 single-thread river reaches in the mid- dle and lower reaches of the Yangtze River. On the basis of the systematic summarization of the fluvial process of the middle and lower reaches of the Yangtze River, the control factors of barrier river reach are summarized and extracted： the planar morphology of single-thread and meandering; with no flow deflecting node distributed in the upper or middle part of the river reach; the hydraulic geometric coefficient is less than 4; the longitudinal gradient is greater than 12‰, the clay content of the concave bank is greater than 9.5%, and the median diameter of the bed sediment is greater than 0.158 mm. From the Navier-Stokes equation ,the calculation formula of the bending radius of flow dynamic axis is deduced and then the roles of these control factors on restricting the migration of the flow dynamic axis and the formation of the barrier river reach are analyzed. The barrier river reach is considered Such. When the ratio of the migration force of the flow dynamic

关键词： barrier river reaches flow dynamic axis channel boundary the middle and lower Yangtze River

Co-occurrence of nitrite-dependent anaerobic methane oxidizing and anaerobic ammonia oxidizing bacteria in two Qinghai-Tibetan saline lakes

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Frontiers of Earth Science 2012年第4期6卷 383-391页

作者： Jian YANG Hongchen JIANG Geng WU weiguo hou Yongjuan SUN Zhongping LAI Hailiang DONG State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences Wuhan 430074 China State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences Beijing 100083 China Qinghai Institute of Salt Lakes Chinese Academy of Sciences Xining 810008 China State Key Laboratory of Cryospheric Sciences Cold and Arid Regions Environmental and Enginee-ring Research Institute Chinese Academy of Sciences Lanzhou 730000 China Department of Geology and Environmental Earth Science Miami University Oxford OH 45056 USA

Nitrite-dependent anaerobic methane-oxidiz- ing （n-damo） bacteria and anaerobic ammonia oxidizing （anammox） bacteria are two groups of microorganisms involved in global carbon and nitrogen cycling. In order to test whether the n-damo and anammox bacteria co-occur in natural saline environments, the DNA and cDNA samples obtained from the surficial sediments of two saline lakes （with salinity of 32 and 84 g/L, respectively） on the Tibetan Plateau were PCR-amplified with the use of anammox- and n-damo-specific primer sets, followed by clone library construction and phylogenetic analysis. DNA and cDNA- based clones affiliated with n-damo and anammox bacteria were successfully retrieved from the two samples, indicating that these two groups of bacteria can co-occur in natural saline environments with salinity as high as 84g/L. Our finding has great implications for our understanding of the global carbon and nitrogen cycle in nature.

关键词： anammox n-damo co-occurrence saline lakes Qinghai-Tibetan Plateau

Microbial diversity accumulates in a downstream direction in the Three Gorges Reservoir

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Journal of Environmental Sciences 2021年第3期33卷 156-167页

作者： Shang Wang weiguo hou Hongchen Jiang Liuqin Huang Hailiang Dong Shu Chen Bin Wang Yongcan Chen Binliang Lin Ye Deng CAS Key Laboratory of Environmental Biotechnology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China School of Environment and Resource Southwest University of Science and TechnologySichuan 621010China State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesBeijing 100083China School of Ocean Sciences China University of GeosciencesBeijing 100083China State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesWuhan 430074China Department of Hydraulic Engineering Tsinghua UniversityBeijing 100084China Department of Geology and Environmental Earth Science Miami UniversityOxfordOH 45056USA

Organic and inorganic materials migrate downstream and have important roles in regulating environmental health in the river ***,it remains unclear whether and how a mixture of materials(i.e.,microbial species)from various upstream habitats contribute to microbial community coalescence upstream of a *** we track the spatial variation in microbial abundance and diversity in the Three Gorges Reservoir based on quantitative PCR and 16 S rRNA gene high-throughput sequencing *** further quantitatively assess the relative contributions of microbial species from mainstem,its tributaries,and the surrounding riverbank soils to the area immediately upstream of the Three Gorges Dam(TGD).We found an increase of microbial diversity and the convergent microbial distribution pattern in areas immediately upstream of TGD,suggesting this area become a new confluence for microbial diversity immigrating from ***,the number of shared species increased from upstream to TGD but unique species decreased,indicating immigration of various sources of microbial species overwhelms local environmental conditions in structuring microbial community close to *** quantifying the sources of microbial species close to TGD,we found little contribution from soils as compared to tributaries,especially for sites closer to TGD,suggesting tributary microbes have greater influence on microbial diversity and environmental health in the Three Gorges ***,our results suggest that tracking microbial geographic origin and evaluating accumulating effects of microbial diversity shed light on the ecological processes in microbial communities and provide information for regulating aquatic ecological health.

关键词： Three Gorges Dam Microbial source tracking Microbial community coalescence Immigration Accumulating effect

Progress in Thermal Contact Resistance

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稀有金属材料与工程 2011年第S3期40卷 211-215页

作者： Wang Zongren, Zhang Weifang, Tang Qingyun, hou weiguo Beijing University of Aeronautics and Astronautics, Beijing100191, China Beijing Univ Aeronaut & Astronaut Sch Reliabil & Syst Engn Beijing 100191 Peoples R China

The developments of aeronautics and astronautics require engines of higher quality. The temperature distribution in combustion engine is highly influenced by the thermal conduct resistance. To predict the temperature field of the hot-end assemblies of combustion engine, the thermal contact resistance must be considered. The object of the study is to propose a model of high application including in conditions of high temperature and high pressure. Up to date, many models and empirical or semi-empirical correlations have been developed, also researchers designed different test equipments according to specific conditions. This paper presents several representative models and test equipments, compares the merits and drawbacks with each other, and gives recommendations for further research.

关键词： thermal contact resistance elastic model plastic model test equipment

Microbial diversity in two cold springs on the Qinghai-Tibetan Plateau

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Geoscience Frontiers 2012年第3期3卷 317-325页

作者： Gaoyuan Li Hongchen Jiang weiguo hou Shang Wang Liuqin Huang Huilei Ren Shicai Deng Hailiang Dong State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesBeijing 100083China AE&E Geomicrobial Technologies Inc.Beijing 102200China Department of Geology and Environmental Earth Science Miami UniversityOxfordOH 45056USA

The microbial diversity in Wuli Area, Qinghai-Tibetan Plateau was investigated using 16S rRNA gene phylogenetic analyses. A total of 117 bacterial and 66 archaeal 16S rRNA gene clones were obtained from the Wuli cold springs, The bacterial clones could be classified into Proteobacteria, Acid- obacteria, Deinococci, Sphingobacteria, Flavobacteria, Nitrospirae, Actinobacteria, Gemmatimona- detes, and unclassified-bacteria; and the archaeal clones could be classified into Crenarchaeota and Thaumarchaeota. Among the major groups, Proteobacteria and Crenarchaeota were dominant in the bacterial and archaeal 16S rRNA gene clone libraries, respectively. The clone sequences obtained in Wuli cold springs were closely related to those from cold habitats, such as snow/ice/soils on high mountains or at high latitude. Especially, the microbial community composition of Wuli Area was more similar to that in Tibetan glaciers than cold environments of other locations. The data presented in this study have impli- cations for a better understanding of microbial diversity in cold springs on the Qinghai-Tibetan Plateau.

关键词： Cold spring Microbial diversity Qinghai-Tibetan Plateau

The effects of local government investment on economic growth and employment: evidence from transitional China

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Ecological Economy 2009年第1期5卷 28-37页

作者： Zhang weiguo hou Yongjian Institute of Economics Shandong Academy of Social Sciences Jinan 250002 P. R. China

Based on the panel data of 28 provinces in the year of 1987-2001, this paper examines the effects of the local government investment on economic growth and employment. The empirical result shows that the local government investment plays a significant positive role in economic growth and employment. However, while the proportion of local government investment to GDP had a remarkable rise after 1998, the elasticity of local government investment on economic growth declined, which shows that there is a big room for raising the efficiency of local government investment. Moreover. the empirieal examination shows that although local government investment had positive effect on employment, the elasticity had a decrease after 1994 when the tax-sharing system reform was put into practice. This shows that the positive role of local government investment on employment is also limited This paper argues that the role of local governments as investors must be weakened, and local governments of different levels should lessen direct economic intervention and concentrate on public regulation.

关键词： Local government investment Economic growth Employment

A review of the microbiology of the Rehai geothermal field in Tengchong,Yunnan Province,China

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Geoscience Frontiers 2012年第3期3卷 273-288页

作者： Brian P.Hedlund Jessica K.Cole Amanda J.Williams weiguo hou Enmin Zhou Wenjun Li Hailiang Dong School of Life Sciences University of Nevada Las VegasLas VegasNV 89154-4004USA Geomicrobiology Laboratory State Key Laboratory of Geological Processes and Mineral ResourcesChina University of GeosciencesBeijing 100083China Yunnan Institute of Microbiology Yunnan UniversityKunming 650011China Department of Geology Miami UniversityOxfordOH 45056USA

The Rehai Geothermal Field, located in Tengchong County, in central-western Yunnan Prov- ince, is the largest and most intensively studied geothermal field in China. A wide physicochemical diversity of springs （ambient to -97 ℃; pH from 〈1.8 to≥9.3） provides a multitude of niches for extremophilic microorganisms. A variety of studies have focused on the cultivation, identification, basic physiology, taxonomy, and biotechnological potential of thermophilic microorganisms from Rehai. Ther- mophilic bacteria isolated from Rehai belong to the phyla Firmicutes and Deinococcus-Thermus. Firmicutes include neutrophilic or alkaliphilic Anoxybacillus, Bacillus, Caldalkalibacillus, Caldanaerobacter, Laceyella, and Geobacillus, as well as thermoacidophilic Alicyclobacillus and Sulfobacillus. Isolates from the Deinococcus-Thermus phylum include several Meiothermus and Thermus species. Many of these bacteria synthesize thermostable polymer-degrading enzymes that may be useful for biotech- nology. The thermoacidophilic archaea Acidianus, Metallosphaera, and Sulfolobus have also been isolated and studied. A few studies have reported the isolation of thermophilic viruses belonging to Siphoviridae （TTSP4 and TTSP10） and Fuselloviridae （STSV1） infecting Thermus spp. and Sulfolobus spp., respectively. More recently, cultivation-independent studies using 16S rRNA gene sequences, shotgun metagenomics, or ＂＇functional gene＂ sequences have revealed a mtlch broader diversity of micro- organisms than represented in culture. Studies of the gene and mRNA encoding 113e large subunit of the ammonia monooxygenase （amoA） of ammonia-oxidizing Archaea （AOA） and the tetraether lipid cre- narchaeol, a potential hiomarker for AOA, suggest a wide diversity, but possibly low abundance, of ther- mophilic AOA in Rehai. Finally, we introduce the Tengchong Partnerships in International Research and Education （P1RE） project, an international collaboration between Chinese and U.S. scientists with the goal of

关键词： GeomicrobiologyThermophile Yunnan Rehai Tengchong PIRE