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SOME RULES OF variation coefficient OF ANNUAL RAINFALL IN XINJIANG,CHINA

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Acta meteorologica Sinica 1993年第1期7卷 123-128页

作者：马淑红张学文 Xinjiang Meteorological Research Institute Urumqi 830002

In this paper,the variation of annual rainfall in Xinjiang by variation coefficient (C_v) widely used in statistics and hydrology is *** on analysing of 25 years' observational data in 98 stations,the authors found that the varia- tion coefficient of annual rainfall has better relation with annual rainfall and sea level elevation,which can be expressed by a bivariate *** discovery is no doubt valuable to the study of climatic theory and water resources in the area where data are rare.

关键词： rainfall variation coefficient sea level elevation Xinjiang

Mechanical property statistical analysis of Gd50Al30Co20 amorphous wires for providing reference to design requirements of cooling system

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Journal of Iron and Steel Research International 2018年第3期25卷 261-267页

作者： Bin Luo Hong-xian Shen Lin Lin Hai-chao Li Da-wei Xing Jian-fei Sun School of Mechatronics Engineering Harbin Institute ofTechnology Harbin 150001 Heilongjiang China School of Materials Science and Engineering HarbinInstitute of Technology Harbin 150001 Heilongjiang China

Gd50Al3oCo20 wires show excellent magnetocaloric properties and high heat exchange rate due to the microsize. The Weibull and lognormal methods were used for systematically analyzing its mechanical properties for matching the design requirements in cooling system. The wire exhibits average fracture strength of-969.5 MPa and typical fracture behavior of amorphous character. Moreover, the distributions of stresses for tensile strains at 10 values are estimated by probability plot and Chi-square goodness-of-fit test. The random stresses were best fitted by lognormal probability distribution for most studied cases; however, fracture strength was best fitted by Weibull probability distribution. It is interesting to note that the mean and standard deviation of the stresses （to reach specific tensile strain） increase as the tensile strain grows, accompanied by the coefficients of variation of stresses which decrease smoothly. It is concluded that the inhomogeneity of material does cause the scatter of stresses growth, and the scatter could be considerably large.

关键词： Gd50Al30Co20 amorphous wire Tensile property Statistical analysis variation coefficient

Friction wheel transmission of no-tillage corn planters

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International Journal of Agricultural and Biological Engineering 2017年第4期10卷 87-97页

作者： Jia Honglei Zhang Zhuo Chen Zhi Zheng Tiezhi Zhao Jiale Guo Mingzhuo College of Biological and Agricultural Engineering Jilin UniversityChangchun 130025China Key Laboratory of Bionics Engineering Ministry of EducationJilin UniversityChangchun 130025China China National Machinery Industry Corporation Beijing 100080China Jilin Agricultural Mechanization Management Center Changchun 130022China

To overcome the unfavorable factors of ground wheel-driven chain transmission when a no-tillage planter operates on straw mulching fields,a friction wheel transmission based on ground wheel transmission was designed in this *** stability,i.e.,the effects of friction wheel tyre pressure on stability of machine transmission was investigated via validation of main *** relationships among tyre pressure,deformation and load were determined via theoretical *** tyre pressure extreme for transmission is 25.90 psi,the maximum pressure imposed on the friction wheel tyre is 14 kN,the maximum deformation of friction wheel is 8.7 *** stabilities of friction wheel slip rate and seeding distance were investigated via field tests and alteration of friction wheel tyre *** processing the test data,it can be found that the minimum tyre pressure for acquisition of friction wheel slip rate was 24.35 *** processing the data of seeding distance,it can be validated that the tyre pressure was kept unchanged following the optimal transmission effect of the transmission through the abrupt change of working speed,which further proved the feasibility of the new friction wheel *** transmission of friction wheel can reduce 14.67%in variation coefficient of seed spacing at the speed of 5 km/h,and 16.22%at the speed of 8 km/h.

关键词： no-tillage planter corn friction wheel transmission slip rate field test variation coefficient seeding distance

Research on testing method of resin sand high temperature compressive strength

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China Foundry 2016年第5期13卷 335-341页

作者： Peng Wan Luan-cai Li Long Zhang Wen-qing Wang State Key Laboratory of Materials Processing and Die & Mould Technology Huazhong University of Science & Technology School of Metallurgical Engineering Anhui University of Technology

High temperature compressive strength is one of the most important performances of resin sand; its value directly concerns the quality of castings. In order to seek the best testing method of resin sand high temperature compressive strength, a self-developed instrument was used to carry out experiments, and the sample shape and size were designed and studied. The results show that a hollow cylinder sample can reflect the strength difference of different resin sands better than a solid cylinder sample, and its data is stable. The experiments selected φ20/5×30 mm as the size of the hollow cylinder samples. The high temperature compressive strengths of phenol-formaldehyde resin coated sand, furan resin self-setting sand, and TEA resin sand were each tested. For the resin sand used for cast steel and cast iron, 1,000 ℃ was selected as the test temperature; for the resin sand used for cast non-ferrous alloy, 800 ℃ was selected as the test temperature; and for all the resin sand samples, 1 min was selected as the holding time. This testing method can truthfully reflect the high temperature performance of three kinds of resin sand; it is reproducible, and the variation coefficients of test values are under 10%.

关键词： resin sand high temperature compressive strength hollow cylinder specimens variation coefficient

Evaluation model for process stability of short-circuiting arc welding

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China Welding 2008年第2期17卷 8-14页

作者：蔡艳杨海澜华学明吴毅雄 Welding Engineering Institute Shanghai Jiao Tong University

stability of welding process is the prerequisite and assurance for ideal joint. The structure of stability model and its optimization are the key to on-line evaluation technology of arc welding. Characteristic parameters are extracted from the single transfer period while variation coefficients of the characteristic parameters are concerned for whole welding process of continuous drop transfer. Based on the characteristic parameters and their variation coefficients, stability model of short-circuit arc welding process is established by partial-least-square regression （PLSR） that can overcome multicollinearity of input parameters. The experiment results show that this model can meet the requirement of accuracy.

关键词： process stability characteristic parameters variation coefficient partial-least-square regression

Evaluation model for arc fluctuations of triple-electrode high speed fillet welding

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China Welding 2014年第2期23卷 17-21页

作者： Ma Xiaoli Hua Xueming Wang Fei Wu Yixiong School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240

To improve the welding efficiency of conventional arc welding, triple-electrode fillet welding was proposed and developed. Stability of triple-electrode fillet welding process is the assurance for ideal joint. The evaluation model for arc fluctuations of triple-electrode fillet welding was established based on the characteristic parameters and their variation coefficients. This model indicated that variation coefficients could reflect arc voltage flnctuations of welding process, and its analysis result was consistent with the actual welding process.

关键词： process stability variation coefficient triple-electrode fillet welding

The changes of renewable water resources in China during 1956 –2010

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Science China Earth Sciences 2014年第9期57卷 1825-1833页

作者： LI YuanYuan CAO JianTing SHEN FuXin XIA Jun General Institute of Water Resources and Hydropower Planning and Design Ministry of Water Resources State Key Laboratory of Water Resources & Hydropower Engineering Sciences Key Laboratory of Water Cycle & Related Land Surface Processes Chinese Academy of Sciences

Water is a critical natural resource upon which all social and economic activities and ecosystem functions depend. With a surprising social and economic development in the past decades, water has become an important constraint for China's sustainable development, and a matter concerning economic security, ecological security and national security of the country. Understanding the changes of water resources is greatly helpful in analyzing the impacts of climatic change, formulating plans for utilization and protection of water resources, and making water resource decisions. Based on China's national water resources assessment, the Mann-Kendall's test, and Morlet wavelet, we analyzed the changing trends and periods of China's renewable water resources during 1956–2010. The results as following:(1) There is no significant change trend of water resources on the countrywide scale during the period 1956–2010, the total water resources show a slight increasing trend, and the national annual average water resources during the period 1991–2010 increased by 1% relative to that of the period 1961–1990.(2) The changes of water resources in different level-I water resource regions vary significantly. Annual average water resources of the Haihe River and Yellow River regions in the northern China decreased 19% and 17% respectively in the past 20 years. Water resource increased in Southern and Northwestern rivers regions, particularly in the Northwest rivers region, with the increasing amplitude by nearly 10% in the past 20 years.(3) The inter-annual variation of national water resource became larger in the past 20 years, as compared with that of the period 1961–1990. The coefficients of water resource variation increased in Northwestern and Southwestern rivers regions, while the inter-annual variation tended to decrease in the Haihe and the Yellow River regions where significant decline of water resources happened.(4) A 14-year quasi-periodicity of the national water resource var

关键词： water resources anomaly variation coefficient Mann-Kendall test Morletwavelet

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A Study and improvement on positive and negative relation of Grey Incidence Model

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A Study and improvement on positive and negative relation of...

The Evaluation Method of Road Traffic Safety Based on the Combined Principal Component Cluster Analysis

2009中国控制与决策会议

作者： Huilin Xie~1,Mingxia Cao~2,Yaoguo Dang~3 1.College of Management,China University of Mining and Technology,Xuzhou 221008,China 2.Rural development institute,Jiangsu Academy of Social Sciences,Nanjing 210013,China 3.College of Economics and Management,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China

＜正＞Grey incidence analysis is a multiple factors method that the closeness of the multiple factor’s relationship is judged based on the similarity level of the geometric patterns of sequence ***,slope differences of reference sequences and relevant sequences on every corresponding intervals is used to reflect the closeness of the *** article defined the generalized variation coefficient and put forward a new kind of grey incidence model. This kind of model reflected the positive and negative relation of grey incidence degree to some *** is only relate to the geometric shapes of sequences,and has nothing to do with the spatial position of *** method took full advantage of every intervals’ information and the positive and negative *** last,an example was given to prove the rationality and practicability.

关键词： Grey incidence analysis Degree of Grey Incidence Positive and Negative Relation variation coefficient

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The Evaluation Method of Road Traffic Safety Based on the Co...