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Comprehensive Evaluation on the Regional Economy of Commodity Grain Base in Heilongjiang Province Based on Factor Analysis Method
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作者 SHEN Lei-ming XU Mei +1 位作者 WANG Fu-lin ZHANG Hao 《Asian Agricultural Research》 2010年第6期25-28,共4页
Taking a total of 13 areas in Heilongjiang commodity grain base as the research objects,9 indices are selected,which are regional GDP(X1),per capita GDP(X2),total value of tertiary industry(X3),financial revenue(X4),u... Taking a total of 13 areas in Heilongjiang commodity grain base as the research objects,9 indices are selected,which are regional GDP(X1),per capita GDP(X2),total value of tertiary industry(X3),financial revenue(X4),urban fixed assets investment(X5),average salary(X6),gross industrial output value(X7),total output value of farming,forestry,husbandry and fishing(X8),and retail sales of social consumer goods(X9).Based on this,evaluation index system of regional economy is established.According to the 2006-2008 Heilongjiang Statistical Yearbook,average values within 3 years are used as analytical data.Factor Analysis Method is adopted to establish regression model and to carry out comprehensive analysis.Result shows that Heilongjiang commodity grain base has extremely uneven regional economic development in different areas.According to the score order and actual situation,the 13 areas are divided into 4 types.The first and second types are Harbin and Daqing,respectively.The third type is Qiqihaer,Suihua,Mudanjiang and Jiamusi.And the forth type is Jixi,Shuangyashan,Heihe,Yichun,Qitaihe,Hegang and Daxinganling.Suggestions for the development of these areas are put forward. 展开更多
关键词 Heilongjiang commodity grain base Factor Analysis Method Regional economy Comprehensive evaluation China
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Use of Selection Indices Based on Multivariate Analysis for Improving Grain Yield in Rice 被引量:9
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作者 Hossein SABOURI Babak RABIEI Maryam FAZLALIPOUR 《Rice science》 SCIE 2008年第4期303-310,共8页
In order to study selection indices for improving rice grain yield, a cross was made between an Iranian traditional rice (Oryza sativa L.) variety, Tarommahalli and an improved indica rice variety, Khazar in 2006. The... In order to study selection indices for improving rice grain yield, a cross was made between an Iranian traditional rice (Oryza sativa L.) variety, Tarommahalli and an improved indica rice variety, Khazar in 2006. The traits of the parents (30 plants), F1 (30 plants) and F2 generations (492 individuals) were evaluated at the Rice Research Institute of Iran (RRII) during 2007. Heritabilities of the number of panicles per plant, plant height, days to heading and panicle exsertion were greater than that of grain yield. The selection indices were developed using the results of multivariate analysis. To evaluate selection strategies to maximize grain yield, 14 selection indices were calculated based on two methods (optimum and base) and combinations of 12 traits with various economic weights. Results of selection indices showed that selection for grain weight, number of panicles per plant and panicle length by using their phenotypic and/or genotypic direct effects (path coefficient) as economic weights should serve as an effective selection criterion for using either the optimum or base index. 展开更多
关键词 rice (Oryza sativa) optimum index base index path analysis HERITABILITY grain yield selection index
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GRAIN REFINEMENT IN BULK UNDERCOOLED Ni-BASED ALLOY 被引量:2
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作者 Li,Delin Yang,Gencang Zhou,Yaohe Northwestern Polytechnical University,Xi’an 710072,China 《中国有色金属学会会刊:英文版》 CSCD 1993年第4期66-71,共6页
Fluxing of 5 g bulk melt Ni77Si13B10 permits high undercoolings to be attained prior to nu-cleation onset.Investigations of grain refinement in the bulk undercooled alloy as a function ofundercooling,recalescence beha... Fluxing of 5 g bulk melt Ni77Si13B10 permits high undercoolings to be attained prior to nu-cleation onset.Investigations of grain refinement in the bulk undercooled alloy as a function ofundercooling,recalescence behavior and cooling rate have been reported.A significant inhomo-geneity of reduction in grain size of a bulk sample is observed,which is caused by the different so-lidification conditions:(1)recalescence process,and(2)the followed plateau in which the heatrelease and extraction rates are equal.It is concluded that the homogeneous refined microstructurecan be achieved if the initial undercooling prior to nucleation,or cooling rate after recalescence isfurther increased. 展开更多
关键词 NI-baseD alloy high UNDERCOOLING RECALESCENCE grain REFINEMENT
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Influence of preparation process on sintering behavior and mechanical properties of ultrafine grained Ti(C, N)-based cermets 被引量:2
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作者 丰平 贺跃辉 +2 位作者 肖逸锋 刘文俊 熊惟皓 《中国有色金属学会会刊:英文版》 EI CSCD 2007年第3期531-536,共6页
The influences of forming and sintering processes on distortion, cracking as well as mechanical properties of sintered bodies of ultrafine grained Ti(C, N)-based cermets were investigated. The results show that lubric... The influences of forming and sintering processes on distortion, cracking as well as mechanical properties of sintered bodies of ultrafine grained Ti(C, N)-based cermets were investigated. The results show that lubricant is indispensable to fabrication of ultrafine Ti(C, N)-based cermets, however, with low binder content in powder mixture, the lubrication action of paraffin is attenuated. A appropriate level of 2% (mass fraction) paraffin is determined for a cermet with binder content of 36% (mass fraction). It is also found that the influence of compaction pressure on distortion and cracking of sintered bodies presents a complex relationship. A relatively lower or higher compaction pressure, less than 100 MPa and more than 400 MPa respectively, favors uniform density distribution in green compact. The heating rate of sintering should be strictly controlled. Too fast heating rate results in enclosed pores to burst and forms large size pores in sintering body. A heating rate of 3 ℃/min is recommended. 展开更多
关键词 金属陶瓷 超细结构 滑润剂 烧结技术
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3D random Voronoi grain-based models for simulation of brittle rock damage and fabric-guided micro-fracturing 被引量:31
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作者 E.Ghazvinian M.S.Diederichs R.Quey 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2014年第6期506-521,共16页
A grain-based distinct element model featuring three-dimensional (3D) Voronoi tessellations (randompoly-crystals) is proposed for simulation of crack damage development in brittle rocks. The grainboundaries in pol... A grain-based distinct element model featuring three-dimensional (3D) Voronoi tessellations (randompoly-crystals) is proposed for simulation of crack damage development in brittle rocks. The grainboundaries in poly-crystal structure produced by Voronoi tessellations can represent flaws in intact rockand allow for numerical replication of crack damage progression through initiation and propagation ofmicro-fractures along grain boundaries. The Voronoi modelling scheme has been used widely in the pastfor brittle fracture simulation of rock materials. However the difficulty of generating 3D Voronoi modelshas limited its application to two-dimensional (2D) codes. The proposed approach is implemented inNeper, an open-source engine for generation of 3D Voronoi grains, to generate block geometry files thatcan be read directly into 3DEC. A series of Unconfined Compressive Strength (UCS) tests are simulated in3DEC to verify the proposed methodology for 3D simulation of brittle fractures and to investigate therelationship between each micro-parameter and the model's macro-response. The possibility of numericalreplication of the classical U-shape strength curve for anisotropic rocks is also investigated innumerical UCS tests by using complex-shaped (elongated) grains that are cemented to one another alongtheir adjoining sides. A micro-parameter calibration procedure is established for 3D Voronoi models foraccurate replication of the mechanical behaviour of isotropic and anisotropic (containing a fabric) rocks. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved. 展开更多
关键词 Numerical modelling 3D Voronoi tessellation Discrete element method grain-based model Crack damage thresholds Fabric-guided micro-fracturing Anisotropy
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PC-Based Automated Control System for Jordan Northern Grain Silo
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作者 Salem Y. Al-Agtash 《Engineering(科研)》 2012年第12期914-919,共6页
This paper presents a PC-based automated control system operation of the Northern Grain Silo of Jordan. The system connects to a PLC (programmable logic controller) device, and combines operator interface, PLC program... This paper presents a PC-based automated control system operation of the Northern Grain Silo of Jordan. The system connects to a PLC (programmable logic controller) device, and combines operator interface, PLC programming and monitoring functions into one platform. The PLC portion handles direct operations control, while the PC portion handles interfacing and data intensive functions. A simulation package is developed. The package generates a graphical user interface for real-time graphic animations of the Grain Silo operation. We discuss anticipated benefits of such a system and phases of implementation. 展开更多
关键词 PC based AUTOMATED CONTROL System PLC grain SILO Bus CONTROL Topology
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EFFECT OF GRAIN REFINING ON FATIGUE-CREEP INTERACTION BEHAVIOURIN A Ni-BASE SUPERALLOY
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作者 YANG Wangyue ZHA NG Jishan CHEN Guoliang Beijing University of Science and Technology,Beijing,ChinaTIAN Shusen GENG Qingquan Fushun Steel Works,Fushun,Liaoning,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1989年第1期47-50,共4页
The fatigue-creep interaction behaviour of superalloy GH698 with different grain sizes has been studied at 700℃.The results show that three zones,F,C and FC,can be distinguished at the fatigue-creep interaction curve... The fatigue-creep interaction behaviour of superalloy GH698 with different grain sizes has been studied at 700℃.The results show that three zones,F,C and FC,can be distinguished at the fatigue-creep interaction curves.In zones FC and C,the presence of alternative stresses inhibits the creep deformation process therefore delays the fracture of the alloy.This effect will be enhanced by grain refining.However,in zone F,grain refining exhibits an inverse ef fect under large alternative stresses. 展开更多
关键词 Ni-base alloy GH698 grain refining FATIGUE CREEP
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Grain-v1快速相关攻击的改进 被引量:1
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作者 张英杰 胡磊 +3 位作者 史丹萍 王鹏 孙思维 魏荣 《密码学报》 CSCD 2020年第6期812-825,共14页
快速相关攻击(FCA)是对基于LFSR结构的流密码算法的主流攻击方法之一.Todo等人在2018年美密会提出了基于LFSR结构的流密码算法的一种新性质,并进一步指出基于Grain结构的流密码算法存在多个高相关度的线性逼近.利用这两个发现,他们从线... 快速相关攻击(FCA)是对基于LFSR结构的流密码算法的主流攻击方法之一.Todo等人在2018年美密会提出了基于LFSR结构的流密码算法的一种新性质,并进一步指出基于Grain结构的流密码算法存在多个高相关度的线性逼近.利用这两个发现,他们从线性分析的角度改进了对基于Grain结构的流密码算法的快速相关攻击,并成功地攻击了Grain-128a,Grain-128以及Grain-v1.本文首先以一种便于理解的方式回顾了Todo等人提出的快速相关攻击方法.之后,我们基于NFSR的状态更新函数改进了基于混合整数线性规划(MILP)搜索校验等式的方法.我们利用改进后的方法搜到了Grain-v1的新的检验等式,与Todo等人的结果相比,新的检验等式对应更多高相关度掩码,可将FCA的时间和数据复杂度由2^76:6935和2^75:1085降低为2^75:6724和2^74:0875. 展开更多
关键词 grain-v1 基于LFSR的流密码 快速相关攻击 基于MILP的线性分析
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Optimization of green sand mould system using Taguchi based grey relational analysis 被引量:3
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作者 Srinivasa Rao Pulivarti Anil Kumar Birru 《China Foundry》 SCIE 2018年第2期152-159,共8页
The strength of the mould cavity in sand casting is very much significant to attain high-quality castings. Optimization of green sand process parameters plays a vital role in minimizing casting defects. In the present... The strength of the mould cavity in sand casting is very much significant to attain high-quality castings. Optimization of green sand process parameters plays a vital role in minimizing casting defects. In the present research work, the effect of process parameters such as AFS grain fineness number, water, molasses, bentonite, fly ash, and ramming, and their levels on the resultant mould properties were investigated and optimized using Taguchi based grey relational analysis. The Taguchi L18 orthogonal array and analysis of variance(ANOVA) were used. The quality characteristics viz., green compression strength, permeability, bulk density, mould hardness and shatter index of green sand mould were optimized using grey relational grade, based on the experiments designed using Taguchi's Design of Experiments. ANOVA analysis indicated that water content is the most influential parameter followed by bentonite, and degree of ramming that contributes to the quality characteristics. The results are confirmed by calculating confidence intervals, which lies within the interval limits. Finally, microstructure observations and X-ray diffraction analysis have been performed for the optimal sand parametric combination. Results show that presence of maximum amount of SiO_2, which might be the reason for enhancement of the physical properties of the sand. 展开更多
关键词 green sand BENTONITE fly ash MOLASSES Taguchi based grey relational analysis grain fineness number
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EFFECTS OF THREE DIMENSIONAL DIRECTION OF SECOND DENDRITE ON COMPETITIVE GRAIN GROWTH IN DD8 SUPERALLOY 被引量:1
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作者 Liu Zhiyi Wei Pengyi Fu Hengzhi(State Key Lab of Solidification Processing,Northwestern Polytechnical University , Xi′an 710072) 《中国有色金属学会会刊:英文版》 CSCD 1996年第2期111-116,共6页
EFFECTSOFTHREEDIMENSIONALDIRECTIONOFSECONDDENDRITEONCOMPETITIVEGRAINGROWTHINDD8SUPERALLOYLiuZhiyi;WeiPengyi;... EFFECTSOFTHREEDIMENSIONALDIRECTIONOFSECONDDENDRITEONCOMPETITIVEGRAINGROWTHINDD8SUPERALLOYLiuZhiyi;WeiPengyi;FuHengzhi(StateKe... 展开更多
关键词 SECOND DENDRITE nickel base SUPERALLOY three DIMENSIONAL direction COMPETITIVE grain growth
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A RESEARCH ON THE MEDIUM TEMPERATURE SINTERED BaTiO_3-BASE CERAMIC MATERIAL FOR MLC WITH X7R BEHAVIOR
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作者 孙目珍 江涛 +2 位作者 陈绍茂 郭育源 刘会冲 《华南理工大学学报(自然科学版)》 EI CAS CSCD 北大核心 1997年第10期11-14,共4页
采用加入Bi2O3_PbO_ZnO玻璃及Bi、Co、Nb掺杂的方法,使BaTiO3基铁电瓷料中温烧结(1080~1140℃)。在实验结果的基础上,探讨X7R铁电瓷料中的第二相和晶粒尺寸对MLC的ε_t性能的影响,并研... 采用加入Bi2O3_PbO_ZnO玻璃及Bi、Co、Nb掺杂的方法,使BaTiO3基铁电瓷料中温烧结(1080~1140℃)。在实验结果的基础上,探讨X7R铁电瓷料中的第二相和晶粒尺寸对MLC的ε_t性能的影响,并研究其烧结机制。 展开更多
关键词 中温烧结 BaTiO_3基瓷料 壳结构 晶粒效应 ε-t性能
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Using friction stir processing to produce ultrafine-grained microstructure in AZ61 magnesium alloy 被引量:8
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作者 杜兴蒿 武保林 《中国有色金属学会会刊:英文版》 EI CSCD 2008年第3期562-565,共4页
In order to obtain fine-microstructure magnesium alloys with superior mechanical properties, AZ61 alloy was processed by friction stir processing(FSP) combined with rapid heat sink. It is found that ultrafine-grained ... In order to obtain fine-microstructure magnesium alloys with superior mechanical properties, AZ61 alloy was processed by friction stir processing(FSP) combined with rapid heat sink. It is found that ultrafine-grained microstructure with average size less than 300 nm is observed in the resultant AZ61 alloy. The mean microhardness of the ultra-fine region reaches Hv120-130, two times higher than that of AZ61 substrate. All these results demonstrate clearly that under a cooling rate high enough, ultra-fine structure inAZ61 alloy with superior mechanical properties can be produced by one pass FSP via dynamic recrystallization. 展开更多
关键词 镁合金 AZ61合金 摩擦焊接 微结构
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Superplastic behavior of TiAl based alloy at relatively low temperatures ranging from 800℃ to 1075℃ 被引量:3
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作者 黄伯云 张俊红 +3 位作者 贺跃辉 刘咏 孙坚 吴建生 《中国有色金属学会会刊:英文版》 CSCD 2002年第4期577-581,共5页
Superplastic behaviors of TiAl based alloy with initial grain size of about 2?μm obtained by multistep forging were investigated at 800 ~ 1?075?℃ with strain rates of 8×10 -5 s -1 ~2×10 -3 s -1 . The res... Superplastic behaviors of TiAl based alloy with initial grain size of about 2?μm obtained by multistep forging were investigated at 800 ~ 1?075?℃ with strain rates of 8×10 -5 s -1 ~2×10 -3 s -1 . The results show that the material exhibits excellent low temperature superplasticity. Flow softing resulting from dynamic recrystallization is observed at relatively low temperatures (≤ 1?000?℃) or at higher strain rates (≥2×10 -4 s -1 ). Continuous strain hardening resulting from strain enhanced grain growth occurs at higher temperatures or at lower strain rates. A maximum elongation of 533% is obtained at 800?℃ with strain rate of 2×10 -5 s -1 , and at 1?050?℃, a maximum elongation of 570% is obtained at strain rate of 8×10 -5 s -1 . At a fixed strain rate of 2×10 -4 s -1 , when the alloy is deformed at 850?℃, the microstructure is refined, however at 1?050?℃, is coarsened. The as deformed microstructure shows relatively high strain rate sensitivity value and it keeps nearly stable during deformation. The activation energy is calculated to be 290?kJ/mol at 950 ~ 1?075?℃, with the grain size exponent, p =2, and 224?kJ/mol at 800 ~ 900?℃ with p =3. Therefore, it is suggested that the dominant mechanism during superplastic deformation at 800 ~ 900?℃ is grain boundary sliding controlled by grain boundary diffusion; however at 950 ~ 1?075?℃ is grain boundary sliding controlled by lattice diffusion. 展开更多
关键词 TIAL合金 超塑性 激活能 高温合金
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Effect of nitrogen addition on microstructures and mechanical propeties of TiAl based alloys
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作者 唐建成 黄伯云 +1 位作者 贺跃辉 谢鲲 《中国有色金属学会会刊:英文版》 CSCD 1999年第4期692-695,共4页
关键词 TIAL based alloys microstructure NITROGEN ADDITION grain REFINEMENT
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Grain refinement of AZ31 magnesium alloy by new Al-Ti-C master alloys 被引量:7
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作者 韩广 刘相法 丁海民 《中国有色金属学会会刊:英文版》 EI CSCD 2009年第5期1057-1064,共8页
New Al4C3-containing Al-Ti-C master alloys (Al-0.6Ti-1C and Al-1Ti-1C) were developed by introducing Ti element into Al-C melt using melt reaction method,in which most of the TiC particles distribute around Al4C3 part... New Al4C3-containing Al-Ti-C master alloys (Al-0.6Ti-1C and Al-1Ti-1C) were developed by introducing Ti element into Al-C melt using melt reaction method,in which most of the TiC particles distribute around Al4C3 particles. It is believed that most of the C firstly reacts with Al melt and form Al4C3 particles by the reaction Al(l)+C(s)→Al4C3(s),and after adding Ti into the Al-C melt,the size of Al4C3 particles is decreased and the distribution of Al4C3 is improved through the reaction Ti(solute)+Al4C3(s)→ TiC(s)+Al(l). With the addition of 1% Al-1Ti-1C master alloy,the average grain size of AZ31 is reduced sharply from 850 μm to 200 μm,and the grain morphology of α-Mg transits from a fully-developed equiaxed dendritic structure to a petal-like shape. Al-C-O-Mn-Fe compounds are proposed to be potent nucleating substrates for primary Mg. Appropriate addition of Ti is believed to increase the grain refinement efficiency of Al4C3-containing Al-Ti-C master alloys in AZ31 alloy. 展开更多
关键词 AZ31镁合金 TIC颗粒 中间合金 晶粒细化 AL4C3 熔体反应法 颗粒分布
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Increasing Subsidies to Main Grain Production Area——Necessity of the Rejuvenation of Northeast China
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作者 WEIHeng LIYou-hua CONGDan-yang 《Journal of Northeast Agricultural University(English Edition)》 CAS 2004年第2期187-190,共4页
As an old industrial base, Northeast China is one of the most important grain production base. To rejuvenate Northeast China, it is necessary to strengthen farming products processing, lengthen industrial chain and de... As an old industrial base, Northeast China is one of the most important grain production base. To rejuvenate Northeast China, it is necessary to strengthen farming products processing, lengthen industrial chain and develop sustainable agriculture. 展开更多
关键词 old industrial base main grain production area development
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Agricultural Ecological Zoning Plan of Old Industrial Bases in Liaoning Province, China 被引量:2
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作者 LIU Ning1,2 1. China Center for Industrial Security Research, Beijing Jiaotong University, Beijing 100044, China 2. College of Philosophy and Public Administration, Liaoning University, Shenyang 110036, China 《Asian Agricultural Research》 2010年第9期13-16,共4页
On the basis of brief description of current situation of old industrial bases and primary industry of Liaoning Province, the paper introduces the general situation of agriculture-ecological zoning plan in Liaoning Pr... On the basis of brief description of current situation of old industrial bases and primary industry of Liaoning Province, the paper introduces the general situation of agriculture-ecological zoning plan in Liaoning Province. First, the ecological bases of agricultural zoning plan are introduced through various topographic and geomorphic types, regional climate differences and imbalanced distribution of natural resources; Second, in accordance with the theory of comparative advantage, distribution of production and resource economics, on the basis of comprehensive evaluation of agricultural natural resources, with the principle of fully excavating economic function of different natural resources, and in order to improve allocation efficiency of the two resources of market and government, the formation of ecological zoning plan of agriculture in Liaoning Province is analyzed; Third, according to Regional Layout Planning of Characteristic Agricultural Products of Liaoning Province (2006-2010), the paper describes basic layout of agriculture-ecological zoning plan in Liaoning Province. The policy support of agriculture-ecological zoning plan in Liaoning Province is analyzed from three aspects-support policy of functional zone major in producing grain, support policy of other characteristic agriculture-ecological zone and support measures of development of agriculture-ecological zone. The paper also analyzes experiences of agricultural development of old industrial bases in ecological zoning plan: First, agriculture-ecological zoning plan is a effective way of the revitalization of old industrial bases; Second, scientificity of plan is the basis of improving competitiveness of regional agriculture; Third, multi-input mechanism guiding by government is the key of agricultural packing effect; Fourth, integrated agricultural industrial chain is guarantee of realizing industrialization in ecological zone. 展开更多
关键词 OLD industrial baseS of LIAONING Province Ecologic
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Relationship between Grain Size and Fatigue-Creep Interaction Behaviour of Superalloy GH698
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作者 杨王玥 张济山 +2 位作者 陈国良 田树森 耿清全 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1989年第1期19-25,共7页
The deformation and fracture behaviour of nickel-base superalloy GH698 with different grain size have been studied at 700℃ under fatigue-creep interaction conditions. Compared with coarse-grained specimens, the grain... The deformation and fracture behaviour of nickel-base superalloy GH698 with different grain size have been studied at 700℃ under fatigue-creep interaction conditions. Compared with coarse-grained specimens, the grain refining process shows obvious effect on the mechanical behaviour of the alloy, i. e. in F and C zones, the fraction of pure fatigue and creep fracture on fracture surfaces is greatly reduced, which decreases and increases the fracture life in zones F and C respectively, in FC and C zones, creep deformation is greatly restrained by the alternating stress component, which increases the fracture life remarkably. It is also proved that in spite of the difference in microstru- tures such as grain size, for a constant tem- perature, a unique life equation t_r=A^n can be used to predict rupture life within the stress region controlled by the same fracture mode. 展开更多
关键词 Ni-base superalloy rupture life equation grain size
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Microstructure of Nano-Y_2O_3/Cobalt Based Alloy Composite Coating by Laser Cladding
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作者 何宜柱 李明喜 +1 位作者 袁晓敏 斯松华 《Journal of Rare Earths》 SCIE EI CAS CSCD 2004年第5期683-686,共4页
Composite coatings made of nano-Y_2O_3/cobalt-based alloy and produced by crosscurrent CO_2 laser on Ni-based superalloy are introduced. Cross-section or surface of the coatings was examined to reveal their microstruc... Composite coatings made of nano-Y_2O_3/cobalt-based alloy and produced by crosscurrent CO_2 laser on Ni-based superalloy are introduced. Cross-section or surface of the coatings was examined to reveal their microstructure using optical microscope, SEM, including EDS microanalysis, TEM and XRD. The results show that some equilibrium or non-equilibrium phases, such as γ-Co, Cr_(23)C_6, Y_2O_3 and ε-Co exist in the coatings. Fine and short dendritic microstructure and columnar to equiaxed transition (CET) occurred by adding nano-Y_2O_3 particles. With the increasing amount of nano-Y_2O_3 (1%, mass fraction), fully equiaxed crystallization appeared. These are caused by nano-Y_2O_3 particles acting as new nucleation site and rapid solidification of the melt. The results also show that inhomogeneous dispersion of nano-Y_2O_3 results in the formation of ε-Co phase in the coatings. The sub-microstructure of the clad is stacking fault. The mechanism of the formation of equiaxed grains is also analyzed. 展开更多
关键词 metal materials Y_2O_3 nanocrystalline laser cladding Co-based alloy equiaxed grain rare earths
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Attribute-Based Secure Data Sharing with Efficient Revocation in Fog Computing
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作者 Asma Alotaibi Ahmed Barnawi Mohammed Buhari 《Journal of Information Security》 2017年第3期203-222,共20页
Fog computing is a concept that extends the paradigm of cloud computing to the network edge. The goal of fog computing is to situate resources in the vicinity of end users. As with cloud computing, fog computing provi... Fog computing is a concept that extends the paradigm of cloud computing to the network edge. The goal of fog computing is to situate resources in the vicinity of end users. As with cloud computing, fog computing provides storage services. The data owners can store their confidential data in many fog nodes, which could cause more challenges for data sharing security. In this paper, we present a novel architecture for data sharing in a fog environment. We explore the benefits of fog computing in addressing one-to-many data sharing applications. This architecture sought to outperform the cloud-based architecture and to ensure further enhancements to system performance, especially from the perspective of security. We will address the security challenges of data sharing, such as fine-grained access control, data confidentiality, collusion resistance, scalability, and the issue of user revocation. Keeping these issues in mind, we will secure data sharing in fog computing by combining attributebased encryption and proxy re-encryption techniques. Findings of this study indicate that our system has the response and processing time faster than classical cloud systems. Further, experimental results show that our system has an efficient user revocation mechanism, and that it provides high scalability and sharing of data in real time with low latency. 展开更多
关键词 ATTRIBUTE-baseD Encryption FINE-grainED Access Control FOG COMPUTING PROXY Re-Encryption User REVOCATION
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