充分利用了的

Some sufficient conditions for oscillation of neutral differential equation with positive and negative coefficients are obtained.

利用数学分析和不动点原理，研究了具有正负系数的中立型时滞微分方程的振动性，得到了方程所有解振动的充分条件。

By using the method of coincidence degree, a set of easily verifiable sufficient conditions are established for the existence of positive periodic solution of this system.

利用重合度理论的延拓定理讨论了此系统周期解的存在性问题，得到了保证周期解存在的充分条件。

At present,new material industry of Ningxia is facing an un- precedented opportunity for development.Therefore,on the basis of systematical investigation on the development sta- tus of new material industries,the paper respectively analyzes the advantages,weaknesses,opportunities and threats that new material industries face.Using different combinations...

在充分调查宁夏新材料产业发展现状的基础上，分别对宁夏新材料产业发展面临的优势、劣势、机遇与挑战进行了分析，利用S-W-O-T的不同组合有针对性地提出了发展的措施，最后，分别从企业层面和政府层面提出了宁夏新材料产业发展的企业运作策略与政府行为选择。

The influences of derivations and adjoint ideal semigroups of prime ring with characteristic 2 on the prime ring are discussed, and several sufficient conditions for the prime ring being communitive ring or S4-ring and some necessary conditions for a class of prime rings being communitive rings are obtained.

先给出了一个利用导子和理想来判断素环的可交换性结论的证明，然后讨论了特征为2的素环的导子和归联理想半群对这个素环的影响，得到了素环成为交换环或者S4-环的几个充分条件及一类素环成为交换环的必要条件。

We next establish certain conditions which arc necessary and sufficient for a projective module over a cellular algebra to be injective.

给出了胞腔代数是标准分层代数的一个充分条件，利用这个条件我们介绍了一种归纳构造标准分层的胞腔代数的方法； 5。

Based on the research of the related fields home and abroad and combined work condition, in allusion to the feature of diesel engine waste-heat generation, the comparison were made between the current equipments utilizing diesel engine waste-heat and the low boiling point working fluid—R11 is chosen, the evaporator, condenser, steam turbine-generator group and so on compose the organic Rankine cycle thermal system model.

文中在对国内外相关领域进行了充分调研的基础上，结合工程实际状况，针对柴油机废气余热发电特点，对现行的柴油机废气余热利用设备进行比较，选择了R11为工质，由蒸发器、冷凝器、汽轮-发电机组等主要部件组成的有机朗肯循环热力系统模型。

Based on predecessor\'s research results, formation condition of oil-gas reservoirs of S_(2+3) oil layer in westslope region was comprehensively and systematicaly studied, through using comprehensively seismics,logging, well logging, core, analysis assay data and paleontology data and adopting the latest theories andtechniques and methods of structural geology, sequence stratigraphy, sedimentography, petroleum geology,and oil-gas accumulation dynamics, etc. Main controlled factors, periods and models of oil-gasaccumulation and distribution were identified, favorable exploration areas were forecasted, throughdissecting typical oil-gas reservoirs and analyzing oil-gas accumulation mechanism and process.

本文在充分借鉴前人研究成果的基础上，综合利用地震、测井、录井、岩心及分析化验和测试资料，采用构造地质学、层序地层学、沉积学、石油地质学、成藏动力学等多学科的最新理论和方法，对西斜坡区萨二、三油层油气成藏条件进行了全面系统的研究，通过西斜坡区萨二、三油层典型油气藏解剖和油气运聚机理及过程分析，搞清了其油气成藏与分布的主控因素、期次和模式，进而预测有利勘探区带。

The spatial,temporal and two-dimensional niche breadths and niche overlaps of Hyalopterus amygda/i, Myzus persicae and their main natural enemies were studied in this paper. The results showed that the synchronism and sympatry of the pests and their natural enemies Harmonia axyridis, Propylaea japonica and Chrysopa septempunctata were both higher, which provided a foundation for protecting and using natural enemies to control the two pests.Key words: Hyalopterus amygdali; Myzus persicae; Natural enemies; Ecological niche

为了保护利用天敌，充分发挥天敌对害虫的自然控制作用，作者对桃粉蚜、桃蚜及其主要大敌在时间维度、空间维度和时—空二维生态位宽度和生态位重叠进行了研究，评价了4种主要大敌异色瓢虫、龟纹瓢虫、大草岭、蜘蛛对这2种害虫在时间和空间上的跟随作用和控制效果，为桃园桃粉蚜、桃蚜两种害虫的生态控制提供理论依据。

Since then,by applying the Leray-Schauder continuation theorem,nonlinear alternative of Leary-Schauder,coincidence degree theory,and Krasnoselskii's fixed point theorem,many researchers have studied more general nonl...

研究了一类二阶非线性常微分方程的三点边值问题多重正解的存在性问题，在非线性项不满足超线性或次线性的条件下，利用不动点指数定理得到了至少存在两个正解的几个充分条件。

This paper discusses singularities, inflection points and convexity of FB-spline curves in terms of their control polygons, and gives the necessary and sufficient conditions for testing when FB-spline curves have one or two inflection points, or a cusp, or a loop, or none of the above points by the envelope theory and the topological mapping method.

文章利用包络理论和拓扑映射的方法，讨论了FB-样条曲线的奇拐点和曲线性质，并给出了依据控制多边形判断FB-样条曲线出现1个或2个拐点、1个尖点、1个二重点以及处处为凸的充分必要条件；最后给出了FB-样条曲线的奇点、拐点以及二重点在λ-μ平面上的分布图。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐