SECOND ORDER EFFECTS IN AN ELASTIC HALF－SPACE ACTED UPON BY A NON－UNIFORM NORMAL LOAD

A closed form solution to the second order elasticity problem ,when an isotropiccompressible elastic half-space undergoes a deformation owing to a non-uniformlydistributed normal load,is presented,The method of integral transform is employedand the case when loading is distributed,in accordance with Hertz'x law ,is discussed.The limiting solution for incompressible isotropic elastic material is also derived.Numerical calculations for the second order elastic material for the displacement and the normal stress in the z-direction are carried out .It is found that,in comparison to the linear elastic case,the displacement increases and the normal stress decreases in the second order elastic material.

Some Results on the Space of Bounded Second Variation Functions in the Sense of Shiba

In this paper, we study the structure of the space of functions of bounded second variation in the sense of Shiba;an integral representation theorem is also proved and necessary conditions are given for that the space be closed under composition of functions. Another significant result is the proof that this space of bounded second variation in the sense of Shiba is a Banach algebra, which is not immediate as it happens in other spaces of generalized bounded variation.

THE ILLUSTRATION CALCULATIONS OF SECOND ORDER EFFECTS IN ELASTIC HALF-SPACE ACTED UPON BY A NON-UNIFORM SHEAR LOAD

This paper is a continuation of [1]. An example is discussed in derail to illustrate the second order effects. Numerical calculations for the second order elastic material for the z-direction displacement and the stress t(rz) are carried out. It is found that the second order effect is to reduce z-direction displacement and to decrease t(rz)inside the circle but to increase its value outside the circle.

THE GENERAL SOLUTION OF SECOND ORDER EFFECTS IN ELASTIC HALF-SPACE ACTED UPON BY A NON-UNIFORM SHEAR LOAD

This paper is a continuation of [1]. A closed form solution to the second order elasticity problem, when an isotropic compressible elastic half-space undergoes a deformation owing to a non-uniformly distributed shear load, is presented. The method of integral transform is employed to determine the solutions.

SOLVABILITY IN HARDY SPACE FOR SECOND ORDER ELLIPTIC EQUATIONS

We obtain a priori estimates and solvability in Hardy type space in a bounded domain of Rn for second order elliptic equations with coefficients of limited smoothness. Such a result can be served as an endpoint case of the classical LP（1 〈 p 〈 ∞） theory for second order elliptic equations. Our approach is based on a standard technique of perturbation rather than that of integral representation formula.

Actively Promoting Regional Space Cooperation——Vice Administrator, Loan Enjie headed a delegation to attend the Second Asia-Pacific Conference on Multilateral Cooperation in Space Technology and Applications

A Chinese delegation of 24 persons headed by Mr. Luan Enjie, Vice Administrator of China National Space Administration (CNSA) attended the Second Asia-Pacific Conference on Multilateral Cooperation in Space Technology and Applications held at Islamabad, the Capital of Pakistan from April 22 to 26, 1995. Following the First AsiaPacific Workshop held in Beijing in December, 1992, and the First Asia-Pacific Conference on Multilateral Cooperation in

Making Cooperation in Space for Better Future Summary of the Keynote Speech at the Second Asia Pacific Conference on Multilateral Cooperation in Space Technology and Applications

Since the Asia Pacific Workshop on Multilateral Cooperation in Space Technology and Applications was held in Beijing in December, 1992, the preparatory committee for Asia-Pacific Space Cooperation Mechanism and the Liaison Committee for AP-MC-STA have done many fruitful works. Thanks to the First Asia Pacific Conference on Multilateral Cooperation in Space Tech-

四川盆地元坝地区千佛崖组二段细粒沉积岩岩相特征及储集性分析

四川盆地侏罗系千佛崖组页岩油气勘探前景良好,但目前对其细粒沉积岩基本沉积特征及发育规律的认识还不足。为此,利用细粒沉积学原理,依据岩心和测井资料,通过岩心精细描述、薄片鉴定、X衍射全岩分析及扫描电子显微镜观察等技术手段,精细描述了元坝地区千佛崖组二段(简称千二段)细粒沉积岩储层的物质组成、沉积构造、储集空间类型等地质特征,划分了岩相类型,并对主要岩相储层的物性特征和储集空间类型进行分析与比较,明确了有利层段发育位置。研究结果显示:(1)千二段陆相细粒沉积岩可划分成“黏土岩”和“粉砂岩”2种岩石类型,15种岩相类型。其中,富有机质块状黏土岩、富有机质块状含粉砂黏土岩、富有机质纹层状含粉砂黏土岩、富有机质条带状含粉砂黏土岩、富有机质块状粉砂质黏土岩和富有机质纹层状粉砂质黏土岩为6种主要岩相类型。(2)储层储集空间类型多样,包括黏土矿物层间缝、层理缝、黏土矿物晶间孔、黄铁矿晶间孔、溶蚀孔及有机孔等,其中黏土矿物晶间孔分布最为广泛。(3)6种主要岩相的平均孔隙度和渗透率分别为2%和0.023×10^(-3)μm^(2),富有机质纹层状含粉砂黏土岩、富有机质纹层状粉砂质黏土岩和富有机质块状粉砂质黏土岩的储集空间类型丰富,分布广、数量多,孔隙度与渗透率均高于其他岩相且TOC值较高,是最有利的储集岩相类型。(4)千二段有利层段位于其(1)小层全段、(2)小层的底部和(3)小层的中下部。

“Second Life”中的图书馆2.0

文章简要介绍了Second life的应用情况,并主要对在Second life中建立和延伸图书馆服务的意义和国外的应用发展状况进行了阐述。

We Live on a Small Space Comet: The Third Extraordinary Motion of Earth towards the North Pole and Its Various Effects

The idea of research started with a crazy imaginary theory in the field of astrogeography, saying: We often taught ourselves and then convinced the students that the planet Earth moves despite not feeling the vibrations of traffic, and we listed successive scientific confirmations to indicate the rotation of the planet in a regular movement around its axis once every 24 hours, and it is running in another second movement around the sun once every 365¼ days, so are they only two movements, no more?! Is it possible for him to run at a regular speed in an additional direction?

高碳中锰耐磨钢凝固过程溶质微观偏析模型

通过定向凝固、电子探针(EPMA)、Factsage等多种实验与理论计算相结合的手段对中锰耐磨钢凝固过程溶质元素微观偏析行为进行了系统研究.研究表明在定向凝固试验中当拉速为50μm·s-1时,中锰钢的二次枝晶间距平均值为59.77μm;中锰钢凝固过程组织转变为L→L+γ→γ属于奥氏体凝固模式,无包晶反应的发生,也无铁素体相及其他相的出现;中锰钢定向凝固过程中Mn、Cr在枝晶间的含量明显高于枝晶内,表明Mn、Cr元素发生了明显的正偏析行为;通过对各特征参数求解,构建了中锰钢溶质元素微观偏析模型,发现中锰钢定向凝固过程中Mn元素偏析指数与Brody–Flemings模型符合较好,而Cr元素偏析指数与Clyne–Kurz模型分布较为一致.

一种基于RC链的私家车位分配方案

随着共享经济的快速发展,车位共享平台应运而生。车位自动分配技术因能大大缩减泊车人寻找车位的时间并提高车位的利用率而逐渐被车位共享平台使用。然而,在私家车位共享场景下,现有车位共享平台在分配车位时只追求车位利用率的最大化而忽略了车位分配的公平性,一定程度上影响了用户使用平台的热情。针对这个问题,研究设计了一种基于RC链(Resilient and Consensus-based Chain)的私家车位分配方案。该方案结合RC链技术与第二拍卖价格策略,在车位分配过程中保证了公平性和高效性。通过使用RemixIDE、Hyperledger Sawtooth和Hyperledger Caliper等工具对方案进行仿真分析,证明了该方案相比传统方案有着更好的公平性和高效性。

新文科视域下的计算社会语言学研究

新文科建设的目标之一是:多种学科在研究内容和理论方法上进行交叉与融合,从而形成新的学科方向、研究范式,以及相应的复合型人才培养模式。为此,本文提出一种可操作的路径:利用已经发展起来的若干第一代交叉学科,融汇成第二代交叉学科。比如,对于“社交网络—语言的社会变异—计算建模”这种头绪繁多的研究领域,可以借助“计算语言学”与“社会语言学”等第一代交叉学科,形成第二代交叉学科“计算社会语言学”。这种操作路线可以细化与落实新文科建设,并提供必要的学科规训。文章还以当代社会的“物理—精神—信息”三元空间,以及其中说话者的社会身份、个体人格和社交互动对语言使用和变异选择的影响为例,阐明计算社会语言学的理论、方法和议题。

Characterizations of Sobolev spaces in Euclidean spaces and Heisenberg groups

Recently, many new features of Sobolev spaces W k,p ？RN ？ were studied in [4-6, 32]. This paper is devoted to giving a brief review of some known characterizations of Sobolev spaces in Euclidean spaces and describing our recent study of new characterizations of Sobolev spaces on both Heisenberg groups and Euclidean spaces obtained in [12] and [13] and outlining their proofs. Our results extend those characterizations of first order Sobolev spaces in [32] to the Heisenberg group setting. Moreover, our theorems also provide diff erent characterizations for the second order Sobolev spaces in Euclidean spaces from those in [4, 5].

段场类TOD项目规划设计方案技术要点探索

在新协同发展背景下,现有国家针对段场综合开发相关技术标准要求相对分散,难以有效系统地解决城市交通基础设施建设与城市居住区发展空间建设过程中出现的问题。为解决在段场类TOD实践过程中车辆基地与城市居住区空间发展的不匹配困境,同时避免一二级开发过程中资源重复配置,文章探讨段场类TOD实践过程中设计层面的技术逻辑及要点,依据前端政策要求、城市空间要素及技术设计要点把控及理解,通过盖上盖下集成创新互联设计,从而推动一级开发车辆基地与二级物业开发的相互联动,有效积极稳妥地促进交通基础设施与城市居住区开发合理利用及协同发展。

六相全桥逆变器驱动PMSM的简化模型预测电流控制

全桥逆变器电机驱动或称开绕组结构虽然兼具相间电气隔离、容错性能好及器件开关频率低等优点,但存在逆变器输出电压矢量多、冗余严重且控制约束等问题。文中以共直流母线供电的六相全桥逆变器驱动六相永磁同步电机为研究对象,提出了一种基于二级矢量优化的简化模型预测电流控制算法,在实现电机定子基波电流有效跟踪控制的同时有效抑制了定子电流的谐波及零序分量。文中基于矢量空间解耦理论对六相全桥逆变器的输出电压矢量进行了分层分析,以定子基波电流控制、谐波及零序电流抑制为准则对逆变器输出的729个电压矢量进行二级优化,得到候选的12个电压矢量,以此为基础设计了模型预测电流控制算法。实验结果表明,该简化模型预测电流控制方法具有良好的动静态性能,能在基波电流控制的同时有效抑制谐波及零序电流分量,可为多相电机驱动系统研究提供一定的理论支撑。

Compact Space-like Submanifolds in Pseudo-Riemann Manifold

We first establish a integral inequality for compact maximal space-like subman-ifolds in pseudo-Riemannian manifolds N^np+p. Then, we investigate compact space-like sub-manifolds and hupersurfaces with parallel second fundamental form in N^np+p and some other N^np+pambient spaces. We obtain some distribution theorems for the square norm of the secondfundamental form.

Approximate Controllability of Second-Order Neutral Stochastic Differential Equations with Infinite Delay and Poisson Jumps

The modelling of risky asset by stochastic processes with continuous paths, based on Brow- nian motions, suffers from several defects. First, the path continuity assumption does not seem reason- able in view of the possibility of sudden price variations （jumps） resulting of market crashes. A solution is to use stochastic processes with jumps, that will account for sudden variations of the asset prices. On the other hand, such jump models are generally based on the Poisson random measure. Many popular economic and financial models described by stochastic differential equations with Poisson jumps. This paper deals with the approximate controllability of a class of second-order neutral stochastic differential equations with infinite delay and Poisson jumps. By using the cosine family of operators, stochastic analysis techniques, a new set of sufficient conditions are derived for the approximate controllability of the above control system. An example is provided to illustrate the obtained theory.

扬子克拉通与周缘各盆地第二深度空间天然气潜能与供需前景

海相碳酸盐岩天然气在全球化石能源配置中占有重要地位。在中国,通过近20年的勘探、开发,相关理论、方法、技术不断提升,全国各大沉积盆地陆续发现新的天然气田,同时气的产出量亦在逐年增长,而在扬子克拉通基础上发育的四川盆地及其东缘地带在诸天然气沉积盆地具有极大的优势,即不论从岩相、埋深、产气量与气质水平均具优势。综合研究表明:(1)第二深度空间的页岩气(≥5000~10000 m)乃21世纪中叶前后在中国化石能源配置中将会占有主要地位,即60%左右的份额;(2)扬子克拉通中四川盆地与其东缘的碳酸盐岩及礁滩相沉积是优质烃源岩和页岩气成藏、成储的主体岩相;(3)高精度三维地震勘探与解释、大深度钻井与井下开发技术的提升是产出率提高的关键;(4)页岩气勘探与开采压裂响应及致灾与污染影响示范是页岩气可持续发展的重要环节。

DYNAMIC VARIATION OF NITROGEN CONTENT IN THE SECOND SONGHUA RIVER

The space time variation laws of nitrogen content in different river sections, water periods and years in the Second Songhua River in China is described in detail. The results show that there is direct relation between the nitrogen content variation in river water and that in wastewater from cities and runoff water of both banks of the river. Nitrate and nitrite contents in water in flood period are higher than that in mid and low water periods. In flood period, nitrate content in water increases gradually with the extension of river section, ammonia content in polluted river section is higher than that in unpolluted river section. Nitrate and nitrite contents in water in the flood, mid and low water periods from 1985 to 1989 were slightly higher than that from 1980 to 1984 and from 1990 to 1994, ammonia content in water increased annually.