C~3I系统中软件的程序设计方法问题

软件的可靠性是Ｃ￣３Ｉ系统成败的关键之一,用规范和程序分离的办法设计软件,其可靠性无法得到保证。该文阐述了应研究形式化程序设计方法的意见,以及目前在这一领域尚存在的困难和解决的途径。     

粘土的结构性与超固结

土体中的结构性与超固结都可以使土体表现出超固结特性。通过结构性与超固结对土体力学性质影响比较,揭示了它们对土体力学性质的影响存在本质差异,需要将它们区分开来。基于土体中的结构性、超固结对土体固结特性的影响差异及粘土的正常固结线的唯一性,提出了粘土的结构性与超固结的定量描述方法,据此对原状粘土进行分类。土体的结构性主要包括土体的化学胶结等真正改变了土样结构的因素,用结构性参数来定量描述,而次固结、干缩作用可看成与超固结作用一致,一起用超固结参数来定量描述。     

结构教学与多媒体

本文按照结构论的具体要求 ,为使得在多媒体教学中获得良好的教学效果 ,根据多媒体教学的特点 ,提出了辅助教学结构 ,给出了辅助教学的特点及实施后的几点启示     

minimax问题的广义共轭向量法

本文按照共轭向量法的理论,针对非奇异对称矩阵提出了广义共轭向量的概念,并论述了它的三个重要性质(线性独立性、可寻驻点和可扩展性)。在此基础上,构造了极小极大(minimax)问题的广义共轭向量法。理论分析表明,该算法具有二次终止性质,且在每一维搜索时具有确定的寻优特征(求极小或求极大)。该算法为用拉格朗日乘子法求解数学规划提供了一个可能的途径。计算实例表明该算法是有效的。     

Experimental investigation on the anti-detonation performance of composite structure containing foam geopolymer backfill material

The compression and energy absorption properties of foam geopolymers increase stress wave attenua-tion under explosion impacts,reducing the vibration effect on the structure.Explosion tests were con-ducted using several composite structure models,including a concrete lining structure(CLS)without foam geopolymer and six foam geopolymer composite structures(FGCS)with different backfill param-eters,to study the dynamic response and wave dissipation mechanisms of FGCS under explosive loading.Pressure,strain,and vibration responses at different locations were synchronously tested.The damage modes and dynamic responses of different models were compared,and how wave elimination and energy absorption efficiencies were affected by foam geopolymer backfill parameters was analyzed.The results showed that the foam geopolymer absorbed and dissipated the impact energy through contin-uous compressive deformation under high strain rates and dynamic loading,reducing the strain in the liner structure by 52％and increasing the pressure attenuation rate by 28％.Additionally,the foam geopolymer backfill reduced structural vibration and liner deformation,with the FGCS structure showing 35％less displacement and 70％less acceleration compared to the CLS.The FGCS model with thicker,less dense foam geopolymer backfill,having more pores and higher porosity,demonstrated better compression and energy absorption under dynamic impact,increasing stress wave attenuation efficiency.By analyzing the stress wave propagation and the compression characteristics of the porous medium,it was concluded that the stress transfer ratio of FGCS-p-579 was 77％lower than that of CLS,and the transmitted wave energy was 90％lower.The results of this study provide a scientific basis for optimizing underground composite structure interlayer parameters.     

Alternatives for defense in the Post‐Soviet World: A guide for economists to the U.S. debate

The defense establishments of all major powers are changing to reflect changes in the foundations of national security strategy and resource allocation. The authors believe economists should play an active role in formulating these changes and offer an orientation to the U.S. debate, presenting three major alternatives: the “Base Force” (Bush Administration), Mr. Aspin's Force “C,” and the “Low” Alternative (Prof. Kaufmann and Dr. Steinbruner). These alternatives are compared using first‐order measures of capabilities, budgets and risk. Budgetary estimates are based on newly‐developed analytical tools.