Degenerate four-wave mixing spectroscopy excited by ultrashort laser pulses

A new method is described for spectroscopic diagnostics of combustion and explosion products, which makes it possible to study processes occurring at short times in hot and dense molecular gases. Pis’ma Zh. Tekh. Fiz. 23, 16–19 (March 26, 1997)     

A mixed design approach for probabilistic structural durability

In this paper, a mixed approach for probabilistic structural durability design of mechanical systems is proposed. In this approach, a deterministic design optimization that considers structural crack initiation and crack propagation lives at critical points of the structural component as design constraints is performed first. After an optimal design is obtained, a reliability analysis is performed to ascertain if the deterministic optimal design is reliable. If the probability of the failure of the deterministic optimal design is found to be acceptable, a reliability-based design approach that employs a set of interactive design steps, such as trade-off analysis and what-if study, is used to obtain a near-optimal design that is reliable with an affordable computational cost. A 3-D tracked vehicle roadarm is employed to demonstrate the feasibility of the proposed approach.     

高速铝箔分卷机的设计

介绍了一种成功开发及应用的高速铝箔分卷机的主要原理及结构特点。     

也谈轻型钢结构房屋柱基设计

对柱脚抗剪键的设置和计算中所取用的荷载组合提出个人观点,同时对轻钢结构柱脚螺栓受拉计算提出注意事项.     

The transmission capacity of a nonlinear classical communication channel

The transmission capacity of a nonlinear classical communications channel that does not obey the well-known Shannon formula describing a linear additive channel is analyzed. According to the Landauer principle, no finite energy is required to transmit a bit of information, which, in principle, makes reversible data transmission possible. The process of data transmission is analyzed using a model of the transmitting medium representing a ferroelectric crystal possessing a center of symmetry. Using this model, it is possible to trace an analogy between the process of bit setting and transmission, on the one hand, and the violation of the lattice symmetry as a result of the second-order phase transition at the Curie temperature, on the other hand. An expression for the transmission capacity is obtained using the well-known cnoidal solution of the corresponding nonlinear equations in the absence of damping. The transmission capacity of an arbitrary nonlinear classical communication channel is estimated.     

Effect of the size of martensite laths and carbide particles on the “brittle” strength of low-carbon martensitic steels

Results of experimental and theoretical studies of the effect of the size of martensite laths and carbide particles on the value of the minimum stress of brittle fracture (brittle strength) of steel 12KhN3MFA subjected to uniaxial extension are presented. The critical proportion of the sizes of carbide particles and martensite laths is determined at which the microstructural component that controls the level of the brittle strength changes. Quantitative dependences for predicting the effect of the nonuniformity of the grain structure on the brittle strength of martensitic steels are obtained. Parameters of the microstructure, which make it possible to raise the brittle strength of low-carbon martensitic steels, are determined and the efficiency of rapid heat treatment for creating such structural states is demonstrated.     

水利工程施工过程中的现场签证

现场签证作为工程管理的一种辅助手段，其产生并得以广泛运用有其必然性，并且在工程管理中发挥了重要作用。但由于到目前为止还没有统一的定义和格式，再加上参与各方对现场签证的重视程度不同、参与各方人员素质不一，所以目前现场签证在具体操作过程中还存在诸多问题。本文主要就现场签证现状、现场签证应遵循的原则、提高现场签证质量的措施等方面谈谈自己的一点观点和看法，希望能起到抛砖引玉的作用。     

Experimental study of the effect of external signal on microwave oscillations in a nonrelativistic electron beam with virtual cathode

The effect of an external harmonic signal on the characteristics of microwave generation in a non-relativistic electron beam with virtual cathode (VC) formed in a static retarding electric field (low-voltage vircator system) has been experimentally studied. A significant increase in the vircator generation power is observed when the frequency of the external signal is close to the frequency of VC oscillations. At large detunings, a broadband chaotic generation is observed.     

一种低压低功耗SRAM/SOI单元设计

提出一种改进4管自体偏压结构SRAM/SOI单元.基于TSUPREM4和MEDICI软件的模拟和结构性能的分析,设计单元结构并选取结构参数.该结构采用nMOS栅下的含p+埋沟的衬底体电阻代替传统6管CMOSSRAM单元中的pMOS元件,具有面积小、工艺简单的优点.该结构可以在0.5V的电源电压下正常工作,与6管单元相比,该单元瞬态响应正常,功耗只有6管单元的1/10,满足低压低功耗的要求.     

准噶尔盆地加快天然气勘探有利条件及预探领域分析

准噶尔盆地天然气资源十分丰富,勘探潜力巨大。该盆地具备形成大气区的地质背景,发育石炭系、二叠系、侏罗系三套气源岩,演化程度高,气源条件充足;发育多类型、多套储集体和四套区域盖层,形成了有利的储盖组合及成藏配置。通过对五彩湾、滴西、莫索湾、莫北地区典型气藏的分析研究,该盆地发育多种气藏类型,包括构造型、古潜山型、火山岩内幕型及地层(不整合遮挡)型。通过研究指出,天然气勘探的现实领域有陆东—五彩湾地区、陆西—莫北—莫索湾地区;待突破的领域有腹部下组合大型古隆起及岩性气藏、南缘冲断带;正在准备的勘探领域主要为煤层气。