The effect of hypokinesia on lipid metabolism in adipose tissue

The increase of nonesterified fatty acid (NEFA) concentration in plasma was observed in rats subjected to hypokinesia for 1-60 days. In the period of recovery (7 and 21 days after 60 days immobilization) the content of NEFA returned to control values. The increase of fatty acid release from adipose tissue was observed in hypokinetic rats, however the stimulation of lipolysis by norepinephrine was lower in rats exposed to hypokinesis. The decrease of the binding capacity and a diminished number of beta-adrenergic receptors were found in animals after hypokinesia. The augmentation of the incorporation of glucose into lipids and the marked increase in the stimulation of lipogenesis by insulin were found in adipose tissue of rats subjected to long-term hypokinesia. These results showed an important effect of hypokinesia on lipid mobilization, on lipogenesis and on the processes of hormone regulation in adipose tissue.     

Applications of Magnesium Alloys in Aerospace and Aviation

Magnesium alloys are well applied in aerospace and aviation because of their mass saving potential, good electromagnetic shielding performance, and high damping capacity. To further promote the applications, in this paper, the applications of magnesium alloys are reviewed, which could provide insights for researchers and application designers. Firstly, the applications in aerospace are reviewed, including missile, satellite, rocket, and spacecraft. Secondly, the applications and commercial magnesium alloys in aviation are summarized. Thirdly, the bottleneck and existing problems for such magnesium alloys applied in aerospace and aviation are discussed. The requirements for the magnesium alloy performance in aerospace and aviation are evaluated and elaborated.     

关于IPTS—68在0℃以下的修订

本文根据近年来在温度计量方面所取得进展进一步讨论了如何对1968年国际实用温标进行修订。论述了该温标在0℃以下的不足以及有可能改进的建议。要解决的主要问题仍然是关于68年国际实用温标向13.81K 以下的延伸方法。从该温区与其它温区可以得出结论,新温标将采纳可选择的定义,以便使实用性和精确性协调起来。     

数字力传感器

本文叙述一种数字力传感器装置,更准确地定义为间接数字装置。该装置保持模拟力传感器的大部分优点,并具有数字系统的稳定性和与计算机的相容性。数字力传感器可处理700克以内的力,用普遍采用的敏感元件,二进制8位,分辨率4克。询问率为7仟赫,可识别频率大大超过1仟赫的力。线性度优于±0.1％±二进制最低位的1/2,重复率优于满量程的±0.25％。所述的装置在三年内几乎每天使用,经考核是十分可靠的。此传感器用作全数字张力测试仪的总体部分,其性能超过测试系统的需要。与联结大批生产的模一数硬件的模拟传感器相比,此传感器在设计和制造上是经济的。     

散射干扰自适应对消

一、引言本文是研究自适应对消散射干扰方法的一个总结报告。报告内容涉及到对雷达主瓣的散射干扰,和来自地面或干扰体照射的箔条对通讯系统的散射干扰。这些方法也能用于接收天线附近的散射源对接收天线旁瓣或主瓣的散射干扰,也就是说,适用于解决某些自适应弱信号系统中的多路问题(多路问题的应用,原来受到很大限制)。用辅助天线所接收的干扰延迟复制信号作为对消散射干扰的技术,如第二节所述。在应用某些散射对消器时,需要大量的自适应加权。当干扰机干扰大片区域时、或在主瓣内有大     

Fullerenes and interplanetary dust at the Permian-Triassic boundary

We recently presented new evidence that an impact occurred approximately 250 million years ago at the Permian-Triassic boundary (PTB), triggering the most severe mass extinction in the history of life on Earth. We used a new extraterrestrial tracer, fullerene, a third carbon carrier of noble gases besides diamond and graphite. By exploiting the unique properties of this molecule to trap noble gases inside of its caged structure (helium, neon, argon), the origin of the fullerenes can be determined. Here, we present new evidence for fullerenes with extraterrestrial noble gases in the PTB at Graphite Peak, Antarctica, similar to PTB fullerenes from Meishan, China and Sasayama, Japan. In addition, we isolated a (3)He-rich magnetic carrier phase in three fractions from the Graphite Peak section. The noble gases in this magnetic fraction were similar to zero-age deep-sea interplanetary dust particles (IDPs) and some magnetic grains isolated from the Cretaceous-Tertiary boundary. The helium and neon isotopic compositions for both the bulk Graphite Peak sediments and an isolated magnetic fraction from the bulk material are consistent with solar-type gases measured in zero-age deep-sea sediments and point to a common source, namely, the flux of IDPs to the Earth's surface. In this instance, the IDP noble gas signature for the bulk sediment can be uniquely decoupled from fullerene, demonstrating that two separate tracers are present (direct flux of IDPs for (3)He vs. giant impact for fullerene).     

Locating potential biosignatures on Europa from surface geology observations

We evaluated the astrobiological potential of the major classes of geologic units on Europa with respect to possible biosignatures preservation on the basis of surface geology observations. These observations are independent of any formational model and therefore provide an objective, though preliminary, evaluation. The assessment criteria include high mobility of material, surface concentration of non-ice components, relative youth, textural roughness, and environmental stability. Our review determined that, as feature classes, low-albedo smooth plains, smooth bands, and chaos hold the highest potential, primarily because of their relative young age, the emplacement of low-viscosity material, and indications of material exchange with the subsurface. Some lineaments and impact craters may be promising sites for closer study despite the comparatively lower astrobiological potential of their classes. This assessment will be expanded by multidisciplinary examination of the potential for habitability of specific features.     

Mars habitat modules: launch, scaling and functional design considerations

The Sasakawa International Center for Space Architecture (SICSA) is undertaking a multi-year research, planning and design study that is exploring near- and long-term commercial space development opportunities. The central goal of this activity is to conceptualize a scenario of sequential, integrated private enterprise initiatives that can carry humankind forward to Mars. Each development stage is planned as a building block to provide the economic foundation, technology advancements and operational infrastructure to support others that follow. This report presents fundamental issues and requirements associated with planning human Mars initiatives that can transfer crews, habitats and equipment from Earth to Mars orbit, deliver them to the planet's surface, and return people and samples safely back to Earth. The study builds in part upon previous studies which are summarized in SICSA's: Commercial Space Development Plan and the Artificial Gravity Science and Excursion Vehicle reports. Information and conclusions produced in this study provide assumptions and a conceptual foundation for a subsequent report titled The First Mars Outpost: Planning and Concepts.     

固体火箭药柱瞬变热应力计算

由于环境温度的变化,以及气动加热、冷却等原因,致使固体火箭经常承受瞬变热应力的作用。特别是当这些应力事实上是周期性变化时,它们可能大得足以引起药柱破坏。近来试验研究表明,多年来用于预估固体火箭推进剂瞬变热应力的单体结构理论是不合适的,该理论过分地低估了应力值,并可能导致非保守的设计。本文提出的修正理论考虑了结构理论方面温度变化的影响。假设温度变换函数不仅取决于作为热流变学单体情况的瞬时温度,而且还取决于温度变化率。修正理论业已表明,适合于预估某些瞬变热试验的结果。     

S玻璃-环氧复合材料在持久拉伸载荷下的寿命估算

设计长期使用的纤维复合材料结构件时,估算其寿命是很重要的。为研究这一课题,在1969年,开始对 S 玻璃、芳香族(1971)纤维和一些石墨纤维制成的简单的环氧复合材料进行了实验研究工作。其办法是将这些经过预浸的纤维束在拉伸状态下进行寿命试验(也称应力破坏或静态疲劳试验)。选取纤维束做试样是因为它们真正代表着复合材料的基本结构坯料。当获得这些数据后,就用不同的方法对它们进行分析,并已在过去10年间陆续予以发表。1980年1月,加利福尼亚州北部的一次大地震破坏了大部份试验试样。因而实际上终