注装梯恩梯(TNT)装药冲击Hugoniot参数的实验测定

本文利用一级轻气炮实验技术，对注装梯恩梯药进行了高应变率下的动态冲击实验，对实验方法进行了改进，设计了一种新型的轻气炮延伸炮管。根据实验数据结果，得到了注装ＴＮＴ装药的冲击Ｈｕｇｏｎｉｏｔ参数。     

世界上最壮丽的景色——意大利恺撒奥古斯都酒店

概况海拔1000英尺以上的悬崖上,意大利奥古斯都恺撒酒店提供卡普里岛的最壮观的景色之一。从酒店的客房内,你可以眺望到令人惊叹的美景。那不勒斯湾附近,维苏威火山,索伦托海岸,伊斯基亚和卡普里岛包括由Axel Munthe,我们的别墅是令人惊叹的风景庆祝。     

天堂也不过如此 让人心旷神怡的斐济

斐济位于西南太平洋中心,是南太平洋地区的交通枢纽,号称南太平洋的"十字路口"。地跨东、西半球,180度经线贯穿其中,因而成为世界上既是最东又是最西的国家。斐济由332个岛屿组成,多为珊瑚礁环绕的火山岛,其中106个岛有人居住。在斐济,很容易让人发出"天堂不过如此"的感叹。清凉的海风吹拂着高耸入云椰林,岛上热带树木浓绿成荫,海滩边洁白的沙滩,海里奇形怪状的珊瑚礁,色彩斑斓的鱼儿将海水搅得五彩缤纷,到处充满热带海洋的原始美感。     

植物能量 助力抗氧化

自由基人若要活着,除了要有食物供给充足的营养外,更需要靠不断地呼吸来获得氧气,氧气更是身体进行各种氧化反应所必需的,然而当人体正在利用氧气进行某些代谢反应时,不可避免地会产生一些不稳定物质,而这些不稳定的物质都是氧气的"变身",它们的个性非常活泼,不喜欢安安稳稳地呆在原地,甚至喜欢去攻击别人,由于它们这种不喜欢受拘束的个性,我们称之为自由基。     

A catalogue of low-resolution IUE spectra of dwarf novae and nova-like stars

A catalogue is presented of all the low-resolution IUE spectra of dwarf novae and nova-like stars that were recorded until the end of 1987. All spectra have been reduced, and are displayed, in a homogeneous way. In addition to details about these data, to the extent available, their position in the outburst light curves is given, physical information about each system, and a comprehensive list of references for published observations in all wavelength ranges.     

TC4钛合金纵弯超声振动铣削装置及其加工性能研究

TC4钛合金因其优异的综合机械性能在航空、航天工业中得到了广泛应用,但其高塑性和低导热系数引起的刀具–切屑黏附是制约其铣削加工性能提升的一个关键因素.针对TC4钛合金铣削加工性能提升的需求,提出了一种基于刀具纵弯复合超声振动辅助铣削的加工方式,通过控制刀具纵弯复合超声振动的幅值和相位实现可控的间歇式切削,降低刀具–切屑...     

Microbial diversity of Indian Ocean hydrothermal vent plumes: microbes tolerant of desiccation, peroxide exposure, and ultraviolet and gamma-irradiation

The microbial diversity of Kali chimney plumes, part of a hydrothermal vent field in the Rodriguez Triple Junction, Indian Ocean (depth approximately 2,240 m), was examined in an attempt to discover "extremotolerant" microorganisms that have evolved unique resistance capabilities to this harsh environment. Water and sediment samples were collected from the vent and from sediments located at various distances (2-20 m) away from and surrounding the chimney. Samples were screened for hypertolerant microbes that are able to withstand multiple stresses. A total of 46 isolates were selected for exposure to a number of perturbations, such as heat shock, desiccation, H(2)O(2), and ultraviolet (UV) and gamma-irradiation. The survival of Psychrobacter sp. L0S3S-03b following exposure to >1,000 J/m(2) UV(254) radiation was particularly intriguing amid a background of varying levels of resistance. Vegetative cells of this non-spore-forming microbe not only survived all of the treatments, but also exhibited a 90% lethal dose of 30 s when exposed to simulated martian UV radiation and a 100% lethal dose of 2 min when exposed to full spectrum UV, which is comparable to findings for bacterial endospores.     

The winter anomaly of 1983/84 as observed in the A3-absorption and 5 kHz atmospherics in Central Europe

The MAP/WINE winter 1983/84 is studied using the LF-MF-HF A3 absorption and 5 kHz atmospherics observed in Czechoslovakia and some other data. The “normal” winter anomaly in Central Europe is developed well in this winter (maximum in mid-January) and appears to be “free of geomagnetic contamination”. The stratospheric warming activity and related changes of prevailing zonal wind in the lower thermosphere in February and March 1984 are followed by decreases of absorption of radio waves. It agrees with our results from preceding winters /1/.     

MAP estimation of target manoeuvre sequence with theexpectation-maximization algorithm

Two algorithms are derived for the problem of tracking a manoeuvring target based on a sequence of noisy measurements of the state. Manoeuvres are modeled as unknown input (acceleration) terms entering linearly into the state equation and chosen from a discrete set. The expectation maximization (EM) algorithm is first applied, resulting in a multi-pass estimator of the MAP sequence of inputs. The expectation step for each pass involves computation of state estimates in a bank of Kalman smoothers tuned to the possible manoeuvre sequences. The maximization computation is efficiently implemented using the Viterbi algorithm. A second, recursive estimator is then derived using a modified EM-type cost function. To obtain a dynamic programming recursion, the target state is assumed to satisfy a Markov property with respect to the manoeuvre sequence. This results in a recursive but suboptimal estimator implementable on a Viterbi trellis. The transition costs of the latter algorithm, which depend on filtered estimates of the state, are compared with the costs arising in a Viterbi-based manoeuvre estimator due to Averbuch, et al. (1991). It is shown that the two criteria differ only in the weighting matrix of the quadratic part of the cost function. Simulations are provided to demonstrate the performance of both the batch and recursive estimators compared with Averbuch's method and the interacting multiple model filter     

A large area multitechnique experiment for hard X-ray astronomy

A balloon-borne multitechnique large area experiment consisting of 2 co-aligned detectors (3200 cm² NaI and 1800 cm² multiwire proportional counters), is described, which is capble of producing observations of the hard X-ray sky with very high sensitivity and good spectral resolution over the whole operative range (15–300 keV).