具不确定观测和相关噪声的最优递推滤波

应用正交投影定理,对于噪声相关系统,在观测不确定的情况下,求出了状态向量的卡尔曼滤波公式。在线性最小方差准则下,解决了状态噪声一步相关,相同时刻的测量噪声和状态噪声相关,以及测量噪声和状态噪声在相邻时刻均相关的情况下的滤波问题,并给出了递推滤波公式。仿真算例说明了它们的有效性。     

铁基金刚石节块的热处理及其耐磨性能研究

首次提出了在烧结型金刚石工具的制造中引入热处理的新工艺，并系统地研究了淬火温度、淬火时间及回火温度等热处理工艺参数对热压烧结型铁基金刚石圆盘锯节块及其胎体材料机械性能的影响，同时对经热处理的铁基金刚石圆盘锯节块在石材旺苍红上进行磨损试验研究。试验结果表明，热压烧结型铁基金刚石圆盘锯节块胎体热处理的最佳工艺参数为：淬火温度为７６０～７９０℃、淬火时间为３．５ｍｉｎ、回火温度为２４５～３１５℃；经热处理后铁基金刚石圆盘锯胎体及节块的强度、硬度等机械性能有显著的提高，热处理也能明显改善铁基金刚石圆盘锯节块的耐磨性能。这说明将热处理工艺用于烧结型金刚石工具的制造中是切实可行的。     

Neoplastic cell transformation by high-LET radiation: molecular mechanisms.

Experimental data on molecular mechanisms are essential for understanding the bioeffects of radiation and for developing biophysical models, which can help in determining the shape of dose-response curves at very low doses, e.g., doses less than 1 cGy. Although it has been shown that ionizing radiation can cause neoplastic cell transformation directly, that high-LET heavy ions in general can be more effective than photons in transforming cells, and that the radiogenic cell transformation is a multi-step process [correction of processes], we know very little about the molecular nature of lesions important for cell transformation, the relationship between lethal and transformational damages, and the evolution of initial damages into final chromosomal aberrations which alter the growth control of cells. Using cultured mouse embryo cells (C3H10T1/2) as a model system, we have collected quantitative data on dose-response curves for heavy ions with various charges and energies. An analysis of these quantitative data suggested that two DNA breaks formed within 80 angstroms may cause cell transformation and that two DNA breaks formed within 20 angstroms may be lethal. Through studies with restriction enzymes which produce DNA damages at specific sites, we have found that DNA double strand breaks, including both blunt- and cohesive-ended breaks, can cause cell transformation in vitro. These results indicate that DNA double strand breaks can be important primary lesions for radiogenic cell transformation and that blunt-ended double strand breaks can form lethal as well as transformational damages due to misrepair or incomplete repair in the cell. The RBE-LET relationship is similar for HGPRT gene mutation, chromosomal deletion, and cell transformation, suggesting common lesions may be involved in these radiation effects. The high RBE of high-LET radiation for cell killing and neoplastic cell transformation is most likely related to its effectiveness in producing DNA double strand breaks in mammalian cells. At present the role of oncogenes in radiation cell transformation is unclear.     

Determination of optimal samples for robot calibration based on error similarity

Industrial robots are used for automatic drilling and riveting.The absolute position accuracy of an industrial robot is one of the key performance indexes in aircraft assembly,and can be improved through error compensation to meet aircraft assembly requirements.The achievable accuracy and the difficulty of accuracy compensation implementation are closely related to the choice of sampling points.Therefore,based on the error similarity error compensation method,a method for choosing sampling points on a uniform grid is proposed.A simulation is conducted to analyze the influence of the sample point locations on error compensation.In addition,the grid steps of the sampling points are optimized using a statistical analysis method.The method is used to generate grids and optimize the grid steps of a Kuka KR-210 robot.The experimental results show that the method for planning sampling data can be used to effectively optimize the sampling grid.After error compensation,the position accuracy of the robot meets the position accuracy requirements.     

Integrated Safety Culture Model and Application

A new safety culture model is constructed and is applied to analyze the correlations between safety culture and SMS. On the basis of previous typical definitions, models and theories of safety culture, an in-depth analysis on safety culture＇s structure, composing elements and their correlations was conducted. A new definition of safety culture was proposed from the perspective of sub-culture. 7 types of safety sub-culture, which are safety priority culture, standardizing culture, flexible culture, learning culture, teamwork culture, reporting culture and justice culture were defined later. Then integrated safety culture model （ISCM） was put forward based on the definition. The model divided safety culture into intrinsic latency level and extrinsic indication level and explained the potential relationship between safety sub-culture and all safety culture dimensions. Finally in the analyzing of safety culture and SMS, it concluded that positive safety culture is the basis of im plementing SMS effectively and an advanced SMS will improve safety culture from all around.     

面向21世纪的纳米机械学

本文对纳米机械学的发展历程、定义、特点、研究内容和方向进行了简介.     

Heavy-ion induced genetic changes and evolution processes.

On Moon and Mars, there will be more galactic cosmic rays and higher radiation doses than on earth. Our experimental studies showed that heavy ion radiation can effectively cause mutation and chromosome aberrations and that high-LET heavy-ion induced mutants can be irreversible. Chromosome translocations and deletions are common in cells irradiated by heavy particles, and ionizing radiations are effective in causing hyperploidy. The importance of the genetic changes in the evolution of life is an interesting question. Through evolution, there is an increase of DNA content in cells from lower forms of life to higher organisms. The DNA content, however, reached a plateau in vertebrates. By increasing DNA content, there can be an increase of information in the cell. For a given DNA content, the quality of information can be changed by rearranging the DNA. Because radiation can cause hyperploidy, an increase of DNA content in cells, and can induce DNA rearrangement, it is likely that the evolution of life on Mars will be effected by its radiation environment. A simple analysis shows that the radiation level on Mars may cause a mutation frequency comparable to that of the spontaneous mutation rate on Earth. To the extent that mutation plays a role in adaptation, radiation alone on Mars may thus provide sufficient mutation for the evolution of life.     

PWM full-bridge converter with natural input power factor correction

A pulsewidth modulated (PWM) full-bridge converter that simultaneously performs input power factor correction (PFC) and DC-DC conversion is proposed. The converter is the same as the standard voltage-fed PWM full-bridge converter with a diode-bridge low-pass filter front end, but with a slight modification that results in an improvement in power factor that is sufficient to satisfy the EN61000-3-2 requirements for electrical equipment. The operation of the converter is explained and analyzed, and the results of the analysis are used to determine the converter's steady-state characteristics, which are discussed in detail. A design procedure for the selection of components is then derived and demonstrated with an example. The feasibility of the converter and its ability to satisfy EN61000-3-2 requirements on electrical equipment is shown with results obtained from an experimental prototype.     

高校图书馆向社会服务的探索

本文就高校图书馆在市场经济体制下向社会服务的重要性、可能性、服务的途径和方式进行了探讨。     

Instrumentenentwicklungen für anwendungsaufgaben der fernerkundung photogrammetrie,geophysik und geodäsie

(Instrument Developments for Applications in Remote Sensing, Photogrammetry, Geophysics and Geodesy) The Modular Optoelectronic Multispectral Seanner MOMS-01, a CCD camera using the push-broom scanner principle, is presented in this paper in its flight configuration. This instrument will be the first European-built spaceborne unaging system for remote sensing applications (launch with Shuttle flight No. 7).Follow-on developments of this initial two-channel version are oriented to an extension of capabilities by a panchromatic high-resolution stereoscopic module for thematic mapping and two additional spectral channels in the reflective IR (up to 2.3 μm) offering a high interpretation potential for future earth resources exploration missions. Furthermore the subjects of advanced laser technology studies are introduced: A picosecond pulse laser system for detection of tectonic motions and for geodetic application, a CO laser for ultra precise range rate determination (Earth potential and Geoid) and a laser range finder for intersatellite distance measurements.