Radiations in space: risk estimates

The complexity of radiation environments in space makes estimation of risks more difficult than for the protection of terrestrial populations. In deep space the duration of the mission, position in the solar cycle, number and size of solar particle events (SPE) and the spacecraft shielding are the major determinants of risk. In low-earth orbit missions there are the added factors of altitude and orbital inclination. Different radiation qualities such as protons and heavy ions and secondary radiations inside the spacecraft such as neutrons of various energies, have to be considered. Radiation dose rates in space are low except for short periods during very large SPEs. Risk estimation for space activities is based on the human experience of exposure to gamma rays and to a lesser extent X rays. The doses of protons, heavy ions and neutrons are adjusted to take into account the relative biological effectiveness (RBE) of the different radiation types and thus derive equivalent doses. RBE values and factors to adjust for the effect of dose rate have to be obtained from experimental data. The influence of age and gender on the cancer risk is estimated from the data from atomic bomb survivors. Because of the large number of variables the uncertainities in the probability of the effects are large. Information needed to improve the risk estimates includes: (1) risk of cancer induction by protons, heavy ions and neutrons: (2) influence of dose rate and protraction, particularly on potential tissue effects such as reduced fertility and cataracts: and (3) possible effects of heavy ions on the central nervous system. Risk cannot be eliminated and thus there must be a consensus on what level of risk is acceptable.     

高能ZnO线性电阻器

ZnO线性电阻是一种包括含锌氧化物晶体颗粒和其它金属或半金属元素的氧化锌化合物的晶体颗粒构成的一种复合体,现已研制出性能较优异的ZnO线性电阻体并对其工艺特点,显微结构,导电机理作了一定的分析。     

重点高耗能行业煤利用过程中的节能问题研究

高耗能行业不仅能耗高也是能源密集型产业,并且煤和电占据行业能源消费结构中的主导地位。高耗能行业面对能源资源供应紧张、降低能耗以及低碳可持续发展的迫切需要,必须优先节能,并要重视和发展煤炭利用过程中的节能战略。本文围绕我国石化、钢铁、建材、化工、有色金属、造纸、纺织七个高耗能行业煤炭利用过程中的节能问题开展研究,突出发展要以节能为本的重要理念,在系统掌握当前我国高耗能行业煤炭利用情况的基础上,比较分析国内外技术水平的差距;通过运用态势(SWOT)分析法及产业技术路线图研究,总结各行业在节能方面面临的挑战和机遇;凝练了高耗能行业煤炭利用过程的节能途径及重点节能技术方向;最后强调了煤炭利用过程中节能对高耗能行业可持续发展的重要作用。     

高耗能企业系统化节能模型控制研究

在高耗能企业中采用“系统化节能动态模型控制”技术，将企业电耗分成若干环节，构建各环节的电耗目标函数模型，再将各环节电耗目标函数值作为企业系统目标控制函数中的决策变量，构建企业级电耗目标函数，并进行优化计算与控制，实现企业电耗最小。     

Metallic MoS2 for High Performance Energy Storage and Energy Conversion

Metallic phase 2D molybdenum disulfide (MoS₂) is an emerging class of materials with remarkably higher electrical conductivity and catalytic activities. The goal of this study is to review the atomic structures and electrochemistry of metallic MoS₂, which is essential for a wide range of existing and new enabling technologies. The scope of this paper ranges from the atomic structure, band structure, electrical and optical properties to fabrication methods, and major emerging applications in electrochemical energy storage and energy conversion. This paper also thoroughly covers the atomic structure–properties–application relationships of metallic MoS₂. Understanding the fundamental properties of these structures is crucial for designing and manufacturing products for emerging applications. Today, a more holistic understanding of the interplay between the structure, chemistry, and performance of metallic MoS₂ is advancing actual applications of this material. This new level of understanding also enables a myriad of new and exciting applications, which motivated this review. There are excellent reviews already on the traditional semiconducting MoS₂, and this review, for the first time, focuses on the uniqueness of conducting metallic MoS₂ for energy applications and offers brand new materials for clean energy application.     

The Influence of Ionizing Radiations Upon Different Forms of Collagen

Collagens received increasing doses of radiations β or γ The structural state of each of them is controlled by differential scanning calorimetry and by electrophoresis on polyacrylamide gel. Each of this method allows the study of only a part of the structure of collagen. The hemostatic activity is analysed by agregation test. The changes in the collagens in relation to irradiation are more important when studied by electrophoresis than by differential scanning calorimetry. Ionizing radiations change hemostatic activity of collagens.     

Statistics of High Purity Nickel Microstructure From High Energy X-ray Diffraction Microscopy

We have measured and reconstructed via forward modeling a small volume of microstructure of high purity, well annealed nickel using high energy x-ray diffraction microscopy (HEDM). Statistical distributions characterizing grain orientations, intra-granular misorientations, and nearest neighbor grain misorientations are extracted. Results are consistent with recent electron backscatter diffraction measurements. Peaks in the grain neighbor misorientation angle distribution at 60 degrees (∑3) and 39 degrees (∑9) have resolution limited widths of ≈ 0.14 degree FWHM. The analysis demonstrates that HEDM can recover grain and grain boundary statistics comparable to OIM volume measurements; more extensive data sets will lead to full, five parameter grain boundary character distributions. Due to its non-destructive nature, HEDM can then watch, both statistically and through tracking of individual grains and boundaries, the evolution of such distributions with processing of the sample.     

Energy Saving in Ultra High Vacuum Systems

In UHV, bakeout is employed to reach very low pressure. We have tested two bakeout systems: resistance and IR lamp heaters and we have realised that with IR Lamps we have energy and time saving.     

金刚石膜高能粒子探测器

评述了金刚石膜探测器的优缺点，简要地介绍了由化学气相沉积的多晶金刚石膜所制成的辐射探测器，以及利用此探测器对α粒子进行测量的初步结果。     

High Energy and High Coercivity Sintered NdFeB Magnets by Low Oxygen Process

1. IntroductionSince NdFeB magnets were discovered[ll, theirmagnetic performance has been improved by many researchers. The maximum energy product of sinteredNdFeB magnets has been increased from 240 kJ/m'to 430 kJ/m' by Kaneko et al.[2] in 1993. The maximtun energy product commercially available todayis close to 358 kJ/m'. Because of this high performance of NdFeB products, the applications have increased enormously in the last decade. For example,hard disk drivers (HDD), magnetic reso…