Exploitation of shape memory alloy actuator using resistance feedback control and its development

The relationship between phase transformation and electric re sistivity of Ti-42.6Ni-7Cu SMA was investigated. In the isothermal tensile tests, stress—strain curve shows large hysteresis and nonlinearity, whereas the resistivity—strain curve can be fitted by linearity. The resistivity of SMAs can be determined from the volume fractions of the martensitic and austenitic phas es. This characteristics leads to that the resistance of the SMAs is used as a parameter of strain of SMAs. A SMA actuator using resistance feedback control system was proposed, which can control and retain positioning at any positions without using sensor devices, and the deviation of position of this system was less than 3 μm.     

173W的高自旋态和γ5/2~-[512]转动带的旋称反转

利用150Nd（28Si,5n）熔合蒸发反应居了173W的高旋态.于标准在束核谱学实验测量结果,扩展了于γ7/2＋[633],γ5/2-[512]和γ1/2-[521]准组态的转动带.首次建了173W γ1/2-[521]转动带的能量非优先分支.发现γ5/2-[512]转动带在低旋区出现旋称反转.相似的旋称劈行为表明174Reπ1/2-[541]γ5/2-[512]转动带的旋称反转来位于5/2-[512]轨道的中.旋称反转制有待进一研究.     

High Speed Twin Roll Casting of Aluminum Alloy Strips

The twin roll caster for aluminum alloys has many a dv antages. For example, rapid solidification, low equipment cost, and low running cost, etc. However, the twin roll caster has some disadvantages. They are slow c asting speed and limitation of alloys. In the conventional twin roll caster, the casting speed is slower than 10 m/min. Aluminum alloys, which freezing range is wide, can not be cast. In the present study, break through of these problems wa s tried, and a new type twin roll caster was devised...     

Light-induced conversion of an insulating refractory oxide into a persistent electronic conductor

Materials that are good electrical conductors are not in general optically transparent, yet a combination of high conductivity and transparency is desirable for many emerging opto-electronic applications. To this end, various transparent oxides composed of transition or post-transition metals (such as indium tin oxide) are rendered electrically conducting by ion doping. But such an approach does not work for the abundant transparent oxides of the main-group metals. Here we demonstrate a process by which the transparent insulating oxide 12CaO x 7Al(2)O(3) (refs 7-13) can be converted into an electrical conductor. H(-) ions are incorporated into the subnanometre-sized cages of the oxide by a thermal treatment in a hydrogen atmosphere; subsequent irradiation of the material with ultraviolet light results in a conductive state that persists after irradiation ceases. The photo-activated material exhibits moderate electrical conductivity (approximately 0.3 S cm(-1)) at room temperature, with visible light absorption losses of only one per cent for 200-nm-thick films. We suggest that this concept can be applied to other main-group metal oxides, for the direct optical writing of conducting wires in insulating transparent media and the formation of a high-density optical memory.     

牛磺酸强化轮虫对眼斑拟石首鱼仔鱼的投喂效果

研究用3种不同质量浓度梯度(分别为T0组:0 mg/L;T4组:400 mg/L;T8组:800 mg/L)牛磺酸强化的轮虫(Brachionus plica tilis)对3~20日龄的眼斑拟石首鱼(Sciaenops ocella tus)仔鱼的投喂效果.结果表明,T8组的仔鱼平均全长((8.5±0.8)mm)和成活率(70.5%)都明显高于T0组(平均全长:(6.3±1.0)mm;成活率:28.4%)和T4组(平均全长:(7.0±0.8)mm;成活率:27.4%),T0组和T4组之间生长和成活率并无显著差异;T8组仔鱼的耐干露及耐高盐度(65)能力明显比T0组和T4组强,即仔鱼的抗应激能力受轮虫强化剂牛磺酸的质量浓度影响显著(P<0.05).     

An efficient spatio-temporal data structure for multi version management of engineering drawings

In the engineering database system, multiple versions of a design including engineering drawings should be managed efficiently. The paper proposes an efficient spatial data structure, that is an expansion of the R-tree and HR-tree, for version management of engineering drawings. A novel mechanism to manage the difference between drawings is introduced to the HR-tree to eliminate redundant duplications and to reduce the amount of storage required for the data structure. Data management mechanism and structural properties of our data structure called the MVR -tree are described.     

Modified Multi-Resolution Telescopic Search Algorithm for Block-Matching Motion Estimation

SOFTWARE,ALGORITHM AND SIMULATION1. INTRODUCTIONRecently low cost and low-power video encoders are in demand, in which motion estimation is an importanttechnology. The block-matching motion estimation is widely used in various video encoders. The direct fullsearch block-matching algorithm (FSBMA) demands massive computational effort and is not suit for VLSIimplementation.The multi-resolution telescOPic search algorithm (MRTlcSA) [1] is considered as a good trade-off betw…     

环境政策思想与社会性共识的形成

人类文明的可持续发展,不但要依托科技创新、更须借助思想文化的前瞻性引领,还得需要一个健康清洁和谐的生态环境资作人类的"家园"。在此,生态哲学作为一种共轭性坐标,将人类的伦理文化、科技文化乃至政治文化、经济文化加以贯通协调。2006年召开的"国际东亚哲学学术讨论会",即是有关上述前瞻性探索的智思交锋与爱心闪辉。本部特选四则论文,以飨广大读者和知识界、教育界同仁。