The Distribution of a CP-asymmetric quantity in the decay channel J / Ψ → π + π ? π 0

The distribution of a CP-asymmetric quantityA in the decay channelJ/ψ→π ⁺ π ⁻ π ⁰ is investigated. This dimensionless quantityA is constructed from the momenta of the π-meson final states, namely A=P _x ^{π +} P _y ^{π −} -P _x ^{π −} P _y ^{π −}, whereP _h,P _x ^h andP _y ^h are the module of the momentum of a hadron h, the x- and y-components of that momentum respectively, theJ/ψ particle is produced by e⁺ e⁻ collision, and the direction of the momentum of e⁺ is taken to be the positive direction ofz axis. There would exists the violation under the combined transformation of charge conjugation and space reflection (CP violation) when the average ofA among a lot of events, 〈A〉, be examined to be nonzero clearly from data. In this way, 748 events are selected from the BES experimental data, and analyzed. The corresponding averageA-value is measured to be 〈A〉 = 0.010 39 ± 0.014 61 ± 0.015 2. Further, some discussion of our result, the size of the data sample being need for further attempt and a possible perspective are given.     

一种有效的运动目标辨别方法

提出了一种利用图像序列中两帧相邻图像从分割所得二值图像的各个候选目标块中确定真实目标的有效算法．背景配准后，可获得背景噪声分布的直方图，同时获得具有对应关系的候选目标块间的噪声分布直方图，通过比较它们与背景噪声分布直方图之间的差异性，即可准确地辨别出真实目标．通过对实际图像序列进行实验，证实了本方法的有效性．     

Geochronology of source materials from high-pressure and ultrahigh-pressure metamorphic rocks in Jurassic sedimentary rocks of Hefei Basin

Eclogite cobbles were discovered by Wang et al. (2001) in the Fenghuangtai Formation of the northern margin of Dabie Mountains in the Dushan area of Anhui Province, China[1]. They proposed that after the formation during the Triassic, the high-pressure (HP) and ultra-high-pressure (UHP) metamorphic rocks reached the sur-face through exhumation and uplifting before the late Ju-rassic. However, they have not provided any evidence about isotopic ages. One kind of cobbles of HP-UHP rocks w…     

联合收割机自动控制研究现状与展望

总结国内外联合收割机自动控制研究成果及存在问题，指出联合收割机智能模糊控制的发展趋势，提出适应我国国情的联合收割机智能模糊控制新模式为集中控制与分散监测相结合．     

心脏机械瓣替换术后抗凝治疗的研究

目的：研究机械瓣替换术后抗凝治疗期间并发症的发生率及分布规律、调整抗凝药的用量。方法：对167例心脏机械瓣替换术的病人进行1～8年的凝血酶原时间随访研究。结果：血栓率0．72％病人·年；出血率9．21％病人·年。血栓集中在非风湿性心脏病及倾斜机械瓣置换者；出血集中在风湿性心脏病及术后心功能不全、肝瘀血者。结论：抗凝治疗期间注意了解病人的心功能、肝功能情况，对不同的人群，采用不同的凝血酶原时间比值，抗凝期间进行中、小手术时采用停服抗凝药三天的方法有较好的效果。     

偶偶核166Hf高自旋态的微观描述

从壳模型组态及核子－核子有效相互作用出发，用一种在截断的态空间中研究偶偶核高自旋态的理论方案，以偶偶核＾１６６Ｈｆ为对象作了计算和讨论。结果表明，该理论方案很好地描述了稀土区偶偶核高自旋态的性质。     

Identification and gene mapping of a narrow and upper-albino leaf mutant in rice (Oryza sativa L.)

The leaf blade consists of color and shape traits. Studies of leaf-blade development are important for improvement of rice yield and quality because it is an essential organ for photosynthesis. A narrow and upper-albino leaf mutant (nul1) was identified from among progeny of the indica restorer line Jinhui10 raised from seeds treated with ethyl methane sulfonate. Under field conditions, the mutant displayed narrow and upper-albino leaf blades with significantly decreased photosynthetic pigment contents throughout their development. The narrow-leaf trait is caused by a decreased number of small veins. In contrast to the wild type, the growth period was extended by approximately 8 d and agronomic traits, such as effective panicle number, percentage seed set and 1000-grain weight, declined significantly in the nul1 mutant. Genetic analysis suggested that the narrow and upper-albino leaf characteristics showed coseparation and were controlled by one recessive gene. The Nul1 gene was mapped onto chromosome 7 between the Indel marker Ind07-1 and the Simple Sequence Repeat marker RM21637. The physical distance between the markers was 75 kb and eight genes were annotated in this region based on the rice Nipponbare genome sequence. These results provide a foundation for cloning and function analysis of Nul1.     

串并联个数和温度对光伏电池结电容的影响研究

研究光伏电池的动态参数对设计光伏发电系统相应后级控制器至关重要.从分析光伏电池物理机理出发,推导出光伏电池单体/模组/阵列的结电容与偏置电压之间的较精确表达式;在提取模型中等效串联电阻和饱和电流的值的基础上,使用LambertW函数推导出偏置电压与输出电压之间的显式表达式;采用工程数学模型结合本征载流子浓度表达式推导了结电容与温度的较精确关系式;分别在不同串并联个数和温度下对结电容的影响做了仿真分析.仿真结果与部分文献的实验结果相吻合,验证了理论的正确性.     

The Absolute and Its Measurement: William Thomson on Temperature

In this paper we give a full account of the work of William Thomson (Lord Kelvin) on absolute temperature, which to this day provides the theoretical underpinnings for the most rigorous measurements of temperature. When Thomson fashioned his concepts of ‘absolute’ temperature, his main concern was to make the definition of temperature independent of the properties of particular thermometric substances (rather than to count temperature from an absolute zero). He tried out a succession of definitions based on the thermodynamics of ideal heat engines; most notably, in 1854 he gave the ratio of two temperatures as the ratio of quantities of heat taken in and given out at those temperatures in a Carnot cycle. But there were difficulties with using such definitions for experimental work, since it was not possible even to approximate an ideal Carnot engine in reality. More generally, it is not trivial to connect an abstract concept with concrete operations in order to make physical measurements possible. In the end, Thomson argued that an ideal gas thermometer would indicate his absolute temperature, and that the deviation of actual gas thermometers from the ideal could be estimated by means of the Joule‐Thomson effect. However, the measurement of the Joule‐Thomson effect itself required measurements of temperature, so there was a problem of circularity.     

不锈钢太阳能集热器的防腐蚀结构—对若干日本专利的评述

本文对几份日本专利如何从结构上防止不锈钢太阳能集热器的缝隙腐蚀进行了评介。