A neutron-star-driven X-ray flash associated with supernova SN 2006aj

Supernovae connected with long-duration gamma-ray bursts (GRBs) are hyper-energetic explosions resulting from the collapse of very massive stars ( approximately 40 M\circ, where M\circ is the mass of the Sun) stripped of their outer hydrogen and helium envelopes. A very massive progenitor, collapsing to a black hole, was thought to be a requirement for the launch of a GRB. Here we report the results of modelling the spectra and light curve of SN 2006aj (ref. 9), which demonstrate that the supernova had a much smaller explosion energy and ejected much less mass than the other GRB-supernovae, suggesting that it was produced by a star whose initial mass was only approximately 20 M\circ. A star of this mass is expected to form a neutron star rather than a black hole when its core collapses. The smaller explosion energy of SN 2006aj is matched by the weakness and softness of GRB 060218 (an X-ray flash), and the weakness of the radio flux of the supernova. Our results indicate that the supernova-GRB connection extends to a much broader range of stellar masses than previously thought, possibly involving different physical mechanisms: a 'collapsar' (ref. 8) for the more massive stars collapsing to a black hole, and magnetic activity of the nascent neutron star for the less massive stars.     

基于自组织理论的航运服务产业系统演化分析

为了揭示航运服务产业系统的发展过程,基于自组织理论对航运服务产业的协同演化机理进行研究。分析了航运服务产业的自组织性和演化动力,引入自组织理论的分形理论模型,构建了航运服务产业系统的演化模型。最后,以某沿海城市航运服务产业系统为研究对象,基于提出的分形理论模型对该城市航运服务产业系统的演化过程进行实例分析。实验结果表明,提出的自组织演化模型能够准确地刻画航运服务产业系统的演化发展过程。     

壮医塞病论

论述了壮医三气同步整体观,介绍了脏腑官窍结构理论、三道两路联系通道、气血津液等物质、能量、信息媒介物,阐述了以塞为病、以通为用的病理观,分析了塞病的基本类型及其临床症状,总结了塞病的治疗方法及其常用药物.认为塞病理论是壮医独特的医学理论,值得总结与提高.     

不同民族大学生乙肝病毒基因型分布状况调查

为了解不同民族大学生乙型肝炎病毒（hepatitis B virus,HBV）基因型和亚型分布状况,采用限制性片段长度多态性聚合酶链反应（PCR-RFLP）技术,对中南民族大学93例来自15个民族乙肝大三阳学生血清HBV进行基因分型.结果表明：患者中HBV基因B型占61.3%（57/93）,C型占25.8%（24/93）,D型占4.3%（4/93）.说明各民族HBV基因型分布中,B型占绝对优势,C型次之,D型最少（P〈0.01）.且不同民族不影响HBV基因型的分布（P〉0.05）,C型和D型分布基本符合我国HBV基因型地理区域分布规律.     

迎接第二次绿色革命 构建新型农业体系

生命科学与生物技术的发展推动了＂生物经济＂概念与平台的形成与生物经济时代的来临,导致农业正在发生深刻变革,并最终形成第二次绿色革命。为把握第二次绿色革命的时代机遇,在比较分析第二次绿色革命的特点及其功能定位与动力机制的基础上,提出了构建新型农业体系＂超农业＂发展观与战略对策。     

模糊PD控制器在电液伺服阀控制系统中的应用

应用模糊控制原理设计先导式电液伺服阀的模糊PD控制器,采用AMESim软件建立伺服阀的仿真模型,采用Simulink软件建立PD控制器和模糊PD控制器的仿真模型,通过AMESim/Simulink联合仿真得到伺服阀在两种控制方式下的阶跃信号响应曲线。仿真结果表明,与常规的PD控制器相比,模糊PD控制器能够提高控制精度,有效改善伺服阀的性能。     

Study on Sustainable Development Capability of Shandong Province

Based on the indicator system of Sustainable Development(SD), Shandong Province was selected as an example for assessment with AHP method and the standard year was 1978. The conclusion was that Shandong Province’s ability of SD was being strengthened step by step, and there were also some restrictive factors, and according to the basic conditions of Shandong Province, countermeasures and strategy of SD were put forward.     

Four-Parameter Signal Decomposition and Related Adaptive Time-Frequency Distribution

1. INTaODUCTIOMIn order to express the properties of the signal time-varying spectrum, we need to developa class of approaches to analyze signal in time and frequency domain simultaneously. Since1980's, the time-frequency analysis (TFA) methods, such as short time FOurier transform(STFT), Gabor expansion, wavelet transform and Wigner--Ville distribution (WVD), havebeen widely studied and implemellted, which provides powerful tools to analyze and processvarious signals in TF plane. T…     

It(O)型随机系统的仿真--离散相似法

研究Ｉｔｏ型随机系统的仿真，采用离莠相似法得到了Ｉｔｏ型随机系统数值计算的两种差分格式，分析了差分格式的精度和用于Ｉｔｏ型随机系统仿真的有效性，文末用实例演示了所得方法的应用。     

问号皮瓣修复圆形缺损25例

对于体表，特别是颜面部的手术，病人总是希望医生既能去除病灶，又能将疤痕减少到最少最小程度，以达到最大限度地不影响其局部形态及器官功能的目的。体表圆形或近似圆形的病灶在临床上较为常见，切除后如何较好地修复是整形美容外科领域一直探讨的问题。问号皮瓣修复圆...