A complete sequence and comparative analysis of a SARS-associated virus(Isolate BJ01)

Severe Acute Respiratory Syndrome (SARS) is a newly identified infectious disease[1—5]. The global outbreak of SARS has been threatening the health of people worldwide and has killed 353 people and infected more than 5462 in 27 countries, as reported by WHO on April 29, 2003 (http://www.who.int/csr/sarscountry/en). Although it has been recognized that a variant of virus from the family of coronavirus might be the candidate pathogen of SARS[1—5], its identity as the unique pathogen sti…     

A new species of Gobiconodon （Triconodonta, Mammalia） and its implication for the age of Jehol Biota

A new species of Gobiconodon is found from the Yixian Formation of western Liaonlng, China. The new taxa,G zofiae sp. nov., has a confluent opening for branches Ⅱand Ⅲ of the trigeminal nerve on the anterior lamina of the petrosal. G zofiae sp. nov. is similar to Repenomamus in having an ossified Meckel‘s cartilage connecting the lower jaws and ear region. The new species, with enlarged I^1/I1, posteriorly located infraorbital foramen and four mental foramina,distinctly differs from the other species of Gobiconodon. The new material indicates that Gobiconodon has four, not five,upper molariforms. The presence of Gobiconodon in Jchol Biota makes it possible to correlate Jehol Biota with faunas in eastern Asia and North America, and suggests the age of the Yixian Formation to be Early Cretaceous.     

地球上远程抛射体的运动轨迹及计算机模拟

本导出了远程抛射体的运动轨迹，建立了一种计算机模拟实验的方法并画出了轨道图像．为理论研究提供了一种实验方法．     

The age of formation of the mirabilite and sand wedges in the Hexi Corridor and their paleoclimatic interpretation

The Hexi Corridor is located at the transition zone of the Asian summer monsoon and westerly airflow, and lies in an important position in terms of its ecological fragility and climatic sensitivity. During a recent field expedition to this region, we found a sedimentary mirabilite layer in a number of localities including Suwushan, Yanchi, Baitujing, Yanchi Gaotai, Huahai, Yumen, Halanuo扙r, and Dunhuang (Fig. 1), which have the potential to provide important information about environmenta…     

长成冻时间的深部调驱剂研究

长成冻时间的深部调驱剂是以 HPAM为主的复配聚合物 ,由树脂交联剂 1 0 3交联形成的 .由冻胶强度级别的划分定性地测定成冻时间和突破真空度的方法定量测定冻胶强度 .评价了不同聚合物、交联剂及矿化度在不同温度下的成冻时间及强度 ,并作出了成冻时间及强度等值图 .结果表明 :成冻时间在 1～ 3 0 d范围内可调 ,强度 (即 p BV值 )在 - 0 .0 6 0～ - 0 .0 3 0 MPa范围内可调 .由成冻时间和强度等值图可找出具体地层条件下的不同成冻时间及不同强度调驱剂配方     

烟仓麦蛾茧蜂HABROBRACON HEBETOR(SAY)的生物学生态学特性研究

本文对烟仓麦蛾茧蜂的生物学和生态学特性进行了研究。结果表明,麦蛾茧蜂在烟仓的消长有2个高峰期,第1个高峰期发生在4月份,第2个高峰期发生在10月份。温度(T)对麦蛾茧蜂的寄生率(P)、卵孵化率(H)、成蜂的产卵量(L)和茧的羽化率(C)影响显著,其关系式可分别表达为:P=—352.67+32.54T—0.61T~2、H=—381.82+35.79T—0.67T~2、L=—82.05+16.32T+0.27T~2、C=—119.18+16.52T—0.32T~2。在不同的营养中,5％蜂蜜水对麦蛾茧蜂的影响最为显著。在同一温度下,麦蛾茧蜂成蜂的发育历期最长,其次是蛹,幼虫的历期高于卵的历期;对于同一虫态,随着温度的升高,其发育历期逐渐缩短。麦蛾茧蜂成蜂的发育起点最低,但其所需的有效积温最高;幼虫的发育起点温度最高;卵的有效积温最低。     

基体改性对碳/碳复合材料烧蚀率影响的神经网络模拟

将人工神经网络的典型模型－－误差后传播（BP）算法用于改性的碳／碳复合材料氧化烧蚀率的研究，建立了碳／碳复合材料改性添加剂组成－氧化烧蚀率BP网络模型。研究结果表明，所建模型较好地反映了添加剂含量与试样氧化烧蚀率间的内在规律，预测的氧化烧蚀率与实验值间的误差小于0．32％。将模型筛选出的最优添加剂配方用于基体改性，试样的氧化烧蚀率下降49．3％，说明将人工神经网络用于基体改性是可行和有效的。     

单晶硅中离子注入及快速热退火后浓度分布模型

在考虑B，P，As离子注入单晶硅中的浓度分布模型的基础上，讨论了快速热退火对3种注入离子浓度分布的影响，提出了3种离子在快速热退火后浓度分布的修正模型，由修正后的模型得到的多次离子注入模拟结果与实验结果符合很好。     

水杨醛甘氨酸席夫碱配体2种互变异构体的DFT研究

通过密度泛函理论(DFT)计算，获得了水杨醛甘氨酸席夫碱2种异构体在真空条件下及在水、甲醇、乙醇、乙醚溶剂中的优化几何构型以及电子结构、分子偶极矩等参数，从理论上分析水杨醛甘氨酸席夫碱2种异构体的性质差异，解释了一些实验现象，为药物设计奠定了基础。