和频过程中的Rabi振荡与Landau-Zener遂穿过程

依据宏观现象与量子物理现象之间的相类似之处,利用干涉原理解释了和频场强度随着传输距离发生类似于原子系统中的Rabi振荡的物理机理,从Landau—Zener遂穿（LZT）N角度揭示了光学参量转换过程中的能量转移机理,以渐进解、解析解的形式详细展示出和频产生过程中的能量转移过程．     

An aqueous extract of Liu Wei Di Huang Wan alters the labeling of blood constituents with Technetium-99m

The Liu Wei Di Huang Wan is a formula of a traditional Chinese medicine that is used to treat asthma patients and has been shown to have several important properties,such as antioxidant and free radical scavenging activities.The influence of an extract of Liu Wei Di Huang Wan on the labeling of blood constituents with technetium-99m was investigated.Anticoagulated blood(Wistar rats) was incubated with the extract,stannous chloride and technetium-99m,as sodium pertechnetate.Samples were centrifuged and aliquots of plasma and blood cells were separated and precipitated with trichloroacetic acid,to obtain soluble and insoluble fractions of the blood constituents.The percentage of radioactivity(%ATI) in all the fractions was determined.The analysis of the results shows that the extract at the highest concentration used(70 mg/mL) decreased significantly(P<0.05) the %ATI(from 96.48 ± 1.19 to 54.46 ± 7.38) on blood cells compartment,(from 81.11 ± 4.15 to 61.33 ± 4.74) on insoluble fractions of blood cells and(from 65.91 ± 2.44 to 13.15 ± 3.62) on insoluble fractions of plasma.In conclusion,the results suggest that the substances present on this extract can alter this labeling process,probably due to(i) redox properties(antioxidant and chelator activities) and/or(ii) specific actions in the binding sites where the 99mTc would be bound on the blood constituents.As a consequence,precaution is suggested on the interpretation of the nuclear medicine results from performed with blood constituents labeled with 99m Tc in patients that have undertaken LWDHW,although the current findings were obtained in experimental animal models.     

气-固相催化环合N-甲基哌嗪的研究

本文研究了合成N-甲基哌嗪的新方法.即以二乙醇胺和甲胺为原料,选用不同类型催化剂,通过固定床反应器,气固相催化环合制取N-甲基哌嗪的方法.并对反应温度、压力、物料配比等因素对反应的影响作了系统的研究.确定了该环合反应所用最佳催化剂为硅铝比为30的HZSM-5型分子筛催化剂,最佳反应条件为反应温度为300℃,操作压力为8 MPa,二乙醇胺和甲胺的物质的量比为1∶2,空速为0.5 L./h.在此条件下,N-甲基哌嗪的收率可达80％以上,选择性可达90％.     

论高职院校校长领导力的核心作用

高职院校的校长是高职院校领导班子的核心,也是高职院校发展和改革的领头人和带路人,其所具备的规划力、决策力、执行力、凝聚力等各种领导能力关系着高职院校未来的生存和发展。通过对高职院校校长领导力的核心作用及提升高职院校校长领导力的关键因素进行分析探讨,将有助于更好的开展高职院校校长领导力建设的相关研究,同时对高职院校内涵建设与战略发展也有所裨益。     

略论鄱阳湖生态经济区人才资源开发

江西省委省政府提出建设鄱阳湖生态经济区的科学决策.要实现鄱阳湖生态经济区的战略目标,必须在盘活现有人才存量的基础上,加大人才资源的开发力度.本文通过对鄱阳湖生态经济区人才的现状分析,分析人才队伍建设中存在的问题,提出加强鄱阳湖生态经济区人才资源的开发对策和建议.     

基于FPGA的CORDIC算法研究

CORDIC（TheCoordinateRotationalDigitalComputer）算法是将复杂的数学函数化成简单的加法和移位操作,因此被广泛应用到数字信号处理算法的硬件实现中。基于CORDIC算法的流水线型的正／余弦运算电路具有精度高、误差小、电路结构简单等特点。     

卓越法律人才的教育培养与法学实习基地建设

依法治国方略的实施呼唤能够熟练运用法律的应用型人才。卓越法律人才的教育培养计划要求增强学生的法律实务技能。培养应用型法律人才已经成为法学教育的当务之急。应用型人才由实训而来,实习基地为法科生的实训架设了平台。通过建立一批高标准的、涉及面厂的实习基地、延长实习时间、严格实习基地管理制度、打造一支高水平的实习指导教师队伍等方式可以强化法学实习基地地建设。实习基地作用的充分发挥必然会促进卓越法律人才教育培养计划的实现,推动中国法治建设的进程。     

Molecular architecture of native HIV-1 gp120 trimers

The envelope glycoproteins (Env) of human and simian immunodeficiency viruses (HIV and SIV, respectively) mediate virus binding to the cell surface receptor CD4 on target cells to initiate infection. Env is a heterodimer of a transmembrane glycoprotein (gp41) and a surface glycoprotein (gp120), and forms trimers on the surface of the viral membrane. Using cryo-electron tomography combined with three-dimensional image classification and averaging, we report the three-dimensional structures of trimeric Env displayed on native HIV-1 in the unliganded state, in complex with the broadly neutralizing antibody b12 and in a ternary complex with CD4 and the 17b antibody. By fitting the known crystal structures of the monomeric gp120 core in the b12- and CD4/17b-bound conformations into the density maps derived by electron tomography, we derive molecular models for the native HIV-1 gp120 trimer in unliganded and CD4-bound states. We demonstrate that CD4 binding results in a major reorganization of the Env trimer, causing an outward rotation and displacement of each gp120 monomer. This appears to be coupled with a rearrangement of the gp41 region along the central axis of the trimer, leading to closer contact between the viral and target cell membranes. Our findings elucidate the structure and conformational changes of trimeric HIV-1 gp120 relevant to antibody neutralization and attachment to target cells.     

AlMgB_（14）三元超硬硼化物的实验制备与理论研究

三元硼化物AlMgB14材料具有高硬度,高韧性,低密度,低摩擦系数以及抗高温氧化腐蚀等众多优异性能,在工具、模具、微机械制造及航空航天关键零部件等领域具有重要的应用前景.本文采用多靶射频磁控共溅射技术,以高纯度Al（99.99%）,Mg（99.95%）,B（99.9%）材料为溅射靶源,在单晶Si（100）衬底上溅射沉积得到了表面均匀致密,不同化学组分的Al-Mg-B三元非晶态薄膜,通过调控溅射参数,可以实现原子比接近Al：Mg：B=1：1：14.对于所制备的薄膜样品,在三元相图上沿Al-Mg等含量线,Al-Mg-B材料的硬度,随着B元素含量增加由13GPa增大到32GPa,其中AlMgB14附近成分点的硬度达到25~32GPa.同时,采用第一性原理计算,得到AlMgB14晶体的维氏硬度为27.6GPa,与实验值接近.通过电子结构分析,我们进一步探讨了AlMgB14晶体和其他相似结构富B三元化合物硬度的起源,发现他们共同具有的B12二十面体骨架是决定硬度的主要因素.Al,Mg等金属元素主要通过向B12的电荷转移对材料硬度进行微调,Al-B之间形成了弱的共价键而Mg-B之间形成离子键,这点同时也为XPS实验谱图所证实.采用准简谐近似德拜模型,我们还研究了AlMgB14晶体的热学性质以及温度对体弹性模量的影响,发现体模量随温度增加明显的减小,同实验上提高衬底温度对硬度的增强呈现了相反的变化趋势.这从侧面说明了衬底温度提高导致的硬度增强并不是改变了材料的本征硬度,而可能由于加强了薄膜同衬底间附着力.