基于等高线与植被图的后向散射系数估算方法

通过对等高线与土地利用图的处理,建立了数字高程模型和土地类型数据库,提出了一种在大范围复杂地形条件下雷达地面归一化后向散射系数的估算方法。与实测数据对比,显示了这种方法的正确性。     

“新婚姻法现象”中婚外情等争论带来的启示

“新婚姻法现象”不仅是一个立法事件,更是当前我国婚姻家庭关系领域内伦理道德矛盾的集中反映。一部法律的修订并不能解决所有矛盾,我们迫切需要有针对性地研究新问题,加强婚姻家庭关系领域的道德建设。     

端午节起源新考

人们普遍认为 ,端午节源于南方“龙图腾祭”仪式 ,但经对北方端午登山习俗的考证得出结论 ,它是起源于中原华夏族的祭天祈年仪式 ,后与南方楚越文化交融 ,演变为赛龙舟祭屈原的节俗。     

换热器管束流体激振的研究现状评估及新方法

换热器管束的流体激振问题是严重影响其运行安全性的一个关键问题。该文对近年来国内外对此问题的研究进行了综述与评估。根据以往在叶轮机械流体激振研究方面开创的理论系统和研究方法,作者提出了通过应用振荡流体力学原理和参数多项式方法去求解流体基本方程,从而确定流体激振力的方法,应用全功能分析方法来准确预估流体弹性振动的稳定性边界,应用振荡压力传播理论来分析包括声共振在内的流体激振现象。这些思想为换热器管束流体激振研究指引了一条新途径。     

Modulation of presynaptic nAChRs on postsynaptic GABA receptor in optic tectum of juvenile<Emphasis Type="Italic">Xenopus</Emphasis>

Using the blind patch-clamp technique with the whole-cell mode,we have studied the modulation presynaptic receptor on postsynaptic γ-raminobutyric acid (GABA) receptor measuring miniature inhibitory postsynaptic currents (mIPSCs)in optic tectum of Xenopus during critical peroid.It was demonstrated that compared with mature neurons,mIPSCs recorded from immature neurons had smaller amplitude and longer decay time.mIPSCs are mediated by GABAa receptor.The nicotinic acetylcholine receptor agonists(carbachol,cytisine,nicotine,DMPP and so on) could increase the frequency of mIPSCs.The enhancement of mIPSCs frequency induced by nAChR agonists was calcium-dependent.However,the choline,a product of hydrolyzed acetylcholine,could not increase the frequency of mIPSCs.DH-β-E,a competitive antagonist of nAChR,blocked the increase of mIPSCs frequency induced by carbachol.Mecamyllamine,an α3β4 subtype of nAChR antagonist,also blocked the carbachol-induced enhancement of mIPSCs.On the other hand,MLA,α7 subtype of nAChR antagonist,had no effect on it .Thus,it seems that nAChR could presynaptically modulate the mIPSCs and α3β4 subtype of nAChR might be involved.But α7 nAChR subtype of nAChR would not be involved.The modulation is calcium-dependent.Meanwhile,we found that Ca^2 -free solution could elicit giant PSCs.The frequency of mIPSCs also is related with the level of HP.     

Structural stability of infinite-layer CaCuCO<Subscript>2</Subscript> under high pressure

Since the discovery of high temperature supercon-ductivity by Bednorz et al. in 1986[1], many series of cu- prate superconductors have been synthesized. Critical temperature has been improved continuously. But no verdict has been given upon what mechanism causes su- perconductivity. CaCuO2 conductive layers are the parent structure of the high Tc cuprate superconductors, such as Cu-12 (n-1)n[2], Tl-12(n-1)n[3] and Hg-12(n-1)n[4,5] super- conductor families. In 1988, infinite-layer (Ca0.86S…     

Adsorption and catalytic combustion of ARB on CuO-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>

CuO-Fe2O3 composite material with strong magnetism and a large surface area is prepared by the co-precipitate method. Its adsorption properties towards Acid Red B (ARB) and the regeneration by catalytic combastion of organic compounds have been studied. The results show that the prepared CuO-Fe2O3 composite is an excellent adsorbent for ARB adsorption at acid condition. The presence of Cl^- has no effect on ARB adsorption. But the SO4^2- can inhibit ARB adsorption. After being recovered by the magnetic separation method, the adsorbent can be regenerated by catalytic oxidation of absorbate at 300℃ in air atmosphere. The combustion reactions of ARB in the presence or absence of CuO-Fe2O3 are studied by in situ diffuse refieclion FTIR. The results indicate that, in the presence of CuO-Fe2O3, the degradation temperature is significantly lowered by the catalysis of CuO-Fe2O3, and ARB can be oxidized completely without volatile organic compound by-product; in comparison, in the absence of CuO-Fe2O3, the temperature needed for oxidation of ARB is higher and the reaction is incomplete with some N-containing harmful compounds produced. The reusability of CuO-Fe2O3 is also studied in successive seven adsorption-regeneration cycles.     

Calcium signalling in the guidance of nerve growth by netrin-1

Pathfinding by growing axons in the developing nervous system is guided by diffusible or bound factors that attract or repel the axonal growth cone. The cytoplasmic signalling mechanisms that trigger the responses of the growth cone to guidance factors are mostly unknown. Previous studies have shown that the level and temporal patterns of cytoplasmic Ca2+ can regulate the rate of growth-cone extension in vitro and in vivo. Here we report that Ca2+ also mediates the turning behaviour of the growth cones of cultured Xenopus neurons that are induced by an extracellular gradient of netrin-1, an established diffusible guidance factor in vivo. The netrin-1-induced turning response depends on Ca2+ influx through plasma membrane Ca2+ channels, as well as Ca2+-induced Ca2+ release from cytoplasmic stores. Reduction of Ca2+ signals by blocking either of these two Ca2+ sources converted the netrin-1-induced response from attraction to repulsion. Activation of Ca2+-induced Ca2+ release from internal stores with a gradient of ryanodine in the absence of netrin-1 was sufficient to trigger either attractive or repulsive responses, depending on the ryanodine concentration used. These results support the model that cytoplasmic Ca2+ signals mediate growth-cone guidance by netrin-1, and different patterns of Ca2+ elevation trigger attractive and repulsive turning responses.     

水稻花培育种技术操作和无性系变异体选择

概述了水稻花培育种的技术操作程序和细胞无性系变异的选择方法。选择合适的水稻花培起始材料,选用适宜的培养基配方,对于水稻花培中愈伤组织诱导和分化至关重要。某些增效因子（例如水解乳蛋白、单核苷酸、ＡｇＮＯ３等）可提高灿稻花培的绿苗分化率。无性系变异为农作物细胞工程育种提供丰富的选择材料。通过对细胞变异的研究,建立了裸米选择－测米培胚的技术方法,并选育出多个高蛋白量的水稻优质品种（品系）。     

相关检测算法在全光纤电流互感器数据处理系统中的应用

介绍了当前国内外在进行数据处理时的研究现状和主要问题,详述了相关检测的原理,分析了相关检测算法在全光纤电流互感器数据处理系统中的应用,并画出了具体电路设计框图及其FPGA程序设计的组成框图。