复方中药制剂对人工感染肾型IBV的蛋雏鸡血清免疫球蛋白的影响的研究

为了研究复方中药制剂对感染蛋雏鸡血清免疫球蛋白的影响,将蛋雏鸡随机分为6组(空白对照组、攻毒对照组、复方中药高剂量组、中剂量组、低剂量组、西药治疗组)。分别于给药后3、6、9、14、19d采样处理,测定血清免疫球蛋白(IgG、IgA、IgM)的变化。结果显示,攻毒对照组三者含量高于空白对照组。IgG、IgM含量在给药后3、6、9、14d各治疗组与攻毒对照组差异显著(P0.05);IgA含量各治疗组都高于攻毒对照组。表明复方中药煎剂可显著提高感染肾型传染性支气管炎病毒蛋雏鸡血清免疫球蛋白的含量。     

冰冻/解冻对低合金耐候钢大气腐蚀的影响

采用事内、室内+冰冻和户外三种不同环境的曝晒实验,研究了冰冻/解冻循环对两种耐候钢初期大气腐蚀行为的影响.利用失重实验和电化学方法评价了实验钢的耐腐蚀性能,用扫描电镜观察了锈层形貌,用能谱分析仪分析了合金元素在锈层中的分布.结果表明:低温、低湿环境促进致密锈层的形成,而温度、湿-度较高的环境中形成的锈层致密度较低;冰冻/解冻循环导致非致密锈层内产生裂纹,其原因是疏松锈层中的孔洞中含有大量液态水,在液固相变时产生较大的应力,致使锈层开裂.致密锈层不含液态水,基本不受其影响.     

刺老苞根皮黄酮对H_2O_2诱导的MC3T3-E1成骨细胞损伤改善

在H2O2胁迫下,研究刺老苞根皮(Aralia echinocauIis)黄酮增强MC3T3-E1成骨细胞抗自由基损伤的作用.为此用H2O2作用MC3T3-E1成骨细胞,建立自由基损伤细胞模型.培养的成骨细胞分为对照组、模型组、刺老苞根皮黄酮低剂量组(1×10-8mol/L)、刺老苞根皮黄酮中剂量组(1×10-7mol/L)和刺老苞根皮黄酮高剂量组(1×10-6mol/L).测定不同处理组细胞活力、超氧化物歧化酶(superoxide dismutase,SOD)活性、活性自由氧(reactive oxygen species,ROS)含量、脂质过氧化物(lipid oxygen,LPO)含量,同时利用荧光偏振法测定细胞膜流动性.结果显示与模型组相比,刺老苞根皮黄酮组细胞活力、SOD活性、细胞膜流动性均显著升高(P<0.01),而ROS含量、LPO含量则显著降低(P<0.01),并呈现一定的量效关系.可以认为H2O2摄入会导致MC3T3-E1成骨细胞的氧化损伤,而刺老苞根皮黄酮可以预防或降低此类损伤对细胞的影响.     

基于非线性特征的旅游系统模型研究

对旅游系统模型的研究不同的学者切入点不同所建立的模型也有出入.现有的旅游系统模型主要包括三类:旅游功能系统模型、旅游混沌模型和旅游地理系统模型.但是,在建立模型时,对旅游系统的非线性这一主要特征的考虑还很欠缺.本文选取旅游系统的非线性特征这一切入点,在揭示非线性产生的原因后,以系统的信息反馈为基础建立了基于非线性特征的旅游系统模型.     

Characterization of the heteroepitaxial growth of 3C-SiC on Si during low pressure chemical vapor deposition

3C-SiC heteroepitaxial layers were grown on Si substrates using a horizontal, hot-wall low pressure chemical vapor deposition system. The crystal quality, surface morphology and thickness uniformity of the layers were characterized by X-ray diffraction, atomic force microcopy and Fourier transform infrared spectroscopy, respectively. Growth of the epitaxial layer was determined to follow a three-dimensional island mode initially and then switch to a step-flow mode as the growth time increases. Barrier epithelia, especially airway epithelial cells, are persistently exposed to micro-organisms and environmental factors. To protect the host from these microbial challenges, many immune strategies have evolved. The airway epithelium participates in the critical innate immune response through the secretion of immune effectors such as mucin, antimicrobial peptides (AMP), and reactive oxygen species (ROS) to entrap or kill invading microbes. In addition, airway epithelial cells can act as mediators connecting innate and adaptive immunity by producing various cytokines and chemokines. Here, we present an overview of the role of mucosal immunity in airway epithelium, emphasizing the framework of bacterial and viral infections along with regulatory mechanisms of immune effectors in human cells and selected animal models. We also describe pathophysiological roles for immune effectors in human airway disease.     

Effect of additive boron on type-Ib gem diamond single crystals synthesized under HPHT

The boron-doped type-Ib gem diamond crystals were synthesized successfully by adding amorphous boron into a system of graphite and Kovar catalyst under high pressure and high temperature (HPHT).The effect of additive boron on type-Ib gem diamond was extensively studied including the growth characteristic,morphology and nitrogen concentration.The synthesized boron-doped type-Ib gem diamond crystals were characterized by optical microscope (OM),scanning electron microscope (SEM) and infrared spectrometer (IR)...     

Effects of size variation and spatial structure on plastic response of plant height to light competition

Plants only interact with neighbors over restricted distances,so local conditions are of great significance for plants.In this study,a spatially-explicit,individual-based model was constructed to explore the effects of size variation and spatial structure on adaptive plasticity of plant height in response to light competition.In the model a plant maintains its height at an optimal value in order to maximize its growth rate,and this optimal height increases with the increase of the intensity of light competi...     

Solving surface plasmon resonances and near field in metallic nanostructures: Green’s matrix method and its applications

With the development of nanotechnology, many new optical phenomena in nanoscale have been demonstrated. Through the coupling of optical waves and collective oscillations of free electrons in metallic nanostructures, surface plasmon polaritons can be excited accompanying a strong near field enhancement that decays in a subwavelength scale, which have potential applications in the surface-enhanced Raman scattering, biosensor, optical communication, solar cells, and nonlinear optical frequency mixing. In the present article, we review the Green’s matrix method for solving the surface plasmon resonances and near field in arbitrarily shaped nanostructures and in binary metallic nanostructures. Using this method, we design the plasmonic nanostructures whose resonances are tunable from the visible to near-infrared, study the interplay of plasmon resonances, and propose a new way to control plasmonic resonances in binary metallic nanostructures.     

基于图像质量评估的MIMO-SAR等效相位中心误差界

受等效相位中心误差的影响,新体制的多输入多输出合成孔径雷达(MIMO-SAR)方位成像结果存在"假峰"而导致成像质量下降。该文提出基于虚假旁瓣比、积分旁瓣比及峰值能量损失等图像质量指标联合评价"假峰"对SAR成像质量的影响,进而确定MIMO-SAR等效相位中心误差界,为系统设计和信号处理提供了依据。结果表明:当等效相位中心误差超过0.2rad时,一般需要对其进行补偿以满足常规指标要求;星载系统较机载系统更适合等效相位中心处理,通常可忽略等效相位中心误差的补偿环节。     

In_(0.53)Ga_(0.47)As/In_(0.52)Al_(0.48)As量子阱二维电子气的零场自旋分裂

用分子束外延(molecular beam epitaxy,MBE)方法在半绝缘InP衬底上生长In0.52Al0.48As/In0.53Ga0.47As/In0.52Al0.48As量子阱样品。在In0.52Al0.48As势垒层中进行元素Si的δ掺杂,元素Si电离的电子转移到量子阱中,在量子阱中形成二维电子气(two-dimensional electron gas,2DEG)。对该样品在低温下进行了磁输运测试,得到了2DEG纵向电阻(磁电阻)和横向电阻(Hall电阻)在不同温度下随磁场的变化曲线。观察到磁电阻的Shubnikov-de Haas(SdH)振荡和由零场自旋分裂引起的SdH振荡在低场下的拍频效应。也观察到Hall电阻出现量子Hall效应所特有的Hall平台。对Hall电阻在低场部分的直线拟合获得2DEG的Hall浓度,并根据Hall浓度和零场电导获得2DEG的Hall迁移率。对磁电阻曲线的快速傅立叶变换(fast Fourier trans-form,FFT)分析获得的2DEG浓度与Hall浓度一致。对拍频节点进行分析,获得了2DEG的自旋轨道耦合常数,并由此得到了零场自旋分裂能、自旋弛豫时间、自旋进动长度等实现自旋器件的相关参数。