An ERP study for the degrees of the difficulty in visual search

The present study mainly probed the relationships between ERP components and the degrees of difficulty in visual search. Three experimental and one controlled conditions were randomly selected. Results showed that the P1, N1, and P2 amplitudes and latencies had no significant differences among the three experimental and one controlled conditions, and the ERP waveforms of low perceptual load of visual search were different from that of high perceptual load. These results might indicate that the latencies and amplitudes of initial P1, N1 and P2 in high and low perceptual load conditions were almost the same. The ERP waveforms of parallel search were very different from that of serial search, and the ERP waveforms of serial search were very similar. The P3 amplitudes increased as the degrees of the difficulty in visual search decreased.     

宁夏枸杞花粉形态的扫描电镜观察

首次报道了宁夏枸杞３个品种、一个变种的花粉在扫描电镜下的形态特征．结果表明：供试花粉均为小花粉类型，椭圆形，或近球形，三孔沟，等极，表面有夹带二岐分叉的条状纹饰作纵向排列．具不同条状纹饰和条纹表面的不规则细横纹是供试花粉的区别点．花粉的大小和形状，在供试各品种之间也有不同程度的差异     

熵、巨势与开放的近平衡系统热力学第二定律的两种表现形式

从分析局域平衡理论框架内封闭热力学系统之熵产生与特性函数变率的关系入手，阐明了非平衡态的热力学特征，即非负耗散强度及非平衡线性区向最小耗散态演化的趋势，实际上是分别体现在热力学势的一阶及二阶变率层次上的状态演化方向。同时，提出了以巨势为基础的开放非平衡系热力学第二定律的表述形式，论证了在近平衡区与最小熵产生原理的等价关系。     

AUTOCAD图形环境下NC自动编程的实现

AUTOCAD是目前国内外最流行的CAD软件之一，它在机械、电子、化工、土木、服装等方面被广泛应用。然而由于其通用性目标，使AUTOCAD不可能在某一专项应用中有特别具体的辅助功能，本文叙述了在AUTOCAD（RELEASE11．0以上版本）图形环境下与C语言接口的一般方法，结合自己编程中的一些经验，介绍了在AUTOCAD图形环境下实现平面内含有多个不加工的岛的多个单连域的NC（NumericalControl）自动编程、干涉校验、轨迹仿真，该工作是对作者提出的复杂槽型机械加工普遍算法的具体实现，并输出了刀位数据文件，也可通过RS－232C串行通讯口直接送到数控机床实现DNC（DirectNumericalControl）控制。本文是AUTOCAD下用C语言进行二次开发的具体实例，实现了在CAD环境下直接利用CAD数据进行CAM（ComputerAidedManufacturing）。     

Therapeutic applications of bone marrow-derived stem cells in liver transplantation for end-stage liver diseases

Today, liver transplantation (LT) is the only established treatment for end-stage liver diseases. The de- velopment of LT, including OLT, cadaveric LT, split LT, living donor LT (LDLT), brings hopes to patients with these diseases. However, increasing donor shortage, rejection and life-long immunosuppression with its side effects are the major limitations of this therapy strategy. Bone marrow-derived stem cells (BMDSCs) are capable of differentiating into hepatocyte-like cells and contribute to liver injury repair. The microenvironment of liver injury caused by rejection, ischemia/reperfusion, loss of liver mass, recurrence of HCV and "small-for-size syndrome" after LT can attract a variety of bone marrow-derived stem cell population to the peripheral circulation and then migration to the injury liver to promote the hepatic function restoration. Additionally, BMDSCs can also take part in the functional regeneration of living donor liver after LDLT. This participation in liver regeneration may be associated to the interac- tion between SDF-1and its receptor CXCR4, involving HGF, IL-8, MMP9, and VEGF/VEGFR-2. BMDSC with its bio-characteristics could maintain the allograft tolerance from different angles and in different ways. In conclusion, BMDSCs transplantation, as a new assistant therapeutic method for LT, will ex- pand the space of LT, and provide more survival opportunities for the patients suffering liver diseases in the future.     

脆性统计损伤模型在岩土工程中的应用研究

采用脆性破坏统计理论研究结构性土体的损伤性质,提出了应用土体强度关于Weibull分布的分析方法得到了结构性土体的宏观损伤演化方程和本构模型．根据损伤容限定义了稳定安全系数．开挖与加载均质土坡稳定性的计算反映出牵引式滑动与推移式滑动的失稳机理．     

一个新混沌系统不稳定平衡点的镇定

用线性反馈控制和自适应控制方法研究了一个新的混沌系统不稳定平衡点的镇定问题.当系统参数已知时,借助系统在平衡点附近的线性化模型,利用状态线性反馈控制器可以镇定系统所有的平衡点;当参数未知时,利用自适应控制策略,可以把系统镇定到期望的不稳定平衡点.利用Lyapunov函数和LaSalle不变原理对结论给予了严格证明,并用数值仿真说明了这种方法的有效性.     

带参数校正模型的三维超声重建算法

在采用旋转扫描的三维超声系统中,基于传统的三维重建算法提出了一种带校正参数模型的三维重建算法.通过引入该参数模型,更加准确地描述了用于三维重建的二维序列图像的空间位置,从而可获得更高重建精度和更小几何变形的三维超声图像.校正参数模型通过参数优化的方法获得.该方法在模拟数据和实际三维超声数据中获得了验证,与传统三维重建方法相比,具有更高的重建精度,为在低制造精度下获得高精度三维超声图像提供了一种有效手段.     

道德判断的双加工模型述评

情绪和认知在道德判断过程中的作用一直存在争议。传统的理性模型认为道德判断是一个理性推理的过程,强调认知的作用;而社会直觉模型认为道德判断是一个直觉过程,强调情绪的作用。G reene在二者的基础上提出了双加工模型,认为道德判断是情绪和认知共同作用的结果,并且现有的许多研究成果也证实了认知和情绪在道德判断过程中的重要作用。双加工模型的提出为道德判断机制的研究提供了一种新视角。