离散空间中的一般均衡理论

在消费者偏好函数是强凸、连续和严格单调的条件下给出了不可分市场的一般均衡存在定理,因而也给出了离散空间中一般均衡存在的一个充分条件.     

Probe Gain without Probe field in a V-type System with an External Field Coupling Two Upper Levels

We report a new coherence and interference phenomenon in a V-typesystem with an external field coupling two upper levels. It is found that the probe gain can be generated even when no probe field is applied to the system, we attribute this result to the existence of the external field. By comparing with the conventional probe gain, the probe gain without the probe field is enhanced greatly because of the absence of the population inversion term.     

微波灰化-液相色谱-电感耦合等离子体质谱联用测定干食用菌中的三价铬和六价铬

建立了干食用菌中三价铬(Cr(Ⅲ))和六价铬(Cr(Ⅵ))的液相色谱-电感耦合等离子体质谱(LC-ICP-MS)检测方法。采用微波灰化技术对食用菌样品进行灰化处理,灰化样品用乙二胺四乙酸(EDTA)二钠盐稳定其中的Cr(Ⅲ),并使其保留在阴离子交换柱(250 mm×4.6 mm,10 μm)上;用含有60 mmol/L硝酸(pH 9.3)的流动相分离其中的Cr(Ⅲ)和Cr(Ⅵ),电感耦合等离子体质谱仪测定。标准溶液中Cr(Ⅲ)和Cr(Ⅵ)的质量浓度在0.5~50 μg/L范围内呈良好的线性关系,线性回归系数均达到0.9999。食用菌样品中Cr(Ⅲ)和Cr(Ⅵ)不同加入量的平均回收率为78.0%~90.7%,相对标准偏差小于4%(n=6);定量限均为0.5 μg/L。该方法稳定、可靠、灵敏,可满足干食用菌中Cr(Ⅲ)和Cr(Ⅵ)的测定。     

提高平板玻璃折射率测量实验中干涉条纹清晰度的方法

用分光仪测量平板玻璃折射率时,如果钠光偏离玻璃法线约25°斜入射,则能观察到清晰的干涉条纹.对上述现象分析,发现其原因在于平板玻璃透射光干涉条纹的衬比度低于反射光干涉条纹的对比度.进而,基于上述分析设计了测量平板玻璃折射率的改进方法.     

Decaying solitary waves propagating in one-dimensional damped granular chain

We numerically investigate the nonlinear waves propagating in a one-dimensional particle chain when the damping effect is taken into account. It is found that decaying solitary waves exist, in which the amplitude of the wave decreases exponentially as time increases. Meanwhile, the velocity of the solitary wave also slows down as time goes. This result implies that the damping coefficient is an important parameter in such a nonlinear system. Theoretical analysis has also been done by the reductive perturbation method. The result indicates that the nonlinear waves propagating in such a system can be described by the damped KdV equation.     

基于副边LLC谐振变换器的功率处理单元建模与分析

随着航空航天技术的不断发展,航天器对于霍尔电推进功率处理单元（PPU）的需求不断提高,高增益、大功率以及高效的PPU成为研究的主流方向。LLC拓扑能够在全负载范围内实现软开关,因此在PPU阳极电源中具有广阔的应用前景。原边LLC因其原副边增益特性,给阳极电源高增益变换器的谐振电感设计带来极大的挑战。针对上述问题,提出了一种改进的副边LLC谐振拓扑,在保留原边LLC谐振电路软开关特性的同时,有效解决了谐振电感设计问题,使得PPU阳极电源具备高增益的性能。首先利用时域分析法建立了副边LLC拓扑数学模型,其次在模型的基础上给出其峰值增益的计算方法,最后通过一台样机验证了所建模型的正确性并验证了副边LLC电路的有效性。     

In vitro three-dimensional cancer metastasis modeling:Past,present, and future

Metastasis is the leading cause of most cancer deaths, as opposed to dysregulated cell growth of the primary tumor.Molecular mechanisms of metastasis have been studied for decades and the findings have evolved our understanding of the progression of malignancy. However, most of the molecular mechanisms fail to address the causes of cancer and its evolutionary origin, demonstrating an inability to find a solution for complete cure of cancer. After being a neglected area of tumor biology for quite some time, recently several studies have focused on the impact of the tumor microenvironment on cancer growth. The importance of the tumor microenvironment is gradually gaining attention, particularly from the perspective of biophysics. In vitro three-dimensional(3-D) metastatic models are an indispensable platform for investigating the tumor microenvironment, as they mimic the in vivo tumor tissue. In 3-D metastatic in vitro models, static factors such as the mechanical properties, biochemical factors, as well as dynamic factors such as cell–cell, cell–ECM interactions, and fluid shear stress can be studied quantitatively. With increasing focus on basic cancer research and drug development, the in vitro 3-D models offer unique advantages in fundamental and clinical biomedical studies.     

铷钟扩捕方法研究

铷钟的捕获带和其能否锁定密切相关,它通常比较小。对原子钟扩捕问题进行了研究,设计了主要由二次谐波幅度检测电路和由单片机同DA构成的扫描电路等组成的扩捕电路。工作时扫描电路输出三角波扫描信号,带动本振的频率扫动同时检测二次谐波的幅度,当幅值超过设定时,说明本振的频率已进入铷钟以前的捕获带,停止扫描,铷钟靠环路的作用便能锁定。以铷钟为对象进行了实验研究,实验结果是当把本振的频率调偏到捕获带以外时,不用扩捕电路环路没法锁定而使用扩捕电路后环路正常锁定,实验结果和理论分析一致。     

1588时间同步技术在PON系统中的实现

介绍了IEEE1588时间同步技术实现的核心机制,分析了1588时间同步技术在PON系统中实现和应用中面临的问题,如频率同步、时间戳技术、最佳主时钟算法等相关问题。提出了在一种PON系统中实现1588时间同步技术的具体解决方案,得到的实验数据验证了该解决方案的可行性。     

图像处理在织物表面质量检测评定中的应用

本文通过对织物表面检测及织物等级评定的研究,说明图像处理技术在这领域的重要作用。