Magnetic exchange behavior of a long-range Cu system through the diamagnetic Cu2 unit bridge: A DFT study

The mechanism of magnetic exchange interaction in an interesting Cu^II coordination polymer with the Cu^I₂X₂ (X = I or Br) moiety bridge is investigated by the calculations based on density functional theory combined with the broken-symmetry approach (DFT-BS). Surprisingly, different from the experiment results, the calculations reveal that the complex between the magnetic Cu^II centers has a fairly weak antiferromagnetic interaction for the long distance (∼10 Å). The analyses show of the molecular orbitals and the spin density distribution favor the very weak antiferromagnetic coupling interactions of the systems.     

Passive automatic exposure mechanism

In this paper, we will propose a passive automatic exposure mechanism. Different from general automatic exposure mechanism, the passive exposure mechanism directly searches suitable exposure images through the content of images. As exposure is one of the main factors to successfully take pictures, how to find an accurate exposure value is an important issue. Passive automatic exposure is the new trend and key issue of image processing. We will experiment and prove that the method we propose is effective.     

High resolution‐HMBC (HR‐HMBC), a new method for measuring heteronuclear long‐range coupling constants

A useful pulse sequence for measuring long‐range C? H coupling constants (J_{C? H}) named high resolution‐HMBC (HR‐HMBC) has been developed. In this pulse sequence, the J‐scaling pulse [(nt₁)/2? 180° (H/C) ? (nt₁)/2] is incorporated after the spin evolution period, and then followed by an ¹H 180° pulse to reverse the magnetization of J_{C? H} couplings. As a result, splittings of the cross peaks due to the long‐range J_{C? H} are realigned with separations of nJ_{C? H} along the F₁ dimension, and thus even the small long‐range J_{C? H} values can easily be determined. The efficiency of measuring the long‐range J_{C? H} using the proposed pulse sequences has been demonstrated in application to the complicated natural product, portmicin. Copyright © 2010 John Wiley & Sons, Ltd.     

Stability of T. Chan＇s Preconditioner from Numerical Range

A matrix is said to be stable if the real parts of all the eigenvalues are negative. In this paper, for any matrix An, we discuss the stability properties of T. Chan＇s preconditioner cU（An） from the viewpoint of the numerical range. An application in numerical ODEs is also given.     

Some new results of IR systems'' sensitivity equations

Typical IR systems' sensitivity equations have been established for decades, these include the NETD equation for IR imaging systems, and the acquisition and tracking range equations for IR searching and tracking systems, but they only fit the specific or simplified conditions. For example, the NETD equation can only be used for systems tested under the standard condition. In the field application, we must deal with the noise equivalent radiance difference NELD, not the NETD, and give out its explicit equation for concrete calculation. For the range equation, when the small target, often called a point source, is not strong enouph, i. e., when the target contrast is seriously decreased, we must consider the unneglectable background effect. In this paper, we summarrize some more general and valuable IR systems' sensitivity equations, which can be used for the practical engineering analysis and projection effectively.     

CCD激光测距实验

CCD激光测距实验是集光、机、电为一体的综合性实验，学生可以用简单的几何光学知识、采用激光遥感方式实现距离的非接触精确测量．本文简述了实验原理，给出了计算机自动处理和显示的系统硬件和软件环境，以及系统的校准方法，最后介绍了模拟实验结果。     

一种物理实验教学网络系统

利用网络技术建立了物理实验网络，提高了教学质量。     

凸函数的支撑凸集及其集映射

本文研究了线性空间中凸函数的支撑泛函存在性以及支撑泛函的数值域,利用子空间中支撑泛函延拓的方法,构造出在线性空间任意点的支撑泛函,确定在同一支撑点上支撑泛函的数值域,从而得到支撑泛函具有唯一性的充分必要条件,最后对支撑凸集到支撑泛函集的集映射进行讨论.     

Intensity range as a function of task and training

This study examined intensity range as a function of elicitation task (reading and automatic speech sequences), musical training, and the interaction between task and musical training in 31 college students. The results indicated significant differences in loudness range by experiental task. Intensity range for the descending automatic sequence was significantly greater than that for the ascending and reading tasks. While the overall effect of musical training was nonsignificant, there was a significant interaction between task and training, with musicians having a significantly greater mean range on the ascending task. A comparison between ascending and descending tasks indicated a significant mean difference between lower limits and no significant mean difference between upper limits. The range for the reading probe was located approximately in the middle of the total available intensity range.     

HM-J16双光子电子直线加速器

简要叙述了 HM-J1 6加速器的设计思想和设计特点。设计了一台采用射频功率反馈的射线能量范围为 6～ 1 6Me V的双光子电子直线加速器。其最大辐射野为 4 0 cm× 4 0 cm,双光子剂量率均大于3 60 c Gy/ (min·m)。