Study of YBaCo4O7 + δ thin films grown by sputtering technique on (1012)-oriented sapphire substrates

We report the growth of thin films of the cobaltite YBaCo₄O_7 + δ by means of the dc magnetron sputtering technique at high oxygen pressure onto r (1012) sapphire substrates. The films were characterized according to their structural, morphological, electrical, magnetic, and optical properties. An analysis of the X-ray diffraction pattern indicates that the films grown on r-sapphire substrates are single phase polycrystalline. Despite the high growth temperature (850 °C), no indication of interface reaction (formation of BaAlO₄ or Y₂O₃) is detected. Measurements of resistivity as a function of temperature reveal a semiconductor-like character of the grown films. No indication of possible transitions is observed in the temperature range 50-300 K. The electronic transport mechanism seems to be dominated by Mott variable range hopping (VRH) conduction. Fitting the VRH model to the experimental data allows one to estimate the density of states of the material at the Fermi level N(E_F). The resistivity measured in magnetic fields as strong as 5 T increases notably, and positive magnetoresistance values as high as ~ 60% at 100 K are obtained. Magnetization measurements show well defined hysteresis loops at 300 K and 5 K. Nevertheless, calculated values of the magnetization have ended up being too small for the ferro- or ferrimagnetic states. Raman spectra, in turn, allow one to identify bands associated with vibrating modes of CoO₄ and YO₆ in tetrahedral and octahedral configurations, respectively. Additional bands which seem to stem from Co ions in octahedral configuration are also clearly identified. Measurements of transmittance and reflectance show two well defined energy gaps at 3.7 and 2.2 eV.     

论情势变更原则适用的有关问题

本通过对情势变更原则的概述，从基于公平与诚信对合同当事人之间的权利和义务进行调整，以消除因情势变更所造成的不公平后果，维护当事人的合法权益的实践出发，阐明了情势变更原则适用合同纠纷的条件和程序，以及该原则与不可抗力、商业风险、显失公平等法律规则的区别。     

岸基雷达模拟器的设计与实现

针对岸基雷达工作的海面环境和目标特点,在雷达模拟器中设置了目标的雷达截面积（RCS）起伏、检测概率计算及海杂波模型。对于海面舰船目标而言,其RCS通常受舰船的姿态、方位角等状态影响较大,在此通过计算舰船相对于雷达站的方位实现目标的RCS起伏。再根据目标的RCS利用Albersheim公式即可获得目标的检测概率。另外,雷达的工作状态不同,检测到的海杂波分布模型亦不同。这里介绍了2种最常用的海杂波分布模型,分别是Rayleigh分布和对数正态分布。改进后的雷达模拟器能够更加真实准确地模拟岸基雷达的实际工作环境。     

The effects of three types of aggression on vascular processes.

"Eighty college-age-subjects underwent either a frustrating or nonfrustrating experience and subsequently were placed in one of four aggression-conditions: Physical, Verbal, Fantasy, or No Aggression. The intent of this 2 X 4 factorial design experiment was to measure the effects of each type of aggression on frustration-produced-elevations in systolic blood pressure and heart rate. The results indicated that frustrated subjects who were given an opportunity to physically or verbally aggress against the frustrator, manifested returns on both physiological measures to the levels of the Low Frustration control subjects. Frustrated subjects in the Fantasy and No Aggression conditions exhibited significantly elevated systolic pressures and heart rates at the post-aggression-recording of these measures." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Frustration, aggression, and murder.

"… 51 male murderers and their 51 nearest-age brothers were investigated with respect to frustration in infancy, childhood, and adolescence… . The central hypothesis was: There is a significant positive relationship between the amount of frustration experienced by persons in infancy, childhood, and adolescence… and whether or not they later commit murder… . [The results showed that] significantly more murderers than control brothers scored high on the Indices of Physical, Psychological, and General Frustration." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of physiological arousal level, frustration, and task complexity on performance.

This paper investigates the effects of initial heart-rate level, frustration, and task complexity on digit-symbol performance. Low (LD) and high (HD) heart-rate Ss worked on a digit-symbol problem immediately before and after a frustration manipulation which raised heart rate about 20 beats/min. The results indicated that HD Ss achieved higher initial performance scores than LD Ss on tasks of relatively low complexity; however, following frustration LD Ss manifested a significantly greater increment in performance than HD Ss. The latter group showed a trend toward a decrement in performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Administration of corticosterone after the first downshift trial enhances consummatory successive negative contrast.

Rats given access to a 32% sucrose solution and then downshifted to a 4% solution exhibit less contact with the sipper tube than unshifted controls always given access to 4% solution. This phenomenon, called consummatory successive negative contrast, was facilitated in Experiment 1 by a posttrial injection of corticosterone (3 mg/kg) administered immediately after the first downshift trial. Experiment 2 demonstrated that this facilitatory effect of posttrial corticosterone does not occur when administered 3 hr after the first downshift trial. These results support the hypothesis that corticosterone strengthens an aversive emotional component elicited by the surprising downshift in reward magnitude during the initial downshift trial. (PsycINFO Database Record (c) 2010 APA, all rights reserved)