有机半导体的异质结(Hetero-junction)问题

有机异质结在有机电子器件中起到十分重要的作用,它不仅对有机器件中载流子的运动起到控制和调节的作用,而且对器件的基本功能特征,诸如光-电转换,电-光转换器件中某些要害步骤(如电子转移,能量转移等)起到重要的作用.本文扼要地从层间能量关系对有关有机异质结进行分类和讨论,并对异质结的界面能量关系中存在的问题及其进展作了介绍.显然,这将对有关器件设计的思路有所帮助.     

Effects of Hunger and Predation Risk on Foraging Behavior of Graybelly Salamanders, Eurycea multiplicata

We examined the effects of predation and hunger levels on foraging behavior of adult neotenic graybelly salamanders, Eurycea multiplicata griseogaster. Hungry and satiated salamanders were exposed to chemical stimuli from a predatory fish (sculpin, Cottus carolinae) and from two nonpredatory species, golden redhorse fish (Moxostoma erythrurum) and tadpoles of leopard frogs (Rana sphenocephala). Latency to attack prey was lengthened in the presence of chemical stimuli from predators regardless of hunger levels, but hungry salamanders had shorter latency times than satiated salamanders. There was no interaction between hunger and threat levels. In addition, salamanders distinguished between chemical stimuli from predatory (sculpin) and nonpredatory (redhorse) fishes; responses to redhorse and tadpole stimuli were not different. Handling times were not affected by either predator treatment or hunger level. In summary, graybelly salamanders can (1) recognize sculpin predators based solely on chemical cues, (2) distinguish between chemical stimuli from predatory and nonpredatory fish, and (3) adjust their foraging behavior according to both hunger and predation risk.     

Domino Sonogashira Coupling/Cyclization Reaction Catalyzed by Copper and ppb Levels of Palladium: A Concise Route to Indoles and Benzo[b]furans

Both indoles and benzo[b]furans can be obtained in high yield by the reactions of 2‐iodoaniline derivatives and 2‐iodophenols with terminal alkynes under mild conditions, namely in the presence of cuprous iodide (10 mol%) and a base in ethanol or 1,4‐dioxane. Further investigation reveals that palladium contaminants as low as 100 ppb are responsible for these successful couplings. It is worth noting that simple aliphatic substituted terminal alkynes could be tolerated to smoothly produce indole and benzo[b]furan derivatives.     

MATERIAL RESPONSE-BASED KILN CONTROL SYSTEM

ABSTRACT

The origin of material response (changing shrinkage rates) during drying is changing stress levels within the lumber as was determined in a previous paper. The object of this research was to demonstrate that a kiln control system based on material response parameters can reduce the drying time while incurring no additional drying defects. One control run and two pilot runs were performed. The results showed that it is possible to advance the kiln schedule using only material response as the controlling parameter and maintain or improve the quality of the lumber. Accelerating the drying substantially reduced the residual stress levels in the final product.     

Antioxidant Enzymatic Activities and Gene Expression Associated with Heat Tolerance in the Stems and Roots of Two Cucurbit Species (“Cucurbita maxima” and “Cucurbita moschata”) and Their Interspecific Inbred Line “Maxchata”

The elucidation of heat tolerance mechanisms is required to combat the challenges of global warming. This study aimed to determine the antioxidant enzyme responses to heat stress, at the enzymatic activity and gene expression levels, and to investigate the antioxidative alterations associated with heat tolerance in the stems and roots of squashes using three genotypes differing in heat tolerance. Plants of heat-tolerant “C. moschata”, thermolabile “C. maxima” and moderately heat-tolerant interspecific inbred line “Maxchata” genotypes were exposed to moderate (37 °C) and severe (42 °C) heat shocks. “C. moschata” exhibited comparatively little oxidative damage, with the lowest hydrogen peroxide (H₂O₂), superoxide (O₂⁻) and malondialdehyde (MDA) contents in the roots compared to stems, followed by “Maxchata”. The enzyme activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD) were found to be increased with heat stress in tolerant genotypes. The significant inductions of FeSOD, MnSOD, APX2, CAT1 and CAT3 isoforms in tolerant genotypes suggested their participation in heat tolerance. The differential isoform patterns of SOD, APX and CAT between stems and roots also indicated their tissue specificity. Furthermore, despite the sequence similarity of the studied antioxidant genes among “C. maxima” and “Maxchata”, most of these genes were highly induced under heat stress in “Maxchata”, which contributed to its heat tolerance. This phenomenon also indicated the involvement of other unknown genetic and/or epigenetic factors in controlling the expression of these antioxidant genes in squashes, which demands further exploration.     

非热压罐预浸料制备及成型工艺研究

采用单面胶膜浸渍的方法制备非热压罐(Out of Autoclave,以下简称"OoA")预浸料。采用三种方法测定预浸料的浸渍度,通过预浸料的细观形貌、层压板孔隙率及力学性能,系统地分析了浸渍度对碳纤维增强复合材料(CFRP)质量的影响,22%的浸渍度时性能最优。与OoA预浸料相匹配的固化工艺至关重要,通过无损检测、孔隙率、微观结构及力学性能对比分析,120℃/2 h作为第一阶段的固化工艺最适合,同时层压板热性能、力学性能与热压罐相媲美。     

Improved Wavelengths and Energy Levels of Doubly-Ionized Argon (Ar III)

New measurements of Ar III wavelengths between 508 Å and 4183 Å are combined with measurements from the literature to find improved values for the energy of most of the known levels in Ar III. Parameters derived from fitting the new level energies to an LS-coupling model are presented along with eigenvector compositions of the levels. On the basis of this analysis new designations are recommended for several levels.     

Energy Levels of Singly-Ionized Platinum

The analysis of Pt II is extended by using accurate wavelength measurements by Sansonetti et al. Forty-three new even and 104 new odd levels have been found. The Slater-Condon parametric method is used for the interpretation of the 5d⁹, 5d⁸6s, and 5d⁷6s² low even configurations and the 5d⁸(7s+6d) high even configurations with root mean square deviations smaller than 80 cm⁻¹. The importance of the 5d⁸–5d⁷6s core interaction in interpreting the even-parity levels is stressed.     

Estrogen-induced changes in place and response learning in young adult female rats.

Many findings suggest that changes in circulating estrogen levels influence cognition, in some cases impairing performance and in others enhancing performance. One interpretation of these mixed effects is that estrogen biases the strategy used to solve a task. To test this idea, young adult female rats, ovariectomized for 21 days, were trained after acute hormone or control treatment in 2 very similar tasks with different cognitive requirements. One task required place learning and the other response learning. Rats given two 10-μg injections of estradiol 48 and 24 hr before training learned the place task significantly faster than did rats without estradiol. Conversely, rats without estradiol performed better on the response task than did rats with replacement. These data suggest that the cognitive actions of estrogen may be task-specific by modulating the relative contribution of different learning and memory systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Deep level electronic structure of ZnSe/GaAs heterostructures

We performed 1—2 keVcathodoluminescence measurements and He-Ne and HeCd excited photoluminescence studies of ZnSe/GaAs( 100) heterostructures grown by molecular beam epitaxy. Our goal was to investigate the deep level electronic structure and its connection with the heterojunction band offsets. We observed novel deep level emission features at 0.8, 0.98, 1.14, and 1.3 eV which are characteristic of the ZnSe overlayer and independent in energy of overlayer thickness. The corresponding deep levels lie far below those of the near-bandedge features commonly used to characterize the ZnSe crystal quality. The relative intensity and spatial distribution of the deep level emission was found to be strongly affected by the Zn/Se atomic flux ratio employed during ZnSe growth. The same flux ratio has been shown to influence both the quality of the ZnSe overlayer and the band offset in ZnSe/GaAs heterojunctions. In heterostructures fabricated in Se-rich growth conditions, that minimize the valence band offset and the concentration of Se vacancies, the dominant deep level emission is at 1.3 eV. For heterostructures fabricated in Zn-rich growth conditions, emission by multiple levels at 0.88,0.98, and 1.14 eV dominates. The spectral energies and intensities of deep level transitions reported here provide a characteristic indicator of ZnSe epilayer stoichiometry and near-interface defect densities.