Semiconductors used in optoelectronic devices — An overview

Optoelectronic applications of semiconductors have been growing rapidly. They comprise photodetectors, solar cells, light emitting diodes and lasers. This article aims to provide a general picture of the material aspect of these devices. Emphasis is placed on material selection and underlying reasons, as well as the state-of-the-art performance.     

Chlorination of quinoline

Chlorination of Quinoline at 160–190° without solvent gave a mixture of compounds. The five major components were isolated and identified as 3,4-dichloro-, 3,4,6-, 3,4,8-trichloro-, 3,4,6,8-tetrachloro- and 3,4,6,7,8-pentachloroquinolines.     

One-dimensional supramolecular assemblies based on a Re2(III,III) synthon and their solid-state phosphorescence

Reactions between Re2(DMBA)4(NO3)2 (1; DMBA is dimethylbenzamidinate) and a bidentate dianion, either tungstate (WO4(2-)) or terephthalte (1,4-(O2C)2C6H4(2-)), resulted in the one-dimensional coordination polymers [Re2(DMBA)4(mu-O,O'-WO4)](infinity) (2) and [Re2(DMBA)4(mu-O,O'-1,4-(O2C)2C6H4)](infinity) (3), respectively. Both polymers display phosphorescence from a 3(delta --> delta*) state, which is significantly blue shifted from the phosphorescence previously observed for Re2(DMBA)4Cl2 type compounds.     

Wavelet coding of volumetric medical images for high throughput and operability

This paper presents a new three-dimensional (3-D) wavelet-based scalable lossless coding scheme for compression of volumetric medical images. Aiming to improve the productivity of radiologists and the cost-effectiveness of the system, we strive to achieve high decoder throughput, random access to coded data volume, progressive transmission, and high compression ratio in a balanced design approach. These desirable functionalities are realized by a modified 3-D dyadic wavelet transform tailored to volumetric medical images and an optimized Rice code of very low complexity.     

基于小波包变换的模拟电路故障诊断

把小波包变换用于模拟电路故障诊断中。由于输出信号的各频率成分能量的变化表征了电路中某些元器件的损坏情况,因此,利用小波包变换有效地提取故障特征信息,提出了“能量——故障”的故障诊断方法。计算和实验结果表明：该方法可以快速高效地进行模拟电路故障诊断与定位。     

A novel high-spin heterometallic Ni12K4 cluster incorporating large Ni-azide circles and an in situ cyanomethylated di-2-pyridyl ketone

Reaction of di-2-pyridyl ketone (dpk) with nickel acetate and azide in the presence of potassium tert-butylate as a catalytic base generates the title compound, which contains the largest [Ni(mu(1,1)-N3)]6 circles in the discrete ferromagnetically-coupled M(II)-azide cluster family, and shows an unprecedented in situ cyanomethylation of ketone.     

Resistance-network representation of radiative heat transfer with particulate scattering

The resistance-network representation for radiative heat transfer is developed for a planar absorbing-scattering medium on the basis of the two-flux model and the linear anisotropic scattering model. Particular attention is given to the scattering effect due to particulates such as flame soot or smoke particles. Limiting relations for various radiative regimes are derived and the physical significance of the resistances are discussed. An illustrative example is presented for thermal radiation from a smoke layer. Extension to two-phase dispersed systems is also demonstrated.