微腔与腔量子电动力学研究进展

光学微腔中原子之自发辐射与自由空间中原子的自发辐射有着重要的不同。微腔能够控制腔内原子的自发辐射，使自发辐射得到抑制或增强，并有可能使自发辐射成为一个可逆过程。由此发展起来的腔量子电动力学能够阐述腔场与原子的相互作用。本文简要介绍了这一研究领域的背景和进展，同时介绍了微腔的重要应用一无阈值激光器。     

节能减排与清洁发展机制

中国的能源利用效率不高,万元GDP能耗水平是发达国家的3到11倍.同时中国是发展中国家,完成"十一五"的节能减排目标面临巨大的资金和技术压力.清洁发展机制(CDM)是《京都议定书》规定的发达国家和发展中国家的一种国际合作方式,充分利用清洁发展机制,有助于节能减排目标的实现.     

高温低氧燃烧技术在唐钢高线厂的应用

为了使应用高温低氧燃烧技术的加热炉达到高效节能、低污染物特别是低NO_x排放的目的,采用计算机数值模拟优化设计了加热炉的蓄热式燃烧系统,并运用冶金反应工程学方法开发了成套技术.该技术在唐钢高速线材厂的实际应用表明:在热装钢坯条件下单位能耗为0.879 GJ/t,炉子热效率在67%以上,各蓄热室的排烟温度在160℃以下,NO_x排放小于40×10^-6(体积分数).     

Characterisation of rare earth minerals with field emission scanning electron microscopy

Abstract

Rare earth elements are becoming increasingly in demand, due to their prevalence in both renewable energy devices and high end electronics. The characterisation of the composition and morphology of the various phases that have valuable rare earth elements in the ores are needed in conjunction with the study of their physicochemical properties to optimise industrial process to extract the minerals containing the rare earth elements. Rare earth bearing minerals contain many elements with overlapping X-ray peaks (L- and M-lines) with an energy dispersive spectrometry detector, requiring a high degree of X-ray energy resolution. A program was developed to obtain the intensity of each peak by deconvolution of the X-ray spectrum. Low accelerating voltage of less than 5 kV and small beam diameter of less than 10 nm of a cold field emission scanning electron microscope allow x-ray microanalysis on the nanometre scale. A 100 nm wide phase was observed at 4 kV on a backscattered electron micrograph. Furthermore, a small beam diameter of less than 10 nm was used for identification of small phases of a few micrometres.

Les éléments de terre rare sont de plus en plus en demande, grâce à leur prévalence tant dans les dispositifs d’énergie renouvelable que dans l’électronique de haute gamme. On a besoin de caractériser la composition et la morphologie des différentes phases qui contiennent des terres rares de valeur dans les minerais, en combinaison avec l’étude de leurs propriétés physico-chimiques, afin d’optimiser le procédé industriel d’extraction des minéraux contenant les terres rares. Les minéraux porteurs de terre rare contiennent plusieurs éléments ayant des pics de rayons x qui se chevauchent (lignes L et M) avec un détecteur de spectroscopie à dispersion d’énergie, nécessitant une haute résolution énergétique. On a développé un programme visant à obtenir l’intensité de chaque pic par déconvolution du spectre de rayons x. Un faible voltage d’accélération de moins que 5 kV et un faisceau à faible diamètre de moins que 10 nm d’un microscope électronique à balayage par cathode froide permettent la microanalyse des rayons x à l’échelle du nanomètre. On a observé une phase de 100 nm de largeur à 4 kV sur une micrographe d’électrons rétrodiffusés. De plus, on a utilisé un faisceau de faible diamètre de moins que 10 nm pour l’identification de petites phases de quelques μm.     

Current–voltage characteristics of AlCdO Schottky contact on the polished and unpolished p-type Si surfaces with and without light illumination

In this study, the current-voltage characteristics of the AlCdO/unpolished p-type Si and AlCdO/polished p-type Si Schottky diodes with and without light illumination were examined. It is found that the Schottky barrier height (the series resistance) of the AlCdO/unpolished p-type Si Schottky diode is higher (lower) than that of the AlCdO/polished p-type Si Schottky diode. The power conversion efficiency of the AlCdO/p-type Si devices in the light (AM 1.5 G, 100 mW/cm²) was improved by increasing built-in potential at the AlCdO/p-type Si interfaces and reducing the device series resistance and surface reflectivity. It is shown that the device surface roughness plays an essential role in improving the device performance.     

Solution-phase chemical route to branched single-crystalline CdS nanoarchitectures and their field emission property

A facile solution chemical method is developed to prepare hierarchical branched single-crystalline CdS architectures. A mechanism of “nucleate-aggregate-grow-ripen-separate” process is proposed to illustrate the growth of the CdS architectures. The obtained branched CdS architectures exhibit superior FE properties with the lower turn-on field (Eto) of 7.1 V μm⁻¹ at a current density of 10 μA cm⁻², and threshold field (Ethr) of 8.3 V μm⁻¹ at a current density of 100 μA cm⁻², which shows that the obtained products have greatly potential application as FE devices.     

Zwitterionic diaminodicyanoquinodimethanes with enhanced blue-green emission in the solid state

Diaminodicyanoquinodimethane molecules which show strong solid state emission in the blue-green region are developed. The new materials are structurally characterized; extended supramolecular assemblies mediated by H-bond interactions are observed in the crystal lattice. Spectroscopic studies including life-time and fluorescence quantum yield measurements in the solution and solid states are carried out. Emission in the solid state is ∼400 times stronger than that in solution; this can be attributed to the inhibition of the excited state geometry relaxation to a non-radiative state, in the solid. Impact of the molecular structure in the crystals on the solid state light emission is discussed. Semiempirical computational studies provide useful insight into the various structural and spectroscopic features of the new materials. The present observations serve as a pointer to further design strategies for realizing novel blue photoluminescent molecular materials based on the diaminodicyanoquinodimethane framework.     

火花源原子发射光谱法在线测定电工钢中的超低碳

采用火花源原子发射光谱分析测定电工钢中超低C,研究试样制备方法、Ar纯度和压力等条件对分析结果的影响,并对工作曲线进行了优化,实现了一次分析同时测定电工钢的多种元素,满足炉前和精炼在线分析的要求。     

实现我国承诺的2020年减排指标的设想

介绍气候变化的危害原因和我国能源利用效率与发达国家的差距,提出推进碳减排工作及发展低碳经济,以实现我国承诺的2020年减排指标的设想。     

论低碳经济与清洁生产

本文论述了低碳经济和清洁生产的内涵,介绍了低碳经济的发展过程、影响碳排放的因素、碳减排的方法。阐述了清洁生产和低碳经济之间的关系。