Hydrogen analysis of mineral samples at University of Tsukuba

This study reports the present status of our work on the hydrogen analysis of mineral and rock samples. The preparation of a standard material by means of ion implantation, a method of its calibration and the application of the method are described. The number of hydrogen atoms per unit volume in the standard material can be determined from the simultaneous observation of -particles, γ rays and –γ coincidence events for the ¹H(¹⁹F,γ) reaction at the 16.44 MeV resonance energy. The hydrogen content in a natural obsidian determined with the method mentioned above is in agreement with that obtained by FTIR. A heavy-ion microbeam system under construction, which consists of a Russian-type quadrupole magnet for beam focusing, a beam defining slit system and a γ-ray detector, is also described.     

Wood and bark of some poplar and willow clones as fuelwood

Poplars and willows are widely used to produce biomass for energy. Calorific values of wood and bark, as well as for whole tree of Populus × euramericana (cl. I-214), Populus deltoides (cl.PE 19/66) and white willow Salix alba (cl.378) of different ages were determined. one- and 2-year-old rooted cuttings were grown in plantations with high planting density, in order to produce a high biomass yield per hectare. Mature trees in both species (poplar and willow) originated from the corresponding plantations; willow 14-year old, and poplar 12 years (cl.I-214) and 8 years (cl.PE 19/66). As the share of bark depends on the age of wood, calorific values were determined separately for bark and for wood. The share of bark (proportion of total weight) in 1- and 2-year-old rooted cuttings ranged between 18% and 27%, and in older trees it was from 10% to 15%. The higher heating values of oven dry poplar wood (calculated for the whole tree, based on the proportion of bark) were from 15,787 (cl. I-214 1-year old) to 24,275 kJ/kg (cl.I-214 2-year old). The average calorific values of willow wood (whole tree with bark) were from 16,169 (14-year old) to 22,572 kJ/kg (2-year old). It should be pointed out that the calorific value of wood is more favorable than that of bark, and the highest calorific values refer to 2-year-old trees.     

Supercritical fluid chromatography reduction of hydrogen/deuterium back exchange in solution-phase hydrogen/deuterium exchange with mass spectrometric analysis

The single biggest problem with solution-phase H/D exchange as a mass spectrometric probe of surface exposure in a protein (or protein complex) is back-exchange of H for D after the initial H/D exchange has been quenched. Back-exchange results in loss of pertinent data and also greatly hampers data analysis. Previously, very fast, cold (0-4 degrees C) HPLC was performed to help reduce back-exchange, but calculated back-exchange still averages approximately 30%. In this report, supercritical fluid chromatography replaces HPLC as the desalting/separation technique prior to mass analysis, providing a dramatic reduction in back-exchange compared to the fast, cold HPLC methods.     

Effect of Al3+ on the spectroscopic properties of Eu2+- and Tb3+-Doped high silica glass

In this study, Eu²⁺/Al³⁺-, Eu²⁺/Tb³⁺-, and Eu²⁺/Tb³⁺/Al³⁺-doped high silica glasses were prepared, and the effect of Al³⁺ on the spectroscopic properties of Eu²⁺ and Tb³⁺ and the energy transfer of Eu²⁺→Tb³⁺ was investigated. The results revealed that the addition of Al³⁺ increased the luminescent intensity of the Eu²⁺-doped glass by approximately 400 times. An obvious Eu²⁺→Tb³⁺ energy transfer occurred in the Eu²⁺/Tb³⁺-doped high silica glass, whose transfer efficiency can reached 66.9%. However, the efficiency continuously decreased as the Al³⁺ concentration increased, and eventually, it dropped to 7.2%. These phenomena can be explained by the following: Al³⁺ not only disperses Eu²⁺ but also changes the field strength and symmetry of its neighboring environment, thus increasing its emission intensity. Moreover, Al³⁺ destroys the strong dipole–dipole interactions between Eu²⁺ and Tb³⁺ in high silica glass due to its dispersive ability, which inhibits the energy transfer of Eu²⁺→Tb³⁺. This indicates that a small amount of Al³⁺ can significantly modify the neighboring environment of Eu²⁺ and change its light-emitting characteristics, potentially yielding efficient blue and green phosphors excited by near-ultraviolet light for use in white light-emitting diodes.     

中国制造业产品质量:基于技术含量视角的实证分析

利用WIOD数据库2000-2014年世界投入产出表,结合生产工序方法测算中国制造业的整体技术含量、国内技术含量和国内技术贡献率,基于技术含量视角分析中国制造业出口产品质量的动态变迁及其影响因素。研究发现:(1)中国制造业及其细分行业技术含量增速较快,但绝对量低于世界其他主要国家(地区),国内生产环节的技术含量有待进一步提升。(2)引进国外技术对制造业产品质量的影响具有“U”形特征,成本效应占优时,表现为负向作用;技术溢出效应占优时,表现为促进作用。随着国内技术含量的增加,国外技术引进的抑制作用开始显现,在技术密集型行业中,技术引进总体表现为抑制作用。(3)行业自主研发是出口产品质量升级的重要推动力,分别与国内技术以及行业开放具有互补效应,即自主研发可以增加行业对技术的消化吸收能力,提高技术溢出效应,且互补效应在资本密集型行业和技术密集型行业中更为显著。     

High-temperature stability multilayers for extreme-ultraviolet condenser optics

We investigate the thermal stability of Mo/SiC multilayer coatings at elevated temperatures. Transmission electron microscopy and x-ray diffraction studies show that, upon annealing, a thermally induced structural relaxation occurs that transforms the polycrystalline Mo and amorphous SiC layers in as-deposited multilayers into an amorphous Mo-Si-C alloy and crystalline SiC, respectively. After this relaxation process is complete, the multilayer is stable at temperatures up to 400 degrees C.     

Coexistence of Vortex Liquid and Solid in Rotating Bose-Einstein Condensate

No Heading We perform computer simulations for the Gross-Pilaevskii equation with a tiny damping in order to study the condensate wave-function in 3-D rotating Bose-Einstein condensate under the trapping potential. We find that the wave-function is divided into two kinds of phases in terms of its coherent feature. The first one is a coherent phase which is characterized by the static vortex lattice located close to the center of the trapping potential, and the second one is an incoherent one which lies outside the first coherent phase and shows vortex liquid like behaviors. The boundary between the two phases is quite sharp like the phase interface as seen in the first-order phase transition. This result suggests that the melting seen in type II superconductors spatially occurs in the rotating Bose-Einstein condensate since the wave-function amplitude decreases with departing from the center of the trap and its coherent feature is overcome by intrinsic fluctuations at a certain distance.PACS numbers: 03.75.Lm, 03.75.Kk, 74.25.Qt, 74.40.+k     

软件可靠性定量评估过程研究

软件可靠性定量评估过程贯穿软件开发和验收使用的全过程,是软件可靠性的重要评价手段。重点介绍该过程中的关键技术与方法,阐述了软件可靠性参数分析、可靠性预测、可靠性模型选择和可靠性测试充分性等主要内容,对软件可靠性定量评估过程进行较全面的分析探讨。