Benchmark experiment of large-angle scattering reaction cross section of iron at 14 MeV using two shadow bars – Comparison of experimental results with ENDF/B-VIII –

ABSTRACT

It is important to perform neutron transport simulations with accurate nuclear data in the neutronics design of a fusion reactor. However, absolute values of large-angle scattering cross sections vary among nuclear data libraries even for well-examined nuclide of iron. Benchmark experiments focusing on large-angle scattering cross sections were thus performed to confirm the correctness of nuclear data libraries. The series benchmark experiments were performed at a DT neutron source facility, OKTAVIAN of Osaka University, Japan, by the unique experimental system established by the authors’ group, which can extract only the contribution of large-angle scattering reactions. This system consists of two shadow bars, target plate (iron), and neutron detector (niobium). Two types of shadow bars were used and four irradiations were conducted for one experiment, so that contribution of room-return neutrons was effectively removed and only large-angle scattering neutrons were extracted from the measured four Nb reaction rates. The obtained experimental results were compared with calculations for five nuclear data libraries including JENDL-4.0, JEFF.-3.3, FENDL-3.1, ENDF/B- VII, and recently released ENDF/B-VIII. It was found from the comparison that ENDF/B-VIII showed the best result, though ENDF/B-VII showed overestimation and others are in large underestimation at 14 MeV.     

Study on maximum power point tracking of photovoltaic array in irregular shadow

Traditional maximum power point tracking (MPPT) methods can hardly find global maximum power point (MPP) because output characteristics curve of photovoltaic (PV) array may have multi local maximum power points in irregular shadow, and thus easily fall into the local maximum power point. To address this drawback, Considering that sliding mode variable structure (SMVS) control strategy have such advantages as simple structure, fast response and strong robustness, and P&O method have the advantages of simple principle and convenient implementation, so a new algorithm combining SMVS control method and P&O method is proposed, besides, PI controller is applied to reduce system chattering caused by switching sliding surface. It is applied to MPPT control of PV array in irregular shadow to solve the problem of multi-peak optimization in partial shadow. In order to verity the rationality of the proposed algorithm, the experimental circuit is built, which achieves MPPT control by means of the proposed algorithm and P&O method. The experimental results show that compared with the traditional P&O algorithm, the proposed algorithm can fast track the global MPP, tracking speed increases by 60% and the relative error decreased by 20%. Moreover, the system becomes more stable near the MPP, the fluctuations of output power is greatly reduced, and thus make full use of solar energy.     

数字电视用中分辨率74cm纯平彩色显像管BC配列不良的分析与对策

通过对74cm中分辨率纯平彩色显像管BC配列局部严重群散不良的调查分析,确定荫罩受力塌陷是主要原因,通过改良设计、工艺优化及其它方面的综合对策,使以上技术难题得到满意的解决,整管不良率由4.78%下降到0.172%。     

抗洪抢险措施及效果

结合“９８”抗洪抢险实例，对多种险情作了具体分析，通过汛后调查，对抗洪抢险消险措施和效果进行了总结，为今后进一步做好防洪消险工作提供了经验。     

膜吸收技术及其在脱除酸性气体中的应用研究

膜基气体吸收是膜技术与气体吸收技术相结合的新型杂化膜过程，与传统的气流接触吸收相比有诸多优点，通过介绍膜基气体吸收技术的分离机理及其在脱除酸性气体中的应用特点，展示了膜基气体吸收技术在化学工业中的广阔应用前景。     

“三软”煤层综放面特殊情况下支架拆除及沿空留巷

超化煤矿21091(西)综采工作面因出水造成工作面停产,在不超前15 m铺金属网的情况下进行支架拆除,并把原工作面留做炮采面切巷。根据实际情况制定了施工方案,并介绍了实施情况。     

激光微技术的发展现状

介绍了激光微加工技术的特点，与其它微加工技术相比，激光微加工具有非接触、有选择性加工、热影响区域小、高精度与高重复率等优点，既可以通过去除方式，也可以通过材料堆积进行微加工成型。综述了几种常用的激光微加工技术及其发展趋势，微机电系统（MEMS）技术的进一步成熟，必将带动激光微技术快速发展。     

光催化氧化后四环素的分解率与COD去除率之间关系的探讨

以粉状无机半导体（ＺｎＯ）为催化剂，探讨了水溶液中四环素经光催化氧化分解率和ＣＯＤ去除率之间的关系。实验表明，在本实验中四环素的分解率和ＣＯＤ去除率之间有较好的正相关性。当反庆系统中有足量的活性催化剂和足够的光照时间时，绝大部分四环素将被较彻底地氧化分解成ＣＯ２，这不仅有助于光催化反应机理的研究，助于今后在环保中的实际应用。     

Selective area epitaxy of CdTe

We have performed selective area epitaxy (SAE) of CdTe layers grown by molecular beam epitaxy using a shadow mask technique. This technique was chosen over other SAE techniques due to its simplicity and its compatibility with multiple SAE patterning steps. Features as small as 50 microns × 50 microns were obtained with sharp, abrupt side walls and flat mesa tops. Separations between mesas as small as 20 microns were also obtained. Shadowing effects due to the finite thickness of the mask were reduced by placing the CdTe source in a near normal incidence position. Intimate contact between the mask and the substrate was essential in order to achieve good pattern definition.     

荫罩黑化及DX气与煤气成分的探讨

本文介绍了彩色显像管荫罩黑化反应的机理,详细说明了DX气制气流程,以及DX气的成分对黑化膜品质的影响。计算分析了成分不同的煤气在制成DX气时的成分变化。同时还分析了黑化工艺和黑化设备对煤气成分波动的适应性,及在生产实践中改变DX气制气时的煤气空气对黑化膜质量的影响。