Spectral properties of a cascade of holographic reflection gratings separated by a uniform layer

This paper presents the results of experimental studies of the spectral properties of stratified structures consisting of two volume holographic reflection gratings separated by an optically uniform layer. When such structures are illuminated by polychromatic light, the interference of the waves generated by these gratings leads to the formation of a set of narrow spectral passbands. The period of arrangement of the passbands is determined by the optical thickness of the intermediate layer, and their envelope coincides with the spectral selectivity contour of one grating. The existence of this type of spectra with local passbands spaced 2–8 Å apart (in different experiments) was confirmed experimentally. A high-resolution Ramanor U1000 spectrometer and an optical Fabry–Perot interferometer were used. It is found that the nonuniformity of the internal structure of the holographic gratings due to the imperfection of the recording medium substantially distorts the spectral characteristics of the studied structures in comparison with their simple theoretical models: the spectrum is asymmetric and the transmission of the local bands is significantly lower than the estimated value. Similarity between the experimental data and simulation results was achieved by selecting the parameters of said nonuniformity.     

Effects of supplement additives on anaerobic biogas production

Anaerobic digestion (AD) converts biomass to biogas. However, its performance is often affected by the nutrient condition of AD substrate. In this study, a few substrate supplements were selected to promote the biogas production; MgO, FeCl₃, and cellulase were selected based on the result from elemental analyses of the biomass. The potential impact of the additives on AD process was evaluated by performing a series of biochemical methane potential (BMP) tests. BMP reactors with the substrate with one of the selected additives (i.e., MgO of 380 mg Mg L^?1, FeCl₃ of 88 mg Fe L^?1 or cellulase of 25 mg L^?1) exhibited higher microbial activity; 5–15% more biogas production was observed, compared to the blank. Microbial community analysis showed that different additives resulted in proliferation of different microbial species. Therefore, it was decided to add the mixture of the three additives to the biomass. Addition of the mixed additive resulted in 22% more gas production.     

扬州漆艺发展面临的困境与对策

本文以扬州漆艺为例,从扬州漆艺特点和传统文化入手,探讨了面临传统漆艺传承人培养体系不足、技法创新不足以及品牌化意识不强等问题时,扬州漆器厂在产品创新、品牌战略方面采取的一系列措施,期望能从扬州实例中找到当代漆器产业的发展方向。     

利用固液扩散偶研究Mg-40Al与Mg-20Ce的界面反应

本文主要研究了Mg-40Al与Mg-20Ce固液界面在475°C, 500°C和525°C下保温5min至30min的界面反应和扩散层的生长动力学。结果发现，在扩散层中由于Al元素和Ce元素反应生成Al₁₁Ce₃, Al₃Ce and Al₂Ce金属化合物。金属化合物的体积分数随着扩散温度的升高而增加。扩散层的生长满足抛物线生长规律，扩散层的扩散激活能为42±3.7kJ/mol。实验研究的固液扩散为理解合金熔炼过程中金属化合物的形成提供了理论基础。     

Optimization of holographic memory parameters with allowance for cross-talk

The geometric and information parameters of the page-oriented holographic memory are optimized with allowance for the cross-talk influence on the recording density and on the bit error rate.     

微合金化＋控冷工艺开发高强度钢筋工艺研究

高强度钢筋在国内建筑市场正处于推广阶段,特别2008年"5.12"四川汶川大地震之后,高强度钢筋的生产量和使用量明显增多;同时随着全球经济的迅猛发展,金属、合金消耗的增多,社会资源的有限性,导致合金价格的飙升,增大了产品的生产成本;为了适应市场竞争的需要,微合金化+控冷控轧复合工艺也成为了近年国际钢铁制造业工艺技术的最新研究和发展方向.     

HDEHP从硝酸底液中萃取UO_2~(2+)动力学研究

本文采用上升液滴法研究HDEHP-煤油溶液从硝酸底液中萃取UO_2~(2+)的动力学。根据本文实验数据,HDEHP萃取UO_2~(2+)的速率可以下列动力学方程表示:R=K[UO_2~(2+)]aq[HA]~2(o)实验测定了改变温度(15至40℃)对萃取速率的影响,用Arrhenius式可求得萃取反应的表观活化能为16.0kJ/mol。由实验结果推测,HDEHP从硝酸底液萃取UO_2~(2+)的反应,可能按下列三步进行:其中反应(1)生成两相界面配合物是萃取速率的控制步骤.     

丝状菌污泥膨胀的微观研究方法进展

污泥膨胀是一个世界难题.尽管各国科学家们对污泥膨胀问题做了大量的研究.但却至今还没有一种较为彻底的解决方法.由于存在缺陷,药剂法只适合临时应急使用.控制污泥膨胀通用方法的缺乏.使研究者开始关注丝状菌的微观研究.目前,研究丝状菌污泥膨胀的热点之一是鉴别出引起污泥膨胀的特定丝状菌.然后应用PCR扩增技术、原位杂交技术以及微电子自动射线照相等技术研究这些特定丝状菌的生理生态特征,试图找到可以避免这些特定丝状菌引起膨胀的方法,采取一定的措施来限制这些丝状菌过度生长.     

A new product distribution formulation for fischer-Tropsch synthesis. Effect of metal crystallite size distribution

A new product distribution formulation is presented for Fischer-Tropsch synthesis (FTS). This formulation, which contains the effect of the metal crystallite size on the product selectivity, can explain all possible Fischer-Tropsch product distributions. The Anderson-Shulz-Flory distribution formulation can be regarded as its approximation in special cases.