Benchmark Experiment on Vanadium with D-T Neutrons and Validation of Evaluated Nuclear Data Libraries by Analysis of the Experiment

A neutronics benchmark experiment on vanadium, which is a low activation fusion reactor material, was conducted by using the D-T neutron source facility of FNS/JAERI. Neutron spectra, dosimetry reaction rates, γ-ray spectra and γ-ray heating rates were measured in a vanadium experimental assembly. Benchmark tests for four evaluated nuclear data files were performed by analyzing the experiment. As a result, the following problems were pointed out in view of accuracy of fusion reactor designs. (1) JENDL-FF and JENDL-3.2: Total cross section should be reexamined especially at ～2keV. (2) ENDF/B-VI: Double differential cross sections for 14 MeV neutrons should be revised because of the isotropic angular distribution for continuum neutron emission. Gamma-ray production cross sections are too small and discrete γ-ray peaks are not represented clearly. (3) EFF-3: Gamma-ray production cross sections are too large.     

Importance and applications of DOE/optimization methods in PEM fuel cells: A review

Although proton exchange membrane (PEM) fuel cells are seen as one of the energy conversion technologies of the future due to their high energy conversion efficiency, low levels of emissions, low temperature operation, and compact systems, studies continue to reduce their cost, which is the biggest obstacle to commercialization. Design of experiment (DOE) methods are frequently used in optimization of PEM fuel cells to reduce their cost by decreasing experimental runs. This paper reviews the main gains subsuming the usage of several DOE and optimization methods in PEM fuel cell components, design, operation conditions, and model parameters. It firstly focuses on the Taguchi method and response surface methodology (RSM) known to be applied usually in PEM fuel cell studies. In addition to these known methods, other experimental design and optimization methods used in PEM fuel cells are discussed, and the results are summarized.     

Research on the mechanism of heat transfer enhancement in microchannel heat sinks with micropin fins

In this paper, the pressure drop and heat transfer features of a microchannel applying micropin fins are investigated by numerical simulations and experiments. The microchannel, which is 20-mm long, 2.7-mm wide, and 0.3-mm deep, is fabricated with copper and consisted of staggered diamond micropin fins. The visualization experiments, by means of the advanced technology micro-particle image velocimetry (PIV), are conducted to discuss the mechanism of heat transfer by analysing the flow regimes. Meanwhile, 3D-coupled numerical simulations are applied for the combination with experiments in this research. It is found that the vortex-wake flow is stable at Reynolds number (Re) = 0 to 300, and a steady recirculating zone can be observed in the wake, where a pair of symmetrical vortices is formed. All the time, the vortex-wake flow is unstable at Re = 300 to 650. Under this situation, it is due to the decrease of vorticity that the Nusselt number (Nu) is not significantly increased as it was expected. Thus, when Nu in the pin fin microchannel is predicted, the vorticity should be considered as well as turbulent kinetic energy (TKE). Furthermore, comparative study was carried out based on the mechanism proposed in this study among three kinds of microchannel with different fins, including staggered circular pin fins (CPF), square pin fins (SPF), and diamond pin fins (DPF).     

Identification of hydrogen permeability parameters of membrane materials in an aggregated experiment

The study of the hydrogen permeability of materials for membrane-based separation/purification technologies employs a variety of experimental methods with their own specific features, advantages and shortfalls. The method of penetration with vacuum pumping allows determining the diffusion coefficient from so-called lag time. The accuracy of the estimation depends on the degree of proximity to the DLR (diffusion limited regime) mode. The method of “communicating vessels” is more sensitive to surface processes. The thermal desorption (TDS) technique permits “scanning” the material dynamically across a wide range of temperatures. “Separate” application of these methods leads to a situation where the materials studied are in fact somewhat different (for example, due to different impacts on the surface), and significant differences in parameter estimates ensue. This paper suggests and implements a technique for a combined three-stage ‹‹penetration (with and without vacuum pumping)+TDS›› experiment and the corresponding mathematical toolkit. The informative capacity of the experiments and the accuracy of the estimation of hydrogen permeability parameters (adsorption, dissolution, diffusion and desorption) of the membrane materials under study are thus enhanced.     

Optimization of BiVO4 photoelectrodes made by electrodeposition for sun-driven water oxidation

In this work, the synthesis of cheap BiVO₄ photoanodes for the photoelectrochemical water splitting reaction was optimized via the scalable thin film electrodeposition method. Factors affecting the photoelectrochemical activity, such as the electrodeposition time, the ratio of the Bi-KI to benzoquinone-EtOH in the deposition bath, and the calcination temperature, have been investigated by using the Central Composite Design of Experiments. Pristine monoclinic scheelite BiVO₄ photoanodes having a photocurrent density of 0.45 ± 0.05 mA/cm² at 1.23 V vs RHE have been obtained. It was shown that a high photocurrent density is generally dictated by the following physico-chemical properties: a higher crystallite size, optimal thickness and a porous morphology, which give rise to a low charge transfer resistance, low onset potential and a high donor density. Moreover, to the best of our knowledge, this is the first report on the depth profile XPS analysis performed in BiVO₄ photoanodes made by electrodeposition technique, from which it was concluded that the surface V species exist as V⁴⁺ while the bulk V species are V⁵⁺. The V⁴⁺ induces a higher amount of surface oxygen vacancies, which was found to be beneficial for the photoactivity.     

葵花籽多肽的制备及其降压活性研究

试验以低温脱脂葵花籽粕为原料,进行脱脂和脱绿原酸处理后,用碱性蛋白酶制备葵花籽多肽。以水解度和ACE抑制率为评价指标,对底物浓度、加酶量、酶解温度、酶解时间和pH值进行单因素试验,在此基础上采用响应面试验优化碱性蛋白酶制备葵花籽多肽的最佳水解工艺。结果表明:底物浓度为15g/mL、加酶量为3 700U/g、酶解温度为56℃和pH值为8.2的条件下水解3h,ACE抑制率可达63.74%。     

球磨辅助酶解制备南瓜籽ACE抑制肽

以南瓜籽蛋白为原料,通过球磨预处理辅助酶解法制备血管紧张素转换酶（ACE）抑制肽。以ACE抑制率和水解度为评价指标,对蛋白酶进行筛选。采用单因素试验研究球磨时间、酶解时间、底物质量浓度、pH和酶解温度对酶解产物ACE抑制率和水解度的影响,在此基础上,以ACE抑制率为考察指标,采用响应面法对球磨辅助酶解工艺条件进行优化。结果表明：球磨预处理可显著提高南瓜籽蛋白的酶解效率;最佳球磨辅助酶解工艺条件为选用碱性蛋白酶、球磨时间6 min、酶解时间10 h、底物质量浓度0.08 g/mL、pH 8.5、酶解温度55 ℃,在此条件下所得ACE抑制肽的ACE抑制率可达(86.65±0.55)%。     

1株源自如皋火腿的产谷氨酰胺酶腐生葡萄球菌RG-2催化条件的优化

谷氨酰胺酶与发酵肉制品的鲜味形成有关,且能够降低产品的酸度,改善口感。利用从如皋火腿中分离得到的1株产谷氨酰胺酶的腐生葡萄球RG-2,通过单因素试验及响应曲面设计,研究pH、温度、NaCl浓度等因素对菌株RG-2的谷氨酰胺酶催化活力的影响。结果表明:最佳条件为pH6.7、温度43℃、NaCl浓度3.1%,此条件下谷氨酰胺酶酶活达到40.2 U/mL。