嫦娥一号卫星X射线谱仪的性能模拟

本文主要讲述了嫦娥一号卫星(CE-1)X射线谱仪(LOXIA)的性能模拟.包括,探测效率的模拟;探测器能谱响应的模拟;角度响应的模拟三个方面,并对模拟结果进行分析,为谱仪的研制提供了参考.     

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.     

Dynamic behaviour and control strategy of high temperature proton exchange membrane electrolyzer cells (HT-PEMECs) for hydrogen production

A fast and safe dynamic process is a key issue during the start-stop and adjustment of high temperature proton exchange membrane electrolyzer cells (HT-PEMECs). In the paper, a 2D multi-physics model is developed to investigate the dynamic process in an HT-PEMEC. First, the dynamic responses of step scheme, multistep scheme and diagonal scheme are compared. It is found that the step scheme has the fastest dynamic response, but it may cause the problem of reactant starvation. The dynamic response speed of diagonal scheme is slower than the step scheme, but it can prevent the problem of reactant starvation. Subsequently, the dynamic process is optimized with a fast dynamic response without reactant starvation. This paper proposes a fast and safe dynamic process adjustment scheme and forms a basis for subsequent control of the HT-PEMEC stack and system.     

Functional response of adult Cheyletus malaccensis (Acari: Cheyletidae) to different developmental stages of Aleuroglyphus ovatus (Acari: Acaridae)

Cheyletus malaccensis is an important natural enemy of stored pests. In the study, the functional response of C. malaccensis against Aleuroglyphus ovatus was investigated under five constant temperatures of 16, 20, 24, 28 and 32 °C. The results showed that the functional response of adult C. malaccensis to different stages of A. ovatus was conformed to Holling II. Under the temperature between 16 and 32 °C, C. malaccensis females consumed more larvae and nymphs, followed by male and females of A. ovatus. While male C. malaccensis merely consumed larvae and nymphs of prey. Adult C. malaccensis ate few eggs of A. ovatus. The daily consumption and instantaneous attack rate (a/Th) increased with the temperature increasing from 16 °C to 32 °C while the peak was at 28 °C. The maximum daily consumption for larva and a/Th of female C. malaccensis are 135.1 and 110.7, respectively. Cheyletus malaccensis showed positive preference to larvae and nymphs, while negative preference to adults and eggs of A. ovatus. Because of the competition and interference among predators, the predation efficiency decreased with the density of predator increasing, and the interference coefficient (m) was 0.485 at 28 °C. These results could be helpful to provide theoretical basis and practical instructions for the biological control of A. ovatus by C. malaccensis.     

Flexible and Implantable Microelectrodes for Chronically Stable Neural Interfaces

Implantable electrical probes that can record neural activities at single‐neuron and sub‐millisecond resolution are the most widely applied tools in both neuroscience research and neuroprosthetics. However, the structural and mechanical mismatch between conventional rigid probes and neural tissues results in inflammatory responses and signal degradation over chronic recordings. Reducing the cross‐sectional footprints and rigidity of the probes can effectively improve the long‐term stability of neural interfaces. Herein, recent progress in the development of implantable microelectrodes for chronically stable neural interfaces is highlighted, with a focus on the utilization of advanced materials and structural design concepts.     

Identity and overall acceptance of two types of sour rye bread

Response surface methodology was employed to study the influence of four recipe variables (wheat: rye flour ratio, bread acidity, ash content of rye flour and sodium chloride content) on the identity and overall acceptance of two rye bread types (soft and crisp rye bread). The subjects ( n = 79) rated attribute intensities, the extent to which the salient sensory properties and the overall sample corresponded to their expectations of rye bread, and the overall acceptance (pleasantness and purchase intentions). The acidity and ash content contributed the most to the extent to which a sample met subjects' expectations. The NaCl content was not critical. Consumer acceptance was affected by ash content, and by the interactions, NaCl content × acidity and wheat:rye ratio × ash content. The non-significance of NaCl content should encourage the baking industry to put low-salt rye products on the market.