密苏里州立公园ADA指导委员会对公众参与有效性的评价

本文对美国州立公园设计过程中公众参与的有效性进行了探讨。通过国家公园密苏里分部的有关实例研究，讨论了依据《美国伤残人法》(ADA)，市民指导委员会在州立公园体系建设中的作用，以及对公众参与有效性产生影响的因素。     

Facile synthesis of tetrapodal ZnO nanoparticles by modified French process and its photoluminescence

Facile synthesis of tetrapodal ZnO nanoparticles was conducted using a modified French process in which oxygen and nitrogen flow rates were controlled. The synthesized ZnO nanoparticles exhibit photoluminescent characteristics depending on the synthesis conditions. Electron microscopic analysis revealed that the tetrapodal nanostructure of ZnO with high crystallinity which was confirmed by XRD analyses could be controlled by a variation of O₂/N₂ feed ratio. Typical photoluminescence with UV and blue emission of the tetrapodal ZnO nanoparticles was influenced by the particle size and crystallinity, which is manipulated by the oxidation condition.     

Generation of uniform tetrapod-shaped zincoxide nanoparticles by gas-phase reaction with using flow restrictor

Tetrapod-shaped ZnO particles are generated via gas-phase reaction of Zn vapor and oxygen in air, where they undergo homogeneous nucleation from supersaturated ZnO vapor and successive growth by surface reaction. It was found that a simple device for flow restrictor is effective in making ZnO particles of terapod-shape by leaving sufficient amounts of unreacted Zn vapor with the embryos of ZnO. In the absence of the flow restrictor, only spherical particles are formed because the oxidation reaction takes place immediately after mixing and unreacted Zn vapor does not remain for the subsequent crystal growth. The Zn vapor concentration distribution, oxygen concentration distribution, temperature, gas velocity and reaction rate in the reactor were analyzed by using a conventional computational fluid dynamic simulation package. The simulation revealed that the flow restrictor does not enhance mixing between Zn vapor and air but suppresses the mixing and reduces the residence time in the reactor so that sufficient amounts of unreacted Zn vapor remain downstream of the flow restrictor, allowing ZnO particles to grow in tetrapod-shape by abnormal crystal growth.     

Characterization of Reflective Defects in Fabry–Pérot Laser Diodes Through the Power Transmission Spectrum

Reflective defects in Fabry-Peacuterot (FP) laser diodes are characterized through the power transmission spectrum based on the Fourier transform method. From a single measurement, the defect reflection, transmission coefficients and the cosine value of the defect phase shift, are calculated through equations built on the intensities of the peaks associated with defects in the Fourier transformed transmission spectrum. Gain dispersion which is unavoidable in semiconductor laser diodes is taken into account in the calculations. Extensive numerical simulations are made which show that the calculated defect characteristics are not influenced by the defect length and position and better results are obtained as the round-trip gain of the FP laser is relatively low. The simulation also shows that the underestimation of the gain caused by insufficient resolution of the measurement system degrades the calculated parameters. A deconvolution process is accordingly introduced, which is able to greatly reduce the resolution influence. Amplified spontaneous emission from FP laser diodes with a single slot very close to the laser front facet are measured and used to characterize the slot. The slots act as reflective defects in the laser diode and are produced by etching a rectangular well into the laser waveguide. For two lasers on the same bar with nominally the same slot, good agreement in the calculated reflection coefficient and cosine value of the slot phase shift is obtained, but the slot transmission coefficients calculated are different, which is due to the round-trip gain difference observed in the two lasers under the same current injection     

Liraglutide Counteracts Endoplasmic Reticulum Stress in Palmitate-Treated Hypothalamic Neurons without Restoring Mitochondrial Homeostasis

One feature of high-fat diet-induced neurodegeneration in the hypothalamus is an increased level of palmitate, which is associated with endoplasmic reticulum (ER) stress, loss of CoxIV, mitochondrial fragmentation, and decreased abundance of MC4R. To determine whether antidiabetic drugs protect against ER and/or mitochondrial dysfunction by lipid stress, hypothalamic neurons derived from pre-adult mice and neuronal Neuro2A cells were exposed to elevated palmitate. In the hypothalamic neurons, palmitate exposure increased expression of ER resident proteins, including that of SERCA2, indicating ER stress. Liraglutide reverted such altered ER proteostasis, while metformin only normalized SERCA2 expression. In Neuro2A cells liraglutide, but not metformin, also blunted dilation of the ER induced by palmitate treatment, and enhanced abundance and expression of MC4R at the cell surface. Thus, liraglutide counteracts, more effectively than metformin, altered ER proteostasis, morphology, and folding capacity in neurons exposed to fat. In palmitate-treated hypothalamic neurons, mitochondrial fragmentation took place together with loss of CoxIV and decreased mitochondrial membrane potential (MMP). Metformin, but not liraglutide, reverted mitochondrial fragmentation, and both liraglutide and metformin did not protect against either loss of CoxIV abundance or MMP. Thus, ER recovery from lipid stress can take place in hypothalamic neurons in the absence of recovered mitochondrial homeostasis.     

Validating Operator Event Sequence Diagrams: The case of an automated vehicle to human driver handovers

Predicting what drivers will do as vehicle control is handed over to them from automation is a relatively new challenge for the motor vehicle industry. Operator Event Sequence Diagrams (OESDs) offer a way of modeling the interactions between the driver and vehicle automation in the handover of control. In this paper, two studies are presented in which a range of handover strategies are tested. The anticipated driver strategies were modeled using OESDs to serve as predictions of driver behavior. Drivers were then observed in two separate studies: (1) using a Lower-Fidelity (vehicle seat and controls) simulator and (2) using a Higher-Fidelity (whole vehicle) simulator. Driver behavior during a takeover task was categorized according to the signal detection paradigm into hits, misses, false alarms, and correct rejections. The results showed that for all strategies in both sets of studies, the median criterion for validity was exceeded ( > 0.8), suggesting that OESDs made good predictions of driver behavior during the handover of the vehicle from automation to manual control.     

Impact of Changes in Sugar Exudate Created by Biological Damage to Tomato Plants on the Persistence of Escherichia coli O157:H7

ABSTRACT: The survival of enteric pathogens on vegetable leaves improves due to presence of phytopathogens. Phytopathogen damage alters the microenvironment on the leaf surface. The objective of this study was to identify differences in sugar concentrations in tomato leaves damaged by biotropic plant pathogens and determine if these differences affect Escherichia coli O157:H7 survival. E. coli O157:H7 survived better on tomato plants damaged by Xanthomonas campestris than on healthy plants (P = 0.012). The most common sugars and sugar alcohols in the damaged leaf exudate were glucose, fructose, inositol, and sucrose. The abundance of sucrose and inositol differed between the healthy and infected plants (P < 0.05). In this study, it was found that phytopathogen damaged plants increased sugar availability on the leaf surface for E. coli O157:H7 to proliferate. Keeping plants free from biological damage can limit the amount of leaching of sugars that could allow human pathogens to proliferate. There is the possibility of increasing food safety of vegetable products by limiting phytopathogenic damage to plants.     

定制边界滑移平行轴承的挤压效应(英文)

作者最近提出了一种利用滑块入口处的壁面滑移产生流体动压的新型轴承.笔者针对该类新轴承的油膜挤压问题,提出了基于滑移临界剪应力的数学模型,并给出了解析解.结果显示压力分布为分段光滑的抛物线,在滑移/非滑移边界,存在不连续的压力梯度.不同参数条件下的计算给出了不同的压力分布和壁面滑移类型.结果显示,对于代表滑块非浸润区长度的参数xt,最大压力并不总是随参数xt的减小而减小.存在一个参数xt的区间,在该区间内最大压力不变.与经典的挤压膜轴承类似,压力随膜厚的增加或趋进速度的减小而减小.笔者还发现临界剪应力的对挤压效应有重要的影响,揭示了此类新型轴承的一些内在的特性.