Effect of different control strategies on rapid cold start-up of a 30-cell proton exchange membrane fuel cell stack

Many places experience extreme temperatures below −30 °C, which is a great challenge for the fuel cell vehicle (FCV). The aim of this study is to optimize the strategy to achieve rapid cold start-up of the 30-cell stack at different temperature conditions. The test shows that the stack rapidly starts within 30 s at an ambient temperature of −20 °C. Turning on the coolant at −25 °C show stability of the cell voltage at both ends due to the end-plate heating, however, voltage of intermediate cells fluctuates sharply, and successful start-up is completed after 60 s. The cold start strategy changes to load-voltage cooperative control mode when the ambient temperature reduced to −30 °C, the voltage of multiple cells in the middle of the stack fluctuate more drastic, and start-up takes 113 s. The performance and consistency of the stack did not decay after 20 cold start-up experiments, which indicates that our control strategies effectively avoided irreversible damage to the stack caused by freeze-thaw process.     

牛磺酸对运动能力影响的研究进展

牛磺酸是一种含硫条件性必需氨基酸,是人和动物机体内不可缺少的一种生理活性物质。牛磺酸对于机体的运动能力有着重要的影响,本文在介绍牛磺酸的代谢过程及生理作用的基础上,对目前国内外关于补充牛磺酸与提高人体的运动能力的关系、牛磺酸的安全性及副作用等方面研究情况做一综述。牛磺酸已开发成颇具潜力的抗运动性疲劳的营养补充剂,同时在医药、卫生、保健等领域里也具有广泛商业价值和社会价值。     

Ultimate bearing capacity of strip footing resting on clay soil mixed with tire-derived aggregates

This study investigated the use of recycled tire-derived aggregate (TDA) mixed with kaolin as a method of increasing the ultimate bearing capacity ( UBC) of a strip footing. Thirteen 1g physical modeling tests were prepared in a rigid box of 0.6 m × 0.9 m in plan and 0.6 m in height. During sample preparation, 0%, 20%, 40%, or 60% (by weight) of powdery, shredded, small-sized granular (G 1–4 mm) or large-sized granular (G 5–8 mm) TDA was mixed with the kaolin. A strip footing was then placed on the stabilized kaolin and was caused to fail under stress-controlled conditions to determine the UBC. A rigorous 3D finite element analysis was developed in Optum G-3 to determine the UBC values based on the experimental test results. The experimental results showed that, except for the 20% powdery TDA, the TDA showed an increase in the UBC of the strip footing. When kaolin mixed with 20% G (5–8 mm), the UBC showed a threefold increase over that for the unreinforced case. The test with 20% G (1–4 mm) recorded the highest subgrade modulus. It was observed that the UBC calculated using finite element modeling overestimated the experimental UBC by an average of 9%.     

基于蛋白质组学技术研究秦川牛肉宰后贮藏过程中肌红蛋白含量及其衍生物转化

本实验采用4D-非标记蛋白质组学技术研究秦川牛肉贮藏过程中（0～8 d）肌红蛋白含量及其衍生物的转化情况，阐释冷却秦川牛肉中肌红蛋白含量及其衍生物转化的分子机制。结果表明：贮藏过程中，肌红蛋白表达量在宰后0～4 d上升、4～8 d下降，利用非标记蛋白质组学技术鉴定出与肌红蛋白及其衍生物相关的差异蛋白14 种，具体包括代谢酶、氧化还原酶、过氧化物酶、伴侣蛋白4 类，这4 类蛋白的表达共同调控贮藏过程中肌红蛋白含量的变化及其3 种衍生物之间的转化，具体表现为贮藏过程中肌红蛋白表达量整体呈下降趋势，氧合肌红蛋白相对含量持续下降，脱氧肌红蛋白、高铁肌红蛋白相对含量逐渐增加，导致肉色发生褐变。本研究结果有利于理解秦川牛肉贮藏过程肉类变色的复杂生化变化机制。     

基于柠檬酸-铕纳米配位聚合物构建荧光探针快速检测汤煲中5’-肌苷酸含量

基于柠檬酸-铕金属有机纳米配体聚合物（citrate/europium lanthanide coordination polymer nanoparticles，Cit/Eu LCP NPs）构建快速检测肉品汤煲中5’-肌苷酸（inosine-5’-monophosphate，5’-IMP）的荧光探针。研究结果表明，5’-IMP对Cit/Eu?LCP?NPs有良好的荧光猝灭作用。在最佳条件下，该荧光探针在5’-IMP?2.5～200?μg/mL的质量浓度范围内呈现出良好的线性关系，检出限为0.17?μg/mL，且具备良好的抗干扰、稳定性和重复性。为了验证方法可行性，将该方法应用于实际鸡汤样品中的5’-IMP检测，测得加标回收率为97.85%～103.95%，可为快速检测肉品汤煲中5’-IMP提供新的思路和方法。     

一种5 重real-time PCR筛查转基因水稻方法的建立

以转基因水稻中最常用的CaMV35S启动子、NOS终止子、Cry1Ab/Ac基因、HPT基因及SPS水稻内标基因为研究对象，利用5 种不同的荧光信号（FAM、HEX、Taxas Red、Cy5、Cy5.5）进行多重实时聚合酶链式反应（real-time polymerase chain reaction，real-time PCR）检测方法的研究。通过引物组合筛选、反应体系优化、特异性测试、灵敏度测试、适用性测试等一系列实验，建立了5 重real-time PCR方法，灵敏度可达0.032%。此方法具有灵敏度高、结果准确、通量大等优点，可实现水稻中转基因成分的快速、高效检测。     

起·承·转·合 ——解读巍宝山长春洞空间布局的结构章法

长春洞是巍宝山保存最完整的宫 观，虽占地不到两亩①，却在有限的空间中 创造出九楼十院的空间格局。本文以长春洞 空间布局序列为研究对象，从知觉体验的 连续性入手，提出了空间变化对参观者情感 的影响，论述了在建筑空间布局序列中参观 者知觉体验逐层递进的控制机制，探讨了以 “起、承、转、合”为结构，以“知觉体验”为 章法的动态空间布局设计手法，希望为道教 建筑空间与其他超越日常的精神空间的研 究提供启示。     

Study on the blackening phenomenon of leaded glass during microgroove molding using nickel phosphorous mold

Precision glass molding (PGM) is a recently developed method to fabricate glass microgroove components. Lead glass is commonly used as an optical material due to its high refractive index and low transition temperature. A nickel-phosphorous (Ni–P) plated mold is traditionally employed in the PGM process for microstructures optics. However, leaded glass is subject to color change and can blacken during the PGM process, reducing the light transmittance of microgrooves. In this paper, an equation for the redox reaction between Ni and Pb is proposed, which is based on the diffusion of inner Ni atoms to the surface of the mold and the standard electrode potential of the Pb ions in leaded glass. A viscoelastic constitutive model of the glass is established to simulate the compression stress distribution during molding. Finally, the effects of molding pressure, molding temperature, and mold material on glass blackening are studied. The results show that the blackening of leaded glass is caused by Pb enriching the surface. The rise in molding stress and temperature increases the deformation of Ni–P plating, which promotes the diffusion of Ni atoms. By adding a titanium incorporated diamond-like carbon (Ti-DLC) coating, the deformation of the Ni–P plating during molding is suppressed, and the diffusion of Ni atoms can be prevented. In this way, the blackening of leaded glass can be prevented.     

Determining robust reaction kinetics from limited data

Accurate chemical kinetics are essential for reactor design and operation. However, despite recent advances in “big data” approaches, availability of kinetic data is often limited in industrial practice. Herein, we present a comparative proof-of-concept study for kinetic parameter estimation from limited data. Cross-validation (CV) is implemented to nonlinear least-squares (LS) fitting and evaluated against Markov chain Monte Carlo (MCMC) and genetic algorithm (GA) routines using synthetic data generated from a simple model reaction. As expected, conventional LS is fastest but least accurate in predicting true kinetics. MCMC and GA are effective for larger data sets but tend to overfit to noise for limited data. LS-CV strongly outperforms these methods at much reduced computational cost, especially for significant noise. Our findings suggest that implementation of CV with conventional regression provides an efficient approach to kinetic parameter estimation with high accuracy, robustness against noise, and only minimal increase in complexity.     

Suppression of Hypoxia-Inducible Factor 1α by Low-Molecular-Weight Heparin Mitigates Ventilation-Induced Diaphragm Dysfunction in a Murine Endotoxemia Model

Mechanical ventilation (MV) is required to maintain life for patients with sepsis-related acute lung injury but can cause diaphragmatic myotrauma with muscle damage and weakness, known as ventilator-induced diaphragm dysfunction (VIDD). Hypoxia-inducible factor 1α (HIF-1α) plays a crucial role in inducing inflammation and apoptosis. Low-molecular-weight heparin (LMWH) was proven to have anti-inflammatory properties. However, HIF-1α and LMWH affect sepsis-related diaphragm injury has not been investigated. We hypothesized that LMWH would reduce endotoxin-augmented VIDD through HIF-1α. C57BL/6 mice, either wild-type or HIF-1α–deficient, were exposed to MV with or without endotoxemia for 8 h. Enoxaparin (4 mg/kg) was administered subcutaneously 30 min before MV. MV with endotoxemia aggravated VIDD, as demonstrated by increased interleukin-6 and macrophage inflammatory protein-2 levels, oxidative loads, and the expression of HIF-1α, calpain, caspase-3, atrogin-1, muscle ring finger-1, and microtubule-associated protein light chain 3-II. Disorganized myofibrils, disrupted mitochondria, increased numbers of autophagic and apoptotic mediators, substantial apoptosis of diaphragm muscle fibers, and decreased diaphragm function were also observed (p < 0.05). Endotoxin-exacerbated VIDD and myonuclear apoptosis were attenuated by pharmacologic inhibition by LMWH and in HIF-1α–deficient mice (p < 0.05). Our data indicate that enoxaparin reduces endotoxin-augmented MV-induced diaphragmatic injury, partially through HIF-1α pathway inhibition.