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Journal of Iron and Steel Research International 2019年第5期26卷 452-461页

作者： Jian Wang Wan-li Chen Hao-jie Meng Yi-shi Cui Cai-li Zhang Pei-de Han College of Materials Science and Engineering Taiyuan University of Technology Taiyuan 030024 Shanxi China

2707 hyper-duplex stainless steels (HDSSs) contain high contents of alloying elements (Cr, Ni, Mo and N), which may shorten the incubation period and promote both nucleation and growth of sigma (σ) phase. 2707 HDSS was first aged at different temperatures and periods of time for drawing the time-temperature-transformation profiles. The results identified the main precipitates as σ phase, with nose temperature of about 950℃. Also, 2707 specimen was aged at 950℃ for a short time, and the morphology, distribution and amount of σ phase were examined through the scanning electron microscope and X-ray diffraction,σ phase was initially formed at the boundaries of ferrite and austenite and then transformed through the eutectoid reaction (α→σ+γ2). Finally, the precipitation and growth of σ phase in 2707 steels aged at nose temperature for a short period reduced the corrosion resistance and deteriorated the mechanical properties, and the corresponding reason was further analyzed.

关键词： sigma phase Corrosion Mechanical property 2707 hyper-duplex stainless steel Aging treatment

sigma-1 receptor: culprit and rescuer in motor neuron diseases

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Neural Regeneration Research 2021年第1期16卷 106-107页

作者： Jean-Charles Liévens Tangui Maurice MMDN Univ MontpellierINSERMEPHEMontpellierFrance

Initially,the sigma-1 receptor(S1R)was incorrectly categorized as one of the opioid *** it has since become clear that S1R is a non-opioid non-phencyclidine receptor with molecular chaperone activity.S1R is a 223 amino-acid long protein that shares no clear homology with any other known mammalian proteins,its closest homolog being the fungal ERG2 sterol *** its pharmacological counterpart,the sigma-2 receptor that was only recently cloned,is genetically distinct.S1R is more likely considered as an atypical ligand-modulated chaperone protein.S1R is widely expressed in many organs including brain where its function has mainly been explored.

关键词： organs opioid sigma

Six sigma robust design optimization for thermal protection system of hypersonic vehicles based on successive response surface method

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Chinese Journal of Aeronautics 2019年第9期32卷 2095-2108页

作者： Jingjing ZHU Xiaojun WANG Haiguo ZHANG Yuwen LI Ruixing WANG Zhiping QIU Institute of Solid Mechanics School of Aeronautic Science and EngineeringBeihang UniversityBeijing 100083China The 704 Research Institute of CSIC Shanghai 200031China Institute of Mechanics Chinese Academy of ScienceBeijing 100190China

Lightweight design is important for the Thermal Protection System(TPS) of hypersonic vehicles in that it protects the inner structure from severe heating environment. However, due to the existence of uncertainties in material properties and geometry, it is imperative to incorporate uncertainty analysis into the design optimization to obtain reliable results. In this paper, a six sigma robust design optimization based on Successive Response Surface Method(SRSM) is established for the TPS to improve the reliability and robustness with considering the uncertainties. The uncertain parameters related to material properties and thicknesses of insulation layers are considered and characterized by random variables following normal distributions. By employing SRSM, the values of objective function and constraints are approximated by the response surfaces to reduce computational cost. The optimization is an iterative process with response surfaces updating to find the true optimal solution. The optimization of the nose cone of hypersonic vehicle cabin is provided as an example to illustrate the feasibility and effectiveness of the proposed method.

关键词： Hypersonic vehicle Six sigma robust optimization Successive response surface Thermal protection system Uncertainty

sigma-2 receptor as a potential therapeutic target for treating central nervous system disorders

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Neural Regeneration Research 2019年第11期14卷 1893-1894页

作者： Kazuki Terada Keisuke Migita Yukari Matsushima Chiaki Kamei Laboratory of Drug Design and Drug Delivery Faculty of Pharmaceutical SciencesFukuoka UniversityFukuokaJapan Department of Drug Informatics Faculty of Pharmaceutical SciencesFukuoka UniversityFukuokaJapan Department of Pharmacology Faculty of Pharmaceutical SciencesYasuda Women’s UniversityHiroshimaJapan

The sigma receptor (Sig-R) was first reported by Martin et al.(1976) and was initially classified into the opioid receptor family. However, Sig-R was subsequently found to differ from the opioid receptor in various studies including ligand binding assays and autoradiography analysis (Tam and Cook, 1984). Sig-R is widely distributed in tissues such as central nervous, digestive, immune, and endocrine tissues. There are two types of Sig-R: sigma-1 (Sig-1R) and sigma-2 receptors (Sig-2R).

关键词： sigma receptor(Sig-R) Martin sigma-2

A MoClo-Compatible Toolbox of ECF sigma Factor-Based Regulatory Switches for Proteobacterial Chassis

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BioDesign Research 2024年第1期6卷 1-19页

作者： Doreen Meier Christian Rauch Marcel Wagner Paul Klemm Patrick Blumenkamp Raphael Müller Eric Ellenberger Kinnari M.Karia Stefano Vecchione Javier Serrania Marcus Lechner Georg Fritz Alexander Goesmann Anke Becker Center for Synthetic Microbiology(SYNMIKRO)and Department of Biology Philipps-Universität MarburgMarburgGermany Bioinformatics and Systems Biology Justus-Liebig-Universität GiessenGiessenGermany The University of Western Australia School of Molecular SciencesPerthAustralia

The construction of complex synthetic gene circuits with predetermined and reliable output depends on orthogonal regulatory parts that do not inadvertently interfere with the host machinery or with other circuit ***,extracytoplasmic function sigma factors(ECFs),a diverse group of alternative sigma factors with distinct promoter specificities,were shown to have great potential as context-independent regulators,but so far,they have only been used in a few model ***,we show that the alphaproteobacterium Sinorhizobium meliloti,which has been proposed as a plant-associated bacterial chassis for synthetic biology,has a similar phylogenetic ECF acceptance range as the gammaproteobacterium Escherichia coli.A common set of orthogonal ECF-based regulators that can be used in both bacterial hosts was identified and used to create 2-step delay *** genetic circuits were implemented in single copy in *** by chromosomal integration using an established method that utilizes bacteriophage *** ***,we demonstrated the usability of single-copy pABC plasmids as equivalent carriers of the synthetic *** circuits were either implemented on a single pABC or modularly distributed on 3 such *** addition,we provide a toolbox containing pABC plasmids compatible with the Golden Gate(MoClo)cloning standard and a library of basic parts that enable the construction of ECF-based circuits in *** and in *** work contributes to building a context-independent and species-overarching ECF-based toolbox for synthetic biology applications.

关键词： toolbox sigma chassis compatible factor-based moclo proteobacterial regulatory switches

sigma-Point卡尔曼滤波用于OFDM载波频偏估计

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天津大学学报（自然科学与工程技术版） 2013年第5期46卷 458-462页

作者：张鑫明叶锋杨波门爱东北京邮电大学信息与通信工程学院北京100876 中国舰船研究院新技术研究室北京100192 福建师范大学数学与计算机科学学院福州350001

对于非线性的动态状态空间模型,扩展卡尔曼滤波(EKF)通过泰勒展开拟合系统的状态和观测方程,以获得对状态值的估计,但其存在估值波动大、收敛慢等缺点;而基于sigma-point点的卡尔曼滤波方法,则是通过确定性采样实现统计特性上的近似,从... 详细信息

对于非线性的动态状态空间模型,扩展卡尔曼滤波(EKF)通过泰勒展开拟合系统的状态和观测方程,以获得对状态值的估计,但其存在估值波动大、收敛慢等缺点;而基于sigma-point点的卡尔曼滤波方法,则是通过确定性采样实现统计特性上的近似,从而获得更为准确的高阶统计特性.为此,建立了正交频分复用(OFDM)载波频偏的动态状态空间模型,并将sigma-point卡尔曼滤波用于其频偏估计.仿真结果表明,该类方法可以捕捉更为准确的高阶特性,其估值准确、收敛速度快、波动小、对观测噪声大小不敏感.

关键词： sigma point卡尔曼滤波动态状态空间正交频分复用载波频偏

微加速度计中sigma Delta调制与脉冲编码调制的对比分析(英文)

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光学精密工程 2009年第6期17卷 1228-1232页

作者：谭晓昀周贤中姜一鸣陈伟平哈尔滨工业大学MEMS中心黑龙江哈尔滨150001

对sigma Delta调制与脉冲编码调制进行对比,研究了sigma Delta调制与脉冲编码调制的优缺点。建立了微加速度计中两位输出的sigma Delta调制和两位输出的脉冲编码调制的仿真系统。然后,对比使用这两种调制方式的微加速度计的加速度信号,... 详细信息

对sigma Delta调制与脉冲编码调制进行对比,研究了sigma Delta调制与脉冲编码调制的优缺点。建立了微加速度计中两位输出的sigma Delta调制和两位输出的脉冲编码调制的仿真系统。然后,对比使用这两种调制方式的微加速度计的加速度信号,并分析在两种不同调制方式下的输出信号波形的差别。最后,利用周期图法得到了两种调制信号的功率谱密度图,发现在低频段脉冲编码调制信号的量化噪声比sigma Delta调制信号大很多;而在高频段,两种调制方式信号的量化噪声一样严重。仿真结果表明,尽管sigma Delta调制系统比脉冲编码调制系统更加复杂,但是sigma Delta调制得到的信噪比要比脉冲编码调制得到的信噪比高出20dB。

关键词： sigma Delta调制脉冲编码调制微加速度计

sigma B在单核细胞增生李斯特菌耐受环境压力胁迫中的作用

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微生物学报 2009年第10期49卷 1282-1288页

作者：张强冯莹颖周青春罗勤张晓莉秦龙娟华中师范大学生命科学学院遗传调控与整合生物学湖北省重点实验室武汉430079

sigma B(σB)因子在单核细胞增生李斯特菌(Listeria monocytogenes)的压力应答和毒力调控中起着重要的作用。研究发现单核细胞增生李斯特菌的致病力与耐受环境条件的胁迫息息相关。在压力存在的情况下能启动一些基因的表达,以增强细菌... 详细信息

sigma B(σB)因子在单核细胞增生李斯特菌(Listeria monocytogenes)的压力应答和毒力调控中起着重要的作用。研究发现单核细胞增生李斯特菌的致病力与耐受环境条件的胁迫息息相关。在压力存在的情况下能启动一些基因的表达,以增强细菌对环境的耐受性,这些基因包括与耐受渗透压、酸碱性环境、氧化、极端温度和宿主体内胆碱等环境压力相关的基因。本文综述了σB因子在上述几种环境压力胁迫中的作用,为深入了解该菌的生理特征、探讨食品的最佳生产和保藏条件、防止细菌的感染等方面提供新的理论依据。

关键词：单核细胞增生李斯特菌 sigma B因子环境压力胁迫

sigma B因子活性的调节及其在几种革兰氏阳性食源性致病菌中的作用

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微生物学报 2008年第6期48卷 839-843页

作者：冯莹颖张晓莉罗勤周青春华中师范大学生命科学学院遗传调控与整合生物学湖北省重点实验室武汉430079

sigmaB(σB)是许多革兰氏阳性菌对环境胁迫产生应答反应的主要调控因子。不仅在芽孢形成中具有重要作用,而且σB也直接或间接地调控包括蜡样芽孢杆菌(Bacillus cereus)、单核细胞增生李斯特菌(Listeria monocytogenes)和金黄色葡萄球菌(... 详细信息

sigmaB(σB)是许多革兰氏阳性菌对环境胁迫产生应答反应的主要调控因子。不仅在芽孢形成中具有重要作用,而且σB也直接或间接地调控包括蜡样芽孢杆菌(Bacillus cereus)、单核细胞增生李斯特菌(Listeria monocytogenes)和金黄色葡萄球菌(Staphylococcus aureus)在内的一些革兰氏阳性食源性致病菌毒力及毒力相关基因的表达。本文结合作者在国内外的相关工作,综述了σB活性的调节方式及其在上述革兰氏阳性食源性致病菌中相关作用的最新研究进展,为深入研究革兰氏阳性食源性致病菌的致病机理、预防和治疗细菌感染提供新的思路和理论依据。

关键词： sigma B因子革兰氏阳性食源性致病菌压力应答调控毒力

sigma算法在广东省大学生体质分析中的应用

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体育学刊 2019年第4期26卷 110-115页

作者：汪志胜刘承宜华南师范大学体育科学学院激光运动医学实验室广东广州510006 美年大健康广州美年健康富海门诊部有限公司广东广州510620

引入sigma算法对1995—2014年广东省大学生体质健康调研数据进行分析。结果发现:(1)从1995到2010年,广东省男大学生体质健康水平从非自限性过程建立为自限性过程,而广东省女大学生体质健康水平呈时间自相似,但广东省男女大学生体质健康... 详细信息

引入sigma算法对1995—2014年广东省大学生体质健康调研数据进行分析。结果发现:(1)从1995到2010年,广东省男大学生体质健康水平从非自限性过程建立为自限性过程,而广东省女大学生体质健康水平呈时间自相似,但广东省男女大学生体质健康水平从2010到2014年均出现下降;(2)从1995到2014年,广东省大学生体质健康水平不存在城乡、年级、性别差异。结果表明,大学生体质健康水平在时间上形成差异的原因主要与学校教育改革有关。

关键词：体质健康大学生时间自相似 sigma 算法广东省