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Contribution of Microbial Inter-kingdom Balance to Plant Health
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作者 Chunlei Zhang Youming Zhang +1 位作者 Zhaojun Ding Yang Bai 《分子植物:英文版》 SCIE CAS CSCD 2019年第2期148-149,共2页
Soil-borne fungal and oomycetal pathogens cause devastating agricultural losses every year. The abundance and diversity of filamentous eukaryotes in the roots of healthy plants are in flue need by root-associated bact... Soil-borne fungal and oomycetal pathogens cause devastating agricultural losses every year. The abundance and diversity of filamentous eukaryotes in the roots of healthy plants are in flue need by root-associated bacteria that protect host plants from disease caused by fungi and oomycetes (Duran et al., 2018). 展开更多
关键词 MICROBIAL Inter-kingdom BALANCE Plant Health FILAMENTOUS EUKARYOTES
Formation Mechanism of Poor Settlements in Lanzhou City 预览
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作者 Xinhong ZHANG Zhengguan XIE 《亚洲农业研究:英文版》 2017年第5期69-73,共5页
Clarifying the formation mechanism of poor settlements is the ' pathological' basis for urban regeneration and poverty governance.On the basis of scientific determination of 155 poor settlements in Lanzhou Cit... Clarifying the formation mechanism of poor settlements is the ' pathological' basis for urban regeneration and poverty governance.On the basis of scientific determination of 155 poor settlements in Lanzhou City,this paper classified their types and analyzed the characteristics of their quantity distribution and density distribution. From the perspective of spatial and social interaction,and combined the internal factors and external factors,this paper put forward the formation mechanism of poor settlements,namely,superposition of unit society collapse and physical environment degradation,interaction between differentiation of residents’ income and reform of housing institution,interweaving between urban discontinuous planning and jumping construction,coupling between passive urbanization and active urbanization,and derivation of lagged economic development and unique regional culture. 展开更多
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Near-infrared (NIR) controlled reversible cell adhesion on a responsive nano-biointerface
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作者 Haijun Cui 《纳米研究:英文版》 SCIE EI CAS CSCD 2017年第4期1345-1355,共11页
激活光的动态变化支持了聪明的接口的发展,特别 nano-biointerfaces。在这篇文章,在红外线附近(NIR ) 为控制房间粘附的应答的表面被 grafting 设计热应答的聚合物(poly (N-isopropylacrylamide ) , PNIPAM ) 到硅 nanowires (SiNWs... 激活光的动态变化支持了聪明的接口的发展,特别 nano-biointerfaces。在这篇文章,在红外线附近(NIR ) 为控制房间粘附的应答的表面被 grafting 设计热应答的聚合物(poly (N-isopropylacrylamide ) , PNIPAM ) 到硅 nanowires (SiNWs ) 上而不是传统的感光性的一半。NIR 导致了 SiNWs 的 photothermal 效果,并且本地热导致了 PNIPAM 的热力学的阶段转变。用 NIR 放射的应用程序,表面转到一个恐水病的状态,并且当 NIR 被关上时,恢复了到吸水的状态,导致可逆房间粘附和版本。表面和房间粘附 / 版本的可切换的 wettability 甚至在 20 个周期以后高效地发生了。蛋白质用 NIR 经由恐水病的相互作用在表面上被抛锚;一个房间俘获代理人的进一步的连接在完成特定的房间俘获帮助了。经由 NIR 的房间粘附的这动态控制可以为设计功能的 nano-biointerfaces 提供新线索。 展开更多
关键词 房间粘附 photothermal 效果 NANOSTRUCTURES 简历接口 恐水病的相互作用
VideoMap: An interactive and scalable visualization for exploring video content
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作者 Cui-Xia Ma Yang Guo Hong-An Wang 《计算可视媒体(英文版)》 2016年第3期291-304,共14页
Large-scale dynamic relational data visualization has attracted considerable research attention recently. We introduce dynamic data visualization into the multimedia domain, and present an interactive and scalable sys... Large-scale dynamic relational data visualization has attracted considerable research attention recently. We introduce dynamic data visualization into the multimedia domain, and present an interactive and scalable system, Video Map, for exploring large-scale video content. A long video or movie has much content; the associations between the content are complicated. Video Map uses new visual representations to extract meaningful information from video content. Map-based visualization naturally and easily summarizes and reveals important features and events in video. Multi-scale descriptions are used to describe the layout and distribution of temporal information, spatial information, and associations between video content. Firstly, semantic associations are used in which map elements correspond to video contents. Secondly, video contents are visualized hierarchically from a large scale to a fine-detailed scale. Video Map uses a small set of sketch gestures to invoke analysis, and automatically completes charts by synthesizing visual representations from the map and binding them to the underlying data. Furthermore,Video Map allows users to use gestures to move and resize the view, as when using a map, facilitating interactive exploration. Our experimental evaluation of Video Map demonstrates how the system can assist in exploring video content as well as significantly reducing browsing time when trying to understand and find events of interest. 展开更多
关键词 map METAPHOR VIDEO content VISUALIZATION sketch-based interaction association analysis
Orientation Angle of Molecules at Hexadecane-Water Interface Studied with Total Internal Reflection Second Harmonic Generation 预览
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作者 Li-bo Zhang Hui Fang +2 位作者 Shun-li Chen Xue-feng Zhu Wei Gan 《化学物理学报》 SCIE CAS CSCD 2016年第6期650-656,I0001共8页
取向角度是在接口反映分子的结构的一个重要参数。以便获得这个参数,第二包括第二泛音代(SHG ) 订非线性的分光镜的技术并且加频率产生震动的光谱学(SFG -- 对) 成功地从各种各样的极化通过非线性的信号的分析被使用了。在一些 SHG 和 ... 取向角度是在接口反映分子的结构的一个重要参数。以便获得这个参数,第二包括第二泛音代(SHG ) 订非线性的分光镜的技术并且加频率产生震动的光谱学(SFG -- 对) 成功地从各种各样的极化通过非线性的信号的分析被使用了。在一些 SHG 和 SFG -- 对实验,全部的内部思考(TIR ) 配置被采用了得到提高的信号。然而,极化分析和在 TIR 配置下面的界面的分子的取向角度的计算的详细过程上的报告仍然是很少的。在这份报纸,我们在 TIR 和 Non-TIR 下面在 hexadecane 水接口测量了二个分子的取向角度试验性的配置。在 TIR 配置从极化分析测量的结果在于,那些从 Non-TIR 配置获得了。这个工作在 TIR-SHG 配置下面在接口在分子的取向角度的决心表明极化分析的可行性和精确性。 展开更多
关键词 二次谐波产生 分子结构 全内反射 水界面 取向角 十六烷 非线性光谱 偏振分析
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Irradiation and flame retardant effect of poly[bis(phenoxyphosphazene)] and magnesium hydroxide in LDPE composites 预览
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作者 李建喜 张聪 +2 位作者 陈涛 李林繁 李景烨 《核技术:英文版》 SCIE CAS CSCD 2015年第3期57-63,共7页
Poly[bis(phenoxyphosphazene)](PBPP) and magnesium hydroxide(MH) are used as a flame retardant blend with low-density polyethylene(LDPE) for the nuclear cable. This study aims to investigate the effects of PBPP in MH-L... Poly[bis(phenoxyphosphazene)](PBPP) and magnesium hydroxide(MH) are used as a flame retardant blend with low-density polyethylene(LDPE) for the nuclear cable. This study aims to investigate the effects of PBPP in MH-LDPE blend composites on flame retardance and electron beam irradiation. The structure, morphology,and properties of the blend composites irradiated by an electron beam to different absorbed doses were characterized. The results indicated that PBPP provides lubrication during processing. As the PBPP content in the blend increases the melt flow rate at 20 phr MH, meaning the material is easier to process. The higher the PBPP content, the higher the limiting-oxygen index. The elongation at the break of the PBPP containing composites(at 50 phr MH) was evidently higher than the non-PBPP ones at different absorbed doses by electron beam irradiation. The thermogravimetric analysis results indicated that the improved mechanical property, resulting from electron-beam irradiation, could be attributed to the consumption of PBPP. 展开更多
关键词 共混复合材料 电子束辐照 氢氧化镁 LDPE 苯氧基 阻燃效果 磷腈 电子束照射
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Chemically exfoliated WS2 nanosheets efficiently inhibit amyloid β-peptide aggregation and can be used for photothermal treatment of Alzheimer's disease
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作者 Meng Li Andong Zhao Kai Dong Wen Li Jinsong Ren Xiaogang Qu 《纳米研究:英文版》 SCIE CAS CSCD 2015年第10期3216-3227,共12页
关键词 功能纳米材料 阿尔茨海默病 淀粉样蛋白 WS2 聚集体 治疗 近红外辐射 光热
Reweighted ensemble dynamics simulations: Theory, improvement, and application
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作者 龚麟宸 周昕 欧阳钟灿 《中国物理B:英文版》 SCIE EI CAS CSCD 2015年第6期126-137,共12页
Based on multiple parallel short molecular dynamics simulation trajectories,we designed the reweighted ensemble dynamics(RED) method to more efficiently sample complex(biopolymer) systems,and to explore their hierarch... Based on multiple parallel short molecular dynamics simulation trajectories,we designed the reweighted ensemble dynamics(RED) method to more efficiently sample complex(biopolymer) systems,and to explore their hierarchical metastable states.Here we further present an improvement to depress statistical errors of the RED and we discuss a few keys in practical application of the RED,provide schemes on selection of basis functions,and determination of the free parameter in the RED.We illustrate the application of the improvements in two toy models and in the solvated alanine dipeptide.The results show the RED enables us to capture the topology of multiple-state transition networks,to detect the diffusion-like dynamical behavior in an entropy-dominated system,and to identify solvent effects in the solvated peptides.The illustrations serve as general applications of the RED in more complex biopolymer systems. 展开更多
关键词 分子动力学模拟 应用程序 加权 聚合物系统 生物聚合物 动力学行为 溶剂化 亚稳状态
Synchrotron radiation X-ray fluorescence analysis of Fe, Zn and Cu in mice brain associated with Parkinson's disease 预览 被引量:1
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作者 田甜 张继超 +6 位作者 雷豪志 诸颖 施继晔 胡钧 黄庆 樊春海 孙艳红 《核技术:英文版》 SCIE CAS CSCD 2015年第3期100-105,共6页
The contents and distributions of metal elements in the brain are closely related to neurodegenerative diseases.In this study, we examined Fe, Cu and Zn contents in the brain section associated with Parkinson‘s disea... The contents and distributions of metal elements in the brain are closely related to neurodegenerative diseases.In this study, we examined Fe, Cu and Zn contents in the brain section associated with Parkinson‘s disease(PD)using synchrotron radiation X-ray fluorescence(SRXRF). PD mouse model induced by 1-methyl-4-phenyl-1,2,3,6-terahydropyridine(MPTP) was used for the elemental analysis(e.g., Fe, Cu and Zn) in the substantia nigra pars compacta(SNpc) region of mice brain tissue samples. We found that mice in the MPTP group had higher contents of Fe, Cu and Zn in the SNpc than the control group. After treating the PD mice with rapamycin, the contents of Fe, Cu and Zn were reduced, the dopamine neurons and motor function were rescued correspondingly. The results prompted that the SRXRF provided an ideal method for tracing and analyzing the metal elements in the brain section to assess the pathological changes of PD model and the therapeutic effect of drugs. 展开更多
关键词 同步辐射X射线荧光分析 帕金森病 锌含量 鼠脑 低铁 神经退行性疾病 小鼠模型 Fe含量
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Parallelizing AT with open multi-processing and MPI 预览
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作者 罗承明 田顺强 +3 位作者 王坤 张满洲 张庆磊 姜伯承 《核技术:英文版》 SCIE CAS CSCD 2015年第3期17-20,共4页
Simulating charged particle motion through the elements is necessary to understand modern particle accelerators. The particle numbers and the circling turns in a synchrotron are huge, and a simulation can be timeconsu... Simulating charged particle motion through the elements is necessary to understand modern particle accelerators. The particle numbers and the circling turns in a synchrotron are huge, and a simulation can be timeconsuming. Open multi-processing(Open MP) is a convenient method to speed up the computing of multi-cores for computers based on share memory model. Using message passing interface(MPI) which is based on nonuniform memory access architecture, a coarse grain parallel algorithm is set up for the Accelerator Toolbox(AT)for dynamic tracking processes. The computing speedup of the tracking process is 3.77 times with a quad-core CPU computer and the speed almost grows linearly with the number of CPU. 展开更多
关键词 多处理技术 并行算法 MPI 开放式 粒子加速器 带电粒子运动 消息传递接口 动态跟踪
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Magnetic flux leakage analysis and compensation of high-frequency planar insulated core transformer 预览
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作者 田佳甲 刘永好 +2 位作者 李瑞 李德明 卢宋林 《核技术:英文版》 SCIE CAS CSCD 2015年第3期21-25,共5页
A novel high-frequency and high power density planar insulated core transformer(PICT) applied to high voltage DC generator is introduced. PICT’s operating principle and fundamental configuration are described,and pre... A novel high-frequency and high power density planar insulated core transformer(PICT) applied to high voltage DC generator is introduced. PICT’s operating principle and fundamental configuration are described,and preliminary experimental results in self-designed PICT apparatus are presented. Emphatically, magnetic leakage flux(MFL) giving rise to the output voltage drop is analyzed in detail both theoretically and by finite element method(FEM). Showing good consistency with experimental result, FEM simulation is considered to be practicable in physical design of PICT. To cancel out leakage inductance and improve the voltage uniformity,compensation capacitor is adopted and experimental verification is also presented. All shows satisfactory results. 展开更多
关键词 铁心变压器 补偿电容 漏磁 绝缘 平面 高频 直流高压发生器 物理设计
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Digital LLRF controller for SSRF booster RF system upgrade 预览
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作者 张志刚 赵玉彬 +11 位作者 徐凯 郑湘 李正 赵申杰 常强 侯洪涛 马震宇 罗琛 毛冬青 是晶 王岩 刘建飞 《核技术:英文版》 SCIE CAS CSCD 2015年第3期26-32,共7页
The low level radio frequency(LLRF) system for booster accelerator at Shanghai Synchrotron Radiation Facility(SSRF) was upgraded by a digital controller based on field programmable gate array(FPGA) technology.Paramete... The low level radio frequency(LLRF) system for booster accelerator at Shanghai Synchrotron Radiation Facility(SSRF) was upgraded by a digital controller based on field programmable gate array(FPGA) technology.Parameters of voltage, frequency and field flatness in the two 5-cell cavities are controlled to meet the requirements of booster. In this article, the ramping curve of cavity voltage, amplitude and phase control loop with vector sum of the two 5-cell cavities, tuning loop and field flatness loop are analyzed and discussed in detail.A different method in tuning loop is adopted due to the limitations of ADC channels. The function realizes energy ramping of electron beam from 150 Me V to 3.5 Ge V with a repetition rate of 2 Hz. With the new LLRF controller, the phase stability at ramping mode in 10 hours long operation is improved from ±1.5°(RMS) with open loop to ±0.15°(RMS) with close loop, while the detuning phase and field flatness are maintained to within ±2°and ±1%, respectively. 展开更多
关键词 数字控制器 射频系统 SSRF 低电平 增强器 现场可编程门阵列 上海同步辐射装置 控制回路
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A flexible and robust soft-error testing system for microelectronic devices and integrated circuits 预览
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作者 王晓辉 童腾 +7 位作者 苏弘 刘杰 张战刚 古松 刘天奇 孔洁 赵兴文 杨振雷 《核技术:英文版》 SCIE CAS CSCD 2015年第3期64-70,共7页
Single event effects(SEEs) induced by radiations become a significant challenge to the reliability for modern electronic systems. To evaluate SEEs susceptibility for microelectronic devices and integrated circuits(ICs... Single event effects(SEEs) induced by radiations become a significant challenge to the reliability for modern electronic systems. To evaluate SEEs susceptibility for microelectronic devices and integrated circuits(ICs), an SEE testing system with flexibility and robustness was developed at Heavy Ion Research Facility in Lanzhou(HIRFL). The system is compatible with various types of microelectronic devices and ICs, and supports plenty of complex and high-speed test schemes and plans for the irradiated devices under test(DUTs). Thanks to the combination of meticulous circuit design and the hardened logic design, the system has additional performances to avoid an overheated situation and irradiations by stray radiations. The system has been tested and verified by experiments for irradiating devices at HIRFL. 展开更多
关键词 微电子器件 测试系统 集成电路 软误差 重离子研究装置 HIRFL 现代电子系统 辐照装置
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Neutron time-of-flight spectrometer based on HIRFL for studies of spallation reactions related to ADS project 预览
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作者 张苏雅拉吐 陈志强 +8 位作者 韩瑞 Roy Wad 刘星泉 林炜平 刘建立 石福栋 任培培 田国玉 罗飞 《核技术:英文版》 SCIE CAS CSCD 2015年第3期82-85,共4页
A Neutron Time-of-Flight(NTOF) spectrometer, based at the Heavy Ion Research Facility in Lanzhou(HIRFL) was developed for studies of neutron production of proton induced spallation reactions related to the ADS project... A Neutron Time-of-Flight(NTOF) spectrometer, based at the Heavy Ion Research Facility in Lanzhou(HIRFL) was developed for studies of neutron production of proton induced spallation reactions related to the ADS project. After the presentation of comparisons between calculated spallation neutron production doubledifferential cross sections and the available experimental data, a detailed description of the NTOF spectrometer is given. Test beam results show that the spectrometer works well and data analysis procedures are established.The comparisons of the test beam neutron spectra with those of GEANT4 simulations are presented. 展开更多
关键词 飞行时间谱仪 中子能谱 散裂反应 重离子加速器 广告 重离子研究装置 GEANT4 模拟试验
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The Gibbs-free-energy landscape for the solute association in nanoconfined aqueous solutions 预览
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作者 赵亮 王春雷 +1 位作者 方海平 涂育松 《核技术:英文版》 SCIE CAS CSCD 2015年第3期90-94,共5页
The theoretical model and the numerical analyses on the Gibbs-free-energy of the association states of amphiphilic molecules in nanoconfined aqueous solutions are presented in detail. We exhibit the continuous change ... The theoretical model and the numerical analyses on the Gibbs-free-energy of the association states of amphiphilic molecules in nanoconfined aqueous solutions are presented in detail. We exhibit the continuous change of the Gibbs-free-energy trend, which plays a critical role in the association states of the system transforming from the dispersion state, through the 'reversible state', and finally to the aggregation state in amphiphilic molecule solutions. Furthermore, for the 'reversible state', we present the difference in the free-energy barrier heights of the dispersion state and aggregation state, resulting from the competition between the entropy,which makes the solute molecules evenly disperse in the solution and the energy contribution driving the amphiphilic molecules to aggregate into a larger cluster. These findings provide a comprehensive understanding of confinement effects on the solute association processes in aqueous solutions and may further improve the techniques of material fabrication. 展开更多
关键词 吉布斯自由能 溶质分子 水溶液 分散状态 协会 景观 两亲分子 数值分析
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Architecture of PtFe/C catalyst with high activity and durability for oxygen reduction reaction
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作者 Jiayuan Li Guoxiong Wang +5 位作者 Jing Wang Shu Miao Mingming Wei Fan Yang Liang Yu Xinhe Bao 《纳米研究:英文版》 SCIE CAS CSCD 2014年第10期1519-1527,共9页
PtFe/C 催化剂被列在后面由的受精和高温度的减小综合了酸沥滤。X 光检查衍射, X 光检查光电子光谱学和在边光谱学描述附近原子的 X 光检查揭示那磅 < 潜水艇 class= “ a-plus-plus ” > 3 </sub > Fe 合金形成发生在高... PtFe/C 催化剂被列在后面由的受精和高温度的减小综合了酸沥滤。X 光检查衍射, X 光检查光电子光谱学和在边光谱学描述附近原子的 X 光检查揭示那磅 < 潜水艇 class= “ a-plus-plus ” > 3 </sub > Fe 合金形成发生在高温度的减小和那不稳定的 Fe 种期间被溶解进酸溶液。在到表面并且强壮的 O-Fe 结合的从核心区域的 Fe 集中的差别可以驾驶 Fe 的外面的散开到高度弄皱的磅骨骼,并且高度结果驱散表面 FeO <潜水艇class=“ a-plus-plus ”> x </sub>在酸的媒介是稳定的,导致磅的构造<潜水艇class=“ a-plus-plus ”> 3 </sub > Fe@Pt-FeO <潜水艇class=“ a-plus-plus ”> x </sub>建筑学。是准备了 PtFe/C 催化剂与 Pt/C 催化剂相比为氧减小反应表明一项更高的活动和可比较的耐久性,它可能在 PtFe/C 催化剂由于表面和表面下的 Fe 种类的合作效果。 展开更多
关键词 铂/碳催化剂 聚四氟乙烯 氧还原反应 碳/碳 高活性 体系结构 耐久性 X射线光电子能谱
Creation of ^174Yb Bose-Einstein Condensates in a Crossed FORT
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作者 张梦娇 张曦 +3 位作者 刘慧 熊转贤 吕宝龙 贺凌翔 《中国物理快报:英文版》 SCIE CAS CSCD 2014年第8期123-126,共4页
alkaline-earth-like 原子的量退化气体是为量模拟,量计算和量阶段转变的研究使用的唯一的系统。我们报导镱原子的 BoseEinstein 冷凝物的所有光的形成。<SUP>174</SUP 的大约 10 个 <SUP>6</SUP> 原子 > Yb ... alkaline-earth-like 原子的量退化气体是为量模拟,量计算和量阶段转变的研究使用的唯一的系统。我们报导镱原子的 BoseEinstein 冷凝物的所有光的形成。<SUP>174</SUP 的大约 10 个 <SUP>6</SUP> 原子 > Yb 被转移到 far-off-resonance 光陷井(堡垒) 然后由成为蒸气的冷却冷却了。阶段转变发生在 520 nK 的批评温度。包含约 2 &#x00d7 的纯冷凝物;10 个 <SUP>4</SUP> 原子在穿过的堡垒被获得了,与 ~ 的原子山峰密度 8 &#x00d7;10 <SUP>14</SUP> 厘米 <SUP>3</SUP> 。冷凝物一生超过 1 s。 展开更多
关键词 爱因斯坦凝聚 玻色 创作 量子模拟 镱原子 量子简并 量子计算 原子转移
Passive Phase Locking of Three Nanosecond Fiber Amplifiers Using a Dammann Grating Spatial Filter
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作者 杨依枫 郑也 +5 位作者 何兵 周军 刘厚康 胡曼 魏运荣 楼祺洪 《中国物理快报:英文版》 SCIE CAS CSCD 2014年第8期84-86,共3页
三毫微秒的被动协调横梁联合由一个所有光的反馈环的做 Yb 的纤维放大器被 Dammann 栅栏 intracavity 认识到空间过滤器。由使用这 diffractive-optics-based 空间过滤技术,三根瓦孔激光横梁与 1.02 kW 的山峰力量是锁阶段的。联合脉... 三毫微秒的被动协调横梁联合由一个所有光的反馈环的做 Yb 的纤维放大器被 Dammann 栅栏 intracavity 认识到空间过滤器。由使用这 diffractive-optics-based 空间过滤技术,三根瓦孔激光横梁与 1.02 kW 的山峰力量是锁阶段的。联合脉搏的宽度是 9.6 ns,并且重复频率是 2.208 MHz。远地的干扰模式的可见性直到 82.9% 。结果证明这条途径能可伸缩到更大的数组和更高的力量。 展开更多
关键词 空间滤波器 光纤放大器 相位锁定 达曼光栅 纳秒 相干光束 滤波技术 衍射光学
A Module Test of CCDA: an Array to Select the Centrality of Collisions in Heavy Ion Collisions
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作者 付芬 林炜平 +11 位作者 刘星泉 黄美容 WADARoy 张苏雅拉吐 石福栋 韩瑞 靳增雪 刘建立 任培培 赵明辉 陈志强 王建松 《中国物理快报:英文版》 SCIE CAS CSCD 2014年第8期42-45,共4页
为碰撞中心性察觉者数组(CCDA ) 的一个模块的测试结果,为中心性的事件分类的一个简单察觉者数组,被介绍。CsI (Tl ) 模块有在两结束的 PMT 读出信号。横梁测试结果显示它提供好轻控告的粒子(人员登陆艇) 鉴定和一个合理精力决定。人... 为碰撞中心性察觉者数组(CCDA ) 的一个模块的测试结果,为中心性的事件分类的一个简单察觉者数组,被介绍。CsI (Tl ) 模块有在两结束的 PMT 读出信号。横梁测试结果显示它提供好轻控告的粒子(人员登陆艇) 鉴定和一个合理精力决定。人员登陆艇的精力系列与 GEANT 模拟相比。 展开更多
关键词 模块测试 重离子碰撞 探测器阵列 光电倍增管 GEANT 读出信号 带电粒子 LCP
The Weng’an biota and the Ediacaran radiation of multicellular eukaryotes
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作者 Shuhai Xiao A. D. Muscente +5 位作者 Lei Chen Chuanming Zhou James D. Schiffbauer Andrew D. Wood Nicholas F. Polys Xunlai Yuan 《国家科学评论:英文版》 2014年第4期498-520,共23页
The rise of multicellularity represents a major evolutionary transition and it occurred independently in multiple eukaryote clades.Although simple multicellular organisms may have evolved in the Mesoproterozoic Era or... The rise of multicellularity represents a major evolutionary transition and it occurred independently in multiple eukaryote clades.Although simple multicellular organisms may have evolved in the Mesoproterozoic Era or even earlier,complex multicellular eukaryotes began to diversify only in the Ediacaran Period,just before the Cambrian explosion.hus,the Ediacaran fossil record can provide key paleontological evidence about the early radiation of multicellular eukaryotes that ultimately culminated in the Cambrian explosion.he Ediacaran Weng’an biota in South China hosts exceptionally preserved eukaryote fossils,including various acanthomorphic acritarchs,pseudoparenchymatous thalli,tubular microfossils,and spheroidal fossils such as Megasphaera,Helicoforamina,Spiralicellula,and Caveasphaera.Many of these fossils have been interpreted as multicellular eukaryotes,although alternative interpretations have also been proposed.In this review,we critically examine these various interpretations,focusing particularly on Megasphaera,which has been variously interpreted as a sulfur-oxidizing bacterium,a unicellular protist,a mesomycetozoean-like holozoan,a volvocine green alga,a stem-group animal,or a crown-group animal.We conclude that Megasphaera is a multicellular eukaryote with evidence for cell-to-cell adhesion,a lexible membrane unconstrained by a rigid cell wall,spatial cellular diferentiation,germ–soma separation,and programmed cell death.hese features are inconsistent with the bacterium,unicellular protist,and mesomycetozoean-like holozoan interpretations.hus,the surviving hypotheses,particularly the stem-group animal and algal interpretations,should be further tested with additional evidence.he Weng’an biota also hosts cellularly diferentiated pseudoparenchymatous thalli with specialized reproductive structures indicative of an ainity with lorideophyte red algae.he other Weng’an fossils reviewed here may also be multicellular eukaryotes,although direct cellular evidence is lacking in some and phylogenetic ai 展开更多
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