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TMAHS:a truthful multi-unit double auction framework for heterogeneous spectrum in secondary market
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作者 Li Xin Xie Gang Gao Jinchun 《中国邮电高校学报:英文版》 EI CSCD 2019年第1期82-94,共13页
Auction was widely used to tackle spectrum allocation and sharing in the secondary market under the condition of spectrum scarcity.In real communication system,such as broadband communication,the utilization of spectr... Auction was widely used to tackle spectrum allocation and sharing in the secondary market under the condition of spectrum scarcity.In real communication system,such as broadband communication,the utilization of spectrum resource is various because of different requirements and complex application scenarios.So,these schemes cannot be directly applied to the above wireless communication system.To solve this problem,a new model where sellers/buyers can sell/buy multi-unit for heterogeneous spectrum was proposed and a truthful multi-unit double auction framework was designed for heterogeneous spectrum trading.A valuation function is first applied to represent the buyer's true valuation of the sub-band and reflect the buyer's satisfaction degree and a novel concept termed'virtual player'was introduced.Then the buyer group was constructed based on the conflict graph to reuse the same spectruin among interference-free buyers in both spatial and temporal domains.The winner determination strategy and algorithm of clearing price were designed elaborately.According to the theoretical analysis,the scheme can satisfy three critical economic properties:truthfulness,individual rationality,and budget balance.Finally,simulation results show that the proposed scheme can achieve better user satisfaction,auction efficiency and spectrum reuse rate for the real communication system.The proposed auction framework is practical and effective. 展开更多
关键词 SPECTRUM AUCTION double AUCTION SPECTRUM REUSE HETEROGENEOUS SPECTRUM MULTI-UNIT VALUATION function
Observational constraints on running vacuum model
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作者 张进军 Chung-Chi Lee 耿朝强 《中国物理C:英文版》 SCIE CAS CSCD 2019年第2期132-137,共6页
We investigate the power spectra of the CMB temperature and matter density in the running vacuum model(RVM) with the time-dependent cosmological constant of A=3 vH2+ Λ0, where H is the Hubble parameter. In this model... We investigate the power spectra of the CMB temperature and matter density in the running vacuum model(RVM) with the time-dependent cosmological constant of A=3 vH2+ Λ0, where H is the Hubble parameter. In this model, dark energy decreases in time and decays to both matter and radiation. By using the Markov chain Monte Carlo method, we constrain the model parameter v as well as the cosmological observables. Explicitly, we obtain v ≤1.54× 10-4(68% confidence level) in the RVM with the best-fit χRVM2 =13968.8, which is slightly smaller thanχΛCDM2= 13969.8 in the ΛCDM model of v = 0. 展开更多
关键词 MATTER power SPECTRUM running VACUUM MODEL CMB temperature SPECTRUM COSMOLOGICAL constant
A Dynamic Distributed Spectrum Allocation Mechanism Based on Game Model in Fog Radio Access Networks 预览
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作者 Yao Yu Shumei Liu +1 位作者 Zhongshi Tian Siyu Wang 《中国通信:英文版》 SCIE CSCD 2019年第3期12-21,共10页
With the explosive growth of highspeed wireless data demand and the number of mobile devices,fog radio access networks(F-RAN)with multi-layer network structure becomes a hot topic in recent research.Meanwhile,due to t... With the explosive growth of highspeed wireless data demand and the number of mobile devices,fog radio access networks(F-RAN)with multi-layer network structure becomes a hot topic in recent research.Meanwhile,due to the rapid growth of mobile communication traffic,high cost and the scarcity of wireless resources,it is especially important to develop an efficient radio resource management mechanism.In this paper,we focus on the shortcomings of resource waste,and we consider the actual situation of base station dynamic coverage and user requirements.We propose a spectrum pricing and allocation scheme based on Stackelberg game model under F-RAN framework,realizing the allocation of resource on demand.This scheme studies the double game between the users and the operators,as well as between the traditional operators and the virtual operators,maximizing the profits of the operators.At the same time,spectrum reuse technology is adopted to improve the utilization of network resource.By analyzing the simulation results,it is verified that our proposed scheme can not only avoid resource waste,but also effectively improve the operator’s revenue efficiency and overall network resource utilization. 展开更多
关键词 FOG radio access networks(F-RAN) game theory SPECTRUM REUSE technology base station DYNAMIC COVERAGE SPECTRUM PRICING and allocation
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The Plasmonic Resonances of a Bowtie Antenna 预览
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作者 Eric Bonnetier Charles Dapogny +1 位作者 Faouzi Triki Hai Zhang 《分析理论与应用:英文刊》 CSCD 2019年第1期85-116,共32页
Metallic bowtie-shaped nanostructures are very interesting objects in optics,due to their capability of localizing and enhancing electromagnetic fields in the vicinity of their central neck.In this article,we investig... Metallic bowtie-shaped nanostructures are very interesting objects in optics,due to their capability of localizing and enhancing electromagnetic fields in the vicinity of their central neck.In this article,we investigate the electrostatic plasmonic resonances of two-dimensional bowtie-shaped domains by looking at the spectrum of their Poincare variational operator.In particular,we show that the latter only consists of essential spectrum and fills the whole interval[0,1].This behavior is very different from what occurs in the counterpart situation of a bowtie domain with only close-totouching wings,a case where the essential spectrum of the Poincare variational operator is reduced to an interval oess strictly containing in[0,1].We provide an explanation for this difference by showing that the spectrum of the Poincare variational operator of bowtie-shaped domains with close-to-touching wings has eigenvalues which densify and eventually fill the remaining parts of[0,1]\σess as the distance between the two wings tends to zero. 展开更多
关键词 Neumann-Poincaréoperator CORNER SINGULARITY SPECTRUM RESONANCE
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Correlation of Gut Microbiome Between ASD Children and Mothers and Potential Biomarkers for Risk Assessment
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作者 Ning Li Junjie Yang +14 位作者 Jiaming Zhang Cheng Liang Ying Wang Bin Chen Changying Zhao Jingwen Wang Guangye Zhang Dongmei Zhao Yi Liu Lehai Zhang Jun Yang Guimei Li Zhongtao Gai Lei Zhang Guoping Zhao 《基因组蛋白质组与生物信息学报:英文版》 CAS CSCD 2019年第1期26-38,共13页
Variation of maternal gut microbiota may increase the risk of autism spectrum disorders(ASDs)in offspring.Animal studies have indicated that maternal gut microbiota is related to neurodevelopmental abnormalities in mo... Variation of maternal gut microbiota may increase the risk of autism spectrum disorders(ASDs)in offspring.Animal studies have indicated that maternal gut microbiota is related to neurodevelopmental abnormalities in mouse offspring,while it is unclear whether there is a correlation between gut microbiota of ASD children and their mothers.We examined the relationships between gut microbiome profiles of ASD children and those of their mothers,and evaluated the clinical discriminatory power of discovered bacterial biomarkers.Gut microbiome was profiled and evaluated by 16S ribosomal RNA gene sequencing in stool samples of 59 mother-child pairs of ASD children and 30 matched mother-child pairs of healthy children.Significant differences were observed in the gut microbiome composition between ASD and healthy children in our Chinese cohort.Several unique bacterial biomarkers,such as Alcaligenaceae and Acinetobacter,were identified.Mothers of ASD children had more Proteobacteria,Alphaproteobacteria,Moraxellaceae,and Acinetobacter than mothers of healthy children.There was a clear correlation between gut microbiome profiles of children and their mothers;however,children with ASD still had unique bacterial biomarkers,such as Alcaligenaceae,Enterobacteriaceae,and Clostridium.Candidate biomarkers discovered in this study had remarkable discriminatory power.The identified patterns of mother-child gut microbiome profiles may be important for assessing risks during the early stage and planning of person?alized treatment and prevention of ASD via microbiota modulation. 展开更多
关键词 AUTISM spectrum DISORDERS GUT MICROBIOME Biomarker Mother-child pair Microbiota-gut-immunebrain axis
基于程序谱的方法级别错误定位技术 预览
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作者 徐迟 苏小红 王甜甜 《智能计算机与应用》 2019年第2期251-254,共4页
自动化的软件错误定位是软件调试过程中的一个热点问题,旨在更高效地发现软件中的错误。然而,目前的软件错误定位技术大多是针对语句级别的定位,而语句级别的定位精度不是很高,一旦定位失败,程序员就会很难发现软件中的错误。为了进一... 自动化的软件错误定位是软件调试过程中的一个热点问题,旨在更高效地发现软件中的错误。然而,目前的软件错误定位技术大多是针对语句级别的定位,而语句级别的定位精度不是很高,一旦定位失败,程序员就会很难发现软件中的错误。为了进一步地提高软件错误定位的效率,本文提出了一种基于程序谱的方法级别错误定位技术。方法级别的错误定位相比于语句级别的错误定位,其优势在于,方法级别定位的效率会更高,可以首先确定bug语句存在于待测程序的某个方法中,然后通过人工调试的方法进一步确定bug语句的具体位置。本文首先提出了一种基于程序谱的方法级别错误定位方法,随后,对本文的方法进行了实验分析。实验表明,本文方法能够有效提高方法级别错误定位的精度。 展开更多
关键词 错误定位 程序谱 方法级别
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Multi-Strategy Dynamic Spectrum Access in Cognitive Radio Networks:Modeling,Analysis and Optimization 预览
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作者 Yi Yang Qinyu Zhang +3 位作者 Ye Wang Takahiro Emoto Masatake Akutagawa Shinsuke Konaka 《中国通信:英文版》 SCIE CSCD 2019年第3期103-121,共19页
Dynamic spectrum access(DSA)based on cognitive radios(CR)technique is an effective approach to address the“spectrum scarcity”issue.However,traditional CR-enabled DSA system employs only single DSA strategy,which mig... Dynamic spectrum access(DSA)based on cognitive radios(CR)technique is an effective approach to address the“spectrum scarcity”issue.However,traditional CR-enabled DSA system employs only single DSA strategy,which might not be suited to the dynamic network environment.In this paper,we propose a multi-strategy DSA(MS-DSA)system,where the primary and the secondary system share spectrum resources with multiple DSA strategies simultaneously.To analyze the performance of the proposed MS-DSA system,we model it as a continuous-time Markov chain(CTMC)and derive the expressions to compute the corresponding performance metrics.Based on this,we define a utility function involving the concerns of effective throughput,interference quantity on primary users,and spectrum leasing cost.Two optimization schemes,named as spectrum allocation and false alarm probability selection,are proposed to maximize the utility function.Finally,numerical simulations are provided to validate our analysis and demonstrate that the performance can be significantly improved caused by virtues of the proposed MS-DSA system. 展开更多
关键词 COGNITIVE RADIO networks dynamic SPECTRUM access multi-strategy performance analysis optimization
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Spectrum Density Factor of Photons and Its Application in the Casimir Force
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作者 高先龙 孟烨铭 +1 位作者 吴飓昊 汪克林 《理论物理通讯:英文版》 SCIE CAS CSCD 2019年第4期397-402,共6页
The observables of continuous eigenvalues are de?ned in an in?nite-dimensional ket space. The complete set of such eigenstates demands a spectrum density factor, for example, for the photons in the free space and elec... The observables of continuous eigenvalues are de?ned in an in?nite-dimensional ket space. The complete set of such eigenstates demands a spectrum density factor, for example, for the photons in the free space and electrons in the vacuum. From the derivation of the Casimir force without an arti?cial regulator we determine the explicit expression of the spectrum density factor for the photon ?eld to be an exponential function. The undetermined constant in the function is ?xed by the experimental data for the Lamb shift. With that, we predict that there exists a correction to the Casimir force. 展开更多
关键词 SPECTRUM DENSITY FACTOR CASIMIR force Lamb shift
基于Unity 3D的光谱实验教学系统研究 预览
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作者 刘钊 徐富新 《计算机技术与发展》 2019年第6期119-124,共6页
在教学中运用虚拟现实技术是当今的一个热门话题。教育正在进入网络的时代,这既是一种趋势,也是教育的未来。对实验室进行虚拟化技术的研发,通过先进的计算机技术以更好地满足对教学的需求。文中将建模软件3DMax和虚拟仿真软件Unity3D... 在教学中运用虚拟现实技术是当今的一个热门话题。教育正在进入网络的时代,这既是一种趋势,也是教育的未来。对实验室进行虚拟化技术的研发,通过先进的计算机技术以更好地满足对教学的需求。文中将建模软件3DMax和虚拟仿真软件Unity3D应用于物理实验教学,结合虚拟现实的特点,设计了光栅光谱虚拟仿真实验系统,给出了系统的整体结构和部分实现的关键技术,模拟一个真实的实验环境。该系统采用基于Bmob后端云服务器,以节约成本,提高开发效率。实验内容结合了3D和互动仿真的两大优点,界面直观、操作简单,通过对MVC登录设计、实验操作交互技术、动态光谱图技术的研究,结合实验实际需求,使得光学实验变得简单。学生能够更快掌握原理,熟悉实验操作来缩短真实实验周期,提高实验教学的效率,达到良好的实验教学效果。 展开更多
关键词 3DMax UNITY3D 虚拟仿真 物理实验 光谱
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蓝光与眼睛 预览
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作者 成知函 John Hayes(指导) 《中国眼镜科技杂志》 2019年第3期110-112,共3页
蓝光是光谱中波长为400nm~500nm的可见光。蓝光可分为短波蓝光即有害蓝光,和长波蓝光即有益蓝光。短波蓝光危害人们的视力,并导致特定疾病,而长波蓝光则有助于人们维护正常的生理功能,调节生物节律,并治疗特定疾病。目前防控蓝光的方法... 蓝光是光谱中波长为400nm~500nm的可见光。蓝光可分为短波蓝光即有害蓝光,和长波蓝光即有益蓝光。短波蓝光危害人们的视力,并导致特定疾病,而长波蓝光则有助于人们维护正常的生理功能,调节生物节律,并治疗特定疾病。目前防控蓝光的方法正在逐渐发明与完善中。 展开更多
关键词 短波蓝光 长波蓝光 光谱 视力
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Carbon deposition in porous nickel/yttria-stabilized zirconia anode under methane atmosphere 预览
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作者 Zhi-yuan Chen Li-jun Wang +3 位作者 Xiao-jia Du Zai-hong Sun Fu-shen Li Kuo-Chih Chou 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2019年第3期350-359,共10页
A commercial solid oxide fuel cell with a Ni/YSZ anode was characterized under a pure methane atmosphere. The amount of deposited carbon increased with an increase in temperature but decreased when the temperature exc... A commercial solid oxide fuel cell with a Ni/YSZ anode was characterized under a pure methane atmosphere. The amount of deposited carbon increased with an increase in temperature but decreased when the temperature exceeded 700℃. The reactivity of carbon decreased with increasing deposition temperature. Filamentous carbon was deposited from 400 to 600℃, whereas flake carbon was deposited at 700 and 800℃. With increasing temperature, the intensity ratio of the D band over the sum of the G and D bands was constant at the beginning and then decreased with the transformation of the carbon morphology. The crystallite size increased from 2.9 to 13 nm with increasing temperature. The results also indicated that the structure of the deposited carbon was better ordered with increasing deposition temperature. In comparison with pure Ni powders, the interaction between the YSZ substrate and Ni particles could not only modify the carbon deposition kinetics but also reduce the temperature effect on the structure and reactivity variation of carbon. 展开更多
关键词 solid oxide FUEL cell COKING RAMAN spectrum HYDROCARBON FUEL ANODE
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Influence of rooftop telecommunication tower on set back-step back building resting on different ground slopes 预览
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作者 Amit Thakur Deepankar Kumar Ashish Surender Kumar Verma 《地震工程与工程振动:英文版》 SCIE EI CSCD 2019年第2期351-362,共12页
In the hilly region due to scarcity of the plain area, buildings like set back-step back are more often used and also as a big surge in the telecommunication industries, rooftop tower adaptation is very common story n... In the hilly region due to scarcity of the plain area, buildings like set back-step back are more often used and also as a big surge in the telecommunication industries, rooftop tower adaptation is very common story nowadays. In the present study an analogy has been drawn to find out the influence of the rooftop telecommunication tower on the setback-step back building resting on ground at 20° and 30° slopes. A dynamic analysis has been performed and compared on the 4 legged angled section telecommunication tower which is located on the roof top of set back-step back building by varying positions of tower with the existing host structure built up on ground slope of 20° and 30° in both directions(X and Y). 展开更多
关键词 rooftop telecommunication tower SET back-step BACK BUILDING response spectrum analysis steel RC frame earthquake SAP2000
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宽光谱大面积多阶梯光场光谱感光仪 预览
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作者 李超洋 黄元申 +1 位作者 盛斌 庄松林 《光电工程》 CAS CSCD 北大核心 2019年第2期65-72,共8页
研制了一种新型光谱感光仪,其特点是宽光谱(340nm~900nm),大曝光面(202mm×90.5mm),且面上具有多阶梯光强;制备具有18级光密度值的高精密阶梯光楔板,每个台阶的光密度值误差不大于0.01;根据光源的光谱特性镀制滤光膜,消除光栅二级... 研制了一种新型光谱感光仪,其特点是宽光谱(340nm~900nm),大曝光面(202mm×90.5mm),且面上具有多阶梯光强;制备具有18级光密度值的高精密阶梯光楔板,每个台阶的光密度值误差不大于0.01;根据光源的光谱特性镀制滤光膜,消除光栅二级光谱。自动控制采集系统采用LabVIEW与PLC一体机开发,水平方向采用光栅位移传感器构成闭环控制,波长定位偏差小于0.05nm;竖直方向采用线性补偿方法,高度位置偏差小于0.05mm。仪器能够自动测量光楔板上不同波长不同光强区域的单位面积光功率,用快门控制曝光时间,在宽光谱范围内对感光材料进行一次曝光。在显影定影后,用光密度计测量其光密度值,根据国标(GB10557-89)绘制出感光材料某一确定光密度值的光谱灵敏度曲线。 展开更多
关键词 光谱灵敏度 光密度 光谱 光强 阶梯光楔板
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NIR光谱法快速预测小麦籽粒干物质含量 预览
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作者 何鸿举 王玉玲 +5 位作者 乔红 欧行奇 刘红 王慧 蒋圣启 王魏 《海南师范大学学报:自然科学版》 CAS 2019年第1期33-38,共6页
通过采集百农201、百农207、百农307、百旱207、AK-58、冠麦1号、周麦18等7个不同品种完整小麦籽粒的近红外光谱(900~1700 nm)信息,经高斯滤波平滑(Gaussian Filtering Smoothing,GFS)、标准化校正(Normalization Correction)和卷积平滑... 通过采集百农201、百农207、百农307、百旱207、AK-58、冠麦1号、周麦18等7个不同品种完整小麦籽粒的近红外光谱(900~1700 nm)信息,经高斯滤波平滑(Gaussian Filtering Smoothing,GFS)、标准化校正(Normalization Correction)和卷积平滑(Savitzky-Golay Convolution Smoothing,SGCS)三种预处理后,利用偏最小二乘回归(Partial Least Squares Regression,PLSR)算法寻找光谱信息与小麦籽粒干物质含量之间的定量关系。结果显示,经GFS预处理的近红外光谱(100个波长)构建的全波段PLSR模型(PLSR)预测相关系数(RP)为0.952,预测误差(RMSEP)为0.158%,RMSEC与RMSEP绝对值差(ΔE)为0.082,预测效果优于其他两种预处理光谱。从GFS光谱中经PLSR-β法筛选获得17个最优波长,构建的优化模型(O-PLSR)RP为0.928,RMSEP为0.191%,ΔE为0.049,其预测效果接近于PLSR模型。试验表明,利用900~1700 nm光谱可被潜在用于快速无损预测小麦籽粒干物质含量。 展开更多
关键词 光谱 检测 小麦 干物质
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西藏阿里太阳辐射观测 预览
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作者 晋亚铭 诺桑 +1 位作者 措加旺姆 拉瓜登顿 《黑龙江科学》 2019年第2期28-30,34共4页
利用太阳总辐射仪和太阳光谱仪在2016年12月至2018年9月期间对西藏最西部阿里地区进行了太阳总辐射和太阳光谱实地观测研究。观测研究了阿里太阳总辐射强度逐日、逐月以及二分二至的特征值及其变化特征;研究了云层等调制因子对太阳总辐... 利用太阳总辐射仪和太阳光谱仪在2016年12月至2018年9月期间对西藏最西部阿里地区进行了太阳总辐射和太阳光谱实地观测研究。观测研究了阿里太阳总辐射强度逐日、逐月以及二分二至的特征值及其变化特征;研究了云层等调制因子对太阳总辐射的影响特征;研究了阿里年晴天数特征,首次观测了阿里冬至太阳光谱特征。观测结果表明:西藏最西部阿里年太阳辐射总量达到7 094 MJ/W2,而西藏东部林芝同年只有5 916 MJ/W2;西部阿里夏季太阳总辐射量最高值达到2 166. 1 MJ/W2,而东部林芝春季达到最高值约1 727. 4 MJ/W2;2017全年观测发现阿里仅有17 d太阳总辐射瞬时值超过太阳常数,而林芝多达145 d;阿里太阳总辐射瞬时最大值达到1 494. 6 W/m2,林芝略高为(1 698. 6 W/m2);阿里太阳光谱观测显示西藏阿里太阳紫外线B(280~320 nm)强度约占紫外线A (320~400 nm)的16. 77%,光合有效辐射强度(400~700 nm)约占全光谱辐射量的50. 43%。 展开更多
关键词 西藏阿里 太阳辐射 光谱
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Alkyl group functionalization-induced phonon thermal conductivity attenuation in graphene nanoribbons
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作者 王彩云 鲁爽 +1 位作者 于晓东 李海鹏 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第1期522-526,共5页
We calculated the room-temperature phonon thermal conductivity and phonon spectrum of alkyl group-functionalized zigzag graphene nanoribbons(ZGNRs) with molecular dynamics simulations. The increase in both chain lengt... We calculated the room-temperature phonon thermal conductivity and phonon spectrum of alkyl group-functionalized zigzag graphene nanoribbons(ZGNRs) with molecular dynamics simulations. The increase in both chain length and concentration of alkyl groups caused remarkable reduction of phonon thermal conductivity in functionalized ZGNRs. Phonon spectra analysis showed that functionalization of ZGNR with alkyl functional groups induced phonon–structural defect scattering, thus leading to the reduction of phonon thermal conductivity of ZGNR. Our study showed that surface functionalization is an effective routine to tune the phonon thermal conductivity of GNRs, which is useful in graphene thermal-related applications. 展开更多
关键词 graphene nanoribbons(GNRs) thermal CONDUCTIVITY PHONON spectrum surface FUNCTIONALIZATION molecular dynamics simulations
Probiotic Therapy for Treating Behavioral and Gastrointestinal Symptoms in Autism Spectrum Disorder:A Systematic Review of Clinical Trials 预览
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作者 Jun LIU Guo-bing WAN +7 位作者 Ming-shi HUANG George Agyapong Tian-le ZOU Xue-ying ZHANG Yen-Wenn LIU Yi-qing SONG Ying-Chieh Tsai Xue-jun KONG 《当代医学科学(英文)》 SCIE CAS 2019年第2期173-184,共12页
The therapeutic potentials of probiotics in autism spectrum disorder(ASD)remains controversial,with the only existing systematic review on this topic published in 2015.Results from new trials have become available in ... The therapeutic potentials of probiotics in autism spectrum disorder(ASD)remains controversial,with the only existing systematic review on this topic published in 2015.Results from new trials have become available in recent years.We therefore conducted an updated systematic review,to assess the efficacy of probiotics in relieving behavioral symptoms of ASD and gastrointestinal comorbidities.Our review includes two randomized controlled trials,which showed improvement of ASD behaviors,and three open trials,all which exhibited a trend of improvement.Four of these trials concluded from subjective measures that gastrointestinal function indices showed a trend of improvement with probiotic therapy.Additional rigorous trials are needed to evaluate the effects of probiotic supplements in ASD. 展开更多
关键词 AUTISM SPECTRUM DISORDER PROBIOTICS systematic review
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时间监控法制备窄带滤光膜系工艺技术 预览
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作者 张金豹 王明慧 +2 位作者 耿浩 史成浡 孙亚威 《陕西理工大学学报:自然科学版》 2019年第2期12-16,共5页
基于规整全介质窄带滤光膜系初始结构,采用光学薄膜软件中单纯形算法优化出了所需光谱特性曲线,并对制备结果进行了拟合反演,依靠时间监控的离子束溅射镀膜机制备了中心波长950±2 nm,半宽度50 nm,峰值透过率大于90%,截止透射率小于... 基于规整全介质窄带滤光膜系初始结构,采用光学薄膜软件中单纯形算法优化出了所需光谱特性曲线,并对制备结果进行了拟合反演,依靠时间监控的离子束溅射镀膜机制备了中心波长950±2 nm,半宽度50 nm,峰值透过率大于90%,截止透射率小于0. 5%的窄带滤光膜系。 展开更多
关键词 窄带滤光膜 时间监控 拟合 光谱
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表面等离子激元双增强β-NaYF4:Er^3+上转换研究 预览
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作者 黄海 林林 +4 位作者 黄莉莉 冯卓宏 郑标 王哲哲 郑志强 《光子学报》 EI CAS CSCD 北大核心 2019年第2期190-197,共8页
用共沉淀法制备了β-NaYF4∶Er^3+纳米颗粒.通过化学还原法、晶种生长法分别制备银纳米立方颗粒及金纳米棒,并将其掺杂到β-NaYF4∶2%Er^3+纳米颗粒中形成复合体系,利用表面等离子激元增强效应分别实现β-NaYF4∶Er^3+上转换发光的激发... 用共沉淀法制备了β-NaYF4∶Er^3+纳米颗粒.通过化学还原法、晶种生长法分别制备银纳米立方颗粒及金纳米棒,并将其掺杂到β-NaYF4∶2%Er^3+纳米颗粒中形成复合体系,利用表面等离子激元增强效应分别实现β-NaYF4∶Er^3+上转换发光的激发和发射增强.当银纳米立方颗粒掺杂量为60μL时,上转换发光强度整体增强4.0倍;当金纳米棒掺杂量为60μL时,上转换发光强度整体增强7.8倍.在此基础上,将两种贵金属纳米颗粒同时掺杂到β-NaYF4∶Er^3+纳米颗粒材料中,实现了该材料上转换发光激发和发射双增强,上转换发光强度增强了16.0倍. 展开更多
关键词 上转换 表面等离子激元增强 光谱 银纳米立方颗粒 金纳米棒 β-NaYF4∶Er^3+纳米颗粒
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某660MW汽轮机振动原因分析及处理 预览
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作者 徐国生 周天旺 《能源研究与管理》 2019年第1期92-94,共3页
围绕某电厂660MW汽轮发电机组在A修后机组启动过程中振动异常的原因分析、处理过程和处理效果进行了论述,通过振动频谱特征分析,查明了汽轮机振动大的原因为汽封与转子碰摩导致转轴产生了热弯曲,在采取控制振动幅值的前提下让其动静摩... 围绕某电厂660MW汽轮发电机组在A修后机组启动过程中振动异常的原因分析、处理过程和处理效果进行了论述,通过振动频谱特征分析,查明了汽轮机振动大的原因为汽封与转子碰摩导致转轴产生了热弯曲,在采取控制振动幅值的前提下让其动静摩擦等措施后收到明显的效果,为其他机组查找此类振动原因提供了参考。 展开更多
关键词 660MW 振动 频谱 诊断
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