检索结果-南通市图书馆

Short-Time Dynamics of the Random n-Vector Model

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2001年第11期36卷 611-616页

作者： CheN Yuan LI zhi-Bing fang Hai he Shun-Shan SITU Shu-Ping Department of Physics Guangzhou UniversityGuangzhou 510405China Department of PhysicsZhongshan UniversityGuangzhou 510275China Department of PhysicsZhongshan UniversityGuangzhou 510275China Department of PhysicsZhongshan UniversityGuangzhou 510275China Department of PhysicsZhongshan UniversityGuangzhou 510275China

Short-time critical behavior of the random n-vector model is studied by the theoretic renormalization-group *** scaling laws are studied in a frame of the expansion in e = 4 - d for n ≠ 1 and for n = *** d ＜ 4,the initial slip exponents θ′ for the order parameter and θ for the response function are calculated up to the second order in e ＝ 4 - d for n ≠ 1 and for n ＝ 1 at the random fixed point *** results show that the random impurities exert a strong influence on the short-time dynamics for d ＜ 4 and n ＜ nc.

关键词： n-vector model,short-time critical dynamics,quenched impurities,initial slip exponent

Dynamics of the Random Ising Model with Long-Range Interaction

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2001年第10期36卷 469-472页

作者： CheN Yuan LI zhi-Bing fang Hai he Shun-Shan SITU Shu-Ping Department of Physics Guangzhou University Guangzhou 510405 China Department of Physics Zhongshan University Guangzhou 510275 China Associate Member of ICTP Trieste Italy Department of Physics Zhongshan University Guangzhou 510275 China Department of Physics Zhongshan University Guangzhou 510275 China Department of Physics Zhongshan University Guangzhou 510275 China

Critical dynamics of the random Ising model with long-range interaction decaying as r-(d+σ) where d is the dimensionality) is studied by the theoretic renormalization-group approach. The system is released to an evolution within a model A dynamics. Asymptotic scaling laws are studied in a frame of the expansion in = 2σ - d. In dimensions d ＜ 2σ. the dynamic exponent z is calculated to the second order in at the random fixed point.

关键词： Ising model, critical dynamics, long-range interaction, quenched impurities

Polarization control and tuning efficiency of tunable vertical-cavity surface-emitting laser with internal-cavity sub-wavelength grating

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第8期29卷 310-316页

作者： Xiao-Long Wang Yong-Gang Zou zhi-fang he Guo-Jun Liu Xiao-Hui Ma State Key Laboratory of High-Power Laser Diodes Changchun University of Science and TechnologyChangchun 130022China

We design an 850 nm tunable vertical-cavity surface-emitting laser(VCSEL)structure using an internal-cavity sub-wavelength *** use of such a tuning structure allows for wider wavelength tuning range and more stable single-polarization as compared to conventional tunable *** features of the internal-cavity grating effect on the wavelength tuning and polarization characteristics of the tunable VCSEL are *** simulation results show that the largest wavelength tuning range achieves 44.2 nm,and the maximum orthogonal polarization suppression ratio(OPSR)is 33.4 dB(TE-type)and 38.7 dB(TM-type).

关键词： sub-wavelength grating polarization mode tunable VCSEL wavelength tuning

Positive effect of Mo on mechanical properties of a Ni-42W-10Co-x Mo medium heavy alloy

在线全文

学校读者我要写书评

暂无评论

China Foundry 2025年

作者： Guo-xin Cao Jian-xin Dong Yong-sheng he he Jiang fang Hao zhi-hua Nie Teng-fei Ma Bao-quan Fu School of Materials Science and Engineering University of Science and Technology Beijing Xi'an Superalloy Technology Co. Ltd. School of Materials Science and Engineering Beijing Institute of Technology Key Laboratory of Air-driven Equipment Technology of Zhejiang Province Quzhou University

In this study,a novel Ni-W-Co-Mo medium heavy alloy (MHA) was designed to improve its mechanical strength via Mo *** the Ni-42W-10Co-xM o alloy series,where x represents the weight percent of Mo and varies between 0,1,2,5,and 10,the microstructure transitions from a dendritic structure to a hypoeutectic structure as the Mo content increases from 0 to 5wt.%.Moreover,as the Mo content increases from 0to 10wt.%,the distribution of theμ-phase shifts from being individually dispersed to forming aggregates,and its volume fraction rises from 0.5%to 7.9%.Notably,theμ-phase evolves into an eutectic microstructure,which helps in minimizing the segregation of *** change is accompanied by a substantial enhancement in mechanical properties;specifically,the compressive yield strength at room temperature increases from 350 MPa to 646 MPa,indicating a significant 85%***,the microhardness increases from 230 HV to 304 *** dynamics simulations further reveal that the strengthening mechanism of Ni-42W-10Co-xM o alloys is Mo-induced solid solution strengthening and precipitation strengthening.

关键词：

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

基于信誉值的P2P访问控制模型

计算机工程与应用 2010年第33期46卷 78-81页

作者：段志鹏何鸿君罗莉方志鹤汪洋国防科学技术大学计算机学院长沙410073

P2P网络是一种基于对等实体的数据交换方式,在数据交换协作过程由于用户的未知性、动态性,使得另一方会面临很大的风险。而传统的访问控制模型都是基于授权在资源使用之前,应用于相对静态的系统中,对于属性值动态更改的系统不能很好地... 详细信息

P2P网络是一种基于对等实体的数据交换方式,在数据交换协作过程由于用户的未知性、动态性,使得另一方会面临很大的风险。而传统的访问控制模型都是基于授权在资源使用之前,应用于相对静态的系统中,对于属性值动态更改的系统不能很好地适用。首先对P2P传统的信誉值计算方法进行了改进,对影响信誉值的多种因素进行了综合考虑,提出了一种比较准确全面的信誉值评估算法。然后从现今研究比较热的UCON模型出发,利用其属性的可变性以及授权的连续性等特点,提出了一种P2P的动态访问控制模型。

关键词：点对点技术(P2P) 信誉值使用控制模型(UCON)

Lightweight Al-Nb-Ti-V-Cr high entropy alloys with high hardness and enhanced mechanical properties via doping Co

在线全文

学校读者我要写书评

暂无评论

China Foundry 2025年

作者： fang-dong Xu De-zhi Chen Rui-run Chen Bin Gan Jing-yue Yu National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology Suzhou Laboratory

To develop high-hardness and high-strength lightweight high entropy alloys （LheAs）,a series of CoxAlNbTiVCr alloys were *** phase constitution,distribution,and crystal structure of the Laves phase in alloys can be altered by adjusting the composition of heAs,which in turn influences their mechanical *** Nb Ti VCr （x=0,0.5,1,1.5,and 2,atomic ratio percentage） LheAs were designed and prepared to characterize the microstructure and tailor the mechanical *** introduction of Co changes the microstructure of LheAs from a single B2 structure to a mixture dendrite structure,which consists of B2 phase,C14 and C15 Laves *** the C14 and C15 Laves phases exhibit coupled *** parameters including mixing enthalpy (ΔHmix),valence electron concentration （VEC）,atomic radius size （δ）,mixing entropy （ΔS）,and electronegativity difference （Δχ） are used to predict the formation of B2 and Laves phase in *** the Co content increases from 0 to 1.5at.%,Laves phase volume fraction gradually increases,which leads to an enhancement in the compressive strength from 1,520.8 MPa to 1,844.4 ***1.5Al Nb Ti VCr alloy exhibits the maximum Vickers hardness of 699.4 *** improvement of mechanical properties mainly originates from solid solution strengthening and second phase strengthening.

关键词：

鸡贫血病毒VP1和VP2蛋白在家蚕中的联合表达

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

生物工程学报 2001年第3期17卷 283-287页

作者：肖庆利张志芳何家禄农业部家蚕生物技术重点开放实验室中国农业科学院蚕业研究所镇江212018

将鸡贫血病毒vp1和vp2基因分别克隆入转移载体pBacPAK8中 ,获得重组转移质粒pBac vp1和pBac vp2。以上两质粒分别与CvnⅠ酶切线性化的亲本病毒Bm BacPAK6DNA共转染家蚕细胞 ,通过蓝白斑筛选 ,纯化得到重组病毒Bm vp1和Bm vp2。PCR分析表... 详细信息

将鸡贫血病毒vp1和vp2基因分别克隆入转移载体pBacPAK8中 ,获得重组转移质粒pBac vp1和pBac vp2。以上两质粒分别与CvnⅠ酶切线性化的亲本病毒Bm BacPAK6DNA共转染家蚕细胞 ,通过蓝白斑筛选 ,纯化得到重组病毒Bm vp1和Bm vp2。PCR分析表明vp1和vp2基因已整合进杆状病毒基因组中。将Bm vp1和Bm vp2共感染 5龄家蚕 ,通过表达产物免疫SPF鸡产生的抗血清与CAV感染的MDCC MSB1细胞的间接荧光抗体分析 ,证明表达产物能诱导鸡产生相应的抗体 ,而且能够保护子代鸡免受CAV的攻击。该研究表明 ,表达VP1和VP2蛋白的重组家蚕杆状病毒 (RecombinantBmNPV)

关键词：鸡贫血病毒 VP1 VP2 重组杆状病毒家蚕基因表达

在线全文

学校读者我要写书评

暂无评论

坑槽冷补材料的疲劳损伤本构模型分析

三明学院学报 2020年第6期37卷 77-82页

作者：张倩方志河张家伟西安建筑科技大学土木工程学院陕西西安710055 西安建筑科技大学陕西省岩土与地下空间工程重点实验室陕西西安710055

重复荷载引起的疲劳累积损伤是沥青路面坑槽修补后再次破坏的主要原因之一。为深入了解沥青路面坑槽修补料的疲劳损伤,在已有疲劳研究理论的基础上,考虑损伤对修补材料疲劳性能的影响,推导适用于坑槽修补冷补料的损伤本构模型,用以描述... 详细信息

重复荷载引起的疲劳累积损伤是沥青路面坑槽修补后再次破坏的主要原因之一。为深入了解沥青路面坑槽修补料的疲劳损伤,在已有疲劳研究理论的基础上,考虑损伤对修补材料疲劳性能的影响,推导适用于坑槽修补冷补料的损伤本构模型,用以描述坑槽冷补料的疲劳损伤变化特征。为验证损伤本构模型的正确性,对两种坑槽修补料进行了疲劳试验。结果表明:推导的修补料本构模型与试验结果吻合良好;疲劳寿命受材料类型及应力比影响明显,且应变速率受应力比影响较大。

关键词：道路工程沥青路面冷补料疲劳损伤本构关系

600 MW双背压机组真空低原因分析及改进

在线全文

学校读者我要写书评

暂无评论

华北电力技术 2006年第2期 38-41页

作者：杨德荣方志和韩志成大唐国际托克托发电有限责任公司内蒙古托克托010206

通过对托电一、二期4×600 MW机组的真空分析,找出了影响双背压机组低压凝汽器真空的主要因素为,抽真空系统设置不合理使不凝结气体聚集,导致端差增大,并通过试验验证了理论分析的正确性,进而提出了解决方法。

关键词：双背压凝汽器端差真空