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Non-adiabatic quantum dynamical studies of Na(3p) + HD(v = 1, j5) = 0)→NaH/NaD + D/H reaction
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作者 温月佩 布仁巴雅尔 陈茂笃 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第6期169-175,共7页
Non-adiabatic dynamical calculations are carried out for the Na(3 p)+HD(ν = 1, j = 0)→NaH/NaD+D/H reaction on the diabatic potential energy surfaces of Wang et al.(Sci. Rep. 2018, 8, 17960) by using the time-depende... Non-adiabatic dynamical calculations are carried out for the Na(3 p)+HD(ν = 1, j = 0)→NaH/NaD+D/H reaction on the diabatic potential energy surfaces of Wang et al.(Sci. Rep. 2018, 8, 17960) by using the time-dependent wave packet method. The state-to-state integral cross sections and differential cross sections of two reaction channels(NaH/NaD+D/H)are calculated for collision energy up to 0.4 eV. The cross section branching ratio indicates that the dominant reaction channel changes from NaD+H to NaH+D when the collision energy is larger than 0.227 eV. The products from two reaction channels both prefer to form in vibrationally cold but rotationally hot states, and they both tend to forward scattering. 展开更多
关键词 TIME-DEPENDENT wave packet method NON-ADIABATIC REACTION integral CROSS SECTION differential CROSS SECTION
Linkage analysis and integrated software GAPL for pure-line populations derived from four-way and eight-way crosses 预览
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作者 Luyan Zhang Lei Meng Jiankang Wang 《作物学报:英文版》 CAS CSCD 2019年第3期283-293,共11页
Pure lines derived from multiple parents provide abundant variation for genetic study.However,efficient genetic analysis methods and user-friendly software are still lacking.In this study, we developed linkage analysi... Pure lines derived from multiple parents provide abundant variation for genetic study.However,efficient genetic analysis methods and user-friendly software are still lacking.In this study, we developed linkage analysis methods and integrated analysis software for pure-line populations derived from four-way and eight-way crosses.First, polymorphic markers are classified into different categories according to the number of identifiable alleles in the inbred parents.Expected genotypic probability is then derived for each pair of complete markers, and based on them a maximum likelihood estimate(MLE) of recombination frequency is calculated.An EM algorithm is proposed for calculating recombination frequencies in scenarios that at least one marker is incomplete.A linkage map can thus be constructed using estimated recombination frequencies.We describe a software package called GAPL for recombination frequency estimation and linkage map construction in multi-parental pure-line populations.Both simulation studies and results from a reported four-way cross recombinant inbred line population demonstrate that the proposed method and software can build more accurate linkage maps in shorter times than other published software packages.The GAPL software is freely available from www.isbreeding.net and can also be used for QTL mapping in multi-parental populations. 展开更多
关键词 Pure lines Four-way CROSS Eight-way CROSS Recombination frequency estimation Integrated software
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拟南芥bzip 19-2/bzip 23-1/bzip24-2三突变体植株获取及其PCR鉴定 预览
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作者 曹家升 任永兵 +2 位作者 孟云 曹树青 阳立波 《合肥工业大学学报:自然科学版》 CAS 北大核心 2019年第1期125-129,共5页
近年来植物所受非生物胁迫的影响日益严峻,是造成农业减产的主要因素之一。bZIP类转录因子参与多种生物学功能并起着重要调控作用,尤其是对植物生长发育以及逆境胁迫应答的调控。因此文章以拟南芥bZIP19、bZIP23、bZIP24基因的突变体为... 近年来植物所受非生物胁迫的影响日益严峻,是造成农业减产的主要因素之一。bZIP类转录因子参与多种生物学功能并起着重要调控作用,尤其是对植物生长发育以及逆境胁迫应答的调控。因此文章以拟南芥bZIP19、bZIP23、bZIP24基因的突变体为实验材料,通过遗传杂交技术构建bzip19-2/bzip23-1/bzip24-2三突变体,结合聚合酶链式反应(polymerase chain reaction,PCR)鉴定技术,最终获得纯合三突变体实验材料,为研究bZIP类转录因子的功能及其间相互作用奠定了基础。 展开更多
关键词 拟南芥 bZIP转录因子 杂交 聚合酶链式反应(PCR) 三突变体
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China's export of rare earth permanent magnet products was stable tn April 2019 预览
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《中国稀土信息:英文版》 2019年第6期1-8,共8页
China is a global prcducec and expoCec of rcrc each perma nent mag net products. ExpoC is one of the impoCant salos channels for many large and medium-sized magnetin materinl prcductinn entercrises in China.
关键词 China is the Red Cross Society of China Rare Earth PERMANENT MAGNET PRODUCTS Global SOURCING
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Cross-section prediction for isotopes near neutron drip line in 70, 80Zn projectile fragmentation reactions
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作者 魏慧玲 宋一丹 +2 位作者 马春旺 李志宏 苏俊 《中国物理C:英文版》 SCIE CAS CSCD 2019年第7期48-52,共5页
The cross sections for 59,60Ca, recently measured in the 345 A MeV 70Zn+9 Be reaction,were estimated using the FRACS parametrization and an empirical formula,which are in good agreement.The FRACS parametrization and t... The cross sections for 59,60Ca, recently measured in the 345 A MeV 70Zn+9 Be reaction,were estimated using the FRACS parametrization and an empirical formula,which are in good agreement.The FRACS parametrization and the empirical formula are combined to predict the cross sections for extreme calcium isotopes 66,70Ca in the70,80Zn+9 Be reactions at the incident energies of 60,80,and 345 A MeV.The dependence of emperical formula parameters on the reaction system,as well as the incident energy,are discussed.The results indicate that 66,70Ca can be discovered in reactions of 60,80A MeV 80Zn+9 Be.The predicted binding energy for extreme neutron-rich isotopes by the spherical relativistic continuum Hartree-Bogoliubov theory was adopted in the calculation.Hence,the planned Beijing Isotope-Separation-On Line Neutron-Rich Beam Facility(BISOL),which is a third generation radioactive ion beam facility,could provide the opportunity to discover 66,70 Ca and neighboring neutron-drip line nuclei. 展开更多
关键词 neutron-drip line PROJECTILE FRAGMENTATION FRACS cross section Ca-60 Ca-70
盾构穿越深厚垃圾填埋砂石坑技术方案研究 预览
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作者 张胜勇 王雷 +1 位作者 杨进新 张鹏 《水利水电技术》 北大核心 2019年第S1期220-227,共8页
团九二期输水隧洞施工一标盾构穿越深厚垃圾填埋砂石坑,该地层组成物质来源复杂,结构疏松,施工沉降变形难以控制,风险极大。为了使盾构能够安全掘进穿越,进行补充勘察和人工挖孔勘察,确定了填埋物的组成成分、数量、强度和尺寸,进行了... 团九二期输水隧洞施工一标盾构穿越深厚垃圾填埋砂石坑,该地层组成物质来源复杂,结构疏松,施工沉降变形难以控制,风险极大。为了使盾构能够安全掘进穿越,进行补充勘察和人工挖孔勘察,确定了填埋物的组成成分、数量、强度和尺寸,进行了专项设计与施工。通过对明挖法、暗挖法和盾构法的比较,确定了采用盾构法施工;针对垃圾填埋地层松散的情况,采用地面注浆和洞内二次注浆等措施,使得松散的土体变得密实,保证了盾构机掘进过程中姿态稳定;通过对盾构机的适应性改造,加强刀盘的耐磨性和抗冲击性能,保证盾构在垃圾坑段正常掘进;同时,凭借监控量测等科学手段指导施工,及时调整盾构机掘进参数,成功解决了沉降难题,化解了工程风险。实际施工效果表明:通过土体改良和合理的盾构机改造,盾构机可以安全穿越深厚垃圾填埋地层。研究成果为盾构穿越垃圾坑地层等类似案例提供参考。 展开更多
关键词 团九二期 盾构 垃圾坑 穿越 掘进技术
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Space debris laser ranging with a 60 W single-frequency slab nanosecond green laser at 200 Hz
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作者 张海峰 龙明亮 +3 位作者 邓华荣 吴志波 程志恩 张忠萍 《中国光学快报:英文版》 SCIE EI CAS CSCD 2019年第5期44-48,共5页
Space debris laser ranging was achieved with a 60 W, 200 Hz, 532 nm nanosecond slab, single-frequency green laser at the Shanghai Astronomical Observatory's 60 cm satellite laser ranging systern. There were 174 pa... Space debris laser ranging was achieved with a 60 W, 200 Hz, 532 nm nanosecond slab, single-frequency green laser at the Shanghai Astronomical Observatory's 60 cm satellite laser ranging systern. There were 174 passes of space debris measured in 2017, with the minimum radar cross section (RCS) being 0.25 m2 and the highest ranging precision up to 13.6 cm. The RCS of space debris measured with the farthest distances in 174 passes was analyzed. The results show that the farthest measurement distance (R) and RCS (S) were fitted to R = 1388.159S024312, indicating that this laser can measure the distance of 1388.159 km at an RCS of 1 m2, which is very helpful to surveillance and research on low-Earth-orbit space debris. 展开更多
关键词 Space debris LASER ranging radar cross section(RCS) 60 W SINGLE-FREQUENCY SLAB nanosecond green LASER
Validation method for simulation models with cross iteration 预览
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作者 FANG Ke ZHAO Kaibin ZHOU Yuchen 《系统工程与电子技术:英文版》 SCIE EI CSCD 2019年第3期555-563,共9页
Cross iteration often exists in the computational process of the simulation models, especially for control models. There is a credibility defect tracing problem in the validation of models with cross iteration. In ord... Cross iteration often exists in the computational process of the simulation models, especially for control models. There is a credibility defect tracing problem in the validation of models with cross iteration. In order to resolve this problem, after the problem formulation, a validation theorem on the cross iteration is proposed, and the proof of the theorem is given under the cross iteration circumstance. Meanwhile, applying the proposed theorem, the credibility calculation algorithm is provided, and the solvent of the defect tracing is explained. Further, based on the validation theorem on the cross iteration, a validation method for simulation models with the cross iteration is proposed, which is illustrated by a flowchart step by step. Finally, a validation example of a sixdegree of freedom (DOF) flight vehicle model is provided, and the validation process is performed by using the validation method. The result analysis shows that the method is effective to obtain the credibility of the model and accomplish the defect tracing of the validation. 展开更多
关键词 VALIDATION METHOD simulation model CROSS ITERATION VALIDATION THEOREM VALIDATION EXAMPLE
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A Reversible Data Hiding with Quality Controllable Scheme for Encrypted-Compressed Image
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作者 LI Xinyan MOU Huajian +1 位作者 YAN Bing GAO Li 《武汉大学学报:自然科学英文版》 CAS CSCD 2019年第5期383-390,共8页
In order to achieve image encryption and data embedding simultaneously, a reversible data hiding(RDH) algorithm for encrypted-compressed image in wavelet domain is proposed. This scheme employs the quality controllabl... In order to achieve image encryption and data embedding simultaneously, a reversible data hiding(RDH) algorithm for encrypted-compressed image in wavelet domain is proposed. This scheme employs the quality controllable parameter. Moreover it has larger embedding capacity and smaller quality control parameters than other methods in literatures. Meanwhile, the cross chaotic map is employed to generate chaotic sequences, and the total keys of the algorithm is far large. Experimental results and comparisons show that the proposed scheme has large capacity, high security, and strong resistance to brute-force. 展开更多
关键词 REVERSIBLE data hiding in encrypted image cross CHAOTIC map DIFFUSE and SCRAMBLE encryption-compression
又见熊本熊——本田发布2019款CROSS CUB 预览
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作者 加菲 《摩托车信息》 2019年第5期36-39,共4页
近日,本田发布了旗下经典的越野幼兽CROSS CUB的2019款全新配色,包含110和50两种车型,并宣布新车将于7月19日起在日本上市销售。同时,官方还推出了它们的熊本熊涂装版本,并宣布将于6月21日起在日本上市销售。新车分为CC110和CC50两个排... 近日,本田发布了旗下经典的越野幼兽CROSS CUB的2019款全新配色,包含110和50两种车型,并宣布新车将于7月19日起在日本上市销售。同时,官方还推出了它们的熊本熊涂装版本,并宣布将于6月21日起在日本上市销售。新车分为CC110和CC50两个排量,其中CC是CROSSCUB的缩写,意为供用户日常生活及周末玩乐使用。在具体配色上,2019款CROSSCUB110共有三种颜色,分别是白色、黄色和绿色。 展开更多
关键词 CROSS CUB 110 四冲程发动机 轮胎规格 吉祥物 最大扭矩 油箱容积 熊本县 变速器 启动方式 燃油供给
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Separation, Quantification and Structural Study of (+)-Catechin and (-)-Epicatechin by Ion Mobility Mass Spectrometry Combined with Theoretical Algorithms
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作者 Xinyu Bian Bing Zhao +4 位作者 Bo Pang Zhong Zheng Shu Liu Zhiqiang Liu Fengrui Song 《中国化学:英文版》 SCIE CAS CSCD 2019年第6期581-587,共7页
Two catechin epimers and their non-covalent complexes with γ-cyclodextrin were studied by using ion mobility coupled with mass spectrometry (IM-MS). Rapid separation of complexes was achieved with the peak-to-peak re... Two catechin epimers and their non-covalent complexes with γ-cyclodextrin were studied by using ion mobility coupled with mass spectrometry (IM-MS). Rapid separation of complexes was achieved with the peak-to-peak resolution reaching 0.86 after optimization of IM condition. Collision cross section (CCS) was measured to explore the structural difference of complexes. A gap of 11.75 A^2 between two complexes was found. Molecular modeling and theoretical CCS calculation were adopted to explain the measurement results. Two binding ways of both complexes were found and the calculated CCS corresponds accurately to the measured CCS. Quantification of catechins in mixtures was performed and the relative error was less than 15%, indicating the effectiveness of quantification by IM-MS. 展开更多
关键词 IM-MS CATECHIN cycodextrin THEORETICAL modeling COLLISION cross section CHIRAL resolution
Applicability of 9 Be global optical potential to reactions of 7,10,11,12Be
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作者 徐永丽 韩银录 +3 位作者 梁海英 吴振东 郭海瑞 蔡崇海 《中国物理C:英文版》 SCIE CAS CSCD 2019年第9期55-61,共7页
Elastic scattering angular distributions and total reaction cross-sections of 7,10,11,12Be projectiles are predicted by the systematic 9Be global phenomenological optical model potential for target mass numbers rangin... Elastic scattering angular distributions and total reaction cross-sections of 7,10,11,12Be projectiles are predicted by the systematic 9Be global phenomenological optical model potential for target mass numbers ranging from 24 to 209.These predictions provide a detailed analysis by their comparison with the available experimental data.Furthermore,these elastic scattering observables are also predicted for some targets out of the mass number range.The results are in reasonable agreement with the existing experimental data,and they are presented in this study. 展开更多
关键词 global PHENOMENOLOGICAL optical model potential elastic scattering ANGULAR DISTRIBUTIONS total reaction cross SECTIONS
比利时杜鹃与几种野生杜鹃杂交亲和性研究 预览
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作者 李叶芳 尹杨萍 +2 位作者 杜娟 关文灵 杨婷 《西南林业大学学报》 CAS 北大核心 2019年第5期177-181,共5页
以比利时杜鹃为母本,常绿杜鹃亚属、映山红亚属、杜鹃亚属、糙叶杜鹃亚属、羊踯躅亚属的11个野生种及1个栽培种为父本进行远缘杂交研究,对父本花粉活力进行测定,并对杂交坐果率、结实率和种子萌发率进行统计分析,探讨杜鹃属植物远缘杂... 以比利时杜鹃为母本,常绿杜鹃亚属、映山红亚属、杜鹃亚属、糙叶杜鹃亚属、羊踯躅亚属的11个野生种及1个栽培种为父本进行远缘杂交研究,对父本花粉活力进行测定,并对杂交坐果率、结实率和种子萌发率进行统计分析,探讨杜鹃属植物远缘杂交的亲和性。结果表明:比利时杜鹃与不同的杜鹃杂交,其坐果率、结实率及种子萌发率各不相同,反映出不同的杂交亲和性。其中露珠杜鹃、云上杜鹃、富源杜鹃、马缨杜鹃、基毛杜鹃作为父本杂交,未得到杂交种子,属于杂交不亲和;云锦杜鹃、映山红、羊踯躅、金踯躅作为父本杂交具有较高的坐果率、结实率及种子萌发率,杂交亲和性强;大白花杜鹃、高尚杜鹃及云南杜鹃作为父本杂交具有弱亲和性。 展开更多
关键词 杜鹃 杂交 花粉活力 亲和性 野生种 栽培种
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Observation of e+e?→D+sDˉˉˉˉ(?)0K?e+e?→Ds+Dˉ(?)0K?and study of the P-wave DsDs mesons
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作者 麦迪娜 M.N.Achasov +143 位作者 S.Ahmed M.Albrecht M.Alekseev A.Amoroso 安芬芬 安琪 白羽 O.Bakina R.Baldini Ferroli 班勇 K.Begzsuren D.W.Bennett J.V.Bennett N.Berger M.Bertani D.Bettoni F.Bianchi I.Boyko R.A.Briere 蔡浩 蔡啸 A.Calcaterra 曹国富 S.A.Cetin J.Chai 常劲帆 W.L.Chang G.Chelkov 陈刚 陈和生 陈江川 陈玛丽 陈申见 陈元柏 成伟帅 G.Cibinetto F.Cossio 代洪亮 代建平 A.Dbeyssi D.Dedovich 邓子艳 A.Denig I.Denysenko M.Destefanis F.De Mori 丁勇 董超 董静 董燎原 董明义 豆正磊 杜书先 范荆州 方建 房双世 方易 R.Farinelli L.Fava F.Feldbauer G.Felici 封常青 M.Fritsch 傅成栋 付颖 高清 高鑫磊 高原宁 高勇贵 高榛 B.Garillon I.Garzia A.Gilman K.Goetzen 龚丽 龚文煊 W.Gradl M.Greco 谷立民 顾旻皓 顾珊 顾运厅 郭爱强 郭立波 郭如盼 郭玉萍 A.Guskov Z.Haddadi 韩爽 郝喜庆 F.A.Harris 何康林 F.H.Heinsius T.Held 衡月昆 侯治龙 胡海明 胡继峰 胡涛 胡誉 黄光顺 黄金书 黄性涛 黄晓忠 黄智玲 N.Huesken T.Hussain W.Ikegami Andersson W.Imoehl M.Irshad 纪全 姬清平 季晓斌 季筱璐 姜侯兵 江晓山 蒋兴雨 焦健斌 焦铮 金大鹏 金山 金毅 T.Johansson N.Kalantar-Nayestanaki 康晓珅 M.Kavatsyuk 柯百谦 I.K.Keshk T.Khan A.Khoukaz P.Kiese R.Kiuchi R.Kliemt L.Koch O.B.Kolcu B.Kopf M.Kuemmel M.Kuessner A.Kupsc M.Kurth W.Kühn J.S.Lange P.Larin L. 《中国物理C:英文版》 SCIE CAS CSCD 2019年第3期5-16,共12页
Studies of e+e?→D+sDˉˉˉˉ(?)0K?e+e?→Ds+Dˉ(?)0K?and the PP-wave charmed-strange mesons are performed based on an e+e?e+e?collision data sample corresponding to an integrated luminosity of 567 pb?1 collected with ... Studies of e+e?→D+sDˉˉˉˉ(?)0K?e+e?→Ds+Dˉ(?)0K?and the PP-wave charmed-strange mesons are performed based on an e+e?e+e?collision data sample corresponding to an integrated luminosity of 567 pb?1 collected with the BESIII detector at s√=4.600s=4.600 GeV.The processes of e+e?→D+sDˉˉˉˉ?0K?e+e?→Ds+Dˉ?0K?and D+sDˉˉˉˉ0K?Ds+Dˉ0K?are observed for the first time and are found to be dominated by the modes D+sDs1(2536)?Ds+Ds1(2536)?and D+sD?s2(2573)?Ds+Ds2?(2573)?,respectively.The Born cross sections are measured to beσB(e+e?→D+sDˉˉˉˉ?0K?)=(10.1±2.3±0.8)σB(e+e?→Ds+Dˉ?0K?)=(10.1±2.3±0.8)pb andσB(e+e?→D+sDˉˉˉˉ0K?)=(19.4±2.3±1.6)σB(e+e?→Ds+Dˉ0K?)=(19.4±2.3±1.6)pb,and the products of Born cross section and the decay branching fraction are measured to beσB(e+e?→D+sDs1(2536)?+c.c.)?σB(e+e?→Ds+Ds1(2536)?+c.c.)?B(Ds1(2536)?→Dˉˉˉˉ?0K?)=(7.5±1.8±0.7)B(Ds1(2536)?→Dˉ?0K?)=(7.5±1.8±0.7)pb andσB(e+e?→D+sD?s2(2573)?+c.c.)?B(D?s2(2573)?→Dˉˉˉˉ0K?)=σB(e+e?→Ds+Ds2?(2573)?+c.c.)?B(Ds2?(2573)?→Dˉ0K?)=(19.7±2.9±2.0)(19.7±2.9±2.0)pb.For the Ds1(2536)?Ds1(2536)?and D?s2(2573)?Ds2?(2573)?mesons,the masses and widths are measured to be M(Ds1(2536)?)=(2537.7±0.5±3.1)MeV/c2M(Ds1(2536)?)=(2537.7±0.5±3.1)MeV/c2,Γ(Ds1(2536)?)=(1.7±1.2±0.6)Γ(Ds1(2536)?)=(1.7±1.2±0.6)MeV,and M(D?s2(2573)?)=M(Ds2?(2573)?)=(2570.7±2.0±1.7)MeV/c2,(2570.7±2.0±1.7)MeV/c2,Γ(D?s2(2573)?)=(17.2±3.6±1.1)Γ(Ds2?(2573)?)=(17.2±3.6±1.1)MeV.The spin-parity of the D?s2(2573)?Ds2?(2573)?meson is determined to be JP=2+JP=2+.In addition,the processes e+e?→D+sDˉˉˉˉ(?)0K?e+e?→Ds+Dˉ(?)0K?are searched for using the data samples taken at four(two)center-of-mass energies between 4.416(4.527)and 4.575 GeV,and upper limits at the 90%confidence level on the cross sections are determined. 展开更多
关键词 cross section P-WAVE D_s MESONS resonance parameters spin-parity BESIII
Factors influencing electromagnetic scattering from the dielectric periodic surface
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作者 韦尹煜 吴振森 +2 位作者 李海英 吴家骥 屈檀 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第7期202-210,共9页
The scattering characteristics of the periodic surface of infinite and finite media are investigated in detail.The Fourier expression of the scattering field of the periodic surface is obtained in terms of Huygens’ s... The scattering characteristics of the periodic surface of infinite and finite media are investigated in detail.The Fourier expression of the scattering field of the periodic surface is obtained in terms of Huygens’ s principle and Floquet’s theorem.Using the extended boundary condition method(EBCM) and T-matrix method, the scattering amplitude factor is solved,and the correctness of the algorithm is verified by use of the law of conservation of energy.The scattering cross section of the periodic surface in the infinitely long region is derived by improving the scattering cross section of the finite period surface.Furthermore, the effects of the incident wave parameters and the geometric structure parameters on the scattering of the periodic surface are analyzed and discussed.By reasonable approximation, the scattering calculation methods of infinite and finite long surfaces are unified.Besides, numerical results show that the dielectric constant of the periodic dielectric surface has a significant effect on the scattering rate and transmittance.The period and amplitude of the surface determine the number of scattering intensity peaks, and, together with the incident angle, influence the scattering intensity distribution. 展开更多
关键词 PERIODIC SURFACE Floquet’s THEOREM extended boundary condition method(EBCM) SCATTERING cross section energy CONSERVATION
立体裁剪中交叉造型的结构设计方法研究
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作者 许栋樑 《上海纺织科技》 北大核心 2019年第3期40-42,52共4页
从立体裁剪的角度研究交叉造型的结构设计方法,将立体交叉造型分为结构线交叉、编织交叉、缝缩交叉、缠绕交叉、褶裥交叉和综合交叉六类。结合试验法研究了不同交叉造型的设计方法和结构设计,探讨了交叉造型在服装设计中的应用和价值,... 从立体裁剪的角度研究交叉造型的结构设计方法,将立体交叉造型分为结构线交叉、编织交叉、缝缩交叉、缠绕交叉、褶裥交叉和综合交叉六类。结合试验法研究了不同交叉造型的设计方法和结构设计,探讨了交叉造型在服装设计中的应用和价值,指出交叉造型设计可丰富服装造型款式,直观体现比较复杂的服装结构,促进立体裁剪与平面结构的相互补充。 展开更多
关键词 服装设计 立体裁剪 造型设计 结构设计 交叉
Time series analysis of mantle cycles PartⅠ:Periodicities and correlations among seven global isotopic databases 预览
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作者 Stephen J. Puetz Kent C. Condie 《地学前缘:英文版》 CAS CSCD 2019年第4期1305-1326,共22页
In this study,seven isotopic databases are presented and analyzed to identify mantle and crustal episodes on a global scale by focusing on periodicity ranging from 70 to 200 million years(Myr).The databases are the la... In this study,seven isotopic databases are presented and analyzed to identify mantle and crustal episodes on a global scale by focusing on periodicity ranging from 70 to 200 million years(Myr).The databases are the largest,or among the largest,compiled for each type of data-with an objective of finding some samples from every region of every continent,to make each database as global as conceivably possible.The databases contain zircon Lu/Hf isotopic data,whole-rock Sm/Nd isotopic data,U/Pb detrital zircon ages,U/Pb igneous zircon ages,U/Pb non-zircon ages,whole-rock Re/Os isotopic data,and large igneous province ages.Part I of this study focuses on the periodicities of age histograms and geochemical averages developed from the seven databases,via spectral and cross-correlation analyses.Natural physical cycles often propagate in exact integer multiples of a fundamental cycle,referred to as harmonics.The tests show that harmonic geological cycles of~93.5 and~187 Myr have persisted throughout terrestrial history,and the cyclicities are statistically significant for U/Pb igneous zircon ages,U/Pb detrital zircon ages,U/Pb zircon-rim ages,large igneous province ages,meanεHf(t)for all samples,meanεHf(t)values for igneous-only samples,and relative abundance of mafic rocks.Equally important,cross-correlation analyses show these seven time-series are nearly synchronous(±7 Myr)with a model consisting of periodicities of 93.5 and 187 Myr.Additionally,the similarities between peaks in the 93.5 and 187 Myr mantle cycles and terminal ages of established and suspected superchrons provide a framework for predicting and testing superchron periodicity. 展开更多
关键词 ZIRCON Database Isotope Statistical ANALYSIS Spectral ANALYSIS Cross correlation
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基于嵌入超表面的雷达吸波结构带宽拓展方法研究
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作者 庄海燕 杨燚 +2 位作者 叶志民 陈翔 黄程达 《材料开发与应用》 CAS 2019年第3期96-101,共6页
提出了一种基于嵌入十字形超表面的雷达吸波结构带宽拓展方法,仿真了超表面的十字形参数变化对结构材料吸波性能的影响,通过十字形结构单元的表面电流情况分析了产生共振的原因;仿真和实验结果都表明所设计的超表面嵌入雷达吸波结构后,... 提出了一种基于嵌入十字形超表面的雷达吸波结构带宽拓展方法,仿真了超表面的十字形参数变化对结构材料吸波性能的影响,通过十字形结构单元的表面电流情况分析了产生共振的原因;仿真和实验结果都表明所设计的超表面嵌入雷达吸波结构后,在16.6 GHz附近增加了一个较大吸收峰,峰值达到了-33.4 dB,在雷达吸波结构材料厚度及面密度基本不变的情况下拓宽了其高频吸波效果。 展开更多
关键词 超表面 十字形 拓展 吸波结构材料
Measurement of the neutron total cross section of carbon at the Back-n white neutron beam of CSNS 预览
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作者 Xing-Yan Liu Yi-Wei Yang +78 位作者 Rong Liu Jie Wen Zhong-Wei Wen Zi-Jie Han Zhi-Zhou Ren Qi An Huai-Yong Bai Jie Bao Ping Cao Qi-Ping Chen Yong-Hao Chen Pin-Jing Cheng Zeng-Qi Cui Rui-Rui Fan Chang-Qing Feng Min-Hao Gu Feng-Qin Guo Chang-Cai Han Guo-Zhu He Yong-Cheng He Yue-Feng He Han-Xiong Huang Wei-Ling Huang Xi-Ru Huang Xiao-Lu Ji Xu-Yang Ji Hao-Yu Jiang Wei Jiang Han-Tao Jing Ling Kang Ming-Tao Kang Bo Li Lun Li Qiang Li Xiao Li Yang Li Shu-Bin Liu Guang-Yuan Luan Ying-Lin Ma Chang-Jun Ning Bin-Bin Qi Jie Ren Xi-Chao Ruan Zhao-Hui Song Hong Sun Xiao-Yang Sun Zhi-Jia Sun Zhi-Xin Tan Hong-Qing Tang Jing-Yu Tang Peng-Cheng Wang Qi Wang Tao-Feng Wang Yan-Feng Wang Zhao-Hui Wang Zheng Wang Qing-Biao Wu Xiao-Guang Wu Xuan Wu Li-Kun Xie Han Yi Li Yu Tao Yu Yong-Ji Yu Guo-Hui Zhang Jing Zhang Lin-Hao Zhang Li-Ying Zhang Qing-Min Zhang Qi-Wei Zhang Xian-Peng Zhang Yu-Liang Zhang Zhi-Yong Zhang Ying-Tan Zhao Liang Zhou Zu-Ying Zhou Dan-Yang Zhu Ke-Jun Zhu Peng Zhu 《核技术:英文版》 SCIE CAS CSCD 2019年第9期73-82,共10页
To verify the performance of the neutron total cross-sectional spectrometer, the neutron total cross section of carbon is initially measured in the energy range of 1 eV to 20 MeV using the time-of-flight method. The m... To verify the performance of the neutron total cross-sectional spectrometer, the neutron total cross section of carbon is initially measured in the energy range of 1 eV to 20 MeV using the time-of-flight method. The measurement is performed at the Back-n white neutron source with a 76-m time-of-flight path using the China Spallation Neutron Source. A multilayer fast fission chamber with 235U and 238U is employed as the neutron detector. The diameter and thickness of the natural graphite sample are 70 mm and 40 mm, respectively. Signal waveforms are collected using a data acquisition system. Off-line data processing was used to obtain the neutron time-of-flight spectra and transmissions. The uncertainty of the counting statistics is generally approximately 3% for each bin in the energy range of 1–20 MeV. It is determined that the results for the neutron total cross section of carbon obtained using ^235U cells are in good agreement with the results obtained using 238U cells within limits of statistical uncertainty. Moreover, the measured total cross sections show good agreement with the broadening evaluated data. 展开更多
关键词 CSNS Back-n WHITE NEUTRON source NTOX NEUTRON total cross section CARBON Multilayer fast FISSION chamber
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THz time domain monostatic radar cross section measurement of metallic plates and dihedrons 预览
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作者 HUO Yiwei WU Yajun WANG Xiaobing 《太赫兹科学与电子信息学报》 北大核心 2019年第4期567-571,共5页
THz Radar Cross Section(RCS)measurement setup based on THz Time Domain Spectroscopy(TDS)is built to provide large scaled targets test ability in recent years.As calibrations,the metal plates and dihedrons are used in ... THz Radar Cross Section(RCS)measurement setup based on THz Time Domain Spectroscopy(TDS)is built to provide large scaled targets test ability in recent years.As calibrations,the metal plates and dihedrons are used in our experiments.The measurements are performed in a monostatic terahertz time-domain setup.The author proposed time domain and frequency domain calibration methods for angular RCS of calibrations,comparing the measurements with the theory to verify the ability of the time domain measurement setup. 展开更多
关键词 monostatic Radar Cross Section TERAHERTZ metallic plates and dihedrons THz Time Domain Spectroscopy
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