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On the transience and recurrence of Lamperti’s random walk on Galton-Watson trees
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作者 Wenming Hong Minzhi Liu 《中国科学:数学英文版》 SCIE CSCD 2019年第9期1813-1822,共10页
In a Galton-Watson tree generated by a supercritical branching process with offspring N and EN =:m > 1, the conductance assigned to the edge between the vertex x and its parent x* is denoted by C(x) and given by C(... In a Galton-Watson tree generated by a supercritical branching process with offspring N and EN =:m > 1, the conductance assigned to the edge between the vertex x and its parent x* is denoted by C(x) and given by C(x) =(λ +A/|x|α)-|x|, where |x| is the generation of the vertex x. For(Xn)n≥0, a C(x)-biased random walk on the tree, we show that (1) when λ≠ m, α > 0,(Xn)n≥0 is transient/recurrent according to whether λ < m or λ > m, respectively;(2) when λ = m, 0 < α < 1,(Xn)n≥ 0 is transient/recurrent according to whether A < 0 or A > 0, respectively.In particular, if P(N = 1) = 1, the C(x)-biased random walk is Lamperti’s random walk on the nonnegative integers(see Lamperti(1960)). 展开更多
关键词 INHOMOGENEOUS biased random WALK on the branching tree TRANSIENCE RECURRENCE time-inhomogeneous branching process
A branching heuristic for SAT solvers based on complete implication graphs
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作者 Fan XIAO Chu-Min LI +3 位作者 Mao LUO Felip MANYA Zhipeng Lü Yu LI 《中国科学:信息科学(英文版)》 SCIE EI CSCD 2019年第7期170-182,共13页
The performance of modern conflict-driven clause learning(CDCL) SAT solvers strongly depends on branching heuristics. State-of-the-art branching heuristics, such as variable state independent decaying sum(VSIDS) and l... The performance of modern conflict-driven clause learning(CDCL) SAT solvers strongly depends on branching heuristics. State-of-the-art branching heuristics, such as variable state independent decaying sum(VSIDS) and learning rate branching(LRB), are computed and maintained by aggregating the occurrences of the variables in conflicts. However, these heuristics are not sufficiently accurate at the beginning of the search because they are based on very few conflicts. We propose the distance branching heuristic, which,given a conflict, constructs a complete implication graph and increments the score of a variable considering the longest distance between the variable and the conflict rather than the simple presence of the variable in the graph. We implemented the proposed distance branching heuristic in Maple LCM and Glucose-3.0, two of the best CDCL SAT solvers, and used the resulting solvers to solve instances from the application and crafted tracks of the 2014 and 2016 SAT competitions and the main track of the 2017 SAT competition. The empirical results demonstrate that using the proposed distance branching heuristic in the initialization phase of Maple LCM and Glucose-3.0 solvers improves performance. The Maple LCM solver with the proposed distance branching heuristic in the initialization phase won the main track of the 2017 SAT competition. 展开更多
关键词 SAT branching HEURISTIC conflict-driven CLAUSE learning IMPLICATION GRAPH
Asymptotic Behaviors for Critical Branching Processes with Immigration
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作者 Dou Dou LI Mei ZHANG 《数学学报:英文版》 SCIE CSCD 2019年第4期537-549,共13页
In this paper, we investigate the asymptotic behaviors of the critical branching process with immigration {Zn, n ≥ 0}. First we get some estimation for the probability generating function of Zn. Based on it, we get a... In this paper, we investigate the asymptotic behaviors of the critical branching process with immigration {Zn, n ≥ 0}. First we get some estimation for the probability generating function of Zn. Based on it, we get a large deviation for Zn+1/Zn. Lower and upper deviations for Zn are also studied. As a by-product, an upper deviation for max1≤i≤n Zi is obtained. 展开更多
关键词 CRITICAL branching PROCESS IMMIGRATION LARGE DEVIATIONS
L log L criterion for a class of multitype superdiffusions with non-local branching mechanisms
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作者 Zhen-Qing Chen Yan-Xia Ren Renming Song 《中国科学:数学》 CSCD 北大核心 2019年第8期I0001-I0004,共4页
In this paper, we provide a pathwise spine decomposition for multitype superdiffusions with non-local branching mechanisms under a martingale change of measure. As an application of this decomposition, we obtain a nec... In this paper, we provide a pathwise spine decomposition for multitype superdiffusions with non-local branching mechanisms under a martingale change of measure. As an application of this decomposition, we obtain a necessary and sufficient condition (called the L log L criterion) for the limit of the fundamental martingale to be non-degenerate. This result complements the related results obtained in Kyprianou et al.(2012), Kyprianou and Murillo-Salas (2013) and Liu et al.(2009) for superprocesses with purely local branching mechanisms and in Kyprianou and Palau (2018) for super Markov chains. 展开更多
关键词 multitype SUPERDIFFUSION NON-LOCAL branching mechanism SWITCHED diflFusion SPINE decomposition MARTIN GALE
Impact of alkyl chain branching positions on molecular packing and electron transport of dimeric perylenediimide derivatives 预览
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作者 Yuan Guo Guangchao Han Yuanping Yi 《能源化学:英文版》 SCIE EI CAS CSCD 2019年第8期138-143,I0006共7页
Side chains play a critical role in tuning intermolecular interaction and charge transport in organic semiconductors. Here, we have systematically investigated the impact of branching positions of the alkyl side chain... Side chains play a critical role in tuning intermolecular interaction and charge transport in organic semiconductors. Here, we have systematically investigated the impact of branching positions of the alkyl side chains on the molecular packing and electron transport properties of a series of bay-linked dimeric perylenediimide(PDI) derivatives by atomistic molecular dynamics simulations in combination with charge transfer rate theory and kinetic Monte Carlo simulations. The results show that despite of different branching positions of the alkyl chains,π–π stacking is effectively inhibited for all the dimeric PDI derivatives. As the branching position moves away from the PDI backbone, the appearance of the alkyl atoms around the PDI backbone will first decrease and then increase. Correspondingly, the short contacts between the PDI moieties are first enhanced and then reduced. In particular, when the branching position is at the third carbon atom, the intermolecular connectivity becomes the most effective and the electron mobility is significantly increased by 2 times. 展开更多
关键词 Molecular packing Electron MOBILITY Branching POSITION PERYLENEDIIMIDE
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MOMENTS OF CONTINUOUS-STATE BRANCHING PROCESSES IN LEVY RANDOM ENVIRONMENTS 预览
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作者 季丽娜 郑祥祺 《数学物理学报:B辑英文版》 SCIE CSCD 2019年第3期781-796,共16页
For continuous-state branching processes in Levy random environments, the recursion of n-moments and the equivalent condition for the existence of general f-moments are established, where f is a positive continuous fu... For continuous-state branching processes in Levy random environments, the recursion of n-moments and the equivalent condition for the existence of general f-moments are established, where f is a positive continuous function satisfying some standard conditions. 展开更多
关键词 Branching processes continuous-state MOMENTS random environment STOCHASTIC EQUATIONS
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Comparison of Five Endogenous Reference Genes for Specific PCR Detection and Quantification of Rice 预览
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作者 ZHANG Xiujie JIN Wujun +4 位作者 XU Wentao LI Xiaying SHANG Ying LI Sha OUYANG Hongsheng 《水稻科学:英文版》 CSCD 2019年第4期248-256,I0006,I0007共11页
Endogenous reference genes (ERGs) provide vital information regarding genetically modified organisms (GMOs). The successful detection of ERGs can identity GMOs and the source of genes, verify stability and reliability... Endogenous reference genes (ERGs) provide vital information regarding genetically modified organisms (GMOs). The successful detection of ERGs can identity GMOs and the source of genes, verify stability and reliability of the detection system, and calculate the level of genetically modified (GM) ingredients in mixtures. The reported ERGs in rice include sucrose-phosphate synthase (SPS), phospholipase D (PLD), RBE4 and rice root-specific GOS9 genes. Based on the characteristics of ERGs, a new ERG gene, phosphoenolpyruvate carboxylase (PEPC), was selected, and further compared with the four existing genes. A total of 18 rice varieties and 29 non-rice crops were used to verify the interspecies specificity, intraspecies consistency, sensitivity, stability and reliability of these five ERGs using qualitative and quantitative PCR. Qualitative detection indicated that SPS and PEPC displayed sufficient specificity, and the detection sensitivity was 0.05% and 0.005%, respectively. Although the specificity of both RBE4 and GOS9 were adequate, the amplicons were small and easily confused with primer dimers. Non-specific amplification of the PLD gene was present in maize and potato. Real-time quantitative PCR detection indicated that PLD, SPS and PEPC displayed good specificity, with R2 of the standard curve greater than 0.98, while the amplification efficiency ranged between 90% and 110%. Both the detection sensitivities of PLD and PEPC were five copies and that of SPS was ten copies. RBE4 showed typical amplification in maize, beet and Arabidopsis, while GOS9 was found in maize, tobacco and oats. PEPC exhibited excellent detection sensitivity and species specificity, which made it a potentially useful application in GM-rice supervision and administration. Additionally, SPS and PLD are also suitable for GM-rice detection. This study effectively established a foundation for GMO detection, which not only provides vital technical support for GMO identification, but also is of great significance for enhancing the comparability o 展开更多
关键词 ENDOGENOUS reference GENE RICE genetically modified crop PHOSPHOENOLPYRUVATE CARBOXYLASE GENE sucrose-phosphate synthase GENE phospholipase D GENE starch branching enzyme 4 GENE RICE root-specific GOS9 GENE
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Evidence for the decays of ∧c^+→∑^+η and ∑^+η’
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作者 麦迪娜 M.N.Achasov +146 位作者 S.Ahmed M.Albrecht M.Aleksee 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 O.Cakir 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 陈平亮 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 段鹏飞 范荆州 方建 房双世 方易 R.Farinelli L.Fava S.Fegan 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 T.Hussain N.Hu sken W.Ikegami Andersson M.Irshad 纪全 姬清平 季晓斌 季筱璐 江晓山 蒋兴雨 焦健斌 焦铮 金大鹏 金山 金毅 T.Johansson A.Julin 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.Kornicer M.Kuemmel M.Kuessner A.Kupsc M.Kurth W.Kuhn J.S.Lange P.Larin L.La 《中国物理C:英文版》 SCIE CAS CSCD 2019年第8期15-23,共9页
We study the hadronic decays of ∧c^+ to the final states ∑^+η and ∑^+η, using an e^+e^- annihilation data sample of 567 pb^-1 taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BEPCII col... We study the hadronic decays of ∧c^+ to the final states ∑^+η and ∑^+η, using an e^+e^- annihilation data sample of 567 pb^-1 taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BEPCII collider. We find evidence for the decays ∧^+→∑^+η and ∑^+η' and with statistical significance of and , respectively. Normalizing to the reference decays ∧^+→∑^+π^0 and ∑^+ω, we obtain the ratios of the branching fractions B(∧C^+→∑^+η)/V(∧^→∑^+π^0)and B(∧C^+→∑^+η)/B(∧C^+→∑^+ω)to be and , respectively. The upper limits at the 90% confidence level are set to be B(∧C^→∑^+η)/V(∧^+→∑^+π^0)<0.58 and B(∧C^+→∑^+η)/B(∧C^+→∑^+ω)<1.2. Using BESIII measurements of the branching fractions of the reference decays, we determine B(∧C^+→∑^+η)=(0.41±019±0.05)%(<0.68%) and B(∧C^+→∑^+η)=(1.34+0.53+0.19)%(<1.9%). Here, the first uncertainties are statistical and the second systematic. The obtained branching fraction of ∧C^+→∑^+η is consistent with the previous measurement, and the branching fraction of ∧C^+→∑^+η is measured for the first time. 展开更多
关键词 charmed BARYON ∧c^+ DECAYS branching FRACTIONS
L log L criterion for a class of multitype superdiffusions with non-local branching mechanisms
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作者 Zhen-Qing Chen Yan-Xia Ren Renming Song 《中国科学:数学英文版》 SCIE CSCD 2019年第8期1439-1462,共24页
In this paper, we provide a pathwise spine decomposition for multitype superdiffusions with nonlocal branching mechanisms under a martingale change of measure. As an application of this decomposition,we obtain a neces... In this paper, we provide a pathwise spine decomposition for multitype superdiffusions with nonlocal branching mechanisms under a martingale change of measure. As an application of this decomposition,we obtain a necessary and sufficient condition(called the L log L criterion) for the limit of the fundamental martingale to be non-degenerate. This result complements the related results obtained in Kyprianou et al.(2012),Kyprianou and Murillo-Salas(2013) and Liu et al.(2009) for superprocesses with purely local branching mechanisms and in Kyprianou and Palau(2018) for super Markov chains. 展开更多
关键词 multitype SUPERDIFFUSION NON-LOCAL branching mechanism SWITCHED diffusion SPINE decomposition MARTINGALE
Study of the s→dννrare hyperon decays in the Standard Model and new physics
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作者 胡晓会 赵振兴 《中国物理C:英文版》 SCIE CAS CSCD 2019年第9期26-32,共7页
FCNC processes offer important tools to test the Standard Model(SM)and to search for possible new physics.In this work,we investigate the s→dννrare hyperon decays in SM and beyond.We find that in SM the branching r... FCNC processes offer important tools to test the Standard Model(SM)and to search for possible new physics.In this work,we investigate the s→dννrare hyperon decays in SM and beyond.We find that in SM the branching ratios for these rare hyperon decays range from 10^-14 to 10^-11.When all the errors in the form factors are included,we find that the final branching ratios for most decay modes have an uncertainty of about 5%to 10%.After taking into account the contribution from new physics,the generalized SUSY extension of SM and the minimal 331 model,the decay widths for these channels can be enhanced by a factor of 2~7. 展开更多
关键词 branching ratios RARE HYPERON DECAYS FORM factors LIGHT-FRONT approach new PHYSICS
Dendritic branching patterns in platforms of complex Ni-based single crystal castings
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作者 Min Huang Gong Zhang +4 位作者 Dong Wang Zhi-cheng Ge Yu-zhang Lu Xiang-wei Jiang Lang-hong Lou 《中国铸造:英文版》 SCIE 2019年第2期110-117,共8页
Dendritic branching patterns at variable cross-sections in Ni-based single crystal(SX) castings of different generations were investigated using optical microscope(OM), electro probe microanalyzer(EPMA),differential s... Dendritic branching patterns at variable cross-sections in Ni-based single crystal(SX) castings of different generations were investigated using optical microscope(OM), electro probe microanalyzer(EPMA),differential scanning calorimeter(DSC), Thermo-Cal software and Pro-CAST software. Results show that the dendritic branching patterns are similar in outward platform in SXs of different generations. That is, the primary dendrites(PDs) are introduced into the platform by developing a series of secondary dendrites(SDs) to occupy the bottom of the platform, and the ternary dendrites(TDs) originating from these SDs grow upward to fill up the platform. With the SX generation increasing, the undercooling of melts in the inward platform increases significantly due to the increasing alloying elements and the segregation in the directional solidification(DS)process, and the growth velocity of the dendrite tip increases according to the dynamic model of dendrite growth,which is beneficial for the high-order dendrite development. The stronger dendritic branching ability is shown in the inward platform of the higher generation Ni-based SX. 展开更多
关键词 DENDRITIC branching patterns platform UNDERCOOLING
奶牛乳腺分支模型的建立 预览
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作者 崔英俊 于广璞 +5 位作者 汤云飞 李慧铭 边艳杰 孙喆 刘智宇 孙霞 《中国乳品工业》 CAS 北大核心 2019年第1期16-18,共3页
利用从青春期奶牛乳腺中提取的类器官,在Ⅰ型胶原中以镶嵌式进行三维培养,用碱性成纤维细胞生长因子(basic fibroblastgrowth factor,FGF2)处理来建立奶牛乳腺分支模型。结果表明,在Ⅰ型胶原中以镶嵌式培养的青春期奶牛乳腺类器官,在FGF... 利用从青春期奶牛乳腺中提取的类器官,在Ⅰ型胶原中以镶嵌式进行三维培养,用碱性成纤维细胞生长因子(basic fibroblastgrowth factor,FGF2)处理来建立奶牛乳腺分支模型。结果表明,在Ⅰ型胶原中以镶嵌式培养的青春期奶牛乳腺类器官,在FGF2处理下36 h时镜下即可见分支形态出现;且从36 h开始,FGF2组分支率显著高于对照组,表明奶牛乳腺分支化培养模型成功建立。结论:FGF2能使镶嵌在Ⅰ型胶原中的青春期奶牛乳腺类器官产生分支形态。 展开更多
关键词 奶牛 乳腺 分支 Ⅰ型胶原
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光电离速率影响大气压空气正流注分支的机理研究 预览
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作者 涂婧怡 陈赦 汪沨 《物理学报》 SCIE EI CAS CSCD 北大核心 2019年第9期203-211,共9页
大气压空气中的流注放电有广泛的理论和应用研究价值,包括雷电机理、输变电系统空气绝缘理论以及材料表面改性等.流注是一个快速发展的强电离区域,在传播过程中存在着一种重要的特点—分支现象.光电离为正流注发展提供必要的自由电子,... 大气压空气中的流注放电有广泛的理论和应用研究价值,包括雷电机理、输变电系统空气绝缘理论以及材料表面改性等.流注是一个快速发展的强电离区域,在传播过程中存在着一种重要的特点—分支现象.光电离为正流注发展提供必要的自由电子,且实验结果表明分支特征与流注头部的光电离速率密切相关.本文基于新的流注分支判据,采用了粒子网格单元与蒙特卡罗碰撞相结合(PIC-MCC)的三维放电模型(Pamdi3D)进行数值仿真验证.为了研究光电离速率对正流注分支的影响,仿真了毫米尺度间隙针-板电极正流注发展,系统研究了不同光电离参数的影响.当减小氮气-氧气比例、光子吸收截面或光电离效率系数后,流注均更早地出现分支现象.这些计算结果表明大气压空气中流注头部光电离速率的降低将导致其发生分支的概率更高. 展开更多
关键词 流注放电 分支 光电离 PIC-MCC 大气压等离子体
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底板梳状定向钻孔技术理论与实践
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作者 管强盛 《煤矿安全》 CAS 北大核心 2019年第2期72-75,共4页
针对突出薄煤层采用底板穿层钻孔进行瓦斯抽采存在钻孔穿煤长度短、钻孔轨迹无法控制、钻孔有效利用率低等问题,利用底板梳状定向钻孔技术在煤层底板岩层施工长距离钻孔,同时开分支进入煤层,实现对突出薄煤层的瓦斯治理。根据底板梳状... 针对突出薄煤层采用底板穿层钻孔进行瓦斯抽采存在钻孔穿煤长度短、钻孔轨迹无法控制、钻孔有效利用率低等问题,利用底板梳状定向钻孔技术在煤层底板岩层施工长距离钻孔,同时开分支进入煤层,实现对突出薄煤层的瓦斯治理。根据底板梳状定向钻孔施工特点,分析了底板梳状定向钻孔分支孔分支点位置的选择、分支孔间距确定、分支孔开孔施工工艺、钻孔轨迹控制等关键技术并给出了建议。实践证明,通过该套底板梳状定向钻孔技术的应用,能使底板梳状定向钻孔实现对大于500 m范围突出薄煤层的有效覆盖,大大提高钻孔利用率。 展开更多
关键词 突出薄煤层 瓦斯抽采 底板梳状定向钻孔 开分支 钻孔轨迹控制
Properties of Charmonium States in a Phenomenological Approach
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作者 Praveen P D’Souza Antony Prakash Monteiro K.B.Vijaya Kumar 《理论物理通讯:英文版》 SCIE CAS CSCD 2019年第2期192-202,共11页
We investigate the spectrum and decay rates of charmonium states within the framework of the non relativistic quark model by employing a Coulomb like potential from the perturbative one gluon exchange and the linear c... We investigate the spectrum and decay rates of charmonium states within the framework of the non relativistic quark model by employing a Coulomb like potential from the perturbative one gluon exchange and the linear confining potential along with the potential derived from instanton vacuum to account for the hyperfine mass splitting of charmonium states in variational approach. We predict radiative E1, M1, two-photon, lepton and two-gluon decay rates of low lying charmonium states. An overall agreement is obtained with the experimental masses and decay widths.We have estimated the branching ratio of two gluons decaying into light hadrons. 展开更多
关键词 non-relativistic quark model INSTANTONS CHARMONIUM radiative DECAY TWO GLUON DECAY TWO photon DECAY leptonic DECAY branching ratio
A Tree-valued Markov Process Associated with an Admissible Family of Branching Mechanisms
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作者 Hong Wei BI Hui HE 《数学学报:英文版》 SCIE CSCD 2019年第1期135-160,共26页
Let E■R be an interval. By studying an admissible family of branching mechanisms{ψt,t ∈E} introduced in Li [Ann. Probab., 42, 41-79(2014)], we construct a decreasing Levy-CRT-valued process {Tt, t ∈ E} by pruning ... Let E■R be an interval. By studying an admissible family of branching mechanisms{ψt,t ∈E} introduced in Li [Ann. Probab., 42, 41-79(2014)], we construct a decreasing Levy-CRT-valued process {Tt, t ∈ E} by pruning Lévy trees accordingly such that for each t ∈E, Tt is a ψt-Lévy tree. We also obtain an analogous process {Tt*,t ∈E} by pruning a critical Levy tree conditioned to be infinite. Under a regular condition on the admissible family of branching mechanisms, we show that the law of {Tt,t ∈E} at the ascension time A := inf{t ∈E;Tt is finite} can be represented by{Tt*,t∈E}.The results generalize those studied in Abraham and Delmas [Ann. Probab., 40, 1167-1211(2012)]. 展开更多
关键词 PRUNING ADMISSIBLE FAMILY branching PROCESS random TREE Levy TREE tree-valued PROCESS ascension PROCESS
Synthesis, Characterization, and Catalytic Ethylene Oligomerization of Pyridine-imine Palladium Complexes
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作者 Xiao-Lin Chen Jie Gao +2 位作者 Heng Liao Hai-Yang Gao Qing Wu 《高分子科学:英文版》 SCIE CAS CSCD 2018年第2期176-184,共9页
关键词 催化剂结构 建筑群 乙烯 合成 CH3CN 反应温度 催化活动 热稳定性
辐照支化聚乳酸的结晶及流变性能 预览
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作者 雷雁洲 王涛 +2 位作者 吕秦牛 李彪 李振中 《塑料工业》 CSCD 北大核心 2018年第4期47-50,共4页
采用三羟甲基丙烷三丙烯酸酯(TMPTA)、光引发剂、聚乳酸(PLA)作原料,经紫外光辐照,制备了支化聚乳酸。进一步研究了TMPTA添加量对PLA力学性能、结晶性能及流变特性的影响。结果表明,支化结构使分子链的物理缠结点增多,支化PLA表现... 采用三羟甲基丙烷三丙烯酸酯(TMPTA)、光引发剂、聚乳酸(PLA)作原料,经紫外光辐照,制备了支化聚乳酸。进一步研究了TMPTA添加量对PLA力学性能、结晶性能及流变特性的影响。结果表明,支化结构使分子链的物理缠结点增多,支化PLA表现出更高的冷结晶温度(Tcc),其中TMPTA添加量为2.5%的PLA的Tcc比线型PLA提高了9.2℃,也使PLA弹性模量、复数黏度得到提高。另外,支链也使聚合物分子链间距增大,PLA的韧性得到提高,TMPTA添加量为2.5%的PLA的冲击强度达到5.8 kJ/m^2,比线型PLA提高了70.6%。 展开更多
关键词 聚乳酸 紫外光辐照 支化 结晶性 流变特性
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Relative spectral response calibration using Ti plasma lines
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作者 费腾 潘从元 +2 位作者 曾强 王秋平 杜学维 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2018年第4期145-151,共7页
This work introduces the branching ratio (BR) method for determining relative spectral responses,which are needed routinely in laser induced breakdown spectroscopy (LIBS). Neutral and singlyionized Ti lines in the... This work introduces the branching ratio (BR) method for determining relative spectral responses,which are needed routinely in laser induced breakdown spectroscopy (LIBS). Neutral and singlyionized Ti lines in the 250-498 nm spectral range are investigated by measuring laser-induced microplasma near a Ti plate and used to calculate the relative spectral response of an entire LIBS detectionsystem. The results are compared with those of the conventional relative spectral response calibrationmethod using a tungsten halogen lamp, and certain lines available for the BR method are selected. Thestudy supports the common manner of using BRs to calibrate the detection system in LIBS setups. 展开更多
关键词 branching ratio RELATIVE SPECTRAL response calibration titanium laser-inducedbreakdown SPECTROSCOPY
大豆品种分枝数分级标准探索
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作者 张霞 谭冰 +5 位作者 郭勇 孙如建 张勇 刘章雄 洪慧龙 邱丽娟 《植物遗传资源学报》 CSCD 北大核心 2018年第3期510-516,共7页
大豆分枝与株型及其产量关系密切。大豆品种资源分枝数的表型鉴定对提高其利用效率具有重要指导意义。为了探索黑龙江大豆品种在北京异地种植条件下的分枝数.本研究以来源于我国东北生态区的49份大豆品种为材料.于2011年和2012年采用... 大豆分枝与株型及其产量关系密切。大豆品种资源分枝数的表型鉴定对提高其利用效率具有重要指导意义。为了探索黑龙江大豆品种在北京异地种植条件下的分枝数.本研究以来源于我国东北生态区的49份大豆品种为材料.于2011年和2012年采用随机区组试验.在45cm行距条件下,株距分别设置25cm、15cm和5cm.研究品种的分枝数及对种植密度的敏感性。结果表明,不同品种的分枝数存在极显著差异,并且各品种对种植密度的敏感程度不同。根据分枝数目将参试品种分为少分枝、中等分枝和多分枝3类;根据分枝数与种植密度的相关系数将参试品种分为不敏感、低度敏感、中等敏感和高度敏感4类。本研究为参试材料在不同株型优良品种培育中的利用提供了理论依据,也为大豆种质表型鉴定提供了参考。 展开更多
关键词 大豆 种植密度 分枝特性 密度敏感性
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