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溴化顺式-溴·氨·二(乙二胺)合钴(III)绝对不对称合成与拆分机理 被引量:4
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作者 章慧 王宪营 +3 位作者 陈雷奇 方雪明 高景星 徐志固 《物理化学学报》 SCIE CAS CSCD 北大核心 2006年第5期608-615,共8页
分别用绝对不对称合成和改进的拆分方法制备标题配合物!-(+)D-cis-[CoBr(NH3)(en)2]Br2(1)和'-(-)D-cis-[CoBr(NH3)(en)2]Br2(2),以及制备了cis-[CoBr(NH3)(en)2]Br·22H2O(3)(en=1,2-乙二胺).用元素分析、差热-热重、旋光度、U... 分别用绝对不对称合成和改进的拆分方法制备标题配合物!-(+)D-cis-[CoBr(NH3)(en)2]Br2(1)和'-(-)D-cis-[CoBr(NH3)(en)2]Br2(2),以及制备了cis-[CoBr(NH3)(en)2]Br·22H2O(3)(en=1,2-乙二胺).用元素分析、差热-热重、旋光度、UV-Vis、CD光谱等对产物进行了表征.通过CD光谱法获得了绝对不对称合成Co(III)配合物的产物ee值分布图.当利用绝对不对称合成得到的手性Co(III)配合物去“逆向拆分”外消旋溴代樟脑磺酸铵[NH4(dl-BCS)]时只获得部分拆分,初步认为这与交互拆分过程中阴阳离子之间的有效手性识别有关,对于手性Co(III)配合物的绝对不对称合成还提出了一个新的反应机理,即“催化-结晶诱导”机理. 展开更多
关键词 绝对不对称合成 手性对称性破缺 手性Co(Ⅲ)配合物 光学拆分 圆二色光谱 手性识别
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BPOB的绝对不对称合成机理及固体CD光谱 被引量:1
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作者 宣为民 邹方 +3 位作者 陈雷奇 方雪明 连伟 章慧 《物理化学学报》 SCIE CAS CSCD 北大核心 2008年第6期955-960,共6页
以苯乙酮与间苯二甲酸甲酯为原料经由Claisen缩合制备了1,3-二(3-苯基-3-氧代丙烯醇)苯(BPOB).用元素分析、MS、1H NMR、UV吸收光谱、X射线单晶衍射和固体CD光谱等对其进行了表征.晶体结构数据显示,BPOB属于Sohncke空间群P212121,UV和1H... 以苯乙酮与间苯二甲酸甲酯为原料经由Claisen缩合制备了1,3-二(3-苯基-3-氧代丙烯醇)苯(BPOB).用元素分析、MS、1H NMR、UV吸收光谱、X射线单晶衍射和固体CD光谱等对其进行了表征.晶体结构数据显示,BPOB属于Sohncke空间群P212121,UV和1H NMR谱表明,BPOB在溶液中主要以烯醇式存在,固体CD光谱和重结晶实验证明,BPOB手性晶体的形成是结晶诱导的绝对不对称合成. 展开更多
关键词 1 3-二(3-苯基-3-氧代丙烯醇)苯 手性对称性破缺 绝对不对称合成 手性晶体 固体CD光谱
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缩氨基(硫)脲席夫碱化合物的自发对称性破缺研究 被引量:2
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作者 林丽榕 胡望霞 +3 位作者 马杰 章慧 黄荣彬 郑兰荪 《化学学报》 SCIE CAS CSCD 北大核心 2010年第7期703-706,共4页
制备了4-苯基-1-(吡啶-2-亚甲基)氨基脲(PPMSC)和4-苯基-1-(吡啶-2-亚甲基)氨基硫脲(PPMTC).用元素分析、MS、1HNMR、UV吸收光谱、X射线单晶衍射和固体CD光谱等对其进行了表征.晶体结构数据显示PPMSC属于Sohncke P212121空间群,单个分... 制备了4-苯基-1-(吡啶-2-亚甲基)氨基脲(PPMSC)和4-苯基-1-(吡啶-2-亚甲基)氨基硫脲(PPMTC).用元素分析、MS、1HNMR、UV吸收光谱、X射线单晶衍射和固体CD光谱等对其进行了表征.晶体结构数据显示PPMSC属于Sohncke P212121空间群,单个分子之间通过氢键形成一个一维螺旋链状结构,沿a轴形成左手螺旋结构.固体CD光谱和重结晶实验证明,PPMSC手性晶体的形成是结晶诱导的绝对不对称合成.PPMTC的固体CD光谱和重结晶实验具有与PPMSC类似现象. 展开更多
关键词 4-苯基-1-(吡啶-2-亚甲基)氨基脲 4-苯基-1(吡啶-2-亚甲基)氨基硫脲 手性对称性破缺 绝对不对称合成 手性晶体 固体CD光谱
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An Extended Chiral SU(3) Quark Model
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作者 ZHANGZong-Te YUYou-Wen +1 位作者 WANGPing DAILiao-Rong 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第5期569-572,共4页
The chiral SU(3) quark model is extended by including the vector meson exchanges to describe the short range interactions. The phase shifts of NN scattering are studied in this model. Compared with the results of the ... The chiral SU(3) quark model is extended by including the vector meson exchanges to describe the short range interactions. The phase shifts of NN scattering are studied in this model. Compared with the results of the chiral SU(3) quark model in which only the pseudo-scalar and scalar chiralfields are considered, the phase shifts of 1 So wave are obviously improved. 展开更多
关键词 夸克模型 手性对称性 QCD 粒子物理学 强相互作用
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Scalar Susceptibility of QCD from Dyson-Schwinger Approach
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作者 WU Kong-Ping SHI Yuan-Mei +2 位作者 SUN Wei-Min PING Jia-Lun ZONG Hong-Shi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第1期189-192,共4页
In quantum chromodynamics (QCD), the scalar susceptibility represents the modification of the quark condensate, to a small perturbation of the parameter responsible for the explicit breaking of the symmetry, i.e., t... In quantum chromodynamics (QCD), the scalar susceptibility represents the modification of the quark condensate, to a small perturbation of the parameter responsible for the explicit breaking of the symmetry, i.e., the current quark mass. By studying the linear response of the dressed quark propagator to the presence of a nonzero quark mass, we derive a model-independent formula for the scalar susceptibility, which contains the dressed quark propagator G(p) and the dressed scalar vertex F(p, 0). The numerical values of the scalar susceptibility Xs are calculated within the framework of the rainbow-ladder approximation of the Dyson-Schwinger approach by employing two typical forms of model gluon propagator. 展开更多
关键词 scalar susceptibility explicit and dynamical chiral symmetry breaking Dyson-Schwinger equations
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Porous Rh/BINAP polymers as efficient heterogeneous catalysts for asymmetric hydroformylation of styrene:Enhanced enantioselectivity realized by flexible chiral nanopockets 被引量:5
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作者 Tao Wang Wenlong Wang +6 位作者 Yuan Lyu Kai Xiong Cunyao Li Hao Zhang Zhuangping Zhan Zheng Jiang Yunjie Ding 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2017年第4期691-698,共8页
A new chiral monomer,(S)‐5,5′‐divinyl‐BINAP,was successfully synthesized and embedded intotwo different porous organic polymers(Poly‐1and Poly‐2).After loading a Rh species,the catalystswere applied for the hete... A new chiral monomer,(S)‐5,5′‐divinyl‐BINAP,was successfully synthesized and embedded intotwo different porous organic polymers(Poly‐1and Poly‐2).After loading a Rh species,the catalystswere applied for the heterogeneous asymmetric hydroformylation of styrene.Compared with thehomogeneous BINAP analogue,the enantioselectivity of Rh/Poly‐1catalyst was drastically increasedby approximately70%.The improved enantioselectivity of the porous Rh/BINAP polymerswas attributed to the presence of flexible chiral nanopockets resulting from the increased bulk ofthe R groups near the catalytic center. 展开更多
关键词 Porous organic polymer Heterogeneous catalysis Asymmetric hydroformylation Enhanced enatioselectivity Chiral nanopocket
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Quark Condensate in the Strange Matter
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作者 LU-Chang-Fang LUXiao-LU 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第5期593-596,共4页
In a nonlinear chiral SU(3) framework, we investigate the quark condensate in the strange matter including and Λ, making use of chiral symmetry spontaneous breaking Lagrangian and mean-field approximation. The resul... In a nonlinear chiral SU(3) framework, we investigate the quark condensate in the strange matter including and Λ, making use of chiral symmetry spontaneous breaking Lagrangian and mean-field approximation. The results show that the chiral symmetry is restored partially when the strange matter density increases and that plays a very important role in the strange matter which may approach the constituents of the neutron stars. In addition, we can find that the strange matter density where the π-condensate emerges leads to the ratio of the nucleon number to baryon number. 展开更多
关键词 quark condensate chiral symmetry spontaneous breaking Lagrangian Hellmann-Feynman theory
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Neutron Stars in the Model of Non—linear Realization of SU(2) Chiral Symmetry Spontaneous Breaking
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作者 WANGNan SUNBao-Xi +1 位作者 LUEXiao-Fu ZHAOEn-Guang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第5期603-606,共4页
The properties of neutron stars are studied in a relativistic mean-field model with SU(2) chiral symmetry spontaneous breaking being considered. The calculation results indicate that the effects of the chiral symmetry... The properties of neutron stars are studied in a relativistic mean-field model with SU(2) chiral symmetry spontaneous breaking being considered. The calculation results indicate that the effects of the chiral symmetry spontaneous breaking are not negligible. 展开更多
关键词 neutron star chiral symmetry spontaneous breaking relativistic mean-field approximation
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Chiral Phase Transition at Finite Isospin Density in Linear Sigma Model
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作者 SHUSong LIJia-Rong 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第3期487-492,共6页
Using the linear sigma model, we have introduced the pion isospin chemical potential. The chiral phase transition is studied at finite temperatures and finite isospin densities. We have studied the μ - T phase diagra... Using the linear sigma model, we have introduced the pion isospin chemical potential. The chiral phase transition is studied at finite temperatures and finite isospin densities. We have studied the μ - T phase diagram for the chiral phase transition and found the transition cannot happen below a certain low temperature because of the BoseEinstein condensation in this system. Above that temperature, the chiral phase transition is studied by the isotherms of pressure versus density. We indicate that the transition, in the chiral limit, is a first-order transition from a low-density phase to a high-density phase like a gas-liquid phase transition. 展开更多
关键词 finite temperature field theory nuclear matter chiral symmetries
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Ωω States in a Chiral Quark Model
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作者 WANG Wen-Ling HUANG Fei +2 位作者 ZHANG Zong-Ye YU You-Wen LIU Feng 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第4X期695-698,共4页
The structures of Ωω states with spin-parity JP= 5/2^-, 3/2^-, and 1/2^- are dynamically studied in both the chlral SU(3) quark model and the extended chiral SU(3) quark model by solving a resonating group meth... The structures of Ωω states with spin-parity JP= 5/2^-, 3/2^-, and 1/2^- are dynamically studied in both the chlral SU(3) quark model and the extended chiral SU(3) quark model by solving a resonating group method (RGM) equation. The model parameters are taken from our previous work, which gave a satisfactory description of the energies of the baryon ground states, the binding energy of the deuteron, the nucleon-nucleon (NN) scattering phase shifts, and the hyperon-nucleon (YN) cross sections. The calculated results show that the Ωω state has an attractive interaction, and in the extended chiral SU(3) quark model such attraction can make for a Ωω quasi-bound state with spin-parity JP = 3/2^- or 5/2^- and the binding energy of about several MeV. 展开更多
关键词 Ωω quasi-bound states quark model chiral symmetry
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飞秒激光直写玻璃基三维波导拓扑光子学结构(特邀)
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作者 王睿琦 李础 李焱 《光学学报》 EI CAS CSCD 北大核心 2024年第17期197-213,共17页
飞秒激光直写技术具有优异的三维直写能力,可以灵活精确地构造和调控复杂波导阵列的结构和参数,是制备拓扑光子元器件的重要手段。综述了利用飞秒激光直写技术在玻璃内部制备的各类光波导拓扑结构,包括打破和不打破时间反演对称性的周... 飞秒激光直写技术具有优异的三维直写能力,可以灵活精确地构造和调控复杂波导阵列的结构和参数,是制备拓扑光子元器件的重要手段。综述了利用飞秒激光直写技术在玻璃内部制备的各类光波导拓扑结构,包括打破和不打破时间反演对称性的周期性晶格以及非厄米拓扑光波导系统,介绍了相应的研究进展,总结了面临的挑战,并提出了可能的解决方案。 展开更多
关键词 飞秒激光直写 时间反演对称性破缺周期晶格 手性对称性周期晶格 非厄米拓扑
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Low-Energy Kπ Phase Shifts in Chiral SU(3) Quark Model
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作者 HUANG Fei ZHANG Zong-Ye YU You-Wen 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第4X期665-669,共5页
The low-energy region kaon-pion S- and P-wave phase shifts with isospin I = 1/2 and I = 3/2 are dynamically studied in the chiral SU(3) quark model by solving a resonating group method equation. The model parameters a... The low-energy region kaon-pion S- and P-wave phase shifts with isospin I = 1/2 and I = 3/2 are dynamically studied in the chiral SU(3) quark model by solving a resonating group method equation. The model parameters are taken to be the values fitted by the energies of the baryon ground states and the kaon-nucleon elastic scattering phase shifts of different partial waves. As a preliminary study the s-channel q(-q) annihilation interactions are not included since they only act in the very short range and are subsequently assumed to be unimportant in the low-energy domain. The numerical results are in qualitative agreement with the experimental data. 展开更多
关键词 phase shifts quark model chiral symmetry
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引入Polyakov环路的手征模型中的涨落与相变(英文)
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作者 C.Sasaki B.Friman K.Redlich 《高能物理与核物理》 CSCD 北大核心 2007年第12期1141-1144,共4页
We explore the NJL model with Polyakov loops for a system of three colors and two flavors within the mean-field approximation,where both chiral symmetry and confinement are taken into account.We focus on the phase str... We explore the NJL model with Polyakov loops for a system of three colors and two flavors within the mean-field approximation,where both chiral symmetry and confinement are taken into account.We focus on the phase structure of the model and study the chiral and Polyakov loop susceptibilities. 展开更多
关键词 相变 手性对称性 NJL模型 磁化系数 脉动
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