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Chinese Journal of Chemical Physics 2020年第1期33卷 91-100页

作者： Hong Gao Yu Song William M.Jackson cheuk-yiu ng Beijing National Laboratory for Molecular Sciences Institute of ChemistryChinese Academy of SciencesBeijing 100190China Department of Chemistry University of CaliforniaDavis CA 95616USA

The photoabsorption and photodissociation of carbon monoxide(CO)in the vacuum ultraviolet(VUV)region is one of the most important photochemical processes in the interstellar medium,thus it has attracted numerous experimental and theoretical ***,we employed the two-color VUV-VUV laser pump-probe time-slice velocity-map ion imaging method to measure the relative branching ratios[C(3P0)+O(1D)]/{[C(3P0)+O(3P)]+[C(3P0)+O(1D)]}and[C(3P2)+O(1D)]/{[C(3P2)+O(3P)]+[C(3P2)+O(1D)]}in the VUV photoexcitation energy range of 108000-113200 cm^−***,one tunable VUV laser beam is used to excite CO to speci c rovibronic states,and a second independently tunable VUV laser beam is used to state-selectively ionize C(3P0)and C(3P2)for ***-selective photoionization through the 1VUV+1UV/visible resonance-enhanced multiphoton ionization scheme has greatly enhanced the detection sensitivity,which makes many new weak absorption bands observable in the current *** branching ratio measurement shows that the spin-forbidden channels C(3P0)+O(1D)and C(3P2)+O(1D)only open at several discrete narrow energy *** might be caused by certain accidental resonanceenhanced spin-orbit interactions between the directly excited Rydberg states and valence states of triplet type which nally dissociate into the spin-forbidden channels.

关键词： Carbon monoxide Photodissociation Vacuum ultraviolet Branching ratio

High-Resolution Infrared-Vacuum Ultraviolet Photoion and Pulsed Field Ionization-Photoelectron Methods for Spectroscopic Studies of Neutrals and Cations

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Chinese Journal of Chemical Physics 2008年第3期21卷 193-201页

作者： Xi Xing Beth Reed Mi Kyung Bahng Peng Wang Hin Koo Woo Sun Jong Baek Chee Shing Lain cheuk yiu ng Department of Chemistry University of California Davis Davis California 95616 USA

We show that by scanning the frequency of a single mode infrared （IR） optical parametric oscillator （IR- OPO） laser to excite the molecular species of interest and fixing the frequency of a vacuum ultraviolet （VUV） laser to photoionize the IR excited species, high-resolution IR spectra of polyatomic neutrals can be obtained with high sensitivity. The fact that this IR-VUV-photoion （IR-VUV-PI） method is based on VUV photoionization probe, and thus, allows the identification of the neutral IR absorber, makes it applicable for IR spectroscopy measurements of isotopemers, radicals, and clusters, which usually exist as impure samples. The highly resolved IR-VUV-PI measurements achieved using the single mode IR-OPO laser have made possible the selection of single rovibrational states of CH3X （X=Br and I）, C2H4, and C3H4 for VUV-pulsed field ionization-photoelectron （VUV-PFI-PE） measurements, resulting in rovibrationally resolved photoelectron spectra for these polyatomic molecules. These experiments show that the signal- to-noise ratios of the IR-VUV-PI and IR-VUV-PFI-PE spectra obtained by employing the high-resolution IR-OPO laser are significantly higher than those observed in previous IR-VUV-PI and IR-VUV-PFI-PE studies using a low-resolution IR-OPO laser. Further improvement in sensitivity of IR-VUV-PI and IR- VUV-PFI-PE measurements by using the collinear arrangement of IR-VUV lasers and molecular beam is discussed.

关键词： Vacuum ultraviolet Infrared Pulse-field photoelectron High resolution

Quantum State-to-State Vacuum Ultraviolet Photodissociation Dynamics of Small Molecules

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Chinese Journal of Chemical Physics 2019年第1期32卷 23-34,I0001页

作者： Hong Gao cheuk-yiu ng Beijing National Laboratory for Molecular Sciences (BNLMS) Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China Department of Chemistry University of California Davis CA 95616 USA

The present review focused on selected, recent experimental progress of photodissociation dynamics of small molecules covering the vacuum ultraviolet (VUV) range from 6 eV to 20 eV. These advancements come about due to the available laser based VUV light sources along with the developments of advanced experimental techniques, including the velocitymap imaging (VMI), H-atom Rydberg tagging time-of-flight (HRTOF) techniques, as well as the two-color tunable VUV-VUV laser pump-probe detection method. The applications of these experimental techniques have allowed VUV photodissociation studies of many diatomic and triatomic molecules to quantum state-to-state in detail. To highlight the recent accomplishments, we have summarized the results on several important molecular species, including H2 (D2, HD), CO, N2, NO, O2, H2O (D2O, HOD), CO2, and N2O. The detailed VUV photodissociation studies of these molecules are of astrochemical and atmospheric relevance. Since molecular photodissociation initiated by VUV excitation is complex and is often governed by multiple electronic potential energy surfaces, the unraveling of the complex dissociation dynamics requires state-to-state cross section measurements. The newly constructed Dalian Coherent Light Source (DCLS), which is capable of generating coherent VUV radiation with unprecedented brightness in the range of 50-150 nm, promises to propel the photodissociation experiment to the next level.

关键词： Photodissociation State-to-state Velocity-map imaging

The translational, rotational, and vibrational energy effects on the chemical reactivity of the cations: N2+（X~2Σg+;v+,N+） and H2O+(X~2B1;v1+v2+v3+;NKa+Kc++)

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The translational, rotational, and vibrational energy effect...

O(3P0,1,2,1D2) yield ratio measurement in VUV photodissociation of O2

第十三届全国化学动力学会议

作者： cheuk-yiu ng Department of Chemistry University of California

＜正＞The vacuum ultraviolet laser pulsed field ionization-photoion （PFI-PI） technique is employed to prepare reactant N2+ （X2Σg+） and H2O + （X2B1） ions in single rovibronic states. By using a novel electric field pulsing PFI-PI scheme, we have achieved high internal energy selection and high kinetic energy resolution, which allow absolute total cross section measurements of the rovibrationally selected

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O(3P0,1,2,1D2) yield ratio measurement in VUV photodissociat...

Rare case of intussusception in an adult with acute myeloid leukemia

第十五届全国化学动力学会议

作者：刘凯 Yih Chung Chang Konstantinos S.Kalogerakis Tom G.Slanger Bing Zhang William M.Jackson cheuk yiu ng Department of Chemistry University of California State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and MathematicsChinese Academy of Sciences Physical Sciences Division SRI International

The quantum yield of a VUV-induced photodissociation is defined as the ratio of the number of dissociative fragment created to the number of photons absorbed. Neutral photodissociation cross sections often remain significant for several electron volts above the ionization threshold and may be composed of contributions from both direct and indirect processes. We developed a method to measure the yield ratios of O atoms in different spin-orbital state, using VUV-VUV pump-probe lasers and the time-sliced velocity-map-imaging photoion(VMI-PI) method. Combining the quantum dissociation cross section data[1], we calculated the quantum yield for O P, P, P, D and S in VUV photodissociation of O(HП, v’=2) is 0.24(2), 0.31(2), 0.26(2), 0.38(2), 0, respectively.

关键词： superexcited oxygen quantum yield VUV photodissociation

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World Journal of Gastroenterology 2015年第2期21卷 688-693页

作者： Man Fai Law cheuk Kei Wong Chun Yin Pang Hay Nun Chan Ho Kei Lai Chung Yin Ha Celia ng yiu Ming Yeung Sze Fai Yip Department of Medicine Tuen Mun Hospital Department of Medicine and Therapeutics Prince of Wales Hospital Department of Radiology Kwong Wah Hospital Department of Pathology Tuen Mun Hospital

Intussusception is rarely reported in adult patients with acute leukemia. We report a case of intussusception in a 29-year-old woman with acute myeloid leukemia(AML). She developed right lower quadrant pain, fever, and vomiting on day 16 of induction *** examination showed tenderness and guarding at the right lower quadrant of the abdomen. Abdominal computed tomography(CT) showed distension of the cecum and ascending colon, which were filled with loops of small bowel, and herniation of the ileocecal valve into the cecum. We proceeded to laparotomy and revealed ileocecal intussusception with the ileocecal valve as the leading point. The terminal ileum was thickened and invaginated into the cecum, which showed gangrenous changes. Right hemicolectomy was performed and microscopic examination of the colonic tissue showed infiltration of leukemic cells. The patient recovered after the operation and was subsequently able to continue treatment for AML. This case demonstrates that the diagnosis of intussusception is difficult because the presenting symptoms can be non-specific, but abdominal CT can be informative for preoperative diagnosis. Resection of the involved bowel is recommended when malignancy is suspected or confirmed. Intussusception should be considered in any leukemia patients presenting with acute abdomen. A high index of clinical suspicion is important for early diagnosis.

关键词： Intussusception Acute leukemia Abdominal pain Colo

肇庆市“现代农业产业园+乡村旅游”发展策略研究

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南方农业 2020年第35期14卷 116-117页

作者：曾景瑜黄卓娆无广东省理工学院广东肇庆526100 肇庆市种子管理站广东肇庆526040

对怀集县现代农业产业园进行实地调研和资料查阅,进一步了解产业园区内企业实施主体的生产经营情况,农旅融合项目的实现形式、推进思路、存在问题等内容,并提出肇庆市“现代农业产业园+乡村旅游”发展策略,在现代农业产业园创建的基础... 详细信息

对怀集县现代农业产业园进行实地调研和资料查阅,进一步了解产业园区内企业实施主体的生产经营情况,农旅融合项目的实现形式、推进思路、存在问题等内容,并提出肇庆市“现代农业产业园+乡村旅游”发展策略,在现代农业产业园创建的基础上促进农旅融合发展。

关键词：现代农业产业园乡村旅游策略研究广东省肇庆市

基于三苯胺和咔唑的联吡啶铱化合物的合成及其在光催化水产氢中的应用研究

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合成化学 2018年第1期26卷 1-8页

作者：郑众姚思骏王婷何卓琳王启卫中国科学院成都有机化学研究所四川成都610041 中国科学院大学北京100049 香港浸会大学化学系香港999077

以三苯胺、咔唑、4,4'-二羧基联吡啶为原料,设计并合成了两个联吡啶铱(Ⅲ)配合物Ir1和Ir2,其结构经~1H NMR,^(13)C NMR和HR-MS(MALDI-TOF)表征。并利用紫外可见光谱(UV-Vis)、荧光发射光谱(Photoluminescence)和循环伏安法研究了化合物... 详细信息

以三苯胺、咔唑、4,4'-二羧基联吡啶为原料,设计并合成了两个联吡啶铱(Ⅲ)配合物Ir1和Ir2,其结构经~1H NMR,^(13)C NMR和HR-MS(MALDI-TOF)表征。并利用紫外可见光谱(UV-Vis)、荧光发射光谱(Photoluminescence)和循环伏安法研究了化合物的光学和电学性质。结果表明:Ir1和Ir2的紫外可见光吸收波长分别位于456 nm和448 nm,相应的发射波长分别为645 nm和678 nm,说明其均能利用可见光;Ir1和Ir2的HOMO电位为-5.125^-5.510 eV,LOMO电位为-2.880^-0.310 eV,满足作为光敏剂的基本条件。研究了化合物在可见光照射下光催化水分解产生氢气的效果。结果表明:Ir1和Ir2的氢气值TONs(turnover numbers)达到2 827和1 908。

关键词：联吡啶铱三苯胺咔唑合成光催化产氢