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State-to-state Photoionization Dynamics of Vanadium Nitride by Two-color Laser Photoionization and Photoelectron Methods

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Chinese Journal of Chemical Physics 2013年第6期26卷 669-678,I0003页

作者： Huang Huang Zhi-hong Luo Yih Chung Chang kai-Chung lau C. Y. Ng Department of Chemistry University of California Davis CA 95616 USA Department of Biology and Chemistry Oty University of Hone Kong Kowloon Hone Kong China

We have conducted a two-color visible-ultraviolet （VIS-UV） resonance-enhanced laser pho- toionization and pulsed field ionization-photoelectron （PFI-PE） study of gaseous vana- dium mononitride （VN） in the total energy range of 56900-59020 cm-1. The VN molecules were selectively excited to single rotational levels of the intermediate VN（D3H0, v＇=0） state by using a VIS dye laser prior to photoionization by employing a UV laser. This two-color scheme allows the measurements of rovibronically selected and re- solved PFI-PE spectra for the VN＋（X2A; v＋=0, 1, and 2） ion vibrational bands. By simulating the rotationally resolved PFI-PE spectra, J＋=3/2 is determined to be the lowest rotational level of the ground electronic state, indicating that the symmetry of the ground VN＋ electronic state is 2A3/2. The analysis of the PFI-PE spectra for VN＋ also yields accurate values for the adiabatic ionization energy for the formation of VN＋（X2A3/2）, IE（VN）=56909.5＋0.8 cm-1 （7.05588±0.00010 eV）, the vibrational fre- quency wc＋=1068.0±0.8 cm-1, the anharmonicity constant wc＋Xe＋=5.8±0.8 cm-1, the rotational constants Be＋=0.6563±0.0005 cm-1 and ae＋=0.0069±0.0004 cm-1, and the equi-librium bond length, re＋=1.529A, for VN＋（X2A3/2）; along with the rotational constants Bc＋=0.6578i0.0028 cm-1 and a＋=0.0085±0.0028 cm-1, and the equilibrium bond length re＋=1.527A for VN＋（X2As/2）, and the spin-orbit coupling constant A=153.3±0.8 cm-1 for VN＋（X2/k5/2,3/2）. The highly precise energetic and spectroscopic data obtained in the present study are valuable for benchmarking the predictions based on state-of-the-art ab initio quantum calculations.

关键词： Vanadium nitride Vanadium nitride cation Photoionization dynamics Two- color photoionization Pulsed field ionization-photoelectron Ionization energy Bond disso- ciation energy

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RADIATION BOUNDARY CONDITIONS FOR MAXWELL'S EQUATIONS:A REVIEW OF ACCURATE TIME-DOMAIN FORMULATIONS

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Journal of Computational Mathematics 2007年第3期25卷 305-336页

作者： Thomas Hagstrom Stephen lau Department of Mathematics and Statistics University of New MexicoAlbuquerqueNM 87131USA Division of Applied Mathematics Brown University182 George StreetProvidenceRI 02912USA

We review time-domain formulations of radiation boundary conditions for Maxwell＇s equations, focusing on methods which can deliver arbitrary accuracy at acceptable compu-tational cost. Examples include fast evaluations of nonlocal conditions on symmetric and general boundaries, methods based on identifying and evaluating equivalent sources, and local approximations such as the perfectly matched layer and sequences of local boundary conditions. Complexity estimates are derived to assess work and storage requirements as a function of wavelength and simulation time.

关键词： Maxwell's equations Radiation boundary conditions Fast algorithms Kirchoffformulas Perfectly matched layers.

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Effectiveness of digital psychotherapeutic intervention among perinatal women:A systematic review and meta-analysis of randomized controlled trials

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World Journal of Psychiatry 2021年第4期11卷 133-152页

作者： Ying lau Jing-Ying Cheng Sai-Ho Wong kai-Yoong Yen Ling-Jie Cheng Alice Lee Centre for Nursing Studies Yong Loo Lin School of MedicineNational University of SingaporeSingapore 117597Singapore Nursing Research Unit Department of NursingKhoo Teck Puat HospitalYishun Health CampusNational Healthcare GroupSingapore 768828Singapore

BACKGROUND The perinatal period is a challenging time of substantial emotional,physiological,social,and relational ***,anxiety,and stress symptoms are common,and co-exist in the perinatal *** technology continues to grow at an unprecedented pace with wide application,including psychotherapeutic intervention.A growing number of meta-analyses supported the application of digital psychotherapeutic intervention across different populations,but relatively few meta-and meta-regression analyses have concentrated on perinatal *** To evaluate the effectiveness of digital psychotherapeutic intervention on improving psychological outcomes among perinatal women and identify its essential *** Randomized controlled trials(RCTs)were obtained from eight databases,including Cumulative Index to Nursing and Allied Health Literature,Cochrane Library,Embase,Scopus,PsycINFO,PubMed,Web of Science,and ProQuest Dissertation and Theses from inception up until November 24,*** Meta-analysis 3.0 software was used to conduct meta-and metaregression *** Cochrane risk-of-bias tool and the Grading of the Recommendation,Assessment,Development,and Evaluation system were adopted to assess the individual and overall qualities of the evidence,*** A total of 25 RCTs that included 3239 women were ***-analyses revealed that intervention significantly improved depression(Hedges’s g=0.49),anxiety(g=0.25),and stress(g=0.47)symptoms compared to the *** analyses demonstrated that a website platform with≥eight therapistguided sessions using the theoretical principle of cognitive behavioral therapy was more effective than other treatments in improving depression symptoms in postnatal ***-regression analyses observed that the age of perinatal women and the type of psychotherapy also had statistically significant effects on depression ***’s regression asymmetry tests suggested that no pub

关键词： Digital psychotherapeutic intervention Perinatal women Meta-analysis Meta-regression

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Improved breakdown voltage of AlGaN/GaN HEMTs grown on Si substrates using partially Mg-doped GaN buffer layer by MOCVD

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Science China(Physics,Mechanics & Astronomy) 2010年第9期53卷 1578-1581页

作者： lau KeiMay Photonics Technology Center Department of Electronic and Computer EngineeringHong Kong University of Science and Technology

AlGaN/GaN high electron mobility transistors(HEMTs) were grown on Si substrates by *** the HEMT structure,a 1 μm GaN buffer layer was partially doped with Mg in an attempt to increase the resistivity and minimize the buffer *** AlGaN/GaN HEMTs grown on undoped and partially Mg-doped GaN buffer layers were processed and the DC characteristics of the devices were characterized for comparing the effect of Mg *** the device with the partially Mg-doped GaN buffer layer,a lower drain leakage current density of 55.8 nA/mm,a lower gate leakage current density of 2.73 μA/mm,and a higher off-state breakdown voltage of 104 V were achieved with device dimensions Lg/Wg/Lgs/Lgd=1/10/1/1 μm,better than the device with the undoped GaN buffer layer,which has a higher drain leakage current density of 9.2 μA/mm,a higher gate leakage current density of 91.8 μA/mm,and a lower off-state breakdown voltage of 87 V with the same device dimensions.

关键词： AlGaN/GaN HEMT Si substrate MOCVD breakdown voltage Mg-doped

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Inhibitory effect of different Dendrobium species on LPS-induced inflammation in macrophages via suppression of MAPK pathways

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Chinese Journal of Natural Medicines 2018年第7期16卷 481-489页

作者： ZENG Qiang Chun-Hay Ko Wing-Sum Siu LI kai-kai Chun-Wai Wong HAN Xiao-Qiang YANG Liu Clara Bik-San lau HU Jiang-Miao Ping-Chung Leung Institute of Chinese Medicine The Chinese University of Hong Kong State Key Laboratory of Phytochemistry and Plant Resources in West China The Chinese University of Hong Kong Shenzhen Research Institute The Chinese University of Hong Kong Kunming Institute of Botany Chinese Academy of Sciences

Dendrobii Caulis(DC), named ‘Shihu' in Chinese, is a precious herb in traditional Chinese medicine. It is widely used to nourish stomach, enhance body fluid production, tonify "Yin" and reduce heat. More than thirty Dendrobium species are used as folk medicine. Some compounds from DC exhibit inhibitory effects on macrophage inflammation. In the present study, we compared the anti-inflammatory effects among eight Dendrobium species. The results provided evidences to support Dendrobium as folk medicine, which exerted its medicinal function partially by its inhibitory effects on inflammation. To investigate the anti-inflammatory effect of Dendrobium species, mouse macrophage cell line RAW264.7 was activated by lipopolysaccharide. The nitric oxide(NO) level was measured using Griess reagent while the pro-inflammatory cytokines were tested by ELISA. The protein expressions of inducible NO synthase(iNOS), cyclooxygenase-2(COX-2) and mitogen-activated protein kinases(MAPKs) phosphorylation were evaluated by Western blotting analysis. Among the eight Dendrobium species, both water extracts of D. thyrsiflorum ***(DTW) and D. chrysotoxum Lindl(DCHW) showed most significant inhibitory effects on NO production in a concentration-dependent manner. DTW also significantly reduced TNF-α, MCP-1, and IL-6 production. Further investigations showed that DTW suppressed iNOS and COX-2 expression as well as ERK and JNK phosphorylation, suggesting that the inhibitory effects of DTW on LPS-induced macrophage inflammation was through the suppression of MAPK pathways. In conclusion, D. thyrsiflorum *** was demonstrated to have potential to be used as alternative or adjuvant therapy for inflammation.

关键词： Dendrobium species Anti-inflammation Macrophage MAPK pathways

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面向未来的新加坡高密度公共住房可持续设计策略与启示

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世界建筑导报 2024年第3期39卷 13-17页

作者：薛菲章倩刘昇陽刘少瑜深圳大学人因环境与可持续设计研究中心深圳518060 深圳大学建筑与城市规划学院深圳518060 浙江清华长三角研究院新加坡(东南亚)海纳创新中心新加坡068895 香港中文大学建筑学院中国香港999077

近年来,新加坡建屋发展局(HDB)通过“绿色家园计划”、“绿色城镇计划”等一系列政策指引,在高密度公共住房品质提升和环境可持续方面成为全球瞩目的典范。本文从绿色低碳、健康宜居、智慧管理三个视角对新加坡高密度公共住房的可持续... 详细信息

近年来,新加坡建屋发展局(HDB)通过“绿色家园计划”、“绿色城镇计划”等一系列政策指引,在高密度公共住房品质提升和环境可持续方面成为全球瞩目的典范。本文从绿色低碳、健康宜居、智慧管理三个视角对新加坡高密度公共住房的可持续设计策略和典型案例做了深度解析,旨在对我国未来的公共住宅发展提供有益参考。

关键词：绿色低碳健康宜居智慧管理高密度住区可持续设计

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The Pioneering Works of Professor Duzheng YE on Atmospheric Dispersion,Tibetan Plateau Meteorology,and Air–Sea Interaction

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Advances in Atmospheric Sciences 2017年第10期34卷 1137-1149页

作者： Ngar-Cheung lau Institute of Environment Energy and Sustainabilityand Department of Geography and Resource ManagementThe Chinese University of Hong KongShatinN.T.Hong Kong

This paper provides an overview of the impacts of the original works of Professor Duzheng YE on a selected set of observational and model studies with which the present author has been associated over the past several decades. The main themes of these works include atmospheric energy dispersion, air–land interactions over the Tibetan Plateau, and El Ni n？orelated air–sea coupling over East *** dispersive behavior of observed atmospheric fluctuations accompanying cold surge events in East Asia is demonstrated. Cold air outbreaks over Korea and southern China are coincident with the successive downstream development of troughs and ridges, with the group velocity of such wave packets being notably faster than the phase propagation speed of individual troughs and ridges. In a more general context, dispersive features are also discernible from lagged teleconnection charts and cross-spectra of observed and model-simulated geopotential height variations on 10–30-day time *** the output from a high-resolution general circulation model, the relative contributions of condensational, sensible, and radiative heating to the atmospheric energy budget over the Tibetan Plateau are documented. The rapid changes of the upper tropospheric Tibetan anticyclone and East Asian mei-yu（＂plum rain＂） precipitation band associated with the development of the Asian monsoon system are *** principal anomalies in sea level pressure, surface wind, precipitation and sea surface temperature over southeastern China and the Philippine Sea region during El Nio events are presented. The contributions of remote El Nio-related forcing and local air–sea interaction to the occurrence of these anomalies are assessed.

关键词： atmospheric dispersion Tibetan Plateau meteorology El Nio

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Acute appendicitis–advances and controversies

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World Journal of Gastrointestinal Surgery 2021年第11期13卷 1293-1314页

作者： Thomas Zheng Jie Teng Xuan Rong Thong kai Yuan lau Sunder Balasubramaniam Vishal G Shelat Department of General Surgery Tan Tock Seng HospitalSingapore 308433Singapore Department of Undergraduate Medicine Lee Kong Chian School of MedicineSingapore 308232Singapore

Being one of the most common causes of the acute abdomen,acute appendicitis(AA)forms the bread and butter of any general surgeon’s *** the recent advancements in AA’s management,much controversy in diagnostic algorithms,possible differential diagnoses,and weighing the management options has been generated,with no absolute consensus in the *** Alvarado described his eponymous clinical scoring system in 1986 to stratify AA risk,there has been a burgeoning of additional scores for guiding downstream management and mortality ***,advancing literature on the role of antibiotics,variations in appendicectomy,and its adjuncts have expanded the surgeon’s repertoire of management *** to the varied presentation,diagnostic tools,and management of AA have also been proposed in special groups such as pregnant patients,the elderly,and the *** article seeks to raise the critical debates about what is currently known about the above aspects of AA and explore the latest controversies in the *** the ever-evolving coronavirus disease 2019 situation worldwide,we also discuss the pandemic’s repercussions on patients and how surgeons’practices have evolved in the context of AA.

关键词： Appendicitis Diagnosis Management COVID-19 Controversy Advances

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New tricyanoiron(Ⅲ) building blocks for the construction of molecule-based magnets

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Science China Chemistry 2010年第10期53卷 2106-2111页

作者： lau Pui-Ha WONG Wing-Tak lau Tai-Chu Department of Biology and Chemistry City University of Hong Kong Department of Chemistry The University of Hong Kong

A series of tricyanoiron(Ⅲ) complexes with the general formula mer-[FeⅢ(5-Xsap)(CN)3]2-(X = H, Me, MeO, Cl or Br, sapH2 = N-salicylidene-o-aminophenol) have been synthesized. These complexes were characterized by IR, ESI-MS, UV/Vis, elemental analysis and magnetic measurements. The structures of (PPh4)2[FeⅢ(sap)(CN)3] and (PPh4)2[FeⅢ(5-Mesap)(CN)3] have been determined by X-ray crystallography. These low-spin d5 tricyanoiron(Ⅲ) complexes are potential building blocks for the construction of molecule-based magnets.

关键词： cyano iron Schiff base building block molecule-based magnet

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Flow behavior and deposition study of pollen-shape carrier particles in an idealized inhalation path model

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Particuology 2010年第1期8卷 51-59页

作者： Meer Saiful Hassan Raymond lau School of Chemical and Biomedical Engineering (SCBE) Nanyang Technological University (NTU)

Pollen-shape （spiked sphere） hydroxyapatite （HA） particles for drug carrier application are studied. The particle shape and size effect on flow characteristics and deposition are assessed. The pollen-shape HA particles are synthesized to have comparable size as typical carrier particles with mean diameter of 30-50 μm and effective density less than 0.3 g/cm^3. The flow behaviors of HA and commonly used lactose （LA） carrier particles are characterized by the Carr＇s compressibility index （CI）. The HA particles have lower CI than the LA particles for the same size range. The flow fields of HA and LA carrier particles are measured in an idealized inhalation path model using particle image velocimetry （PLY） technique. The particle streamlines indicate that a large portion of particles may deposit at the bending section due to inertial impaction and gravitational deposition. The flow field result shows that HA particles give smaller separation regions than the LA particles for the same size range. The pollen-shape HA particles are found to be able to follow the gas flow in the model and minimize undesired deposition. Deposition result confirms the bending section to have the most deposition. Deposition is found to be a function of particle properties. An empirical correlation is derived for the deposition efficiency of the pollen-shape particles as a function of particles Stokes number.

关键词： Aerosol Fluid mechanics Multiphase flow Particle Powder technology Pulmonary drug delivery

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