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Arctic source for elevated atmospheric mercury(Hg^0) in the western Bering Sea in the summer of 2013

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Journal of Environmental Sciences 2018年第6期30卷 114-121页

作者： v.v.Kalinchuk v.F.Mishukov A.S.Astakhov v.I.Il'ichev Pacific Oceanological Institute of Far Eastern Branch of Russian Academy of Sciences Vladivostok Russia

Measurements of gaseous elemental mercury（Hg^0） in the marine boundary layer of the western Bering Sea were performed using an automatic mercury analyzer RA 915 ＋（Ltd. ＂Lumex＂, St. Petersburg, Russia） aboard the Russian research vessel Academician *** from 3 to 20 August 2013. Hg^0 concentrations varied from 0.3 to 2.1 ng/m^3（n = 4783）;the average value（1.1 ± 0.3 ng/m^3） was lower than both the background range of the Northern Hemisphere（1.5–1.7 ng/m^3） and average values previously observed in the Bering Sea, and corresponded to the background concentrations of the Southern Hemisphere（1.1–1.3 ng/m^3）.Maximum Hg^0 concentrations were observed within air masses that came from the lower troposphere of the central Arctic. Under these conditions, Hg^0 ranged between 1.1 and 2.1 ng/m^3 with an average of 1.5 ± 0.2 ng/m^3（n = 1183）. Except for these periods, Hg^0 concentrations during the rest of the study varied from 0.3 to 1.8 ng/m^3, with an average value of 1.0 ± 0.2 ng/m^3（n = 3600）. Our results support the hypothesis that, in the summer, air masses from the central Arctic Ocean can be an exporter of mercury to lower latitudes. Perhaps the atmospheric transport of elevated concentrations of Hg^0 into lower latitudes may have implications for the biologic and economic health of important fisheries, such as the Bering Sea.

关键词： Mercury Atmosphere Long-range transport Bering Sea Arctic

Embolization of brain arteriovenous malformations with squid co-polymer embolic material:Initial experience

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Journal of Interventional Medicine 2023年第4期6卷 175-178页

作者： Li Shyan Ch'ng Zulkifli Zaki Ahmad Sobri Muda Radiology Department Faculty of Medicine UiTMSungai BulohMalaysia Radiology Department Hospital Sungai BulohSungai BulohMalaysia Radiology Department HSAASFaculty of Medicine and Health SciencesUniversiti Putra MalaysiaMalaysia Radiology Department Faculty of Medicine UiTM Sungai Buloh47000Malaysia

Objective:To analyze the safety and effectiveness of the ethylene-vinyl alcohol copolymer(EvOH)liquid embolic agent Squid(Emboflu,Switzerland)for the treatment of brain arteriovenous *** and procedures:Between April 2015 and July 2017,46 embolization treatments for brain arteriovenous malformations(BAvM)were performed in 25 patients using two Squid formulations(18 and 12).Six female and 19 male patients with a mean age of 34 years(range,9–62 years)were included.A total of 46 procedures were *** BAvMs were classified as Spetzler-Martin gradeⅡin 4 procedures,Ⅲin 27 procedures,and 1v in 15 *** the 25 patients,15 presented with hemorrhage,5 with seizures,and 5 with headache and *** BAvMs were located in the temporal lobe in 5 patients,parietal lobe in 7 patients,frontal lobe in 3 patients,posterior fossa in 6 patients,basal ganglia in 3 patients,and parasagittal lobe in 1 ***:The obliteration rate of the BAvMs ranged from 10%to 100%,with a mean of 33%.Most patients underwent their first or second embolization *** patients(8%)developed intracranial bleeding post procedure,with one death(2%).One patient(2%)experienced a seizure during the procedure;however,no intracranial bleeding was *** patients(15%)experienced perforations during catheter *** case(2%)of fractured catheter was recorded,but no significant complications were *** average volume of copolymer injected was 0.6 ml per *** procedures used the Squid-12 formulation,29 procedures used the Squid-18 formulation,and 3 procedures used a combination of Squid-12 and-18 ***:Squid is a safe and effective embolic agent for treating BAvMs.

关键词： Brain arteriovenous malformation Embolization Ethylene vinyl alcohol copolymer SQUID

Accurate ab initio Predictions of Ionization Energies and Heats of Formation for Cyclopropenylidene, Propargylene and Propadienylidene

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Chinese Journal of Chemical Physics 2006年第1期19卷 29-38页

作者： K. C. Lau C. Y. ng James Franck Institute and Department of Chemistry University of Chicago Chicago 60637 USA Department of Chemistry University of California Davis One Shields Avenue Davis California95616 USA

The ionization energies （IEs） of cyclopropenylidene （c-C3H2）, propargylene （HCCCH） and propadienylidene （H2CCC） have been computed using the CCSD（T）/CBS method, which involves the approxixnation to the complete basis set （CBS） limit at the coupled cluster level with single and double excitations plus quasi-perturbative triple excitation effect （CCSD（T））. The zero-point vibrational energy correction, the core-valence electronic correction, the scalar relativistic effect and the high level correction beyond the CCSD（T） excitations have also been made in these calculations. The CCSD（T）/CBS values for the IN（c-C3H2） and IE（HCCCH） of 9.164, 8.987 ev are in good agreement with the experimental values of （9.15±0.03） and （8.96±0.04） ev. The CCSD（T）/CBS calculations yield the IE values of 10.477 and 10.388 ev for the ionization transitions H2CCC→H2CCC^＋（^2A1, C2v） and H2CCC→H2CCC＋（^2A＇, Cs）, respectively. On the basis of the Franek-Condon factor consideration, the IE of （10.43±0.02） ev determined in the previous single-photon ionization experiment most likely corresponds to the ionization threshold for the H2CCC→H2CCC^＋（^2A1, C2v） transition. Although the precision of the experimental IN measurements fpr c-C3H2, HCCCH, and H2CCC is insufficient to pin down the accuracy of the theoretical calculations to better than ±30 mev, the excellent agreement between the experimental and theoretical IE values observed in the present study indicates that the CCSD（T）/CBS calculations together with high-order correlation corrections are capable of yielding reliable IE predictions for simple hydrocarbon carbenes and bi-radicals. We have also reported the heats of formation at 0 K （△H^of0） and 298 K （△H^of298）for c-C3H2/c-C3H2^＋, HCCCH/HCCCH^＋, and H2CCC/H2CCC^＋, The available experimental △H^of0 and △H^of298 values for c-C3H2/c C3H2^＋, HCCCH/HCCCH^＋ are found to be in good accord with the CCSD（T）/CBS predictions after taking into account the experimental uncertainties.

关键词： Ab intio Ionization energy Heat of formation c-C3H2 HCCCH H2CCC

FCC coprocessing oil sands heavy gas oil and canola oil. 2. Gasoline hydrocarbon type analysis

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Green Energy & Environment 2018年第3期3卷 286-301页

作者： Siauw H.ng Nicole E.Heshka Cecile Lay Edward Little Ying Zheng Qiang Wei Fuchen Ding Natural Resources Canada Canmet ENERGY Natural Resources Canada Geological Survey of Canada Department of Chemical Engineering University of New Brunswick State Key Laboratory of Heavy Oil Processing China University of Petroleum Beijing Institute of Petrochemical Technology

This study set out to gain a deeper understanding of a fluid catalytic cracking(FCC)coprocessing approach using canola oil mixed with bitumen-derived heavy gas oil(HGO),for the production of partially-renewable gasoline,with respect to its composition and *** FCC coprocessing approach may provide an alternative solution to reducing the carbon footprint and to meet government regulatory demands for renewable transportation *** this study,a mixture of 15 v%canola oil in HGO was catalytically cracked with a commercial equilibrium catalyst under typical FCC *** experiments were performed using a bench-scale Advanced Cracking Evaluation(ACE)unit at a fixed weight hourly space velocity of 8 h^(à1),490–530C,and catalyst/oil ratios of 4–12 g/*** total liquid product samples were injected via an automatic sampler and a prefractionator(to removet254C)into a gas chromatographic system containing a series of columns,traps,and valves designed to separate each of the hydrocarbon *** analyzer gives detailed hydrocarbon types of à200C gasoline,classified into paraffins,iso-paraffins,olefins,naphthenes,and aromatics by carbon number up to C_(11)(C_(10)for aromatics).For a feed cracked at a given temperature,the gasoline aromatics show the highest selectivity in terms of weight percent conversion,followed by saturated iso-paraffins,saturated naphthenes,unsaturated iso-paraffins,unsaturated naphthenes,unsaturated normal paraffins,and saturated normal *** conversion increases,both aromatics and saturated iso-paraffins increase monotonically at the expense of other *** type analysis and octane numbers with variation in feed type,process severity(temperature and catalyst/oil ratio),and conversion are also presented and discussed.

关键词： Oil sands heavy gas oil(HGO) Canola oil Advanced Cracking Evaluation(ACE) unit PIONA analysis

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

Appended corrole manganese complexes:Catalysis and axial-ligand effect

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Chinese Chemical Letters 2014年第4期25卷 571-574页

作者： nga-Chun ng Mian HR Mahmood Chi-K.Chang Hai-Yang Liu Fei Yam Lam-Lung Yeung Department of Chemistry and Open Laboratory of Chemical Biology of the Institute of Molecular Technology for Drug Discovery and Synthesis Hong Kong University of Science and Technology Department of Chemistry South China University of Technology Department of Chemistry Michigan State University Chi-K.Changa

A series of N-base appended corroles and their manganese complexes were synthesized and their binding constants with three different nitrogenous ligands, triethylamine, N-methylimidazole and pyridine, were evaluated by spectroscopy. Kinetic studies indicated that the presence of appended N- donor ligands may cause a significant enhancement of the rate of oxygen atom transfers （OAT） from （oxo）manganese（v） corrole to alkene, and the stronger axial ligand binding has impact on the rate of the oxidation reaction. Turnover frequency （TOF） for the catalytic oxidation of alkenes by appended manganese corroles varies with the following ligand order： acetamido 〈 pyridyl 〈 imidazolyl. The influence of the external axial ligands on the catalytic epoxidation was investigated by using appended acetamido manganese corrole as catalyst, with the results revealing that N-methylimidazole gave the best enhancement on the yields of total oxidation products among the investigated nitrogenous ligands.

关键词： Manganese Corrole Catalysis Axial-ligand Oxygen atom transfer

Performance of a small AT-TPC prototype

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Nuclear Science and Techniques 2018年第7期29卷 138-144页

作者： Jin-Yan Xu Qi-Te Li Yan-Lin Ye Jian Gao Jia-Xing Han Shi-Wei Bai Ka-Hou ng School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University

A small prototype of an active-target time projection chamber detector based on the gas electron multiplier(GEM) readout technique was designed and *** calculations were performed to analyze the electric field distribution and optimize the *** particular,a guard ring installed above the GEM foil may play an important role in shaping the electric field in the gas vessel and improving the overall performance of the *** best results were obtained at a guard-ring voltage of-950 *** using a collimated a-particle source,an energy resolution of 3.6–4.0 ke v can be achieved for deposited energies of 18–21 kev,respectively.A position resolution of less 0.2 mm was observed along the electron drift direction,whereas the resolution in the readout plane was approximately 0.45 mm.A time resolution of less than 20 ns was *** using helium as the primary working gas as well as the target material,a t a elastic scattering events can be clearly imaged.

关键词：原型性能优化设计模拟计算工作气体宝石时间电子

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...

Autologous Tendon Grafts Used in Upper Limb Surgery

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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Open Journal of Orthopedics 2013年第2期3卷 74-78页

作者： Avinash Alva v. Kumar R. Sreekumar Chye Yew ng S. C. Talwalkar Blackpool victoria Hospital Blackpool UK Department of Orthopaedics Wrightington Hospital Wigan UK

Tendon autografts play an important role in upper limb reconstruction and a working knowledge of tendon autograft options is essential for the surgeon. Although palmaris longus is often the first choice, other options like plantaris, extensor Hallucis longus, flexor carpi radialis are readily available. Advantages of autografts include easy availability, satisfactory biomechanical properties and the human body tends to accept its own tendons than from a donor. This review highlights the various options available and their anatomical and surgical considerations in procuring grafts for upper limb reconstructive work.

关键词： Autologous Tendon Graft Palmaris Longus Plantaris Extensor Digitorum Longus Extensor Hallucis Longus Flexor Carpi Radialis Hamstrings