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Photoelectrochemical degradation of Methylene Blue with β-PbO_2 electrodes driven by visible light irradiation

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Journal of Environmental Sciences 2011年第6期23卷 998-1003页

作者： Guoting Li HoYin Yip Kin hang wong Chun Hu Jiuhui Qu Po Keung wong Department of Environmental and Municipal Engineering North China University of Water Conservancy and Electric Power Zhengzhou 450011 China School of Life Sciences The Chinese University of Hong Kong Shatin N.T. Hong Kong SAR China State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beifing 100085 China

β-PbO2 electrodes were prepared by electro-deposition and characterized by scanning electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,and linear sweep *** confirmed pure β-PbO2 crystals were on the electrode and it had a high oxygen evolution *** photoactivity and photoelectrochemical（PEC） properties of the β-PbO2 electrode were investigated under visible light irradiation（λ 〉 420 nm） for the decolorization of Methylene *** first-order kinetics parameter（Kapp） for dye decolorization using the β-PbO2 electrode achieved 6.71×10-4 min-1 under visible light irradiation,which indicated its excellent visible light-induced *** Kapp of the PEC process was as much as 1.41×10-3 min-1 and was 1.71 times that of visible light irradiation or electrolysis even in the presence of the β-PbO2 electrode.A significant synergetic effect was observed in the PEC *** also employed TiO2 modified β-PbO2 electrodes in this test,which revealed that the TiO2 immobilized on the β-PbO2 electrode inhibited the visible light-induced PEC efficiency despite the amount of TiO2 used for electrode *** β-PbO2 electrode was also superior to the dimensionally stable anode（Ti/Ru0.3Ti0.7O2） in visible light-induced photoactivity and PEC efficiency.

关键词： photocatalysis photoelectrochemical process visible light β-PbO2 electrode

Individual and combined toxic effects of cypermethrin and chlorpyrifos on earthworm

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Journal of Environmental Sciences 2011年第4期23卷 676-680页

作者： Shiping Zhou Changqun Duan wong hang Gi Michelle Fazhong Yang Xuehua Wang Key Laboratory for Forest Resources Conservation and Use in the Southwest Mountains of China of Ministry of Education Southwest Forestry University Kunming 650224 China Laboratory for Conservation and Utilization of Bio-Resource & School of Life Science Yunnan University Kunming 650091 China

Toxicities were assessed for a pyrethroid （cypermethrin） and an organophosphate insecticide （chlorpyrifos） individually and in combination. A series of tests were conducted on different responses （acute, chronic, behavioral） of earthworms of species Eisenia fetida andrei in the ecological risk assessment of these pesticides. The results showed that the toxicity of the mixture of cypermethrin and chlorpyrifos was significantly higher than either of these pesticides individually, especially on the earthworm’s chronic responses. At a concentration of 5 mg/kg, the mixture caused significant reductions on the growth and reproduction rates of earthworms, but did not cause any significant effect when the individual was tested. The increase in toxicity of the pesticide mixture means that the use of toxicity data obtained exclusively from single-pesticide experiments may underestimate the ecological risk of pesticides that actually present in the field.

关键词： earthworms pesticide combined effects cypermethrin chlorpyrifos

A dual-polarized Fabry-Pérot antenna with high gain and wide bandwidth for millimeter-wave applications

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Frontiers of Information Technology & Electronic Engineering 2021年第4期22卷 599-608页

作者： Qingyi GUO hang wong State Key Laboratory of Terahertz and Millimeter Waves Department of Electrical EngineeringCity University of Hong KongHong Kong 999077China

We introduce a dual-polarized(DP)Fabry–Perot cavity(FPC)antenna operating at the millimeter-wave(mmWave)frequency band with high-gain and wideband characteristics.A DP feeding source and a partially reflective surface(PRS)integrated with a Fresnel zone lens are suggested to realize dual-polarization wave radiation over a wide impedance *** feeding source provides vertical and horizontal polarizations while keeping high isolation between the two *** is used to realize Fabry cavity to produce a directive beam *** integrated Fresnel zone rings are introduced for phase correction,leading to a significant gain enhancement for the *** verification,a 60-GHz FPC antenna prototype with DP radiation is designed and fabricated with measurement *** consists of a feeding source,a PRS integrated with a Fresnel zone lens,a quasi-curved reflector,and four three-dimensional printed *** results illustrate that the peak gains of vertical and horizontal polarizations are 18.4 and 17.6 dBi,*** impedance matching bandwidth for the two polarizations is 14%.The performance ensures that the proposed DP FPC antenna is a promising candidate for the fifth-generation wireless communication systems in the mmWave band.

关键词： Dual polarized Fabry-Perot cavity antenna partially reflective surface integrated with Fresnel zone lens Millimeterwave band High-gain Wideband

Characterization of available automated external def ibrillators in the market based on the product manuals in 2014

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World Journal of Emergency Medicine 2016年第2期7卷 138-146页

作者： Chik Leung Ho Ka Wai Cheng Tze hang Ma Yau hang wong Ka Lok Cheng Chak Wah Kam Department of Accident and Emergency Medicine Tuen Mun Hospital

BACKGROUND: To popularize the wide-spread use of automated external defi brillator(AED) to save life in sudden cardiac arrest, we compared the strength and weakness of different types of AEDs to enable a sound selection based on regional ***: This was a retrospective descriptive study. Different types of AEDs were compared according to the information of AEDs from manuals and brochures provided by the manufacturers. Fifteen types of AEDs were divided into 3 groups, basic, intermediate and ***: Lifeline? AUTO AED had the best performance in price, portability and user-friendly among AEDs of basic level. It required less time for shock charging. Samaritan PAD defi brillator was superior in price, portability, durability and characteristic among AEDs of intermediate level. It had the longest warranty and highest protection against water and dust. Lifeline? PRO AED had the best performance in most of the criteria among AEDs of advanced level and offered CPR video and manual mode for laypersons and clinicians ***: Lifeline? AUTO AED, Samaritan PAD def ibrillator, Lifeline? PRO AED are superior in AEDs of basic, intermediate and advanced levels, respectively. A feasible AED may be chosen by users according to the regional requirement and the current information about the best available products.

关键词： Automated external defi brillator Electrodes Pads Cardiac arrest

A digital microfluidic system with 3D microstructures for single-cell culture

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Microsystems & Nanoengineering 2020年第1期6卷 1296-1305页

作者： Jiao Zhai Haoran Li Ada hang-Heng wong Cheng Dong Shuhong Yi Yanwei Jia Pui-In Mak Chu-Xia Deng Rui PMartins State-Key Laboratory of Analog and Mixed-Signal VLSI Institute of MicroelectronicsUniversity of MacaoMacao SARChina Faculty of Science and Technology-ECE University of MacaoMacao SARChina Cancer Center Faculty of Health SciencesUniversity of MacaoMacao SARChina Liver Transplantation Center the Third Affiliated HospitalSun Yat-sen University510000 GuangzhouChina on leave from Instituto Superior Técnico Universidade de LisboaLisboaPortugal

Despite the precise controllability of droplet samples in digital microfluidic(DMF)systems,their capability in isolating single cells for long-time culture is still limited:typically,only a few cells can be captured on an *** fabricating small-sized hydrophilic micropatches on an electrode aids single-cell capture,the actuation voltage for droplet transportation has to be significantly raised,resulting in a shorter lifetime for the DMF chip and a larger risk of damaging the *** this work,a DMF system with 3D microstructures engineered on-chip is proposed to form semi-closed micro-wells for efficient single-cell isolation and long-time *** optimum results showed that approximately 20%of the micro-wells over a 30×30 array were occupied by isolated single *** addition,low-evaporation-temperature oil and surfactant aided the system in achieving a low droplet actuation voltage of 36V,which was 4 times lower than the typical 150 V,minimizing the potential damage to the cells in the droplets and to the DMF *** exemplify the technological advances,drug sensitivity tests were run in our DMF system to investigate the cell response of breast cancer cells(MDA-MB-231)and breast normal cells(MCF-10A)to a widely used chemotherapeutic drug,Cisplatin(Cis).The results on-chip were consistent with those screened in conventional 96-well *** novel,simple and robust single-cell trapping method has great potential in biological research at the single cell level.

关键词： culture system sized

Design of a Magneto-Electric Dipole Element for Mobile Communication Base Station Antennas

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ZTE Communications 2011年第2期9卷 20-26页

作者： hang wong Kwai Man Luk State Key Laboratory of Millimeter Waves (Hong Kong) Department of Electronic Engineering City University of Hong Kong

The magneto-electric dipole antenna is a kind of complementary antenna composed of a planar electric dipole and a shorted patch antenna. It has excellent electrical characteristics including wide impedance bandwidth, low cross-polarization, low back lobe radiation, nearly identical E-plane and H-plane patterns, stable radiation pattern, and steady antenna gain over the operating frequency range. In this paper, the basic characteristics of a linearly polarized magneto-electric dipole antenna are reviewed, and a dual-polarized antenna element based on the magneto-electric dipole is presented. The design of a conical beam wideband antenna with horizontal polarization is also described. These antennas have practical applications in modern 2G, 3G, LTE, WiFi, and WiMax wireless communication systems.

关键词： base station antenna magneto electric dipole wideband antenna dual polarization

The Perceptions for Hong Kong Male Students Refusing HPV Vaccination: An Exploratory Study

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Journal of Biosciences and Medicines 2019年第5期7卷 71-84页

作者： Keung Sum Chan Lai hang wong School of Nursing Tung Wah College Hong Kong China

Background: Human papillomavirus (HPV) is a group of common viruses that can cause a sexually transmitted infection (STI). People with HPV infection can be susceptible to cervical cancer, anogenital warts, and another HPV-related disease. Although the HPV infection can be prevented by HPV vaccination, the vaccination rate in Hong Kong is relatively low particular in males comparing to other countries. Study design: An exploratory qualitative approach was adopted. Aim: This study attempted to explore the perceptions of male college students refusing HPV vaccination in Hong Kong. Methods: A total of 20 male college students participated in the unstructured interview with audio-tape recording and field-notes done to explore their perceptions refusing HPV vaccination. Content analysis was utilized to extract significant themes and sub-themes. Results: Six major themes were identified including a lack of perceived risk, knowledge deficit, inadequate promotion, a high price of the HPV vaccine, inconvenience to receive the HPV vaccine and peer influence. Conclusion: Exploring the perceptions for Hong Kong male college students refusing HPV vaccination could provide essential information to the local government to establish corresponding health campaign for males to increase receiving HPV vaccination for curbing the HPV-related diseases.

关键词： Perception Human Papillomavirus Vaccine Male College Student Chinese Qualitative Research

Intravenous fluid selection rationales in acute clinical management

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World Journal of Emergency Medicine 2018年第1期9卷 13-19页

作者： Wing Yan Shirley Cheung Wai Kwan Cheung Chun Ho Lam Yeuk Wai Chan Hau Ching Chow Ka Lok Cheng Yau hang wong Chak Wah Kam Accident and Emergency Department Tuen Mun Hospital

BACKGROUND: Intravenous fluid(IVF) is commonly used in acute clinical management. This study aimed to review the choice and primary considerations in IVF prescriptions and to evaluate the adequacy of guidelines and trainings on it in the New Territories West Cluster(NTWC) of Hong ***: This is a descriptive study based on data collected from an online survey. Data were processed by SPSS for statistical analysis. This study focused on a general description and doctor-nurse between group comparison. Participants were asked the choice of IVF for nine acute clinical scenarios and provide reason. A 1–10 scale was used to assess the sufficiency of guideline, training and information, and time for revision on IVF ***: 0.9% sodium chloride was the most familiar IVF(36%), followed by 5% Dextrose solution(26%). In the nine scenarios, the most chosen IVF was 0.9% sodium chloride(37%–61%). There was significant difference in the choice of IVF between doctors and nurses in 7 cases. The second most chosen IVF for doctors was Plasma-Lyte A while that for nurses was Gelofusine. Departmental practice was the most chosen reason to account for the prescription. The adequacy of guideline, information and training, and time for revision was rated 5. Doctors had significantly more time at work than nurses to update knowledge in IVF prescription(5.41 versus 4.57).CONCLUSION: 0.9% sodium chloride was mostly chosen. The choice of IVF was mainly based on departmental practice. Adequacy of guideline, information and training, and time for revision on IVF prescription were average, indicating significant training deficit.

关键词： Intravenous fluid Acute care Resuscitation

Bowtie Slot-and-Dipole Dual-Polarized Antenna

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Bowtie Slot-and-Dipole Dual-Polarized Antenna