检索结果-南通市图书馆

Passive Q-switching in an erbium-doped fiber laser using tungsten sulphoselenide as a saturable absorber

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Optics Letters 2018年第2期16卷 69-73页

作者： H.Ahmad Z.C.Tiu S.I.ooi Photonics Research Centre University of Malaya

A highly stable Q-switched laser incorporating a mechanically exfoliated tungsten sulphoselenide （WSSe） thin sheet saturable absorber （SA） is proposed and demonstrated. The SA assembly, formed by sandwiching a thin WSSe sheet between two fiber ferrules within the erbium-doped fiber laser, is used to effectively modulate the laser cavity losses. The WSSe-based SA has a saturation intensity of ~0.006 MW∕cm^2 and a modulation depth of 7.8%, giving an optimum Q-switched laser output with a maximum repetition rate of 61.81 kHz and a minimum pulse width of 2.6 μs. The laser＇s highest output power of 0.45 mW and highest pulse energy of 7.31 nJ are achieved at the maximum pump power of 280.5 mW. The tunability of the cavity＇s output at the maximum pump power is analyzed with a C-band tunable bandpass filter, giving a broad tunable range of ~40 nm, from 1530 nm to 1570 nm. The output performance of the tunable Q-switched laser correlates well with the gain spectrum of erbium-doped fibers, with the shift in the gain profile as a result of the saturated SA.

关键词： Passive Q-switching in an erbium-doped fiber laser using tungsten sulphoselenide as a saturable absorber SA EDF

Antiviral activities of extracts from Hong Kong seaweeds

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2008年第12期9卷 969-976页

作者： Hui WANG Engchoon Vincent ooi Put O. ANG Jr Medical College Jinan University Guangzhou 510632 China Department of Biology the Chinese University of Hong Kong Shatin N. T. Hong Kong China

We extracted six Hong Kong brown seaweed species with hot water for their antiviral properties. The cytotoxicity and antiviral activity of these extracts were tested by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenlytetrezolium bromide] method, cytopathic effect reduction assay, and plaque reduction assay. The antiviral effect was further determined by flow cytometric analysis. The results showed that most of these extracts inhibited the propagation of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) standard strains with very low cytotoxicity to the host cells. The extracts of Hydroclathrus clathratus and Lobophora variegata showed more potential anti-HSV activities than the extracts of the other four seaweeds. They also had moderate anti- respiratory syncytial virus (RSV) activities but could not inhibit influenza A virus. Hydroclathrus clathratus was further extracted by diluted acid and alkali and the antiviral effects of the extracts were also detected. The result showed that the hot water extract contained the main carbohydrate components that exhibited the antiviral activities against various strains of HSV, including the acyclovir-resistant strain. HI-3, a compound fractionated from this hot water extract, showed a dose-dependent anti-HSV activity in flow cytometric analysis and plaque reduction assay.

关键词： Hong Kong seaweed Hydroclathrus clathratus Antiviral activity Herpes simplex virus (HSV) Flow cytometry

An experimental and numerical study of packing, compression, and caking behaviour of detergent powders

在线全文

学校读者我要写书评

暂无评论

Particuology 2014年第1期12卷 2-12页

作者： Subhash C.Thakur Hossein Ahmadian Jin Sun Jin Y.ooi School of Engineering University of Edinburgh Newcastle Innovation Centre Procter and Gamble Technical Centre Ltd

This paper presents an experimental and numerical study of the packing, compression, and caking behaviour of spray dried detergent （SDD） powders with a two-fold aim： an experimental process of observation and evaluation of the packing, compression and caking behaviour of SDD powders, and a numerical approach based on discrete element modelling （DEM）. The mechanical properties, including the stress-strain response and the corresponding porosity change as a function of consolidation stress in a confined cylinder, the stress-strain response during unconfined shearing and the cake strength as a func- tion of consolidation stress, were evaluated and compared for different SDD powders using an extended uniaxial tester （Edinburgh Powder Tester - EPT）. The experiments using EPT showed excellent repro- ducibility in the measurement of packing, compression and caking behaviour and were therefore very useful for describing the handling characteristics of these powdered products including screening new products and different formulations. It was found that the sample with higher moisture had lower bulk porosity but higher compressibility and cake strength. The porosity, compressibility and cake strength were found to vary across different size fractions of the same sample. The larger sieve-cut samples had higher initial bulk porosity, compressibility and cake strength. It is revealed that moisture plays a sig- nificant role in packing, compression, and shearing behaviour of the powder. Three-dimensional DEM modelling using a recently developed elasto-plastic adhesive-frictional contact model showed that the contact model is able to capture the detergent behaviour reasonably well and can be used to model complex processes involving these powders.

关键词： Discrete element methodPowder flowCohesive materialUniaxial testPlasticityContact model

Detecting maize leaf water status by using digital RGB images

在线全文

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2014年第1期7卷 45-53页

作者： Han Wenting Sun Yu Xu Tengfei Chen Xiangwei Su Ki ooi College of Mechanical and Electronic Engineering Northwest A&F UniversityYangling 712100China Institute of Soil and Water Conservation China Academy of SciencesYangling 712100China College of Food Science and Engineering Northwest A&F UniversityYangLing 712100China National ICT Australia Victoria Research Lab.Department of Electrical and Electronic EngineeringThe University of MelbourneParkvilleVIC 3010Australia

To explore the correlation between crop leaf digital RGB(Red,Green and Blue)image features and the corresponding moisture content of the leaf,a Canon digital camera was used to collect image information from detached leaves of heading-stage maize.A drying method was adopted to measure the moisture content of the leaf samples,and image processing technologies,including gray level co-occurrence matrices and grayscale histograms,was used to extract the maize leaf texture feature parameters and color feature *** correlations of these feature parameters with moisture content were *** is found that the texture parameters of maize leaf RGB images,including contrast,correlation,entropy and energy,were not significantly correlated with moisture ***,it was difficult to use these features to predict moisture *** the six groups of eigenvalues for the leaf color feature parameters,including mean,variance,energy,entropy,kurtosis and skewness,mean and kurtosis were found to be correlated with moisture ***,these features could be used to predict the leaf moisture *** correlation coefficient(R2)of the mean-moisture content relationship model was 0.7017,and the error of the moisture content prediction was within±2%.The R2 of the kurtosis-moisture content relationship model was 0.7175,and the error of the moisture content prediction was within±1.5%.The study results proved that RGB images of crop leaves could be used to measure moisture content.

关键词： maize leaf moisture content image processing color feature extraction texture feature extraction

Prediction of flow patterns during silo discharges using a finite element approach and its preliminary experimental verification

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2015年第1期13卷 42-49页

作者： S.Ding H.Li J.Y.ooi J.M.Rotter Faculty of Science and Engineering University of AgderGrimstadand Tel-TekPorsgrunnNorway School of Material & Mineral Resources Xi'an University of Architecture & Technology Institute for Infrastructure and Environment School of EngineeringUniversity of Edinburgh

Obtaining a reliable discharge of particulate solids from a storage silo is a prerequisite to securing oper- ational adequacy in solids handling processes. If a silo is poorly designed, an unreliable interrupted discharge often occurs. In this study, an in-house finite element （FE） program was modified to predict the particulate solids flow patterns during discharges from silos, and the effect of a double-cone insert on such flow patterns. In FE modeling, a Eulerian approach was adopted with an assumption of steady-state flow-a state that greatly facilitated investigations on the effects of double-cone inserts on the flow of particulate solids. Predictions were carried out on whether the discharge was in mass flow or funnel flow, associated with the inclination angle of the silo＇s hopper. Predicted results were in agreement with the Jenike Chart, and proved that an upper lateral pressure ratio value gave a better critical hopper half angle to achieve mass flow （EN 1991-4, 2006）. The shape and size of the stagnant zone were further discussed to address the flow channel boundary between the flowing and static solids if the discharge was in a funnel pattern. Results also showed the effects of a double-cone insert on the flow patterns which con- verted silos from funnel flow to mass flow up to a certain hopper inclination angle and would improve the flow pattern even for shallower angles. Experiments were carried out to verify some of the predicted results. Some qualitative comparisons were made between the predicted results and experimental mea- surements, which indicated that further efforts are needed in predicting the shape of the stagnant zone （flow channel boundary） during funnel flow discharges.

关键词： Discharge pattern Flow boundary Double-cone insert FE analysis Preliminary verification

Direct Modulation of the Guard Cell Outward- Rectifying Potassium Channel （CORK） by Abscisic Acid

在线全文

学校读者我要写书评

暂无评论

Molecular Plant 2017年第11期10卷 1469-1472页

作者： Amanda ooi Fouad Lemtiri-Chfieh Aloysius Wong Christoph Gehring Division of Biological and Environmental Sciences and Engineering 4700 King Abdullah University of Science and Technology Thuwa123955-6900 Kingdom of Saudi Arabia

Dear Editor,Abscisic acid （ABA） induces turgot loss and hence stomatal closure by promoting rapid net K^＋ efflux from guard cells （GCs） through outward-rectifying K^＋（K^＋out） channels （Schroeder et al., 1987; Blatt, 1990）. The mechanisms of ABA signaling in GCs are detailed elsewhere （see Munemasa et al., 2015; Weiner et al., 2010; Pandey et al., 2007）. Briefly, ABA binds to the PYR/ PYL/RCARs, a family of soluble steroidogenic acute regulatory- related lipid transfer （START） proteins, and, in turn, inactivates the downstream PP2C （type 2C protein phosphatase）, leading to the activation of SnRK2.6 （SNF1 [sucrose non-fermenting-1- related protein kinase]/OST1 [open stomata 1]） protein kinases.

关键词： Direct Modulation of the Guard Cell Outward- Rectifying Potassium Channel (CORK) Abscisic Acid

Synthesis and mesomorphic properties of 4-(4-bromopropyloxy)-4'-(4-alkyloxybenzylidene)anilines

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2012年第7期23卷 769-772页

作者： Guan-Yeow Yeap Yew-Hong ooi Kenji Kubo Masato M.Ito Liquid Crystal Research Laboratory School of Chemical SciencesUniversiti Sains Malaysia11800 MindenPenangMalaysia Department of Environmental Engineering for Symbiosis Faculty of EngineeringSoka UniversityTokyo 192-8577Japan

This article describes the preparation and liquid crystalline properties of a new homologous series of 4-（4-bromopropyloxy）-4＇- （4-alkyloxybenzylidene）anilines in which the phenyl ring is armed by a bromopropyloxy *** thermal behavior and mesomorphic properties of the synthesized compounds were studied with particular attention given to the correlation between their phase transition temperatures and anisotropic change influenced by molecular *** the members displayed enantiotropic smectic phase except for the homologue with the longest alkyloxy chain（R = C_（18）H_（37））,exhibiting only monotropic characteristic. The presence of bromine atom from the propyloxy side chain is found to be capable of altering and influencing the mesomorphic properties.

关键词： 4-(4-Bromopropyloxy)-4'-(4-alkyloxybenzylidene)anilines Mesomorphic properties Enantiotropic smectic DSC

Paraventricular Nucleus P2X7 Receptors Aggravate Acute Myocardial Infarction Injury via ROS-Induced Vasopressin-V1b Activation in Rats

在线全文

学校读者我要写书评

暂无评论

Neuroscience Bulletin 2021年第5期37卷 641-656页

作者： Wenjing Cheng Yinggang Sun Qin Wu Kokwin ooi Yi Feng Chunmei Xia Danian Zhu Department of Physiology and Pathophysiology School of Basic Medical SciencesFudan UniversityShanghai 200032China Department of Cardiovascular Diseases Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghai 200092China Department of Medical Technology Jiangsu Vocational College of MedicineYancheng 224005China Department of Integrative Medicine and Neurobiology School of Basic Medical SciencesFudan UniversityShanghai 200032China

The present study was designed to investigate the mechanisms by which P2X7 receptors(P2X7Rs)mediate the activation of vasopressinergic neurons thereby increasing sympathetic hyperactivity in the paraventricular nucleus(PVN) of the hypothalamus of rats with acute myocardial ischemia(AMI). The left anterior descending branch of the coronary artery was ligated to induce AMI in rats. The rats were pretreated with BBG(brilliant blue G, a P2X7R antagonist), nelivaptan(a vasopressin V1b receptor antagonist), or diphenyleneiodonium(DPI) [an nicotinamide adenine dinucleotide phosphate(NADPH)oxidase inhibitor]. Hemodynamic parameters of the heart were monitored. Myocardial injury and cardiomyocyte apoptosis were assessed. In the PVN of AMI rats, P2X7R mediated microglial activation, while reactive oxygen species(ROS) and NADPH oxidase 2(NOX2) were higher than in the sham group. Intraperitoneal injection of BBG effectively reduced ROS production and vasopressin expression in the PVN of AMI rats. Moreover, both BBG and DPI pretreatment effectively reduced sympathetic hyperactivity and ameliorated AMI injury, as represented by reduced inflammation and apoptosis of ***, microinjection of nelivaptan into the PVN improved cardiac function and reduced the norepinephrine(AE) levels in AMI rats. Collectively, the results suggest that, within the PVN of AMI rats, P2X7R upregulation mediates microglial activation and the overproduction of ROS, which in turn activates vasopressinergic neuron V1b receptors and sympathetic hyperactivity, hence aggravating myocardial injury in the AMI setting.

关键词： PVN P2X7 receptor Vasopressin Reactive oxygen species c-fos Myocardial ischemia

Tunable passively Q-switched ytterbium-doped fiber laser with mechanically exfoliated GaSe saturable absorber

在线全文

学校读者我要写书评

暂无评论

Chinese Optics Letters 2018年第2期16卷 93-97页

作者： H.Ahmad S.N.aidit S.I.ooi Z.C.Tiu Photonics Research Centre University of Malaya

A tunable passively Q-switched ytterbium-doped fiber laser using few-layer gallium selenide（GaSe） as a saturable absorber（SA） is *** few-layer GaSe SA,which is fabricated by the mechanical exfoliation method,is able to generate a Q-switched fiber laser that has a maximum repetition rate of 92.6 kHz and a minimum pulsed width of 2.3 μ*** highest pulse energy exhibited by the generated pulse is 18.8 nJ with a signal to noise ratio of ~40 *** tunability of the proposed laser covers from 1042 to 1082 nm,giving a tuning range of 40 nm.

关键词： Tunable passively Q-switched ytterbium-doped fiber laser with mechanically exfoliated GaSe saturable absorber SA