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An experimental approach to addressing ecological questions related to the conservation of plant biodiversity in China

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植物分类与资源学报 2016年第1期38卷 1-10页

作者： Roy Turkington William L.Harrower Botany Department and Biodiversity Research CentreUniversity of British Columbia

We briefly introduce and describe seven questions related to community structure and biodiversity conservation that can be addressed using field experiments,and provide the context for using the vast geographic diversity,biodiversity,and network of Nature Reserves in China to perform these *** is the world's third largest country,has a diverse topography,covers five climatic zones from cold-temperate to tropical,has 18 vegetation biomes ranging from Arctic / alpine tundra and desert to Tropical rain forest,and supports the richest biodiversity in the temperate northern hemisphere( > 10%of the world total). But this tremendous natural resource is under relentless assault that threatens to destroy biodiversity and negatively impact the services ecosystems provide. In an attempt to prevent the loss of biodiversity,China has established 2,729 nature reserves which cover 14.84% of the nation' s area. Unfortunately underfunding,mismanagement,illegal activities,invasive species and global climate change threaten the effectiveness of these protected areas. Attention has focused on protecting species and their habitats before degradation and loss of either species or habitats occur. Here we argue that we must move beyond the simple protection of ecosystems,beyond their description,and by using experiments,try to understand how ecosystems work. This new understanding will allow us to design conservation programs,perform restoration of damaged or degraded areas,and address resource management concerns( e.g.,agriculture,logging,mining,hunting) more effectively than with the current approach of ad hoc reactions to ecological and environmental problems. We argue that improving our understanding of nature can best be done using well designed,replicated,and typically manipulative field experiments.

关键词：植物学植物分类植物生态学植物演化

Evolution of biomass particles during pelletization process

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Particuology 2024年第3期86卷 182-187页

作者： Hamid Rezaei Maryam Tajilrou Jun Sian Lee Kanages Singaraveloo Anthony Lau Shahab Sokhansanj Biomass and Bioenergy Research Group Department of Chemical and Biological EngineeringUniversity of British ColumbiaVancouverCanada

Pulverizing is an essential unit operation in co-firing biomass with *** are only compatible with pellet forms of fibrous biomass materials and crush them down to their original forming particle *** is why the data on the size distribution of the particles forming a biomass pellet is crucial to achieving optimum combustion *** current study determines the internal particle size distribution of pellets after wet disintegration,following Iso 17830 standard,and aims to suggest improvements to the mentioned standard based on new measured *** were carried out on white wood pellets(no bark)and brown wood pellets containing bark at four water temperatures:20,40,60,and 95℃,with or without *** particle size distribution of the pre-pelletizer wood particles was also measured and compared with particles in the formed *** water temperature of 20℃ was found to be adequate for the complete disintegration of pellets,and no mechanical stirring was *** 30% of particles in the disintegrated pellets were 0.5-1.0 *** changes the particle size distribution to smaller *** disintegrated bark pellets contained more fines than white pellets.

关键词： Wood pellets Particle sizes distribution Wet disintegration Stirring Water temperature

Fabrication and testing of polymer-based capacitive micromachined ultrasound transducers for medical imaging

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Microsystems & Nanoengineering 2018年第1期4卷 178-189页

作者： Carlos D.Gerardo Edmond Cretu Robert Rohling Department of Electrical and Computer Engineering University of British Columbia2332 Main MallVancouverBCCanada Department of Mechanical Engineering University of British Columbia6250 Applied Science LnVancouverBCCanada

The ultrasonic transducer industry is dominated by piezoelectric *** an emerging alternative,capacitive micromachined ultrasound transducers(CMUTs)offer wider bandwidth,better integration with electronics,and ease of fabricating large *** have a sealed cavity between a fixed electrode and a suspended metalized *** cost and sensitivity are limiting factors in current CMUTs that depend on the fabrication equipment and,especially,on the materials *** widespread use of CMUTs,a much lower fabrication cost that uses inexpensive materials,which maintain or improve upon existing sensitivity,is ***,a new fabrication process is described for polymer-based CMUTs(polyCMUTs)using the photopolymer SU-8 and *** first ultrasound B-mode image of a wire phantom created with a 64-element linear array using synthetic aperture beamforming techniques is presented.A 12 VAC signal superimposed on a 10 VDC signal was used on the transmission side,and only a bias-tee,with no amplifiers,was used on the receiving *** low operational voltage and high sensitivity of this device can be partially attributed to a pre-biasing condition on the *** using a novel sacrificial layer combined with a top electrode embedded inside the membrane,we demonstrated that SU-8 can be used to manufacture CMUTs ***,the fabrication used relatively simple equipment,and the number of fabrication steps was reduced compared to traditional CMUT *** new fabrication process has the potential to increase the use of CMUTs in the ultrasound market,including the market for wearable transducers.

关键词： polymer electrode testing

ICVSS:A New Method for Vulnerability Quantitative Grading

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Computers, Materials & Continua 2019年第8期61卷 629-641页

作者： Tiantian Tan Baosheng Wang Yong Tang Xu Zhou Jingwen Han National university of Defense Technology Deya VillageChangshaChina university of british columbia VancouverCanada

Vulnerability technology is the basic of network security technology,vulnerability quantitative grading methods,such as CVSS,WIVSS,ICVSS,provide a reference to vulnerability management,but the problems of ignoring the risk elevation caused by a group of vulnerabilities and low accuracy of exploitable level evaluation exist in current vulnerability quantitative grading *** solve problems above in current network security quantitative evaluation methods,this paper verified the high relevance degree between type and exploitable score of vulnerability,proposed a new vulnerability quantitative grading method ICVSS,ICVSS can explore attack path using continuity level defined by privilege,add vulnerability type to measure indexes of exploitable metrics and use Analytic Hierarchy Process(AHP)to quantify the influence of vulnerability type on exploitable *** with CVSS and WIVSS,ICVSS is proved that it can discover attack path consist of a sequence of vulnerabilities for network security situation evaluation,and has more accuracy and stability.

关键词： Vulnerability dependency exploitable level measure index quantitative grading

A Method for Vulnerability Database Quantitative Evaluation

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Computers, Materials & Continua 2019年第9期61卷 1129-1144页

作者： Tiantian Tan Baosheng Wang Yong Tang Xu Zhou Jingwen Han National university of Defense Technology Deya villageChangshaChina university of british columbia VancouverCanada

During system development,implementation and operation,vulnerability database technique is necessary to system security;there are many vulnerability databases but a lack of quality standardization and general evaluation method are *** paper summarized current international popular vulnerability databases,systematically introduced the present situation of current vulnerability databases,and found the problems of vulnerability database technology,extracted common metrics by analyzing vulnerability data of current popular vulnerability databases,introduced 4 measure indexes:the number scale of vulnerabilities,the independence level,the standardization degree and the integrity of vulnerability description,proposed a method for vulnerability database quantitative evaluation using SCAP protocol and corresponding standard,analyzed a large number of vulnerabilities in current popular vulnerability database,quantitative evaluated vulnerability database by the law of normal distribution,the experimental results show this method has strong versatility and science,and it is beneficial to improve the quality and standardization construction for vulnerability database development.

关键词： Vulnerability management vulnerability database quantitative evaluation

Precision of future experiments measuring primordial tensor fluctuation

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Science China(Physics,Mechanics & Astronomy) 2014年第8期57卷 1466-1470页

作者： WANG Yi MA YinZhe Centre for Theoretical Cosmology DAMTP University of Cambridge Department of Physics and Astronomy University of British Columbia

Recently the second phase of Background Imaging of Cosmic Extragalactic Polarization （BICEP2） claimed a detection of the tensor-to-scalar ratio （r） of primordial fluctuation at 50- confidence level. If it is true, this large and measurable amplitude （r - 0.2） of B-mode polarization indicates that it is possible to measure the shape of CMB B-mode polarization with future experiments. Given the current understanding of the experimental noise and foreground contamination, we forecast the precision of r and the tensor spectral index nt measurements from Planck, Spider and POLARBEAR with nt as a free parameter. We quantitatively determine the signal-to-noise of the measurement in r-nt parameter space for the three experiments. The forecasted signal-to-noise ratio of the B-mode polarization somewhat depends on r/t, but strongly depends on the true value of r.

关键词： B-mode polarization BICEP2 tensor spectral index

Recurrent ectopic pancreatitis of the jejunum and mesentery over a 30-year period

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Hepatobiliary & Pancreatic Diseases International 2011年第2期10卷 218-220页

作者： John CT Wong Charlotte Robinson Edward C Jones Alison Harris Charles Zwirewich Robert Wakefield Richard K Simons Eric M Yoshida Department of Medicine Department of Medicine 2775 Laurel StreetUniversity of British Columbia VancouverBritish ColumbiaCanadaV5Z 1M9 Department of Radiology Department of Medicine 2775 Laurel StreetUniversity of British Columbia VancouverBritish ColumbiaCanadaV5Z 1M9 Department of Pathology and Laboratory Medicine Department of Medicine 2775 Laurel StreetUniversity of British Columbia VancouverBritish ColumbiaCanadaV5Z 1M9 Department of Surgery Department of Medicine 2775 Laurel StreetUniversity of British Columbia VancouverBritish ColumbiaCanadaV5Z 1M9 Division of Gastroenterology Department of Medicine 2775 Laurel StreetUniversity of British Columbia VancouverBritish ColumbiaCanadaV5Z 1M9

BACKGROUND:Ectopic pancreas is defined as pancreatic tissue found outside its usual anatomical position,with no ductal or vascular communication with the native pancreas. We describe a case of ectopic pancreas of the small bowel and mesentery causing recurrent episodes of pancreatitis, initially suspected on computed tomography(CT)and magnetic resonance cholangiopancreatography(MRCP),and confirmed on histological review of the resection. METHODS:A 67-year-old woman presented with clinical symptoms and biochemical evidence of *** had similar episodes over the past 30 years with unrevealing investigations,and was concluded to have idiopathic pancreatitis. She underwent CT and MRCP,with findings suggestive of ectopic pancreas,a diagnosis confirmed on histology of the resection. RESULTS:MRCP identified a mass in the proximal small bowel mesentery isointense to the native pancreas,with a small duct draining into a proximal jejunal *** resected specimen consisted of normal parenchyma with lobulated acinar tissue with scattered islets of Langerhans,an occasional ductular structure,and admixed areas of adipose *** patient remained asymptomatic with normal biochemistry six months post-operatively. CONCLUSION:In an individual with abdominal pain,elevated serum amylase/lipase,but imaging findings of a normal native pancreas,ectopic pancreatitis should be considered,and can be evaluated by CT and MRCP.

关键词： ectopic pancreas gastrointestinal tract endoscopic ultrasound computed tomography magnetic resonance cholangiopancreatography

Electrochemical behavior of Pd(Ⅱ) and Rh(Ⅲ) in [EMIm]NTf_2 ionic liquid

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Nuclear Science and Techniques 2015年第1期26卷 93-97页

作者：顾帅王欣鹏韦悦周方百增 School of Nuclear Science and Engineering Department of Chemical & Biological Engineering University of British Columbia

The electrochemical behavior of Pd(Ⅱ) and Rh(Ⅲ) in [EMIm]NTf2ionic liquid has been studied on Pt working electrodes at 298 K by cyclic voltammetry(CV), polarization curve and galvanostatic transient *** voltammogram of Pd(II) in [EMIm]NTf2consists of two cathodic current peaks located at 1.37 V(E pc2),corresponding to Pd2+/Pd+, and at 0.69 V(E pc1) corresponding to Pd+/Pd. The transfer coefficient α was calculated by the Tafel extrapolation from the polarization curves to be 0.306, which is in agreement with the value reported in an aqueous solution system. For Rh(Ⅲ) in [EMIm]NTf2, a cathodic current peak(E pc) was observed at-0.39 V, corresponding to Rh3+/Rh, and two oxidation peaks were observed at-0.13 V(E pa1) and0.37 V(E pa2) during the reverse scan. A significantly negative shift in the cathodic peak potential was observed with the increase of the scan rate, indicating that the reduction of Pd(II) and Rh(Ⅲ) on the Pt electrode involves kinetic complications. By using the galvanostatic transient technique, the diffusion coefficients of Pd(II) and Rh(Ⅲ) in [EMIm]NTf2ionic liquid solution were found to be ～ 10-7cm2/s. The potential difference between the reduction of Pd(II) to Pd and the reduction of Rh(Ⅲ) to Rh obtained from the CV curves of the Pd(II) and Rh(Ⅲ) co-existing [EMIm]NTf2solution is found to be about 0.74 V, which makes it possible to electrodeposit Pd(II) and Rh(Ⅲ) separately.

关键词：钯(Ⅱ) 电化学行为离子液体 III Rh 极化曲线溶液系统循环伏安

Improving patch-based simulation using Generative Adversial Networks

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Artificial Intelligence in Geosciences 2023年第1期4卷 76-83页

作者： Xiaojin Tan Eldad Haber Department of Earth and Ocean Science The University of British ColumbiaVancouverBCCanada

Multiple-Point Simulation(MPS)is a geostatistical simulation technique commonly used to model complex geological patterns and subsurface *** have been a great variety of implementation methods developed within MPS,of which Patch-Based Simulation is a more recently developed *** we have witnessed great progress in Patch-Based algorithms lately,they are still faced with two challenges:conditioning to point data and the occurrence of verbatim *** of them are partly due to finite size of Training image,from which a limited size of pattern database is *** address these questions,we propose a novel approach that we call Generative-Patched-Simulation(GPSim),which is based on Generative Adversarial Networks(GAN).With this method,we are able to generate sufficient(in theory an infinite)number of new patches based on the current pattern *** demonstrated by the results on a simple 2D binary image,this approach shows its potential to address the two issues and thus improve Patch-based Simulation methods.

关键词： Generative Adversial Networks Patch-based simulation