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QKD system with fast active optical path length compensation

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中国科学：物理学、力学、天文学英文版 2017年第6期60卷 1-7页

作者： Byung Kwon Park Min Soo lee Min Ki Woo Yong-Su Kim Sang-Wook Han Sung Moon Center for Quantum Information Korea Institute of Science and Technology Department of Nano-materials Science and Engineering Korea University of Science and Technology

We develop a quantum key distribution (QKD) system with fast active optical path length compensation. A rapid and reliable active optical path length compensation scheme is proposed and applied to a plug-and-play QKD system. The system monitors changes in key rates and controls it is own operation automatically. The system achieves its optimal performance within three seconds of operation, which includes a sifted key rate of 5.5 kbps and a quantum bit error rate of less than 2% after an abrupt temperature variation along the 25 km quantum channel. The system also operates well over a 24 h period while completing more than 60 active optical path length compensations.

关键词：补偿系统 QKD 光程量子密钥分配分配系统即插即用补偿方案路径长度

Field released transgenic papaya effect on soil microbial communities and enzyme activities

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Journal of Environmental Sciences 2006年第4期18卷 734-740页

作者： WEI Xiang-dong ZOU Hui-ling CHU lee-min LIAO Bin YE Chang-min LAN Chong-yu School of Life Sciences Sun Yat-sen University Guangzhou 510275 China Department of Biology The Chinese University ofHong Kong Shatin Hong Kong China

Soil properties, microbial communities and enzyme activities were studied in soil amended with replicase （RP）-transgenic or non-transgenic papaya under field conditions. Compared with non-transgenic papaya, significant differences （P〈0.05） were observed in total nitrogen in soils grown with transgenic papaya. There were also significant differences （P〈0.05） in the total number of colony forming units （CFUs） of bacteria, actinomycetes and fungi between soils amended with RP-transgenic plants and non-transgenic plants. Compared with non-transgenic papaya, the total CFUs of bacteria, actinomycetes and fungi in soil with transgenic papaya increased by 0.43-1.1, 0.21-0.80 and 0.46-0.73 times respectively. Significantly higher （P〈0.05） CFUs of bacteria, actinomycetes and fungi resistant to kanamycin （km） were obtained in soils with RP-transgenic papaya than those with non-transgenic papaya in all concentrations of km. Higher resistance quotients for km＇（kanamycin resistant） bacteria, actinomycetes and fungi were found in soil planted with RP-transgenic papaya, and the resistance quotients for km＇ bacteria, actinomycetes and fungi in soils with transgenic papaya increased 1.6-4.46, 0.63-2.5 and 0.75-2.30 times. RP-transgenic papaya and non-transgenic papaya produced significantly different enzyme activities in arylsulfatase （5.4-5.9x）, polyphenol oxidase （0.7-1.4x）, invertase （0.5-0.79x）, cellulase （0.23-0.35x） and phosphodiesterase （0.16-0.2x）. The former three soil enzymes appeared to be more sensitive to the transgenic papaya than the others, and could be useful parameters in assessing the effects of transgenic papaya. Transgenic papaya could alter soil chemical properties, enzyme activities and microbial communities.

关键词： transgenic papaya soil microbes enzyme activity kanamycin resistance resistance quotient

Microstructural Characteristics of Underwater Shock Consolidated Aluminum Composites

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Journal of Materials Science & Technology 2003年第4期19卷 341-345页

作者： K.Raghukandan K.Hokamoto J.S.lee A.Chiba B.C.Pai Department of Mechanical Engineering and Materials Science Kumamoto UniversityKumamotoJapanShock Wave and Condensed Matter Research Center2-39-1 KurokamiKumamoto UniversityKumamotoJapanGraduate studentGraduate School of Science and TechnologyKumamoto UniversityKumamotoJapanDepartment of Mechanical Engineering and Materials ScienceKumamoto UniversityKumamotoJapanRegional Research LaboratoryThiruvananthapuramKeralaIndia

Metal matrix composites (MMCs) offer extra strength and high temperature capabilities in comparison with unrein-forced metals. Aluminum composites possess higher stiffness, strength, fatigue properties and low weight advantages. Carbon fiber reinforced Al composites (Al-Cf) and silicon carbide particulate reinforced Al composites (AI-SiCp) were shock densified using axisymmetric assemblies for underwater explosions. Unidirectional planar shock waves were applied to obtain uniform consolidation of the composites. The energy generator was a high explosive of 6.9 km/s detonation velocity. Irregular morphological powders of Al were the base material. The reinforcement ratio was 15 Vol. pet for Al-Cf composites and 30 Vol. pet for AI-SiCp composites. The microstructural and the strength characteristics of the shock consolidated Al composites are reported.

关键词： Shock consolidation Aluminum composites Microstructure Strength characteristics

Evaluation of Unified Model Microphysics in High-resolution NWP Simulations Using Polarimetric Radar Observations

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Advances in Atmospheric Sciences 2018年第7期35卷 771-784页

作者： Marcus JOHNSON Youngsun JUNG Daniel DAWSON Timothy SUPINIE Ming XUE Jongsook PARK Yong-Hee lee Center for Analysis and Prediction of Storms (CAPS) University of Oklahoma Norman OK 73072 USA School of Meteorology University of Oklahoma Norman OK 73072 USA Purdue University West Lafayette IN 47907 USA Korea Meteorological Administration Seoul 07062 Korea

The UK Met Office Unified Model（UM） is employed by many weather forecasting agencies around the globe. This model is designed to run across spatial and time scales and known to produce skillful predictions for large-scale weather systems. However, the model has only recently begun running operationally at horizontal grid spacings of ～1.5 km [e.g.,at the UK Met Office and the Korea Meteorological Administration（kmA）]. As its microphysics scheme was originally designed and tuned for large-scale precipitation systems, we investigate the performance of UM microphysics to determine potential inherent biases or weaknesses. Two rainfall cases from the kmA forecasting system are considered in this study： a Changma（quasi-stationary） front, and Typhoon Sanba（2012）. The UM output is compared to polarimetric radar observations in terms of simulated polarimetric radar variables. Results show that the UM generally underpredicts median reflectivity in stratiform rain, producing high reflectivity cores and precipitation gaps between them. This is partially due to the diagnostic rain intercept parameter formulation used in the one-moment microphysics scheme. Model drop size is generally both underand overpredicted compared to observations. UM frozen hydrometeors favor generic ice（crystals and snow） rather than graupel, which is reasonable for Changma and typhoon cases. The model performed best with the typhoon case in terms of simulated precipitation coverage.

关键词： Unified Model microphysics polarimetric radar radar simulator numerical weather prediction

Influence of volcanic activity on vegetation succession and growth environment on the hillslope of Sakurajima Volcano in southern Kyushu,Japan

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Journal of Forestry Research 2017年第2期28卷 309-317页

作者： Yukiyoshi Teramoto Etsuro Shimokawa Tsugio Ezaki Kun-Woo Chun Suk-Woo Kim Youn-Tae lee Faculty of Agriculture Kagoshima UniversityKagoshima 890-0065Japan Faculty of Agriculture Ehime UniversityMatsuyama 790-8566Japan Division of Forest Science Kangwon National UniversityChuncheon 24341Republic of Korea Department of Forestry and Environmental Systems Graduate SchoolKangwon National UniversityChuncheon 24341Republic of Korea

This study was conducted in order to examine the influence of long-term volcanic activity on vegetative succession and growth on the slope of Sakurajima in southern Kyushu, Japan. We investigated the vegetation,depth of the volcanic ash layer, and dry density and p H of the surface soil at six places on the north-northwestern slope, 2.3–3.4 km from the Minami-dake crater, where a layer of pumice stone was deposited by the Taisho eruption in 1914. The height and diameter at breast height（DBH） of the trees increased with increasing distance from the Minami-dake crater, as did the number of individuals and species, and basal area. The Shannon–Wiener diversity index（H＇） demonstrates that vegetative succession is significantly affected by distance from the Minami-dake crater, as areas farther from the crater exhibited later seral stages. Comparison of the diversity index and species number of the crater region with that of the climax forest in Kagoshima indicates that vegetative growth alone cannot advance succession in the study area, as the local vegetative community is heavily influenced by the harsh environmental conditions associated with continual exposure to long-term volcanic activity. Seral stage, ash layer depth,dry density, and p H of the soil surface layer are governed by distance from the Minami-dake crater. The results of this study indicate that conditions for vegetative growth and succession improve with increasing distance from the source of constant volcanic activity. Thus, soil development is promoted by the acidification of the soil, which decreases the dry density and p H of the soil surface *** introduction of plant species resistant to volcanic ash and gas is recommended to promote soil development and improve the infiltration capacity of the soil.

关键词： volcanic succession vegetation vegetative northwestern eruption basal leaved gentle harsh

Observing the reconnection region in a transequatorial loop system

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Research in Astronomy and Astrophysics 2011年第10期11卷 1209-1228页

作者： Rui Liu Tong-Jiang Wang Jeongwoo lee Guillermo Stenborg Chang Liu Sung-Hong Park Hai-Min Wang Space Weather Research Laboratory Center for Solar-Terrestrial Research NJIT Newark NJ 07102 USA Catholic University of America and NASA Goddard Space Flight Center Greenbelt MD 20771 USA Department of Physics NJIT Newark NJ 07102 USA Interferometrics Inc. Herndon VA 20171 USA Korea Astronomy and Space Science Institute Daejeon 305-348 Republic of Korea

A vertical current sheet is a crucial element in many flare/coronal mass ejection （CME） models. For the first time, Liu et al. reported a vertical current sheet directly imaged during the flare rising phase with the EUV Imaging Telescope （EIT） onboard the Solar and Heliospheric Observatory （SOHO）. As a follow-up study, here we present the comprehensive analysis and detailed physical interpretation of the observation. The current sheet formed due to the gradual rise of a transequatorial loop system. As the loop legs approached each other, plasma flew at - 6 km s^-1 into a local area where a cusp-shaped flare loop subsequently formed and the current sheet was seen as a bright, collimated structure of global length （_〉 0.25 RQ） and macroscopic width （（5-10）× 10^3 km）, extending from 50 Mm above the flaring loop to the border of the EIT field of view （FOV）. The reconnection rate in terms of the Alfven Mach number is estimated to be only 0.005-0.009, albeit a halo CME was accelerated from - 400 km s- 1 to - 1300 km s- 1 within the coronagraph FOV. Drifting pulsating structures at metric frequencies were recorded during the impulsive phase, implying tearing of the current sheet in the high corona. A radio Type III burst occurred when the current sheet was clearly seen in EUV, indicative of accelerated electrons beam- ing upward from the upper tip of the current sheet. A cusp-shaped dimming region was observed to be located above the post-flare arcade during the decay phase in EIT; both the arcade and the dimming expanded with time. With the Coronal Diagnostic Spectrometer （CDS） aboard SOHO, a clear signature of chromospheric evaporation was seen during the decay phase, i.e., the cusp-shaped dimming region was associ- ated with plasma upflows detected with EUV hot emission lines, while the post-flare loop was associated with downflows detected with cold lines. This event provides a comprehensive view of the reconnection geometry and dynamics in the solar corona.

关键词： Sun coronal mass ejections -- Sun flares -- Sun corona

Co-contaminants of microplastics in two seabird species from the Canadian Arctic

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Environmental Science and Ecotechnology 2022年第4期12卷 87-96页

作者： Roxana Sühring julia E.Baak Robert J.Letcher Birgit M.Braune Amila de Silva Cody Dey Kim Fernie Zhe Lu Mark L.Mallory Stephanie Avery-Gomm Jennifer F.Provencher Department of Chemistry and Biology Toronto Metropolitan University(formerly known as Ryerson University)350 Victoria StTorontoONM5B 2K3Canada Department of Natural Resource Science McGill UniversitySainte Anne de BellevueQuebecH9X 3V9Canada Environment and Climate Change Canada National Wildlife Research CentreCarleton UniversityRaven RoadOttawaOntarioK1A 0H3Canada Aquatic Contaminants Research Division Environment and Climate Change CanadaBurlingtonOntarioL7S 1A1Canada Ecotoxicology&Wildlife Health Division Environment and Climate Change CanadaBurlingtonOntarioL7S 1A1Canada Institut des Sciences de la Mer de Rimouski Université du Québec à RimouskiRimouskiQuébecG5L 3A1Canada Department of Biology Acadia UniversityWolfvilleNova ScotiaB4P 2R6Canada

Through ingestion and subsequent egestion,Arctic seabirds can bioaccumulate microplastics at and around their colony breeding *** microplastics in Arctic seabirds have been well documented,it is not yet understood to what extent these particles can act as transport vehicles for plastic-associated contaminants,including legacy persistent organic pollutants(POPs),trace metals,and organic *** investigated the occurrence and pattern of organic and inorganic co-contaminants of microplastics in two seabird species from the Canadian Arctic-northern fulmar(Fulmarus glacialis)and black-legged kittiwake(Rissa tridactyla).We found that fulmars had higher levels of plastic contamination and emerging organic compounds(known to be plastic additives)than kittiwakes,whereas higher concentrations of legacy POPs were found in kittiwakes than the ***,fulmars,the species with the much larger foraging range(~200 km),had higher plastic pollution and overall contaminant burdens,indicating that birds may be acting as long-range transport vectors for plasticassociated *** results suggest a potential connection between plastic additive contamination and plastic pollution burdens in the bird stomachs,highlighting the importance of treating plastic particles and plastic-associated organic additives as co-contaminants rather than separate pollution issues.

关键词： Plastic contaminants Contaminants of emerging arctic concern Arctic Seabirds PFAS OPEs PBDEs Trace metals

Analysis of the <i>trans</i>-Cinnamic Acid Content in <i>Cinnamomum spp.</i>and Commercial Cinnamon Powder Using HPLC

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Journal of Agricultural Chemistry and Environment 2015年第4期4卷 102-108页

作者： Jaemin lee Dong Gu lee Jun Yeon Park Sungwook Chae Sanghyun lee Department of Integrative Plant Science Chung-Ang University Anseong South Korea College of Korean Medicine Gachon University Seongnam South Korea km Convergence Research Division Korea Institute of Oriental Medicine Daejeon South Korea

The present study aimed to quantify the content of trans-cinnamic acid (CA) in Cinnamomum japonicum, C. loureirii, and C. camphora and the commercial application of CA using high performance liquid chromatography (HPLC). A C18 column was used, with water/methanol as the mobile phase gradient. The highest content of CA was observed in the bark of C. loureirii (16.97 mg/g) and cinnamon powder A (47.60 mg/g). The lowest content of CA was observed in leaf and heartwood of C. japonicum (0.10 and 0.10 mg/g, respectively) and cinnamon powder C (22.87 mg/g). This result could be utilized as a guideline for the analysis of the commercial applications of Cinnamomum.

关键词： Cinnamomum spp. trans-Cinnamic Acid HPLC

Sensitivity of Snowfall Characteristics to Meteorological Conditions in the Yeongdong Region of Korea

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Advances in Atmospheric Sciences 2021年第3期38卷 413-429页

作者： Yoo-Jun KIM So-Ra IN Hae-Min KIM Jin-Hwa lee Kyu Rang KIM Seungbum KIM Byung-Gon KIM High Impact Weather Research Department National Institute of Meteorological SciencesGangneung 25457Korea Operational Systems Development Department National Institute of Meteorological SciencesSeogwipo 63568Korea Department of Atmospheric Environmental Sciences Gangneung-Wonju National UniversityGangneung 25457Korea

This study investigates the characteristics of cold clouds and snowfall in both the Yeongdong coastal and mountainous regions under different meteorological conditions based on the integration of numerical modeling and three-hourly rawinsonde observations with snow crystal photographs for a snowfall event that occurred on 29−30 January *** found that rimed particles predominantly observed turned into dendrite particles in the latter period of the episode when the 850 hPa temperature decreased at the coastal site,whereas the snow crystal habits at the mountainous site were largely needle or rimed *** soundings showed a well-defined,two-layered cloud structure along with distinctive wind-directional shear,and an inversion in the equivalent potential temperature above the low-level cloud *** first experiment with a decrease in lower-layer temperature showed that the low-level cloud thickness was reduced to less than 1.5 km,and the accumulated precipitation was decreased by 87%compared with the control *** difference in precipitation amount between the single-layered experiment and control experiment(two-layered)was not so significant to attribute it to the effect of the seeder−feeder *** precipitation in the last experiment by weakening winddirectional shear was increased by 1.4 times greater than the control experiment specifically at the coastal site,with graupel particles accounting for the highest proportion(~62%).The current results would improve snowfall forecasts in complicated geographical environments such as Yeongdong in terms of snow crystal habit as well as snowfall amount in both time and space domains.

关键词： Yeongdong snow crystal rawinsonde cloud-resolving model