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Effect of thinning intensity on tree growth and temporal variation of seed and cone production in a Pinus koraiensis plantation

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Journal of Forestry Research 2019年第3期30卷 835-845页

作者： Thanh Tuan nguyen Dinh Tien Tai Peng Zhang Muhammad Razaq hai-Long Shen School of Forestry Northeast Forestry University Harbin 150040People’s Republic of China Department of Forestry Vietnam Forestry University-Second CampusOkayamaDongnai 810000Vietnam Graduate School of Environmental and Life Science Okayama UniversityOkayamaJapan

Thinning of Korean pine (Pinus koraiensis Sieb. et Zucc.) is used to facilitate timber and cone production. The present study in Northeast China investigated the effects of thinning intensity on individual tree growth, temporal variation in cone yield, and seed quality in Korean pine plantation. In 2005, five thinning intensity levels (none, extreme, heavy, moderate and light) were set in 15 permanent plots in a 32-year-old Korean pine plantation at Mengjiagang Forest Farm, Jiamusi City, Heilongjiang Province. We recorded tree growth and seed cone production from 2013 to 2016, i.e., from 8 to 11 years after thinning. Except for height growth, thinning increased tree growth (diameter at breast height and crown size) and improved cone yield. The extreme thinning treatment (to 300 trees per hectare) resulted in the largest tree diameter, tree volume, crown size and 4-year cone production per tree. The highest cone yield per tree in the mast year (2014) was observed when stands were thinned to 500 trees per hectare (heavy thinning). Although the best cone and seed quality and the largest cone and seed mass per tree were recorded in the heavily thinned stand, no significant differences were found between heavy and moderate thinning stands (750 trees per hectare). At the stand level, the moderately thinned stand had the highest basal area, stock volume and seed cone production per stand. Our results suggest that thinning to 750 trees per hectare will improve timber and cone productivity in 40-year-old P. koraiensis stands.

关键词： Korean pine Thinning intensity Seed yield Tree growth Temporal variation in cone yield

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Hybrid model to optimize object-based land cover classification by meta-heuristic algorithm:an example for supporting urban management in Ha Noi,Viet Nam

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International Journal of Digital Earth 2019年第10期12卷 1118-1132页

作者： Quang-Thanh Bui Manh Pham Van nguyen Thi Thuy Hang Quoc-Huy nguyen nguyen Xuan Linh Pham Minh hai Tran Anh Tuan Pham Van Cu Center for Applied Research in Remote sensing and GIS(CARGIS) VNU University of ScienceHa NoiViet Nam VNU University of Science Ha NoiViet Nam Vietnam Institute of Geodesy and Cartography Ha NoiViet Nam Ministry of Education and Training Ha NoiViet Nam

This study proposed a novel object-based hybrid classification model named GMNN that combines Grasshopper Optimization Algorithm(GOA)and the multiple-class Neural network(MNN)for urban pattern detection in Hanoi,*** bands of SPOT 7 image and derivable NDVI,NDWI were used to generate image segments with associated attributes by PCI Geomatics *** segments were classified into four urban surface types(namely water,impervious surface,vegetation and bare soil)by the proposed ***,three training and validation datasets of different sizes were used to verify the robustness of this *** all tests,the overall accuracies of the classification were approximately 87%,and the Area under Receiver Operating Characteristic curves for each land cover type was ***,the performance of this model was examined by comparing several statistical indicators with common benchmark *** results showed that GMNN out-performed established methods in all comparable *** results suggested that our hybrid model was successfully deployed in the study area and could be used as an alternative classification method for urban land cover *** a broader sense,classification methods will be enriched with the active and fast-growing contribution of metaheuristic algorithms.

关键词： Urban remote sensing object-based classification neural network grasshopper optimization algorithm

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Ni Single Atoms and Ni Phosphate Clusters Synergistically Triggered Surface-Functionalized MoS_(2)Nanosheets for High-performance Freshwater and Seawater Electrolysis

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Energy & Environmental Materials 2022年第4期5卷 1340-1349页

作者： Min Sung Kim Duy Thanh Tran Thanh hai nguyen Van An Dinh Nam Hoon Kim Joong Hee Lee Department of Nano Convergence Engineering Jeonbuk National UniversityJeonju 54896Republic of Korea Department of Precision Engineering Graduate School of EngineeringOsaka University2-1Yamada-okaSuita 565-0871Japan Carbon Composite Research Center Department of Polymer-Nanoscience and TechnologyJeonbuk National UniversityJeonju 54896Republic of Korea

Two-dimensional metal dichalcogenides have been evidenced as potential electrocatalysts for hydrogen evolution reaction(HER);however,their application is limited by a poor oxygen evolution reaction(OER)activity due to insufficient number/types of multi-integrated active *** this study,we report a novel bifunctional catalyst developed by simultaneous engineering of single nickel atoms(Ni_(SA)) and nickel phosphate clusters(Ni_(Pi)) to synergistically trigger surface-functionalized MoS_(2) nanosheets(NSs)resulting in high reactivities for both HER and *** Ni_(SA)-Ni_(Pi)/MoS_(2)NSs material exhibits a fairly Pt-like HER behavior with an overpotential of 94.0 mV and a small OER overpotential of 314.0 mV to reach 10 mA cm^(-2) in freshwater containing 1.0 M *** results of the catalyst are well supported by theoretical study,which reveals the significant modulation of electronic structure and enrichment of electroactive site number/types with their reasonably adjusted free adsorption *** evaluating practicability,the Ni_(SA)-Ni_(Pi)/MoS_(2)NSs-based electrolyzer delivers effective operation voltage of 1.62,1.52,and 1.66 V at 10 mA cm^(-2) and superior long-term stability as compared to Pt/C//RuO_(2) system in freshwater,mimic seawater,and natural seawater,*** present study indicates that the catalyst is a promising candidate for the practical production of green hydrogen via water electrolysis.

关键词： bifunctional electrocatalyst freshwater and seawater electrolysis nickel phosphate clusters nickel single atoms surface-functionalized-MoS_(2)nanosheets

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A time-domain estimation method of rapidly time-varying channels for OFDM-based LTE-R systems

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Digital Communications and Networks 2019年第2期5卷 94-101页

作者： Jin-Kyu Choi Van Due nguyen hai Nam nguyen Van Vinh Duong Tien Hoa nguyen Hanbyeog Cho Hyun-Kyun Choi Seong-Gyoon Park Smart Mobility Research Department of ETR1 DaejeonSouth Korea School of Electronics and Telecommunicalions HUSTViet Nam Electronics and Telecommunications Research Institute DaejeonSouth Korea School of Information and Communication in KongJu National University South Korea

This paper addresses the performance of fast doubly selective fading channel estimation combined with InterCarrier Interference (ICI) cancellation for Long Term Evolution (LTE) communication platform in the High Speed Railway (HSR) environment. We consider the Channel Impulse Response (CIR) coefficients with a critical Doppler frequency shift and multi-path fading that were taken from the WINNER II channel model and the D2a propagation scenario, where the conditions of HSR are analyzed. As multi-path fading increases and the channel varies in the order of the symbol period, we first propose a novel approach for designing a pilot symbol structure in the time domain. Then, we describe the deployment of the proposed pilot symbol structure to estimate the channel in the time domain. Channel information corresponding to the data positions is obtained by linear interpolation. In each OFDM symbol, the slope and the initial value for establishing an interpolation function are estimated to adapt to the time variation of the channel. An accurate estimate of channel state information is used for the purpose of ICI cancellation. The simulation results show that the channel estimated by our proposed method can follow the real channel well, even in a very high Doppler frequency. The estimation method in terms of Mean Squared Error (MSE) significantly outperforms the state-of-the-art methods. The combination of our channel estimator with several interference cancelers provides a considerably better system performance than that achieved when frequency channel estimation is used.

关键词： ICI cancellation OFDM Channel estimation LTE-R

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Successful containment of a COVID-19 outbreak in Bach Mai Hospital by prompt and decisive responses

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Asian Pacific Journal of Tropical Medicine 2021年第5期14卷 234-235页

作者： Van Minh Hoang Thi Phuong Thao Tran Thi Ngoc Phuong nguyen Thi hai Yen nguyen Quang Tuan nguyen Hanoi University of Public Health HanoiVietnam Bach Mai Hospital HanoiVietnam

In low-and middle-income countries,tertiary care hospitals frequently face an extremely heavy workload and shoulder an even heavier burden during the COVID-19 *** Mai Hospital(BMH),one of the leading tertiary hospitals in Vietnam,is on the frontline in the fierce battle against *** letter aims to describe how BMH tackles the COVID-19 outbreak in the hospitallevel battle,which could support policymakers in time-management and well-preparation for this unpredictable pandemic.

关键词： prompt income policy

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Gamma Cascade Transition of 51V(nth, g )52V Reaction

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World Journal of Nuclear Science and Technology 2014年第1期4卷 40-45页

作者： Pham Dinh Khang nguyen Xuan hai Ho Huu Thang Vuong Huu Tan nguyen An son nguyen Duc Hoa Nuclear Research Institute Dalat Vietnam Nuclear Training Center Hanoi Vietnam University of Dalat Dalat Vietnam Vietnam Agency for Radiation and Nuclear Safety Hanoi Vietnam

The thermal neutron capture gamma radiations for 51V(n, g)52V reaction have been studied at Dalat Nuclear Research Reactor (DNRR). The gamma two-step cascade transition was measured by event-event coincidence spectrometer. The added-neutron binding energy in 52V was measured as 7.31 MeV. Energy and the intensity transition of cascades were consistent with prediction of single particle model. Furthermore, the spin and the parity of levels were confined.

关键词： Gamma Two-Step Cascade Neutron Capture Reaction Coincidence

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Upconversion luminescence of Gd2O3:Er3+and Gd2O3:Er3+/silica nanophosphors fabricated by EDTA combustion method

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Journal of Rare Earths 2019年第11期37卷 1126-1131页

作者： Le Quoc Minh Tran Kim Anh nguyen Duy Hung Pham Thi Minh Chau nguyen Thi Quy hai Ho Van Tuyen Vu Thi Thai Ha Vu Duc Tu Wieslaw Strek Institute of Theoretical and Applied Research Duy Tan UniversityDa Nang 55000Viet Nam Advanced Institute for Science and Technology Hanoi University of Science and Technology1 Dai Co VietHai Ba TrungHanoiViet Nam Institute of Materials Science Vietnam Academy of Science and Technology18 Hoang Quoc Viet RoadCau Giay DistrictHanoiViet Nam Institute of Low Temperature and Structure Research Polish Academy of Science 2 OkolnaWroclawPoland

Gd2O3:Er^3+nanophosphors were fabricated by the combustion method in presence of Na2 ethylene diamine tetra acetic acid(EDTA-Na2)as fuel at not high temperature(≤350℃)within a very short time of 5 *** added concentration of Er^3+ions in Gd2O3 matrix was changed from 0.5 mol%to 5.0 mol%.The X-ray diffraction pattern of samples indicates the monoclinic structure of Gd2O3:Er^3+.The morphology and chemical composition analysis of the Gd2O3:Er^3+samples are characterized by a field emission scanning electron microscope(FESEM)and a Fourier-transform infrared spectrometer(FTIR).The photoluminescence(PL),photo luminescence excitation(PLE)and upconversion(UC)at room temperature of the prepared materials with different concentrations of Er^3+were *** PL of Gd2O3:Er^3+nanomaterials are shown in visible at 545,594,623,648,688 nm under excitation at 275 *** emission bands from transitions of Er^3+from 2P3/2 to 4F9/2 are observed,UC luminescent spectra of the Gd2O3:Er^3+/silica nanocomposites under 976 nm excitation show the bands at 548 and 670 *** influence of excitation power at 980 nm for transitions were measured and *** results indicate that the upconversion process of Gd2O3:Er^3+/silica is two photons absorption *** low temperature dependence of UC luminescent intensities of the main bands of Gd2O3:Er^3+was investigated towards development of a nanotemperature sensor in the range of 10-300 K.

关键词： Upconversion luminescence Gd2O3:Er3+ Gd2O3:Er3+/silica Nanophosphors EDTA combustion Rare earths

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Microscopic insight into the single step growth of in-plane heterostructures between graphene and hexagonal boron nitride

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Nano Research 2019年第3期12卷 675-682页

作者： Thanh hai nguyen Daniele Perilli Mattia Cattelan Hongsheng Liu Francesco Sedona Neil A. Fox Cristiana Di Valentin Stefano Agnoli Department of Chemical Science University of Padova Via Francesco Marzolo 1 35131 Padova Ita Dipartimento di Scienza dei Materiali Universita di Milano-Bicocca via R. Cozzi 55 20125 Milano Italy School of Chemistry University of Bristol Cantocks Close Bristol BS81TS UK

Graphene-h-BN hybrid nanostructures are grown in one step on the Pt(111) surface by ultra-high vacuum chemical vapor deposition using a single precursor,the dimethylamino borane *** varying the deposition conditions,different nanostructures ranging from a fully continuous hybrid monolayer to well-separated Janus nanodots can be *** growth starts with heterogeneous nucleation on morphological defects such as Pt step edges and proceeds by the addition of small clusters formed by the decomposition of the dimethylamino borane *** tunneling microscopy measurements indicate that a sharp zigzag in-plane boundary is formed when graphene grows aligned with the Pt substrate and consequently with the h-BN layer as *** graphene is rotated by 30°,the graphene armchair edges are seamlessly connected to h-BN zigzag *** is confirmed by a thorough density functional theory (DFT) *** resolved photoemission spectroscopy (ARPES) data suggests that both h-BN and graphene present the typical electronic structure of self-standing non-interacting materials.

关键词： graphene h-BN heterostructures seanning tunneling microscopy density functional theory (DFT)

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Embryonic, genetic and clinical outcomes of fresh versus vitrified oocyte: A retrospective cohort study

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Asian pacific Journal of Reproduction 2023年第6期12卷 266-272页

作者： Phuong Dao Thi son Dang Truong Thuan nguyen Duc Anh Pham Van Anh Do Tuan Van Hanh nguyen HP Fertility-hai Phong International Hospital of Obstetrics and Pediatrics Haiphong180000Vietnam Graduate University of Science and Technology Vietnam Academy of Science and TechnologyHanoi100000Vietnam Institute of Biotechnology Vietnam Academy of Science and TechnologyHanoi100000Vietnam

Objective:To compare embryonic development,ploidy status and clinical outcomes between fresh and frozen-thawed ***:This retrospective cohort study evaluated 83 fertilization cycles including both fresh and frozen oocytes from 79 patients at the HP Fertility Center of hai Phong International Hospital of Obstetrics and Pediatrics in *** patient underwent several ovarian stimulation cycles to accumulate a certain number of oocytes that would be *** the last oocyte retrieval,all patient’s oocytes including both frozen and fresh would be *** outcomes included the rates of oocyte survival,cleavage embryo,blastocyst,ploidy status,pregnancy,biochemical pregnancy and clinical ***:The oocyte survival rate after thawing was 96.5%.No statistically significant difference was found when comparing fresh and frozen oocytes regarding fertilization rate(78.1%vs.75.5%,P=0.461),usable cleavage embryo rate(86.9%vs.87.2%,P=0.916)but usable blastocyst rate was found higher statistically in the frozen oocyte group(44.4%vs.54.0%,P=0.049).The percentages of euploid,aneuploid and mosaic embryos between the fresh group and the vitrified group had no significant differences(33.8%vs.31.6%,P=0.682;51.0%vs.54.2%,P=0.569;15.2%vs.12.4%,P=0.787;respectively).The rates of pregnancy,biochemical pregnancy and clinical pregnancy had no statistical difference(68.8%vs.64.8%,P=0.764;12.5%vs.3.6%,P=0.258;37.5%vs.46.4%,P=0.565).17 Mature oocytes are the minimum to have at least one euploid ***:Oocyte vitrification does not affect embryonic,genetic and clinical *** number of mature oocytes should be considered for fertilization in some cases.

关键词： Clinical outcomes Embryonic development Genetic outcomes Human oocyte Oocyte accumulation Oocyte cryopreservation Ploidy status Vitrified oocyte

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A Design Configuration of an FPGA-Based Coincident Spectrometry System

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Journal of Analytical Sciences, Methods and Instrumentation 2013年第3期3卷 158-162页

作者： Pham Dinh Khang nguyen Nhi Dien Dang Lanh nguyen Xuan hai Pham Ngoc Tuan nguyen Duc Hoa nguyen An son Nuclear Research Institute Dalat Vietnam Nuclear Training Center Hanoi Vietnam University of Dalat Dalat Vietnam University of Dalat Dalat Vietnam.

In the past, most of popular coincidence spectrometers were normally based on traditional electronics techniques such as time to amplitude conversion or logic selecting coincidence unit. They were complicated and it is not convenient for us to use them. This paper deals with a new design of a contemporary coincidence spectrometer which is based on Field Programmable Gate Arrays (FPGA) devices via Digital Signal Processing (DSP) techniques with Hardware Description Language (VHDL). The outstanding advantage of DSP techniques and FPGA technology is capable of enhancement of the quality of the experimental measurements for nuclear radiation. The designed configuration of the traditional system was tested on the PCI 7811R board of National Instruments while the digital systems were establishing with FPGA devices. The purpose of this work is referring to the principle for construction of an FPGA-based system capable of replacing a conventional system. Therefore, a novel approach for in-house development of digital techniques is presented. The method for designing the system is utilization of slow-fast coincidence configurations with two HPGe detectors obtaining a pair of coincidence events, processing data in DSP algorithms. The significant and noticeable results are the operating frequency of 80 MHz and system timestamp window of approximately 10 ns.

关键词： Digital Signal Processing FPGA VHDL

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