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Nuclear Science and Techniques 2024年第4期35卷 189-199页

作者： Jie-Yu Zhu Yang-Zhou Su Hai-Bo Yang Fen-Hua Lu Yan Yang Xi-Wen Liu Ping Wei Shu-Cai Wan Hao-Qing Xie Xian-Qin Li Cong Dai Hui-Jun Hu Hong-Bang Liu Shu-Wen Tang Cheng-Xin Zhao Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China Guangxi Key Laboratory for Relativistic Astrophysics School of Physical Science and TechnologyGuangxi UniversityNanning 530004China

The high energy cosmic-radiation detection(HERD)facility is planned to launch in 2027 and scheduled to be installed on the china Space *** serves as a dark matter particle detector,a cosmic ray instrument,and an observatory for high-energy gamma rays.A transition radiation detector placed on one of its lateral sides serves dual purpose,(ⅰ)calibrating HERD's electromagnetic calorimeter in the TeV energy range,and(ⅱ)serving as an independent detector for high-energy gamma *** this paper,the prototype readout electronics design of the transition radiation detector is demonstrated,which aims to accurately measure the charge of the anodes using the SAMPA application specific integrated circuit *** electronic performance of the prototype system is evaluated in terms of noise,linearity,and *** the presented design,each electronic channel can achieve a dynamic range of 0–100 fC,the RMS noise level not exceeding 0.15 fC,and the integral nonlinearity was<0.2%.To further verify the readout electronic performance,a joint test with the detector was carried out,and the results show that the prototype system can satisfy the requirements of the detector's scientific goals.

关键词： HERD Dark matter particle detection TRD Readout electronics SAMPA Data acquisition Performance test

NiCo/Al_(2)O_(3)nanocatalysts for the synthesis of 5-amino-1-pentanol and 1,5-pentanediol from biomass-derived 2-hydroxytetrahydropyran

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Green Chemical Engineering 2024年第1期5卷 119-131页

作者： Jian Yang Jia Zhang Enrico Benassi Xuemei Li Hailong Liu Weiguo Fang Junying Tian Chungu Xia Zhiwei Huang State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou730000China School of Petrochemical Engineering Lanzhou University of TechnologyLanzhou730050China Novosibirsk State University Novosibirsk630090Russia University of Chinese Academy of Sciences Beijing100049China

Al_(2)O_(3)-supported monometallic Ni,Co,and bimetallic Ni-Co nanocatalysts originated from layered double hydroxide precursors were synthesized by co-precipitation method,and used for the synthesis of useful 5-amino-1-pentanol(5-AP)and 1,5-pentanediol(1,5-PD)by reductive amination(RA)or direct hydrogenation of biofurfuralderived 2-hydroxytetrahydropyran(2-HTHP),*** both reactions,the yield of the target products decreased monotonously with the increasing amounts of Co in the NiCo/Al_(2)O_(3)catalysts,owing probably to the replacement of highly reactive Ni by Co component with inferior hydrogenation activity at the low reaction temperature of 60℃.However,the incorporation of Co could improve the reducibility of the NiCo/Al_(2)O_(3)bimetallic catalysts and promote the reaction stability of the catalysts,especially for Ni_(2)Co1/Al_(2)O_(3),in both reactions with over 180 h *** of the catalysts before and after the reaction showed that the incorporating Co could inhibit the sintering of metal particles and hinder the surface oxidation of the more reactive Ni0species,thanks to the formation of Ni-Co alloy in the bimetallic ***-based modeling of the reaction mechanisms is also performed,supporting the reaction pathway proposed previously and also the much higher activity of Ni in the RA of 2-HTHP as compared with Co.

关键词： NiCo bimetallic catalysts Layered double hydroxide Reductive amination Amino alcohol Quantum chemical calculations

Unveiling evapotranspiration patterns and energy balance in a subalpine forest of the Qinghai-Tibet Plateau:observations and analysis from an eddy covariance system

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Journal of Forestry Research 2024年第3期35卷 175-188页

作者： Niu Zhu Jinniu Wang Dongliang Luo Xufeng Wang Cheng Shen Ning Wu Ning Zhang Binghui Tian Aihong Gai Chengdu Institute of Biology Chinese Academy of SciencesChengdu 610041People's Republic of China College of Resources and Environmental Sciences Gansu Agricultural UniversityLanzhou 730070People's Republic of China Mangkang Ecological Monitoring Station Tibet Ecological Security Barrier Ecological Monitoring NetworkQamdo 854500People's Republic of China Northwest Institute of Eco Environmental Resources Chinese Academy of SciencesLanzhou 730000People's Republic of China

Evapotranspiration is an important parameter used to characterize the water cycle of *** under-stand the properties of the evapotranspiration and energy balance of a subalpine forest in the southeastern Qinghai-Tibet Plateau,an open-path eddy covariance system was set up to monitor the forest from November 2020 to October 2021 in a core area of the Three Parallel Rivers in the Qing-hai-Tibet *** results show that the evapotranspira-tion peaked daily,the maximum occurring between 11:00 and 15:*** factors had significant effects on evapotranspiration,among them,net radiation the greatest(R^(2)=0.487),and relative humidity the least(R^(2)=0.001).The energy flux varied considerably in different seasons and sensible heat flux accounted for the main part of turbulent *** energy balance ratio in the dormant season was less than that in the growing season,and there is an energy imbalance at the site on an annual time scale.

关键词： Evapotranspiration Energy balance Subalpine forest Three Parallel Rivers region Southeast Qinghai-Tibet Plateau

Design and Application of an S-band Fast Radio Bursts Search Pipeline for the Nanshan 26 m Radio Telescope

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Research in Astronomy and Astrophysics 2024年第7期24卷 114-120页

作者： Yan-Ling Liu Mao-Zheng Chen Jian Li Jian-Ping Yuan Rai Yuen Zhi-Yong Liu Hao Yan Wen-Long Du Nan-Nan Zhai Xinjiang Astronomical Observatory Chinese Academy of Sciences Xinjiang Key Laboratory of Microwave Technology University of Chinese Academy of Sciences

Fast radio bursts(FRBs) are among the most studied radio transients in astrophysics, but their origin and radiation mechanism are still unknown. It is a challenge to search for FRB events in a huge amount of observational data with high speed and high accuracy. With the rapid advancement of the FRB research process, FRB searching has changed from archive data mining to either long-term monitoring of the repeating FRBs or all-sky surveys with specialized equipments. Therefore, establishing a highly efficient and high quality FRB search pipeline is the primary task in FRB research. Deep learning techniques provide new ideas for FRB search processing. We have detected radio bursts from FRB 20201124A in the L-band observational data of the Nanshan 26 m radio telescope(NSRT-26m) using the constructed deep learning based search pipeline named dispersed dynamic spectra search(DDSS). Afterwards, we further retrained the deep learning model and applied the DDSS framework to S-band observations. In this paper, we present the FRB observation system and search pipeline using the S-band *** carried out search experiments, and successfully detected the radio bursts from the magnetar SGR J1935+2145and FRB 20220912A. The experimental results show that the search pipeline can complete the search efficiently and output the search results with high accuracy.

关键词： methods: data analysis methods: observational radio continuum: general

Radial growth in Qinghai spruce is most sensitive to severe drought in the Qilian Mountains of Northwest china

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Journal of Forestry Research 2024年第3期35卷 73-86页

作者： Xuge Wang Liang Jiao Ruhong Xue Peng Zhang Dashi Du Mengyuan Wei Qian Li College of Geography and Environmental Science Northwest Normal UniversityNo.967Anning East RoadLanzhou 730070People's Republic of China Key Laboratory of Resource Environment and Sustainable Development of Oasis Northwest Normal UniversityLanzhou 730070Gansu ProvincePeople's Republicof China

Global warming and frequent extreme drought events lead to tree death and extensive forest decline,but the underlying mechanism is not *** drought years,cambial development is more sensitive to climate change,but in different phenological stages,the response rela-tionship is ***,the dynamic relationship between tree radial growth and climatic/environmental fac-tors needs to be *** thus continuously monitored radial growth of Qinghai spruce(Picea crassifolia Kom.)and environmental factors from January 2021 to November 2022 using point dendrometers and portable meteorological weather stations in the central area of the Qilian *** relationship and stability between the radial growth of Qinghai spruce and environmental factors were compared for different levels of drought in 2021 and *** year 2022 had higher temperatures and less precipitation and was drier than *** with 2021,the growing period in 2022 for Qinghai spruce was 10 days shorter,maximum growth rate(Grmax)was 4.5μm·d^(-1) slower,and the initiation of growth was 6 days *** of Qinghai spruce was always restricted by drought,and the stem radial increment(SRI)was more sensitive to precipitation and air relative *** changes in cumulative radial growth were divided into four phenological stages according to the time of growth onset,cessation,and maximum growth rate(Grmax)of Qinghai *** responses of SRI to climate change were stronger in Stage 3 and Stage 4 of 2021 and stronger in Stage 1(initiation growth stage)and Stage 3 of *** results provide important information on the growth of the trees in response to drought and for specific managing forests as the climate warms.

关键词： Picea crassifolia Radial growth dynamics Severe drought Response stability Point dendrometer

Deep eutectic solvent-driven self-assembly of metal mercaptide complexes with enzyme-mimicking activities for detection of uric acid through one-step cascade catalytic reaction

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Green Chemical Engineering 2024年第1期5卷 75-84页

作者： Jean Claude Munyemana Jia Chen Xin Li Yangxia Han Hao Tang Hongdeng Qiu cas Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou730000China University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing100039China Department of Pharmacy Gansu Provincial HospitalLanzhou730000China

This work presents a generic strategy to create a series of metal mercaptides complexes via coordination selfassembly between transition metals(Mn,Cu,Co,Fe,and Ni)and cysteine(Cys)by forming the sulfur-metal *** strategy involves dissolving metal chlorides and Cys into deep eutectic solvents(DES),followed by the precipitation of metal mercaptides complexes(such as Cys-Mn)by adding water as an antisolvent,where DES serves as the solvent,shape directing,and capping agent,thereby preventing the formation of other metal ***,the prepared complexes possess both laccase and peroxidase-like properties,allowing the design of a technique for the detection of L-3,4-dihydroxyphenylalanine(L-DOPA)and uric acid,*** prepared Cys-Mn can linearly oxidize L-DOPA with its concentrations from 0.1 to 130μM and the detection limit was calculated to be 75.5 n ***,the Cys-Mn can mimic the activity of peroxidase towards oxidization of o-phenylenediamine at neutral p H,allowing single-step and one-pot cascade reactions for visual and fluorometric measurements of uric acid(UA)that could work in the range of 0.2-500μM UA with a detection limit of 0.06μM and 0.054μМ,*** assay was successful in detecting UA in serum and urine samples with relative standard deviation(RSD)ranging from 7.3%to 10.2%and 3.0%-8.5%respectively,suggesting that it may prove useful in medical diagnostic testing.

关键词： Metal-mercaptides Deep eutectic solvents Self-assembly Peroxidase-mimic catalyst Uric acid detection

Water-soluble organic matter with various polarities in PM_(2.5) over Xi'an,china:Abundance,functional groups,and light absorption

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Particuology 2024年第1期84卷 281-289页

作者： Xueting Yang Shasha Huang Dan Li Hongmei Xu Yaling Zeng Liu Yang Diwei Wang Ningning Zhang Junji Cao Zhenxing Shen Department of Environmental Science and Engineering Xi'an Jiaotong UniversityXi'an710049China School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen518055China State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an710049China

Humic-like substances(HULIS)are a major component of brown carbon and consequently play a major role in climate *** this study,70 PM_(2.5) samples were collected from Xi'an in winter 2019 and summer *** HULIS(HULIS-n),acidic HULIS(HULIS-a),and high-polarity water-soluble organic compounds(HP-WSOC)were analyzed to determine their carbon concentrations and measure their ultraviolet-visible absorption and infrared *** the three components,HULIS-n had the highest carbon content in both winter(3.29±1.45μg m^(-3))and in summer(1.38±1.10μg m^(-3)).The semi-quantitative results for the functional groups revealed that HP-WSOC was rich in carboxylic acids and had high aromaticity in winter,whereas HULIS-n was rich in carboxylic acids in ***,HULJS-a was richer in nitrate esters and saturated aliphatic hydrocarbons in summer than in *** results for specific ultraviolet absorbance(SUVA)and E_(250)/E_(365) revealed that HULIS had higher molecular weight and aromaticity in winter than in ***-n dominated in the total light absorption of HULIS+HP-WSOC in both winter(73.08%)and summer(48.57%).Overall,the results on the carbon content,optical properties,and functional groups of WSOCs with differing polarity can improve un-derstanding of environmental and climatic effects.

关键词： Humic-like substances(HULIS) Aromaticity Fourier-transform infrared(FTIR) spectroscopy light absorbance

Land use effects on the dynamics of soil C,N and microbes in the water-wind erosion crisscross region of the northern Loess Plateau,china

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Pedosphere 2024年第1期34卷 181-190页

作者： Yi WANG Chunyue LI Shunjin HU State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationNorthwest A&F UniversityYangling 712100China School of Geography and Tourism Shaanxi Normal UniversityXi'an 710119China Department of Entomology&Plant Pathology North Carolina State UniversityRaleigh 27695USA

The water-wind erosion crisscross region of the northern Loess Plateau in china is under constant pressure from severe erosion due to its windy and dry climate and intensive human activities. Identifying sustainable land use patterns is key to maintaining ecosystem sustainability in the area. Our aim was to appraise the impacts of different land use regimes on the dynamics of soil total organic C(TOC), total N(TN), and microbes in a typical watershed in the northern Loess Plateau to identify suitable land use types that can maintain soil fertility and sustainability. A field experiment was performed in Liudaogou watershed in Shenmu City, Shaanxi Province, china, where the dynamics of soil TOC and TN, microbial biomass C and N, microbial respiration, and net N mineralization in six typical land use types, dam land, rainfed slope land, deciduous broadleaf forest, evergreen coniferous forest, shrubland, and grassland,were measured in three different growing seasons. Land use type and season significantly affected TOC, TN, and the dynamics of microbial biomass and activity. As the most anthropogenically disturbed land use pattern, dam land was an optimal land use pattern for TOC sequestration due to its higher TOC and TN, but lower microbial activity. Soil TOC, TN, and microbial properties demonstrated a decreasing trend after natural grassland was converted to shrubland,forest, and rainfed slope land. Shrubland with exotic N-fixing Korshinsk peashrub(Caragana korshinskii Kom.) can maintain TOC, TN, and microbial properties similar to those in grassland. Soil TOC, NH_(4+)^(-)N, TN, moisture, and extractable C were the principal indexes for soil microbial biomass and activity and explained 88.90% of the total variance. Thus, grassland was the optimal land use pattern in the water-wind erosion crisscross region of the northern Loess Plateau to maintain ecosystem stability and sustainability.

关键词： grassland microbial activity microbial biomass total organic C total N watershed

Simulation of RFI Cancellation Using Subspace Projection Algorithm for PAF Receiver

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Research in Astronomy and Astrophysics 2024年第1期24卷 237-244页

作者： Peng Wu Jian Li Mao-Zheng Chen Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China Xinjiang Key Laboratory of Microwave Technology Urumqi 830011China

The simulation of radio frequency interference(RFI) cancellation by applying a spatial filtering technique for phased array feed(PAF) is presented. In order to better reflect the characteristics of PAF, a new signal model is to add the coupling coefficient among elements of PAF to the conventional array signal model. Then the subspace projection(SP) algorithm is used to cancel RFI from the correlation matrix of the signal, and finally, the 2D power image is drawn. The power variation of signal-of-interest direction and RFI direction before and after using the SP algorithm is analyzed. The new signal model and simulation strategy can be used to test and verify the beamformer.

关键词： methods:analytical techniques:radar astronomy telescopes

Machine Learning-based Identification of Contaminated Images in light Curve Data Preprocessing

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Research in Astronomy and Astrophysics 2024年第4期24卷 287-295页

作者： Hui Li Rong-Wang Li Peng Shu Yu-Qiang Li Yunnan Observatories Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Space Object and Debris Observation Chinese Academy of SciencesNanjing 210023China

Attitude is one of the crucial parameters for space objects and plays a vital role in collision prediction and debris *** light curves to determine attitude is the most commonly used *** photometric observations,outliers may exist in the obtained light curves due to various ***,preprocessing is required to remove these outliers to obtain high quality light *** statistical analysis,the reasons leading to outliers can be categorized into two main types:first,the brightness of the object significantly increases due to the passage of a star nearby,referred to as“stellar contamination,”and second,the brightness markedly decreases due to cloudy cover,referred to as“cloudy contamination.”The traditional approach of manually inspecting images for contamination is time-consuming and ***,we propose the utilization of machine learning methods as a *** Neural Networks and SVMs are employed to identify cases of stellar contamination and cloudy contamination,achieving F1 scores of 1.00 and 0.98 on a test set,*** also explore other machine learning methods such as ResNet-18 and light Gradient Boosting Machine,then conduct comparative analyses of the results.

关键词： techniques:image processing methods:data analysis light pollution