Effects of wind speed, underlying surface, and seed morphological traits on the secondary seed dispersal in the Tengger Desert, China

分类： 生物学 >> 植物学 提交时间： 2024-04-15 合作期刊: 《干旱区科学》

QU Wenjie

摘要： The maintenance of sand-fixing vegetation is important for the stability of artificial sand-fixing systems in which seed dispersal plays a key role. Based on field wind tunnel experiments using 11 common plant species on the southeastern edge of the Tengger Desert, China, we studied the secondary seed dispersal in the fixed and semi-fixed sand dunes as well as in the mobile dunes in order to understand the limitations of vegetation regeneration and the maintenance of its stability. Our results indicated that there were significant variations among the selected 11 plant species in the threshold of wind speed (TWS). The TWS of Caragana korshinskii was the highest among the 11 plant species, whereas that of Echinops gmelinii was the lowest. Seed morphological traits and underlying surface could generally explain the TWS. During the secondary seed dispersal processes, the proportions of seeds that did not disperse (no dispersal) and only dispersed over short distance (short-distance dispersal within the wind tunnel test section) were significantly higher than those of seeds that were buried (including lost seeds) and dispersed over long distance (long-distance dispersal beyond the wind tunnel test section). Compared with other habitats, the mobile dunes were the most difficult places for secondary seed dispersal. Buried seeds were the easiest to be found in the semi-fixed sand dunes, whereas fixed sand dunes were the best sites for seeds that dispersed over long distance. The results of linear mixed models showed that after controlling the dispersal distance, smaller and rounder seeds dispersed farther. Shape index and wind speed were the two significant influencing factors on the burial of seeds. The explanatory power of wind speed, underlying surface, and seed morphological traits on the seeds that did not disperse and dispersed over short distance was far greater than that on the seeds that were buried and dispersed over long distance, implying that the processes and mechanisms of burial and long-distance dispersal are more complex. In summary, most seeds in the study area either did not move, were buried, or dispersed over short distance, promoting local vegetation regeneration.

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Spatiotemporal variability of rain-on-snow events in the arid region of Northwest China

分类： 地球科学 >> 大气科学 提交时间： 2024-04-15 合作期刊: 《干旱区科学》

YANG Zhiwei

摘要： Rain-on-snow (ROS) events involve rainfall on snow surfaces, and the occurrence of ROS events can exacerbate water scarcity and ecosystem vulnerability in the arid region of Northwest China (ARNC). In this study, using daily snow depth data and daily meteorological data from 68 meteorological stations provided by the China Meteorological Administration National Meteorological Information Centre, we investigated the spatiotemporal variability of ROS events in the ARNC from 1978 to 2015 and examined the factors affecting these events and possible changes of future ROS events in the ARNC. The results showed that ROS events in the ARNC mainly occurred from October to May of the following year and were largely distributed in the Qilian Mountains, Tianshan Mountains, Ili River Valley, Tacheng Prefecture, and Altay Prefecture, with the Ili River Valley, Tacheng City, and Altay Mountains exhibiting the most occurrences. Based on the intensity of ROS events, the areas with the highest risk of flooding resulting from ROS events in the ARNC were the Tianshan Mountains, Ili River Valley, Tacheng City, and Altay Mountains. The number and intensity of ROS events in the ARNC largely increased from 1978 to 2015, mainly influenced by air temperature and the number of rainfall days. However, due to the snowpack abundance in areas experiencing frequent ROS events in the ARNC, snowpack changes exerted slight impact on ROS events, which is a temporary phenomenon. Furthermore, elevation imposed lesser impact on ROS events in the ARNC than other factors. In the ARNC, the start time of rainfall and the end time of snowpack gradually advanced from the spring of the current year to the winter of the previous year, while the end time of rainfall and the start time of snowpack gradually delayed from autumn to winter. This may lead to more ROS events in winter in the future. These results could provide a sound basis for managing water resources and mitigating related disasters caused by ROS events in the ARNC.

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Design and Construction of Charged Particle Telescope Array for Study of Exotic Nuclear Clustering Structure

分类： 物理学 >> 核物理学 提交时间： 2024-03-19

Zheng-Li Liao Xi-Guang Cao Yu-Xuan Yang Chang-Bo Fu Xian-Gai Deng

摘要： The exploration of exotic shapes and properties of atomic nuclei, e.g., α cluster and toroidal shape, is afascinating field in nuclear physics. To study the decay of these nuclei, a novel detector aimed at detectingmultiple alpha-particle events was designed and constructed. The detector comprises two layers of double-sidedsilicon strip detectors (DSSD) and a cesium iodide scintillator array coupled with silicon photomultipliers arrayas light sensors, which has the advantages of their small size, fast response, and large dynamic range. DSSDscouple with cesium iodide crystal arrays are used to distinguish multiple alpha hits. The detector array has acompact and integrated design that can be adapted to different experimental conditions. The detector array wassimulated using Geant4, and the excitation energy spectra of some alpha-clustering nuclei were reconstructedto demonstrate the performance. The simulation results show that the detector array has excellent angularand energy resolutions, enabling effective reconstruction of the nuclear excited state by multiple alpha particleevents. This detector offers a new and powerful tool for nuclear physics experiments and has the potential todiscover interesting physical phenomena related to exotic nuclear structures and their decay mechanisms

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Feasibility study of the photonuclear reaction cross section of medical radioisotopes using a laser Compton scattering gamma source

分类： 物理学 >> 核物理学 提交时间： 2024-03-19

Yu-Ning Gu Wei-Juan Zhao Xi-Guang Cao Yu-Xuan Yang Tin-Kai Ma Zheng-Li Liao Fei-Long Xu Yu-Gang Ma

摘要： In recent years, the gap between the supply and demand of medical radioisotopes has increased, necessitating new methods for producing medical radioisotopes. Photonuclear reactions based on gamma sources have unique advantages in terms of producing high specific activity and innovative medical radioisotopes. However, the lack of experimental data on reaction cross sections for photonuclear reactions of medical radioisotopes of interest has severely limited the development and production of photonuclear transmutation medical radioisotopes. In this study, the entire process of the generation, decay, and measurement of medical radioisotopes was simulated using online gamma activation and offline gamma measurements combined with a shielding gammaray spectrometer. Based on a quasi-monochromatic gamma beam from the Shanghai Laser Electron Gamma Source (SLEGS), the feasibility of the measurement of production cross section for surveyed medical isotopes was simulated, and specific solutions for measuring medical radioisotopes with low production cross sections were provided. The feasibility of this method for high precision measurements of the reaction cross section of medical radioisotopes was demonstrated.

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Bunch-length measurement at a bunch-by-bunch rate based on time–frequency-domain joint analysis techniques and its application

分类： 核科学技术 >> 核科学与技术 提交时间： 2024-03-12

Wang, Hongshuang Yang, Xing Leng, Yongbin Zhou, Yimei Wang, Jigang

摘要： This paper presents a new technique for measuring the bunch length of a high-energy electron beam at a bunch-by-bunch rate in storage rings. This technique uses the time–frequency-domain joint analysis of the bunch signal to obtain bunch-by-bunch and turn-by-turn longitudinal parameters, such as bunch length and synchronous phase. The bunch signal is obtained using a button electrode with a bandwidth of several gigahertz. The data acquisition device was a high-speed digital oscilloscope with a sampling rate of more than 10 GS/s, and the single-shot sampling data buffer covered thousands of turns. The bunch length and synchronous phase information were extracted via offline calculations using Python scripts. The calibration coefficient of the system was determined using a commercial streak camera. Moreover, this technique was tested on two different storage rings and successfully captured various longitudinal transient processes during the harmonic cavity debugging process at the Shanghai Synchrotron Radiation Facility (SSRF), and longitudinal instabilities were observed during the single bunch accumulation process at Hefei Light Source (HLS). For Gaussian-distribution bunches, the uncertainty of the bunch phase obtained using this technique was better than 0.2 ps, and the bunch length uncertainty was better than 1 ps. The dynamic range exceeded 10 ms. This technology is a powerful and versatile beam diagnostic tool that can be conveniently deployed in high-energy electron storage rings.

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Feasibility of medical radioisotope production based on the proton beams at China Spallation Neutron Source

分类： 物理学 >> 核物理学 提交时间： 2024-03-10

Bing Jiang Binbin Tian Hantao Jing Qifan Dong

摘要： Theutilization of a proton beam fromthe China Spallation Neutron Source (CSNS) for producingmedical radioisotopes is appealingowing toits high current intensity and high energy. The medical isotope production based on the proton beam at the CSNS is significantfor the development of futureradiopharmaceuticals, particularly for the α-emitting radiopharmaceuticals.The production yield and activity of typical medical isotopes wereestimated using theFLUKA simulation. The results indicate that the 300-MeV proton beam with a power of 100 kW at CSNS-II ishighly suitable for proof-of-principle studies of most medical radioisotopes. In particular, this proton beam offers tremendous advantages for the large-scale production of alpha radioisotopes, such as 225Ac, whose theoretical production yield can reach approximately57 Ci/week. Based on theseresults, we provideperspectives on the use ofCSNS proton beams to produce radioisotopes for medical applications.

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Opportunities for production and property research of neutron-rich nuclei around N=126 at HIAF

分类： 物理学 >> 核物理学 提交时间： 2024-03-09

Xin-Tong Du Xiao-Bao Wei Shao-Bo Ma Li-Na Sheng Xue-Heng Zhang Shi-Tao Wang Kai-Long Wang Chun-Wang Ma Hool-Jin Ong Zhi-Yu Sun Shu-Wen Tang Yu-Hong Yu

摘要： The study of nuclide production and its properties in the N=126 neutron-rich region is the frontier and hot topic in nuclear physics and astrophysics research. The upcoming High energy FRagment Separator (HFRS) at the High Intensity heavy-ion Accelerator Facility (HIAF), an in-flight separator at relativistic energies, is characterized by high beam intensity, large ion-optical acceptance, high magnetic rigidity, and high momentum resolution power. It provides an opportunity for the study of the production and properties of neutron-rich nuclei around N=126. In this paper, an experimental scheme is proposed to produce the neutron-rich nuclei around N=126 and simultaneously measure their mass and lifetime based on the HFRS separator, and the feasibility of this scheme is evaluated by the simulations. The results show that under the high resolution optical mode many new neutron-rich nuclei approaching the r-process abundance peak around A=195 can be produced for the first time, and many nuclei with unknown mass and lifetime can be produced with high statistics. Using the time-of-flight corrected by the measured dispersive position and the energy loss information, the cocktails produced from the 208Pb fragmentation can be unambiguously identified. Moreover, the masses of some neutron-rich nuclei in the vicinity of N=126 can be measured with high precision using the time-of-flight magnetic rigidity technique. This indicates that the HIAF-HFRS facility has potential for the production and property research of neutron-rich nuclei around N=126, which is of great significance for expanding chart of nuclides, developing nuclear theories, and understanding the origin of heavy elements in the universe.

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Molecular basis of ligand recognition and activation of succinate receptor

分类： 药物科学 >> 结构生物学 提交时间： 2024-02-29

Changyao Li Heng Liu Jingru Li Haoran Zhu Wei Fu H. Eric Xu

摘要： Succinic acid, a tricarboxylic acid (TCA) cycle intermediate, significantly influences mitochondrial reactive oxygen species homeostasis through the G protein-coupled succinate receptor (SUCR1, also called GPR91), linking it to various physiological and pathological processes. Despite SUCR1’s pivotal role in mediating effects leading to liver fibrosis, hypertension, angiogenesis, inflammation, and offering a therapeutic target for multiple diseases, its activation mechanism by diverse ligands and interaction with downwards G protein remains poorly understood. This study presents the cryo-electron microscopy (cryo-EM) structures of SUCR1 in complex with inhibitory G protein (Gi) bound to succinic acid, maleic acid, and compound 31, a high-affinity agonist. These structures elucidate the distinct ligand binding modes, uncover the activation signal cascade, and detail the G protein coupling mechanism of SUCR1. Our findings provide a comprehensive structural basis for SUCR1 activation, paving the way for structure-based drug design aimed at SUCR1-related pathologies.

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Reevaluating GPR30: A Paradigm Shift from Estrogen Receptor to Unique Hydrophilic Ligand Activation

分类： 药物科学 >> 结构生物学 提交时间： 2024-02-24

Heng Liu Shimeng Guo Antao Dai Peiyu Xu Xin Li Sijie Huang Xinheng He Kai Wu Xinyue Zhang Dehua Yang Xin Xie H. Eric Xu

摘要： The orphan receptor GPR30, previously classified as a G protein-coupled estrogen receptor (GPER), has been a subject of debate regarding its ligand specificity. Through an integrative approach combining structure elucidation, biochemical binding, and cell signaling assays, we demonstrate that estrogen does not directly bind to or activate GPR30. Cryo-EM structures of GPR30 reveal an unexpected hydrophilic ligand-binding pocket, with striking differences from classical hydrophobic steroid-binding sites, inconsistent with estrogen binding. We further confirmed hydrophilic agonists like Lys05 as true activators of GPR30, providing structural insights into their binding mechanism and receptor activation. Our findings necessitate a paradigm shift in defining GPR30’s role in estrogen signaling, indicating that its activation occurs through mechanisms independent of estrogen binding. This study opens new avenues for developing targeted GPR30 ligands and reinterpreting its role in estrogen-mediated processes.

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Structural Insights into Ligand Recognition, Selectivity and Activation of the human Bombesin Receptor Subtype-3

分类： 药物科学 >> 结构生物学 提交时间： 2024-02-21

Youwei Xu Xinheng He Wenxin Su Jingru Li Xinzhu Li H. Eric Xu Wanchao Yin Changyao Li

摘要： Bombesin receptor subtype-3 (BRS3) is an important orphan G protein-coupled receptor that regulates energy homeostasis and insulin secretion. As a member of the bombesin receptor (BnR) family, which includes neuromedin B receptor (NMBR) and gastrin-releasing peptide receptor (GRPR), the lack of known endogenous ligands and high-resolution structure has impeded understanding of BRS3 signaling and function. Here, we present cryogenic electron microscopy (cryo-EM) structures of BRS3 in complex with heterotrimeric Gq protein in three states: apo, bound to the pan-BnR agonist, BA1, and bound to the synthetic BRS3-specific agonist MK-5046. These structures reveal the architecture of the orthosteric ligand pocket underpinning molecular recognition. Comparisons with BnR members provide insights into the structural basis for BRS3’s selectivity and low affinity for bombesin peptides. Examination of conserved micro-switches suggests a shared activation mechanism among BnRs. Together our results enable deeper exploration of BRS3’s ligand selectivity, signaling, and therapeutic targeting for diabetes and obesity.

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Formation and ecological response of sand patches in the protection system of Shapotou section of the Baotou-Lanzhou railway, China

分类： 地球科学 >> 地理学 提交时间： 2024-02-21 合作期刊: 《干旱区科学》

DUN Yaoquan

摘要： The development of bare patches typically signifies a process of ecosystem degradation. Within the protection system of Shapotou section of the Baotou-Lanzhou railway, the extensive emergence of bare sand patches poses a threat to both stability and sustainability. However, there is limited knowledge regarding the morphology, dynamic changes, and ecological responses associated with these sand patches. Therefore, we analyzed the formation and development process of sand patches within the protection system and its effects on herbaceous vegetation growth and soil nutrients through field observation, survey, and indoor analysis methods. The results showed that sand patch development can be divided into three stages, i.e., formation, expansion, and stabilization, which correspond to the initial, actively developing, and semi-fixed sand patches, respectively. The average dimensions of all sand patch erosional areas were found to be 7.72 m in length, 3.91 m in width, and 0.32 m in depth. The actively developing sand patches were the largest, and the initial sand patches were the smallest. Throughout the stage of formation and expansion, the herbaceous community composition changed, and the plant density decreased by more than 50.95%. Moreover, the coverage and height of herbaceous plants decreased in the erosional area and slightly increased in the depositional lobe; and the fine particles and nutrients of soils in the erosional area and depositional lobe showed a decreasing trend. In the stabilization phases of sand patches, the area from the inlet to the bottom of sand patches becomes initially covered with crusts. Vegetation and 0–2 cm surface soil condition improved in the erosional area, but this improvement was not yet evident in the depositional lobe. Factors such as disturbance, climate change, and surface resistance to erosion exert notable influences on the formation and dynamics of sand patches. The results can provide evidence for the future treatment of sand patches and the management of the protection system of Shapotou section of the Baotou-Lanzhou railway.

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Development and application of high-precision multifunction astronomical plate digitizers in China

分类： 天文学 >> 天文仪器与技术 提交时间： 2024-02-07 合作期刊: 《天文技术与仪器（英文）》

Meiting Yang Yong Yu Liangliang Wang Zhengjun Shang Changshun Liu Lixin Zheng Zhendong Chen Jing Yang Dongmei Da Shan Dong Shiyin Shen Zhenghong Tang Jianhai Zhao

摘要：Before charge-coupled device detectors became widely employed in observational astronomy, for more than a hundred years, the main detection method was photography on astronomical glass plates. Recently, in order to preserve these historical data and maintain their usability, the International Astronomical Union has appealed to all countries for global digitization of astronomical plates by developing or adopting advanced digitization technology. Specialized digitizers with high precision and high measuring speed represent key equipment for this task. The Shanghai Astronomical Observatory and the Nishimura Co., Ltd in Japan cooperated between 2013 and 2016 to develop the first Chinese high-precision astronomical plate digitizer, which was then used for complete digitization of all nighttime-observation astronomical plates in China. Then, in 2019–2021, the Shanghai Astronomical Observatory independently developed new models of plate digitizers that enabled countries such as Uzbekistan and Italy to digitize their astronomical plates. Additionally, a new high-precision and multifunction digitizer was also used to digitize valuable microscope slides from the Shanghai Natural History Museum, providing a successful example of crossdomain application of high-precision digitization technology.

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High-precision X-ray polarimeter based on channel-cut crystals

分类： 物理学 >> 核物理学 提交时间： 2024-02-07

Si, Shangyu Li, Zhongliang Jia, Wenhong Xue, Lian Luo, Hongxin Xu, Jiancai Shen, Baifei Zhang, Lingang Ji, Liangliang Leng, Yuxin Tai, Renzhong

摘要： We report on using synthetic silicon for a high-precision X-ray polarimeter comprising a polarizer and an analyzer, each based on a monolithic channel-cut crystal used at multiple Brewster reflections with a Bragg angle very close to 45. Experiments were performed at the BL09B bending magnet beamline of the Shanghai Synchrotron Radiation Facility using a Si(800) crystal at an X-ray energy of 12.914 keV. A polarization purity of 8.410-9was measured. This result is encouraging, as the measured polarization purity is the best-reported value for the bending magnet source. Notably, this is the firstly systematic study on the hard X-ray polarimeter in China, which is crucial for exploring new physics, such as verifying vacuum birefringence.

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A High-Mass Young Star-forming Core Escaping from Its Parental Filament

分类： 天文学 >> 天体物理学 提交时间： 2023-12-29

Zhiyuan Ren Xi Chen Tie Liu Emma Mannfors Leonardo Bronfman Fengwei Xu Siyi Feng Hongli Liu Fanyi Meng Amelia M. Stutz, Shanghuo Li Chang Won Lee, Ke Wang Jianwen Zhou Di Li Chen Wang Chakali Eswaraiah Anandmayee Tej Long-Fei Chen Hui Shi

摘要： We studied the unique kinematic properties in massive filament G352.63-1.07 at 1000-AU spatial scale with the dense molecular tracers observed with the Atacama Large Millimeter/submillimeter Array (ALMA). We find the central massive core M1 (12 Msun) being separated from the surrounding filament with a velocity difference of v-v_sys=-2 km/s and a transverse separation within 3 arcsec. Meanwhile, as shown in multiple dense-gas tracers, M1 has a spatial extension closely aligned with the main filament and is connected to the filament towards its both ends. M1 thus represents a very beginning state for a massive young star-forming core escaping from the parental filament, within a time scale of ~4000 years. Based on its kinetic energy (3.5x10^44 erg), the core escape is unlikely solely due to the original filament motion or magnetic field, but requires more energetic events such as a rapid intense anisotropic collapse. The released energy also seems to noticeably increase the environmental turbulence. This may help the filament to become stabilized again.

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Atypical radio pulsations from magnetar SGR 1935+2154

分类： 天文学 >> 天文学 提交时间： 2023-12-29

Pei Wang Jian Li Long Ji Xian Hou Erbil Gugercinoglu Di Li Diego F. Torres Yutong Chen Jiarui Niu Weiwei Zhu Bing Zhang En-wei Liang Li Zhang Mingyu Ge Zigao Dai Lin Lin Jinlin Han Yi Feng Chenhui Niu Yongkun Zhang

摘要： Magnetars are neutron stars with extremely strong magnetic fields, frequently powering high-energy activity in X-rays. Pulsed radio emission following some X-ray outbursts have been detected, albeit its physical origin is unclear. It has long been speculated that the origin of magnetars' radio signals is different from those from canonical pulsars, although convincing evidence is still lacking. Five months after magnetar SGR 1935+2154's X-ray outburst and its associated Fast Radio Burst (FRB) 20200428, a radio pulsar phase was discovered. Here we report the discovery of X-ray spectral hardening associated with the emergence of periodic radio pulsations from SGR 1935+2154 and a detailed analysis of the properties of the radio pulses. The complex radio pulse morphology, which contains both narrow-band emission and frequency drifts, has not been seen before in other magnetars, but is similar to those of repeating FRBs - even though the luminosities are many orders of magnitude different. The observations suggest that radio emission originates from the outer magnetosphere of the magnetar, and the surface heating due to the bombardment of inward-going particles from the radio emission region is responsible for the observed X-ray spectral hardening.

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Design and commissioning of a wideband RF system for CSNS-II rapid-cycling synchrotron

分类： 工程与技术科学 >> 工程物理学 分类： 核科学技术 >> 粒子加速器 提交时间： 2023-12-13

Wu,Jian Li,xiang Wu,Bin Zhang,Chunling Liu,Yang Long,Wei Li,Xiao

摘要： The China Spallation Neutron Source (CSNS) upgrade project (CSNS-II) aims to enhance the beam power from 100 to 500 kW. A dual-harmonic accelerating method has been adopted to alleviate the stronger space-charge effect in rapid-cycling synchrotrons owing to the increased beam intensity. To satisfy the requirements of dual-harmonic acceleration, a new radiofrequency (RF) system based on a magnetic alloy-loaded cavity is proposed . This paper presents design considerations and experimental results regarding the performance evaluation of the proposed RF system through high-power tests and beam commissioning. The test results demonstrate that the RF system satisfies the desired specifications and affords significant benefits for CSNS-II .

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Latest Developments in EUV Photoresist Evaluation Capability at Shanghai Synchrotron Radiation Facility

分类： 核科学技术 >> 辐射物理与技术 提交时间： 2023-11-24

Li,Zhenjiang Qi,Chenghang Li,Beining Yang,Shuming Zhao,Jun Lei,Zhidi Zhu,Shijie Shi,Hao Wang,Lu Wu,Yanqing Tai,Renzhong

摘要： Evaluating the comprehensive characteristics of extreme ultraviolet (EUV) photoresists is crucial for their application in EUV lithography, a key process in modern technology. This paper highlights the capabilities of the Shanghai Synchrotron Radiation Facility (SSRF) 08U1B beamline in advancing this field. Specifically, it demonstrates how this beamline can create fringe patterns with a 15-nm half-pitch (HP) on a resist using synchrotron-based EUV lithography (EUV-IL). This achievement is vital for evaluating EUV photoresists at the advanced 5-nm node. We provide a detailed introduction to the methods and experimental setup used at the SSRF 08U1B beamline to assess an EUV photoresist. A significant part of this research involved the fabrication of high-resolution hydrogen silsesquioxane (HSQ) mask gratings. These gratings, with an aspect ratio of approximately 3, were created using electron beam lithography (EBL) on an innovative mask framework. This framework was crucial in eliminating the impact of zeroth-order light on interference patterns. The proposed framework offers a new approach to mask fabrication, particularly beneficial for achromatic Talbot lithography and multicoherent-beam interference applications.

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A multithreaded parallel upwind sweep algorithm for the SN transport equations discretized with discontinuous finite elements

分类： 物理学 >> 核物理学 提交时间： 2023-11-22

Zong, Zhiwei Cheng, Maosong Yu, yingchi Dai, Zhimin

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The bio safety level-2 macromolecular crystallography beamline (BL10U2) at the Shanghai Synchrotron Radiation Facility

分类： 物理学 >> 核物理学 提交时间： 2023-11-22

Qin Xu Hua-Ting Kong Ke Liu Huan Zhou Kun-Hao Zhang Wei-Wei Wang Min-Jun Li Qiang-Yan Pan Xing-Ya Wang Yu-Zhu Wang Feng Yu Xing-Yu Gao Qi-Sheng Wang

摘要： BL10U2 is an undulator-based macromolecular crystallography (MX) beamline located at the 3.5-GeV Shanghai Synchrotron Radiation Facility. BL10U2 is specifically designed for conducting routine and bio safety level-2 (BSL-2) MX experiments utilizing high-flux tunable X-rays with energies from 7 to 18 keV, providing a beam spot size of 20 m (horizontal) 10 m (vertical) at the sample point. Certification by the Shanghai Pudong Municipal Health Commission confirmed the capability to perform BSL-2 MX experiments. The beamline is currently equipped with an Eiger X 16M detector and two newly developed in-house high-precision diffractometers that can be switched to perform conventional or in situ crystal diffraction experiments. An automatic sample changer developed in-house allows fast sample exchange in less than 30s, supporting high-throughput MX experimentation and rapid crystal screening. Data collection from both the diffractometer and detector was controlled by an in-house developed data collection software (Finback) with a user-friendly interface for convenient operation. This study presents a comprehensive overview of the facilities, experimental methods, and performance characteristics of the BL10U2 beamline.

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Environmental significance and hydrochemical characteristics of rivers in the western region of the Altay Mountains, China

分类： 地球科学 >> 地理学 提交时间： 2023-10-17 合作期刊: 《干旱区科学》

LIU Shuangshuang WANG Feiteng XU Chunhai WANG Lin LI Huilin

摘要： Analysis of environmental significance and hydrochemical characteristics of river water in mountainous regions is vital for ensuring water security. In this study, we collected a total of 164 water samples in the western region of the Altay Mountains, China, in 2021. We used principal component analysis and enrichment factor analysis to examine the chemical properties and spatiotemporal variations of major ions (including F, Cl, NO3, SO42, Li+, Na+, NH4+, K+, Mg2+, and Ca2+) present in river water, as well as to identify the factors influencing these variations. Additionally, we assessed the suitability of river water for drinking and irrigation purposes based on the total dissolved solids, soluble sodium percentage, sodium adsorption ratio, and total hardness. Results revealed that river water had an alkaline aquatic environment with a mean pH value of 8.00. The mean ion concentration was ranked as follows: Ca2+>SO42>Na+>NO3>Mg2+>K+>Cl>F>NH4+>Li+. Ca2+, SO42, Na+, and NO3 occupied 83% of the total ion concentration. In addition, compared with other seasons, the spatial variation of the ion concentration in spring was obvious. An analysis of the sources of major ions revealed that these ions originated mainly from carbonate dissolution and silicate weathering. The recharge impact of precipitation and snowmelt merely influenced the concentration of Cl, NO3, SO42, Ca2+, and Na+. Overall, river water was in pristine condition in terms of quality and was suitable for both irrigation and drinking. This study provides a scientific basis for sustainable management of water quality in rivers of the Altay Mountains.

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