Subjects: Nuclear Science and Technology >> Particle Accelerator submitted time 2024-06-10
Abstract： [Background]: In Shanghai Synchrotron Radiation Facility (SSRF) Phase-II Beamline Project, the accelerator performance has been improved. [Purpose]: The beam diagnostic system has been upgraded to meet the requirements of the new hybrid operation mode of the storage ring, mainly including the construction of a bunch cleaning system, a bunch purity measurement system, the upgrading of the transverse feedback system, the construction of a new X-ray diagnostic line, and the upgrade of the original diagnostic line. [Methods]: A bunch cleaning system based on RF pulse signal modulation was developed in the booster, a bunch purity measurement system based on time-correlated single photon counting has been designed in the optical diagnostic hub of the storage ring. The transverse feedback system (TFB) has been upgraded to 3-electrode kickers and using new bunch-by-bunch feedback electronics. The new X-ray beam diagnostic line has been built in cell-6, and the original X-ray diagnostic beam has been extended out of the shielding wall. [Results]: For the first time, SSRF achieves a high-purity hybrid filling mode better than 10^-4 with a large bunch current greater than 22 mA. The new TFB system works normally at high dynamic range. The new X-ray beam diagnostic line was successfully constructed in cell 6, and the original line in cell 1 was extended. [Conclusions]: The beam diagnostic system has been upgraded successfully and helped the beamline project successfully pass the national acceptance inspection.
Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-03-28
Abstract： Background : High frame rate area detectors play a crucial role in experiments such as coherent diffraction imaging and serial crystallography conducted at the Shanghai HIgh repetitioN rate xfel and Extreme light facility (SHINE). Their high data transmission rates and extensive processing needs pose grand challenges for the data acquisition system. Purpose : To support the continuous operation of a megapixel detector working at 10kHz frame rate, the DAQ software must deliver a data throughput of no less than 20 GB·s-1. Methods : In order to meet the requirement of high throughput data readout and processing of many detector modules, this research developed a distributed DAQ software based on C++ language, which is designed to run on multiple servers in parallel. This research adopts a memory based MapReduce-like method to realize the online event reconstruction. And also tested the Bitshuffle+LZ4/ZSTD data compression algorithm. Results : The software successfully achieved a throughput of 20GB·s-1 for data transmission and event reconstruction by using 4 DAQ servers. It also includes the implementation and testing of various functions, such as data calibration, lossless compression, and the distributed operation capability of the whole system. Conclusions : This research will provide essential support for some related experiments using area detectors which require high throughput data acquisition.
Subjects: Physics >> Nuclear Physics submitted time 2023-11-08
Hui-Ling Wei
Meng-Die Zhou
Pu Jiao
Yu-Ting Wang
Jie Pu
Kai-Xuan Cheng
Ya-Fei Guo
Chun-Yuan Qiao,
Gong-Tao Fan
Hong-Wei Wang,
Chun-Wang Ma
Abstract： From the empirical phenomena of fragment distributions in nuclear spallation reactions, semiempirical formulas named SPAGINS were constructed to predict fragment crosssections in high-energy γ-induced nuclear spallation reactions (PNSR). In constructing the SPAGINS formulas, theoretical models, including the TALYS toolkit, SPACS, and Rudstam formulas, were employed to study the general phenomenon of fragment distributions in PNSR with incident energies ranging from 100 to 1000 MeV. Considering the primary characteristics of PNSR, the SPAGINS formulas modify the EPAX and SPACS formulas and efficiently reproduce the measured data. The SPAGINS formulas provide a new and effective tool for predicting fragment production in PNSR.
Subjects: Nuclear Science and Technology >> Nuclear Instrument and Meter submitted time 2023-09-06
Keliang Liao
Xu Zheng
Zhao Li
Zhipeng Xue
Guangzhi Yin
Xinmin Zhang
Xiaolong Li
Yueliang Gu
Peiping Zhu
Abstract： Background : Two x-ray diffractometers produced by HUBER company have been installed at BL02U2 of Shanghai Synchrotron Radiation Facility (SSRF). Purpose : In order to further meet the needs of users for grazing incidence diffraction experimental methods, a new grazing incidence diffractometer was installed between the two HUBER diffractometers. Methods : This paper mainly introduces the overall scheme of the grazing incidence diffractometer, and discusses in detail several important modules such as high-precision, high-load and large-stroke linear stage, three-dimensional adjustment platform for detector, sample stage system, and the control system. Results : The compatible operation of three diffractometers was realized, and the typical experimental result of the grazing incidence diffractometer with MoS2 sample was introduced as an example. Conclusions : The grazing incidence x-ray diffractometer developed has been operated more than two years, and expands the experimental platform for material surface science research at SSRF.
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2019-09-09 Cooperative journals: 《干旱区研究》
Abstract：光合有效辐射是太阳辐射的一部分，是植被进行光合作用和陆地生态系统碳循环的核心因素，对估算植被生产力具有重要影响。本文基于SURFRAD多年观测数据，建立了一个线性回归模型，由上午、下午瞬时光合有效辐射值估算日均值。该模型模拟效果较好，单个观测站的均方误差低于9 W·m-2,判定系数不低于0.96，并适用于不同经纬度、气候条件和海拔高度下的区域，总的均方误差为8.863 1 W·m-2，判定系数R2为0.977，表明该模型和方法有较好的可行性和可靠性。
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-11-29 Cooperative journals: 《计算机应用研究》
Abstract： Aiming at the data association problem of line-based monocular SLAM, this paper proposed a iterative data association algorithm based on confirmation of endpoint patch. The algorithm obtained closest feature line pairs according to approximate collinearity and approximate coincidence of endpoints, then used directional search of endpoint patches to remove the error pairs. Iterative approach is used to improve accuracy. The algorithm comprehensive used geometric constraint and image similarity of feature line pairs. The experiments are carried out on a public dataset. By comparison with other similar methods, it is proved that the proposed data association approach not only satisfy real-time requirement, but also has a good performance on match amount and matching accuracy.
Subjects: Biology >> Bioengineering submitted time 2017-07-24 Cooperative journals: 《中国生物工程杂志》
Abstract： Phenol is a typical environmental pollutant. Biodegradation of phenol Phenol is a typical environmental pollutant. Chlorella sp. is potential strain for wastewater treatment because of its fast growth and strong resistance. Chlorella sp. could degrade phenol in industrial wastewater but oxidative stress induced by high concentration of phenol could cause oxidative damage in algal cells. Adaptive evolution was performed to improve the tolerance to phenol of Chlorella sp (L5). in previous study. The response mechanism of Chlorella sp. to oxidative stress induced by high concentration phenol was explored by de novo comparative transcriptomic analysis on genome scale. It was shown that the evolved strain could tolerate and degrade phenol was related to metabolic regulations in multiple pathways. The results of de novo comparative transcriptomic analysis showed that the genes related to signal transduction, ABC transporter and heat shock protein were significantly up-regulated at 500 mg/L phenol concentration compared to those in the original (L3) cells. Those genes in nitrogen metabolism and tricarboxylic acid cycle (TCA) were also upregulated. The evolved strain (L5) could reduce oxidation pressure induced by high concentration of phenol through the metabolic regulations in these metabolic pathways.
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