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arXiv 2023年

作者： Zhai, Jiyuan Pan, Weimin He, Feisi Ge, Rui Mi, Zhenghui Sha, Peng Jin, Song Han, Ruixiong Wang, Qunyao Lin, Haiying Wang, Guangwei Li, Mei Sang, Minjing Sun, liangrui Ye, Rui Zhao, Tongxian Li, Shaopeng Zhu, Keyu Liu, Baiqi Wang, Xiaolong Yang, Xiangchen Bian, Xiaojuan Zhang, Xiangzhen Ma, Huizhou Dai, xuwen Zhang, Zhanjun Zhang, liang Zhao, Hui Guo, Runbin Mu, Zhihui Yang, Conglai Zheng, Xiaobing Dong, Chao Huang, Tongming Ma, Qiang Zheng, Hongjuan Liu, Ming Wang, Zihan Zhou, Wenzhong Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China Key Laboratory of Particle Acceleration Physics & Technology Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China Center for Superconducting RF and Cryogenics Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China University of Chinese Academy of Sciences Beijing100049 China

World’s first 1.3 GHz cryomodule containing eight 9-cell superconducting radio-frequency (RF) cavities treated by medium-temperature furnace baking (mid-T bake) was developed, assembled and tested at IHEP for the Dalian Advanced Light Source (DALS) and CEPC R&D. The 9-cell cavities in the cryomodule achieved an unprecedented highest average Q0 of 3.8 × 1010 at 16 MV/m and 3.6 × 1010 at 21 MV/m in the horizontal test. The cryomodule can operate stably up to a total CW RF voltage greater than 191 MV, with an average cavity CW accelerating gradient of more than 23 MV/m. The results significantly exceed the specifications of CEPC, DALS and the other high repetition rate free electron laser facilities (LCLS-II, LCLS-II-HE, SHINE, S3FEL). There is evidence that the mid-T bake cavity may not require fast cool-down or long processing time in the cryomodule. This paper reviews the cryomodule performance and discusses some important issues in cryomodule assembly and testing. © 2023, CC BY.

关键词： Free electron lasers

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琼脂糖凝胶电泳法测定人血白蛋白及人免疫球蛋白类制品的纯度

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中国药品标准 2020年第2期21卷 159-166页

作者：穆矛刘冰滢陈宇堃焦旭雯梁蔚阳广东省药品检验所广州510663

目的:建立琼脂糖凝胶电泳法测定人血白蛋白及人免疫球蛋白类制品的纯度。方法:采用Helena公司的SPIFE Touch型自动电泳仪及配套的试剂盒,对琼脂糖凝胶电泳法的方法学进行验证。以供试品浓度5%,对33批人血白蛋白样品以及16批人免疫球蛋... 详细信息

目的:建立琼脂糖凝胶电泳法测定人血白蛋白及人免疫球蛋白类制品的纯度。方法:采用Helena公司的SPIFE Touch型自动电泳仪及配套的试剂盒,对琼脂糖凝胶电泳法的方法学进行验证。以供试品浓度5%,对33批人血白蛋白样品以及16批人免疫球蛋白类制品进行纯度测定,并与《中国药典》2015版规定方法(醋酸纤维素薄膜法)的测定结果进行比较。结果:该方法检测正常人血清中白蛋白与免疫球蛋白的RSD分别为1.15%和1.45%,最佳供试品蛋白浓度为5%,仪器通道间差异的RSD小于0.4%,重复性的RSD均小于0.5%。对比两种方法的检测结果,人血白蛋白的两法结果趋势一致且高度相关(Pearson′s r=0.88),但琼脂糖凝胶电泳法比醋酸纤维素薄膜法测定结果低1%~4%;人免疫球蛋白类制品的检测结果两种方法基本一致(Pearson′s r=0.66,两法差值小于1%)。结论:该法经方法学验证,可作为人血白蛋白和人免疫球蛋白类制品的纯度测定替代方法。

关键词：琼脂糖凝胶电泳人血白蛋白人免疫球蛋白纯度

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铜离子高浓度状态下棕化不良的改善

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印制电路信息 2019年第1期27卷 22-24页

作者：何亮张良昌谢旭文珠海杰赛科技有限公司广东珠海519170 广州杰赛电子有限公司广东广州510032 广州杰赛科技股份有限公司广东广州510310

棕化工艺中的铜离子浓度对棕化效果具有显著影响,当铜离子浓度过高时,棕化缸体的底部或缸壁会不断析出黑色结晶;黑色结晶加剧过滤系统的堵塞以及缸体脏污,从而不断降低药水交换速率及药水活性,进而产生棕化不良现象;本文就铜离子在高浓... 详细信息

棕化工艺中的铜离子浓度对棕化效果具有显著影响,当铜离子浓度过高时,棕化缸体的底部或缸壁会不断析出黑色结晶;黑色结晶加剧过滤系统的堵塞以及缸体脏污,从而不断降低药水交换速率及药水活性,进而产生棕化不良现象;本文就铜离子在高浓度状态下产生棕化不良的改善方法进行阐述。

关键词：铜离子棕化不良过滤效果浓度

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Medium-temperature furnace bake of superconducting radio-frequency cavities at ihep

arXiv

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arXiv 2020年

作者： He, Feisi Pan, Weimin Sha, Peng Zhai, Jiyuan Mi, Zhenghui Dai, xuwen Jin, Song Zhang, Zhanjun Dong, Chao Liu, Baiqi Zhao, Hui Ge, Rui Zhao, Jianbing Mu, Zhihui Du, Lei Sun, liangrui Zhang, liang Yang, Conglai Zheng, Xiaobing Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China Key Laboratory of Particle Acceleration Physics & Technology Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China Center for Superconducting RF and Cryogenics Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China University of Chinese Academy of Sciences Beijing100049 China

Recently, heat treatment between 250 °C and 500 °C has been attempted to improve quality factor (Q) of superconducting radio-frequency cavities at FNAL and KEK. Experiments of such medium temperature (mid-T) bake with furnaces have also been carried out at IHEP. Firstly, over ten 1.3 GHz 1-cell cavities were treated with different temperatures at a small furnace, which all demonstrated improvement of Q and anti-Q-slope phenomenon. The average quality factor has reached 3.6×1010 when the gradient is 16 MV/m，while the highest Q is 4.9×1010@16MV/m;the maximum gradients of these 1-cell cavities are between 25.1 and 36.9 MV/m. Then, the recipe of mid-T furnace bake at 300 °C for 3 hours has been applied to six 1.3 GHz 9-cell cavities at a new big furnace, which have all shown higher Q and anti-Q-slope at medium field (16~24 MV/m). The average quality factor has reached 3.8×1010 when the gradient is 16 MV/m. The maximum gradients of the 9-cell cavities are between 22.7 and 26.5 MV/m. © 2020, CC0.

关键词： Radio waves

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A fully parallel acquisition scheme based on FFT in the presence of Doppler shift and data modulation

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Journal of Computational Information Systems 2015年第7期11卷 2475-2485页

作者： Wu, Kang Chen, Yijun Ding, Sheng liang, xuwen Shanghai Institute of Microsystem and Information Technology Chinese Academy of Science Shanghai China Shanghai Engineering Center for Microsatellites Shanghai China

In this paper, a fully parallel acquisition scheme based on fast Fourier transform (FPA-FFT) is proposed for rapid acquisition of direct sequence spread spectrum (DSSS) signal in the presence of Doppler shift and data modulation. It utilizes FFT to search all PN code phases and frequency offsets simultaneously after differential processing and square processing of the received signal respectively. The reduction of acquisition time and hardware resources can be achieved by sacrificing a slight of signal-to-noise ratio (SNR). The performance of the method is analyzed in detail and simulation results show that it is faster to accomplish the acquisition than conventional methods in the presence of Doppler shift and insensitive to data modulation. ©, 2015, Binary Information Press. All right reserved.

关键词： Fast Fourier transforms

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Estimation and compensation method for the Doppler Frequency shift of high dynamic terminal in LEO satellite communication system

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Journal of Computational Information Systems 2015年第15期11卷 5717-5728页

作者： Hou, Huiling Chen, Yijun Ding, Sheng liang, xuwen Shanghai Institute of Microsystem and Information Technology Chinese Academy of Science Shanghai China Shanghai Engineering Center for Microsatellites Shanghai China

In LEO satellite communication systems, terminal detect severe and fast time-varying Doppler frequency shift in the received signal. In order to ensure the quality of communication, Doppler frequency shift have to be estimated and compensated timely. In this paper, an estimation method for the Doppler Frequency shift of high dynamic terminal using simple satellite orbit parameters and location information of terminal, the corresponding compensation principle and a hardware implementation structure is proposed. The performance of the proposed scheme is simulated in terms of prediction and compensation accuracy. The simulation results showed that the Doppler estimation and compensation accuracy is high, and that the simplicity of the proposed estimation and compensation scheme enable this method has good application prospect for high dynamic terminal. Copyright © 2015 Binary Information Press.

关键词： Doppler effect

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Design Study for a Quasisynchronous CDMA Sensor Data Collection System: An LEO Satellite Uplink Access Technique Based on GPS

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INTERNATIONAL JOURNAL OF DISTRIBUTED SENSOR NETWORKS 2015年第9期11卷 1-15页

作者： Chen, Yijun Ding, Sheng Xie, Zhouchen Qi, Zhuangping liang, xuwen Chinese Acad Sci Shanghai Inst Microsyst & Informat Technol Shanghai 200050 Peoples R China Chinese Acad Sci Shanghai Engn Ctr Microsatellites Shanghai 201203 Peoples R China

With the development of the LEO satellite communication technology, highly dependable wireless communication and sensor data collection using LEO satellites have been getting much attention for emergency, marine research, and forest fire disaster in the remote region. The satellite system is expected to have the following features: rapid production, low cost, and fast construction of the satellite network. In this paper, a QS-CDMA uplink access technique in the LEO satellite is presented and discussed, which is focused on the local clocks using GPS 1PPS timing signals and the Doppler compensation for terminal uplink. The spreading code with length of 1023, which is used for the uplink preamble, selects the shift-m-sequence that can greatly reduce the MAI and increase the number of simultaneous access users. A novel analysis method for the accuracy of clock synchronization and a novel method for the estimation of Doppler shift and propagation delay are presented. These methods are used to guide the specific hardware implementation of the QS-CDMA LEO satellite sensor data collection system. Through simulations and experiments, it results in that this system structure can drastically reduce the complexity in implementing the acquisition in the satellite and increase the adaptability of the satellite system in different environments.

关键词： CODE division multiple access ACQUISITION of data GLOBAL Positioning System WIRELESS sensor networks SIGNAL processing

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Study of multiuser acquisition strategy for LEO satellite quasi-synchronous CDMA uplink access

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Journal of Computational Information Systems 2015年第21期11卷 7893-7905页

作者： Chen, Yijun Ding, Sheng Wu, Kang Qi, Zhuangping liang, xuwen Shanghai Institute of Microsystem and Information Technology Chinese Academy of Science Shanghai China Shanghai Engineering Center for Microsatellites Chinese Academy of Sciences Shanghai China

With the development of the Low Earth Orbit (LEO) satellite communication technology, highlydependable wireless communication using LEO satellites has been getting much attention for emergency, marine research, and forest fire disaster in the remote region. The first stage of the signal processing chain in a conventional CDMA communication system receiver is the acquisition, which provides for a desired terminal coarse code phase and Doppler frequency estimation. Thus, the acquisition is a twodimensional search. Differing from the general acquisitions, which search only one user at an acquisition process, a multiuser acquisition strategy based on the shift-m-sequence for quasi-synchronous CDMA (QS-CDMA) communication system was proposed in this paper. The strategy can search multiuser at an acquisition process. The spreading code with length of 1023, which is used for the uplink preamble, selects the shift-m-sequence that can greatly reduce the multi-access interference (MAI) and increase the number of simultaneous access users. The results are shown that the multiuser acquisition strategy can drastically reduce the complexity in implementing the acquisition in the satellite. Copyright © 2015 Binary Information Press.

关键词： Global positioning system

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公共图书馆建设与文化发展的关系探究

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创新科技 2015年第7期15卷 90-92页

作者：梁旭雯郑州图书馆河南郑州450008

图书馆具有保存文化遗产、开发信息资源、参与社会教育、丰富群众文化生活等职能。党的十八大提出全面建设小康社会,深化改革开放的总体框架,并提出了增强文化软实力的建设目标,那么,公共图书馆在我国文化发展中应该起到什么作用是很值... 详细信息

图书馆具有保存文化遗产、开发信息资源、参与社会教育、丰富群众文化生活等职能。党的十八大提出全面建设小康社会,深化改革开放的总体框架,并提出了增强文化软实力的建设目标,那么,公共图书馆在我国文化发展中应该起到什么作用是很值得讨论的问题。

关键词：公共图书馆建设文化大发展

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神经纤维瘤病Ⅰ型合并腰椎低度恶性神经鞘膜瘤1例

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中国医学影像技术 2019年第3期35卷 479-479页

作者：彭丽君曾旭文梁治平郭威熊玉超暨南大学第一临床医学院医学影像中心广东广州510632 广州市红十字会医院放射科广东广州510220

患者男,59岁,因'腰背部疼痛伴右下肢放射痛半年'入院,既往有神经纤维瘤病Ⅰ型病史。查体:跛行体态,脊柱胸腰椎生理弯曲消失,头颈、四肢及躯干可触及多发肿物,腰背部下段可见肿物,无明显破溃。MRI:L2椎体溶骨性骨质破坏并病理性... 详细信息

患者男,59岁,因'腰背部疼痛伴右下肢放射痛半年'入院,既往有神经纤维瘤病Ⅰ型病史。查体:跛行体态,脊柱胸腰椎生理弯曲消失,头颈、四肢及躯干可触及多发肿物,腰背部下段可见肿物,无明显破溃。MRI:L2椎体溶骨性骨质破坏并病理性压缩骨折,其内见软组织肿块,边缘略呈分叶状,T1WI呈等低信号,T2WI呈不均匀高信号,累及双侧椎弓根;皮肤及皮下见多个大小不等结节状稍长T1长T2肿块(图1)。

关键词：神经纤维瘤病磁共振成像神经鞘瘤

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