The 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 at the Institute of High Energy Physi...
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The 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 at the Institute of High Energy Physics, Chinese Academy of Sciences. The 9-cell cavities in the cryomodule achieved an unprecedented high average intrinsic quality factor (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 continuous wave rf voltage greater than 193 MV, with an average cavity usable accelerating gradient of more than 23 MV/m. The results significantly exceed the specifications of Circular Electron Positron Collider and Dalian advanced light source and the other high repetition rate free electron laser facilities [Linac Coherent Light Source II (LCLS-II), LCLS-II-high energy, Shanghai High Repetition Rate X-ray FEL and Extreme Light Facility, Shenzhen Superconducting Soft X-Ray Free Electron Laser, etc.]. There is evidence that the mid-T bake cavity may not require fast cooldown or long processing time in the cryomodule. This paper reviews the cryomodule performance and discusses some important issues in cryomodule assembly and testing.
Positioning accuracy is of great significance for industrial robots in high-end industries. In addition to kinematic parameter errors, there are also some dynamic parameter errors, which are nonlinear. This paper prop...
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Positioning accuracy is of great significance for industrial robots in high-end industries. In addition to kinematic parameter errors, there are also some dynamic parameter errors, which are nonlinear. This paper proposes a novel method to improve the positioning accuracy of industrial robot, which takes both kinematics and dynamics parameter errors into account. Firstly, the method uses improved Denavit-Hartenberg (DH) model to establish kinematics model and identifies the geometric errors. Then, the deformation of the joint is analysed, and the angle deviation of each joint due to the end load is compensated. Finally, the accuracy improvement experiment is carried out on 6R robot. The experimental results show that the method is very effective.
The sorption of polycyclic aromatic hydrocarbons (PAHs) to montmorillonites is largely influenced by their interactions with dissolved organic matter (DOM). However, the role of DOM rather than humic and fulvic acids ...
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The sorption of polycyclic aromatic hydrocarbons (PAHs) to montmorillonites is largely influenced by their interactions with dissolved organic matter (DOM). However, the role of DOM rather than humic and fulvic acids (e.g., extracellular DNA) in the PAH sorption to soil clays is little known. Here, we demonstrate that extracellular double-stranded salmon testes DNA substantially increased the sorption of phenanthrene and pyrene to Na-, Ca-, and Fe-modified montmorillonites. All PAH sorption isotherms fitted the linear and Freundlich models reasonably well (R-2 = 0.918-0.999). Distribution coefficients were increased from 0.0458-0.103 and 0.0493-0.141 L/g at 0 mg/L DNA to 0.413-0.589 and 0.385-0.560 L/g at 10 mg/L DNA for phenanthrene and pyrene, respectively. Spectroscopic and computational chemistry analyses confirmed that PAHs were first inserted into DNA by binding with the nudeobases via van der Waals and pi-pi electron donor-acceptor interactions. Compared to PAHs, the DNA-PAH complex can be more easily sorbed to cation-modified montmorillonites by complexation between DNA phosphate and exchangeable cations in addition to intercalation into clay interlayers. This work highlights the importance of understanding the control on contaminant sorption by many organic compounds that are ubiquitous in soils but not represented by humic and fulvic acids.
Natural and synthetic progestins in receiving streams can disrupt the normal endocrine systems of fish. Norethindrone (NET) is a widely used synthetic progestin that often appears in wastewater effluents. For this res...
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Natural and synthetic progestins in receiving streams can disrupt the normal endocrine systems of fish. Norethindrone (NET) is a widely used synthetic progestin that often appears in wastewater effluents. For this research, adult female western mosquitofish (Gambusia affinis) were exposed to NET at three concentrations. The effects of NET on the following biological factors were evaluated: the histology of the ovaries and livers, the anal fin morphology, and transcription of genes related to steroidogenesis signaling pathways in the livers. After 42 d exposure to NET at 33.0 ng L-1 and 347.5 ng L-1, rapid masculinization, an increase in the number of atretic and postovulatory follicles in the ovary, enhanced vascularization, degenerated hepatocytes and irregular nuclei in the livers were observed. Exposure to NET did not affect the expression of the androgenic and estrogenic receptor genes and Cyp19a except for a significant up-regulation of Er alpha. However, the expression of Vtg A, Vtg B, and Vtg C were markedly inhibited in the females exposed to three concentrations of NET. Compared to the control female, exposure to NET at 33.0 ng L-1 and 347.5 ng L-1 caused a 4.4- and 5.8-fold increase in the expression of Hsd17 beta 3 in the livers, respectively. The results demonstrate that NET can cause rapid masculinization of female G. affinis, hepatopathological alterations and inhibited expressions of Vtg A, Vtg B, and Vtg C. The results imply that G. affinis populations might be threatened in NET-contaminated environment. (C) 2018 Elsevier Ltd. All rights reserved.
A novel IBAF system (altered conventional biological aerated filter (BAF) for intermittent aeration) was used to treat BDD anodes electrochemical oxidation gasification wastewater effluent, after which 454 pyrosequenc...
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A novel IBAF system (altered conventional biological aerated filter (BAF) for intermittent aeration) was used to treat BDD anodes electrochemical oxidation gasification wastewater effluent, after which 454 pyrosequencing was applied to investigate the bacterial community of IBAF and demonstrate the relationship between dissolved oxygen (DO) and the bacterial community. The results showed that the concentration of COD, NH4+-N and NO3--N reached 55.08, 7.64 and 7.76 mg/L, respectively, in IBAF effluent because of changes in the DO concentration at 30 days after system start-up. The bacterial community results revealed that the 40 cm sample had the highest bacterial diversity. The bacterial species were approximate in total samples at phylum and family level, but the relative abundance was significantly different because of change in DO concentration. In addition, sample distance analysis indicated that the similarity of different samples was related to the DO concentration at different heights.
目的:系统评价玉屏风散加减辅助治疗过敏性鼻炎的疗效和安全性,为临床提供循证参考。方法:计算机检索万方数据库、中文科技期刊数据库、中国期刊全文数据库、中国生物医学文献数据库、Cochrane图书馆、EMBase、Pub Med,收集玉屏风散加减联合化学药(试验组)对比单纯化学药(对照组)治疗过敏性鼻炎的随机对照试验,提取资料并按照Cochrane系统评价员手册5.1.0评价纳入研究质量,采用Rev Man 5.2统计软件进行Meta分析。结果:共纳入15项RCT,合计1 366例患者。Meta分析结果显示,试验组患者总有效率[OR=3.95,95%CI(2.80,5.58),P<0.001]显著高于对照组,复发率[OR=0.37,95%CI(0.22,0.63),P<0.001]和不良反应发生率[OR=0.15,95%CI(0.06,0.35),P<0.001]显著低于对照组,差异均有统计学意义。结论:玉屏风散加减辅助治疗过敏性鼻炎疗效较好,可以降低复发率,安全性亦较好。
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