检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

纵切自动车床环境温度变化误差试验研究

环境技术 2024年第2期42卷 127-131页

作者：吴珊孔令飞习璐张沛咸阳职业技术学院汽车工程学院咸阳712000 西安理工大学机械与精密仪器工程学院西安710048

为研究环境温度变化对纵切自动车床热误差的影响,本文以RTS20瑞士型纵切自动车床为试验载体,通过环境温度变化误差(ETVE)试验装置,开展了恒主轴转速(5000 rpm)变环境温度、变主轴转速(0~8000 rpm)变环境温度的热误差试验,对环境温度对... 详细信息

为研究环境温度变化对纵切自动车床热误差的影响,本文以RTS20瑞士型纵切自动车床为试验载体,通过环境温度变化误差(ETVE)试验装置,开展了恒主轴转速(5000 rpm)变环境温度、变主轴转速(0~8000 rpm)变环境温度的热误差试验,对环境温度对热误差的影响进行了研究分析。结果表明:在相同主轴转速下,环境温度变化影响着车床结构各部位的温升,进而影响热误差;在随机主轴转速下,主轴轴承等温度测点的温升受转速变化的影响,热误差的增长与关键测点温度具有相同变化周期,但不具有相同变化趋势,即温度快速升高时热误差并不一定也正向增长;空调开启后各测点温度有明显降低,最高降幅可达3℃,热误差随之也有明显降低趋势,最高降幅达6μm。

关键词：环境温度温度变化试验纵切车床热误差

Ultrasonic-assisted Oxidation Leaching of Nickel Sulfide Concentrate

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2010年第6期18卷 948-953页

作者： XUE Juanqin lu xi DU Yewei MAO Weibo WANG Yujie LI Jingxian School of Metallurgical Engineering Xi'an University of Architecture and Technology Xi'an 710055 China

The feasibility of oxidation leaching process of nickel from nickel sulfide ore and the form of different components in the lixivium has been studied at first. The method of leaching nickel sulfide concentration directly by oxidants with existence of ultrasonic has been advanced. The process of leaching nickel from nickel sulfide concentration by using the system of persulfate and silver has been determined. The influence of different factors on the leaching rates of nickel,such as with and without ultrasonic,the concentration of Na2S2O8,liquid-solid ratio and the concentration of AgNO3 have been explored. The results show that:(1) in the oxidative leaching system,nickel can be leached completely as Ni2+ or NiSO4(aq.) from nickel sulfide concentration in theory;(2) the nicopyrite can not exist steadily in the persulfate acid leaching system,but Ni2+can. Meanwhile,sulfur may be existed steadily in the leaching process;(3) nicopyrite with much lower electrostatic potential may be leached earlier than chalcopyrite and sideropyrite;and(4) the overall reaction rate of the leaching process can be enhanced with ultrasonic radiation,but it does not change the mechanism of leaching. The more oxidant concentration or higher liquid-solid ratio is,the higher leaching percentage of nickel. The leaching percentage of nickel can be increased significantly by adding a small amount of AgNO3 during the leaching processes. Under the same conditions,the higher concentration of AgNO3 is,the higher leaching yields of nickel will be obtained.

关键词： nickel sulfide concentration potential-pH diagram direct oxidation leaching ultrasonic

Recent advances in nickel-catalyzed reductive hydroalkylation and hydroarylation of electronically unbiased alkenes

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2020年第11期63卷 1586-1600页

作者： xiao-Xu Wang xi lu Yan Li Jia-Wang Wang Yao Fu Hefei National Laboratory for Physical Sciences at the Microscale CAS Key Laboratory of Urban Pollutant ConversionAnhui Province Key Laboratory of Biomass Clean EnergyiChEMUniversity of Science and Technology of ChinaHefei 230026China

The use of simple and easily available feedstock to quickly and efficiently obtain compounds with complex molecular structures through the transition-metal-catalyzed construction of C(sp3)–C bonds has important *** traditional C(sp3)–C coupling reagents,alkylmetallic reagents often have limitations such as air and moisture sensitivity and difficulties in ***-catalyzed reductive olefin hydrocarbonation reactions use alkenes to replace organometallic reagents,reduce the synthesis steps,improve the functional group compatibility,and expand the substrate *** minireview discusses important progress in the hydroalkylation and hydroarylation of electronically unbiased alkenes in recent years and describes the key mechanism and applications.

关键词： nickel electronically unbiased alkenes C-C bond formation reductive hydroalkylation reductive hydroarylation

A Novel Sterilization Method Using Pulsed Discharge Plasma

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1998年第1期15卷 41-42页

作者： WANG xi-lu Akira Mizuno Shijin Katsura Department of Ecological Engineering Toyohashi University of TechnologyTempaku-choToyohashi441Japan Institute of Electrostatics Northeast Normal UniversityChangchun 130024

Pulsed discharge plasma(PDP)has been used to kill bacteria and the curves of the survival rate of bacteria against treatment time are *** structural change in the cell membrane is caused by PDP and the cell is thus **... 详细信息

关键词： PDP Plasma treatment

瑞马唑仑用于病态肥胖患者全身麻醉的有效性和安全性

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国药理学通报 2024年第5期40卷 859-864页

作者：陈功卢彦西李津张帆成灿灿尹欣林汪赛赢常欢中南大学湘雅三医院麻醉科湖南长沙410013

目的评估瑞马唑仑在病态肥胖患者全身麻醉应用中的有效性和安全性。方法选取在本中心接受腹腔镜下袖状胃切除的病态肥胖患者(BMI≥40)108例,男46例,女62例。年龄18~51岁,ASA I~III级。随机分为瑞马唑仑组(R组)和丙泊酚组(P组),分别接受... 详细信息

目的评估瑞马唑仑在病态肥胖患者全身麻醉应用中的有效性和安全性。方法选取在本中心接受腹腔镜下袖状胃切除的病态肥胖患者(BMI≥40)108例,男46例,女62例。年龄18~51岁,ASA I~III级。随机分为瑞马唑仑组(R组)和丙泊酚组(P组),分别接受瑞马唑仑或丙泊酚作为全身麻醉的诱导和维持,对比两组不良事件的发生率及术后恢复情况。结果在全身麻醉诱导期间,P组不良事件的发生率更高,包括低血压(P<0.01)、低氧血症(P<0.05)、心动过缓(P<0.01)及对血管活性药物的需求增加(P<0.05)。P组意识消失和BIS下降到60的时间短于R组(P<0.01)。两组在术后恢复质量(QoR-40评分)、术后24 h疼痛视觉模拟(VAS)评分及吗啡消耗量方面差异无统计学意义。结论瑞马唑仑可有效降低病态肥胖患者全身麻醉诱导期低血压和低氧血症的发生率,且在术后恢复质量方面与丙泊酚相当。

关键词：丙泊酚瑞马唑仑病态肥胖诱导后低血压腹腔镜袖状胃切除术血流动力学

维普期刊数据库博看期刊

Energy return on investment, energy payback time, and greenhouse gas emissions of coal seam gas(CSG) production in China: a case of the Fanzhuang CSG project

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2018年第1期15卷 185-199页

作者： Zhao-Yang Kong xiu-Cheng Dong xi lu xin Wan School of Business Administration China University of Petroleum (Beijing) School of Environment and State Key Joint Laboratory of Environment Simulation and Pollution Control Tsinghua University School of Economics and Management Beijing University of Chemical Technology

The studies and development of coal seam gas（CSG） have been conducted for more than 30 years in China, but few of China＇s CSG projects have achieved large-scale commercial success; faced with the boom of shale gas, some investors are beginning to lose patience and confidence in CSG. China currently faces the following question： Should the government continue to vigorously support the development of the CSG industry？ To provide a reference for policy makers and investors, this paper calculates the EROI_（stnd）[a standardized energy return on investment（EROI） method], EROI_（ide）（the maximum theoretical EROI）, EROI_（3,i）（EROI considering the energy investment in transport）, and EROI_（3,1＋e）（EROI with environmental inputs） of a single vertical CSG well in the Fanzhuang CSG project in the Qinshui Basin. The energy payback time（EPT） and the greenhouse gas（GHG） emissions of the CSG systems are also calculated. The results show that over a 15-year lifetime, EROI_（stnd）, EROI_（ide）, EROI_（3,1）, and EROI_（3,1＋e）are expected to deliver EROIs of approximately11：1, 20：1, 7：1, and 6：1, respectively. The EPT within different boundaries is no more than 2 years, and the life-cycle GHG emissions are approximately 18.8 million kg CO_2 equivalent. The relatively high EROI and short EPT indicate that the government should take more positive measures to promote the development of the CSG industry.

关键词： Coal seam gas EROI Energy payback time Greenhouse gas emissions Global warming potential China

Transcriptome Profiling of Flower Development Reveals Key Genes Mediating Yellow Formation in Tree Peony

在线全文

学校读者我要写书评

暂无评论

Phyton-International Journal of Experimental Botany 2022年第11期91卷 2505-2518页

作者： Yanzhao Zhang Chenyang Yu xi lu Yanwei Cheng Life Science Department Luoyang Normal UniversityLuoyang471934China

Tree peony cultivars with yellow flowers are rare and valuable,but the molecular mechanism of pigment accumulation is not *** this study,the petal transcriptome of three developmental stages were sequenced to determine the differentially expressed genes(DEGs)regulating yellow flowers *** results showed that 10,842 and 12,022 DEGs were screened in stage 1 *** 2 and in stage 2 *** 3,*** analysis of flavonoid structural genes(FSGs),we found that the transcription level of DFR was very low in the three developmental *** a small group of cultivars,the DFR transcription level of red flowers was 862 times higher than that of yellow *** data suggested that the flavonoid pathway is interrupted in the later stage due to the low transcriptional level of DFR,which limits the biosynthesis of anthocyanins in yellow *** transcription levels of F3’H and FLS were upregulated from stage 1 to stage 2,while those of CHI and FLS were downregulated from stage 2 to stage *** addition,67 MYBs and 44 bHLHs showed similar transcription profiles with different members of *** results deepen our understanding of the molecular mechanism of yellow pigment accumulation in tree peony.

关键词： Tree peony yellow flower transcriptome flavonoids DFR gene

Transition-metal-catalyzed C-H functionalization for late-stage modification of peptides and proteins

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2018年第7期29卷 1001-1008页

作者： xi lu Shi-Jiang He Wan-Min Cheng Jing Shi Hefei National Laboratory for Physical Sciences at the Microscale CAS Key Laboratory of Urban Pollutant ConversionAnhui Province Key Laboratory of Biomass Clean EnergyiChEMUniversity of Science and Technology of China

Late-stage modification of peptides and proteins meets the increasing demand in biochemical and pharmaceutical communities. These modification strategies could provide functionalized nonproteinogenic analogues with enhanced biological activities or improved therapeutic capabilities compared to their natural counterparts. Recent years, transition-metal-promoted functionalization of ubiquitous C-H bonds has been emerged as a powerful and tunable tool in this area, both for backbone diversifications and labeling of specific moieties. These reactions were flexible and expedient in both academic and industrial laboratories, especially considering their atom and step-economy, good functional group compatibility, accurate site selectivity. This review surveys the progress achieved in the late-stage modification of peptides and proteins utilizing transition-metal-catalyzed C-H functionalization with C-C and C-X(F, Cl, O, N, B, etc.) bonds formation.

关键词： Transition-metals C-H functionalization Chemo-and site selective Late-stage modification Peptides and proteins

Effect of propofol on generation of inflammatory mediator of monocytes

在线全文

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Medicine 2015年第11期8卷 940-945页

作者： Yun Nie Yan-xi lu Li-Hong Lv Operating Room First People's Hospital of Ji'nan

Objective:To evaluate the effect of propofol with different concentrations on the expression of inflammatory mediators of mterleukin and tumor-necrosis factor- α(TNF- α) by stimulating the mouse primary monocytes and human monocytic cell line with lipopolysaccharide(LPS)and also discuss the effeet of propofol on the secretion of inflammatory mediator and its possible molecular ***:The mononuclear cells of mouse spleen were separated and then purified to obtain the primary *** dose-effect relationship of production of pro-inflammatory cytokines by monocytes which were stimulated by LPS,namely the monocytes were stimulated by the dose of 0-500 ng/mL for 24 *** was employed to detect the concentration of IL-6,TL-8 and TNF-α.The effect of propofol on the secretion of above pro-inflammatory cytokines by the monocytes was *** were divided into the control group,the 0.1%DMSO group,the LPS group and the treatment group with LPS + different dose of propofol(propofol 1-100 μg/mL).ELISA was employed to detect the concentration of IL-6,IL-8 and TNF-α.The change in the expression of important signaling molecules in Toll-like receptor and NF-κ B signaling pathway was detected after THP-1 cells were treated with ***:The concentration of TNF- α was(3 863±153)pg/mL after 12 h of stimulation by LPS and then its concentration was decreased *** the concentration of IL-6 and IL-8 was relatively high after 24 h of stimulation by LPS,(5 627±330) pg/mL and(1 626±200) pg/mL,*** propofol could inhibit the expression of IL-6,IL-8 and TNF- α caused by *** the intervention treatment of 50 μg/mL propofol,the concentration of IL-6,IL-8 and TNF-α was significantly decreased(Plusions:The propofol can inhibit the expression of TLR-4 and NF-κ B to inhibit the activation of p38 and the expression of pro-inflammatory cytokines.

关键词： Propofol LPS IL-6 IL-8 TNF-α Anti-inflammation