检索结果-南通市图书馆

Phase Transformation of a Cold Work Tool Steel during Tempering

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2016年第5期23卷 484-488页

作者： Hong-xiao chi Dang-shen MA Hui-xia XU Wang-long ZHU Jian-qing JIANG School of Materials Science and Engineering Southeast University Jiangsu Engineering Research Center of Tool and Die Steel Tiangong Group Institute for Special Steels Central Iron and Steel Research Institute

The hardness and microstructure evolution of a 8% Cr cold work tool steel during tempering for 40 h were investigated. Transmission electron microscope examinations showed that M_3C carbides precipitated from supersaturated martensite after tempering at 350 ℃. When the tempering temperature was higher than 520 ℃,the M_（23）C_6 carbides precipitated to substitute for M_3C carbides. After ageing at the temperature of 520 ℃ for 40 h,it was observed that very fine and dense secondary Mo_2C precipitates were precipitated. Thus,it can be concluded that the early stage of Mo_2C-carbide precipitation is like to be Gunier-Preston（ G-P） zone formed by [Mo-C] segregation group which is responsible for the secondary hardening peak at 520 ℃. Overageing at 700 ℃ resulted in recovery of martensitic microstructure and precipitation of M_（23）C_6 *** ageing at 700 ℃ for more than 20 h,recrystallization occurred,which resulted in a change of the matrix morphology from martensitic plates to equiaxed ferrite. It was noticed that the size of recrystallized grain / subgrain was very fine,which was attributed to the pinning effect of M_（23）C_6 precipitates.

关键词： cold work tool steel secondary hardening tempering carbide

在线全文

学校读者我要写书评

暂无评论

不同花生品种烤仁加工特性分析

花生学报 2024年第2期53卷 91-97页

作者：赵健鑫殷祥贞姜骁陈娜赵旭红王明清宋虎成钟文梁成伟迟晓元青岛科技大学海洋科学与生物工程学院山东青岛266042 山东省花生研究所山东青岛266100 中粮山萃花生制品(威海)有限公司山东威海264400 山东省种子管理总站山东济南276301

为培育筛选适合烤制加工的花生品种,以传统出口型大花生品种花育22号为对照,以3个高油酸品种花育9111、花育917和花育910为供试品种,研究4个品种在烘烤加工后其感官品质、理化特性、风味物质、氧化稳定性等方面的差异。结果表明,烘烤后... 详细信息

为培育筛选适合烤制加工的花生品种,以传统出口型大花生品种花育22号为对照,以3个高油酸品种花育9111、花育917和花育910为供试品种,研究4个品种在烘烤加工后其感官品质、理化特性、风味物质、氧化稳定性等方面的差异。结果表明,烘烤后花育910色泽较浅;花育9111甜度更优,总体喜欢度好于花育22号。3个高油酸花生烤仁的硬脂酸、油酸、花生酸、花生烯酸的含量极显著高于花育22号,棕榈酸、亚油酸、山嵛酸、二十四烷酸的含量极显著低于花育22号。TPA分析表明,4个品种烤仁的硬度、酥脆性、咀嚼性相当。花育9111、花育917、花育910烤仁货架期预测分别是花育22号的1.50、1.94、1.59倍。采用TOPSIS方法对4个品种烤仁加工品质进行综合排名,发现花育917>花育910>花育9111>花育22号。本研究表明高油酸花生可替代传统大花生用于烤花生生产,对花生的生产和加工具有重要的参考价值。

关键词：加工特性感官评价风味物质氧化稳定性

Microstructure and Properties of Hot Working Die Steel H13MOD

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2013年第9期20卷 117-125页

作者： ZHOU Jian MA Dang-shen chi Hong-xiao CHEN Zai-zhi LI Xiang-yang Central Iron and Steel Research Institute

Compared with H13 steel, the influences of different heat treatment process on the microstructure and properties of the new type of hot working die steel H13MOD were studied. The results show that the complete aus tenitizing temperature of H13MOD is around 1030 ℃ and the quenching hardness achieves the maximum value at this temperature. While for H13, the complete austenitizing temperature is above 1100 ℃ and the quenching hardness rise constantly with the quenching temperature increasing. In quenching process, the undissolved MC carbides can prevent the coarsening of grain in both steels. With the rise of quenching temperature, when MC carbides dissolve completely, the grain grows quickly. The hardness and strength of H13MOD at higher tempering temperature （above 570 ℃） are nearly the same as those of H13, but its toughness is higher than that of H13. Mo2C carbide is the main strengthening phase in H13MOD, which is attributed to the higher content of Mo. The quantity of VC eutectic car- bides is reduced because of lower content of V in H13MOD, which plays an important role in enhancing the impact toughness of H13MOD. Under a certain strength condition, H13MOD steel can be used in the environment that higher toughness is required and the service life of die casting mold can be improved.

关键词： hot working die steel hardness heat treatment impact ductility tensile strength

Particle segregation mechanism of S–D system in a rotating drum

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第10期93卷 300-308页

作者： Erliang xiao Wei Zhang Zhipeng chi Ran Li Hui Yang School of Optical-Electricaland Computer Engineering University of Shanghai for Science and Technology Shanghai 200093Chin Collegeof Medical instrumentation hanghai Universty of Medicine&Health ScienceShanghaiChina

Complex segregation occurs in a binary particle system with differing particle sizes and densities,particularly when the larger particles are heavier(S–D system,i.e.,size minus density system).Predicting the segregation pattern driven by multiple mechanisms simultaneously is often *** study explores the segregation mechanisms in a quasi-2D circular drum containing a S–D system,realizing a transition between the S-core and Core-and-band patterns by adjusting the drum rotation *** the transition of the segregation pattern,only the S-core pattern chiefly driven by the percolation mechanism is initially *** the rotation speed increases,the buoyancy mechanism and particle diffusion gradually strengthen,jointly driving the formation of the Core-and-band pattern.A dimensionless strength ratio,λ=H/h,where H and h respectively represent the diffusion and buoyancy strengths at length scales,is introduced to elucidate this *** Core-and-band pattern emerges whenλreached 1.4.

关键词： Particle segregation S-Dsystem Segregationmechanisms competition Segregation pattern Rotating drum

Identification and Characterization of MicroRNAs and Their Targets in Grapevine(Vitis vinifera)

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

Agricultural Sciences in china 2008年第8期7卷 929-943页

作者： LU Yan-du GAN Qin-hua chi xiao-yuan QIN Song Yantai Institute of Coastal Zone Research for Sustainable Development Chinese Academy of Sciences Yantai 264003 P.R.China Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 P.R.China Graduate School Chinese Academy of Sciences Beijing 100049 P.R.China Technical Center of Inspection and Quarantine Shandong Entry-Exit Inspection and Quarantine Bureau Qingdao 266001 P.R.China

MicroRNAs （miRNAs） are a class of newly identified, small, non-coding RNAs that play vital roles in regulation. Based on miRNAs unique features of expression pattern, evolutionary conservation, secondary structure and genetic requirements for biogenesis, computational predication strategy is adopted to predicate the novel miRNAs. In this research, potential miRNAs and their targets in grapevine （Vitis vinifera） were predicted. We used previously known plant miRNAs against grapevine genome sequence databases to search for potential miRNAs. A total of 81 potential miRNAs were detected following a range of strict filtering criteria. Using these potential miRNA sequences, we could further blast the mRNA database to find the potential targets in this species. Comparative analysis of miRNAs in grapevine and other species reveals that miRNAs exhibit an evolutional conservation, the number and function of miRNAs must have significantly expanded during the evolution of land plants. Furthermore divergence made versatile functions of miRNAs feasible. Cluster of miRNAs likely represents an ancient expression mechanism. Predicted target genes include not only transcription factors but also genes implicated in floral development, signal transduction, diseases and stress response. Till now, little is known about experimental or computational identification of miRNA in grapevine species. Increased knowledge of the biological mechanisms of the grapevine will allow targeted approaches to increase the quality of fruit and reduce the impact of parasites together with stress, which could enable a sustainable, environmentally-sound, farming policv.

关键词： microRNAs prediction targets Vitis vinifera evolution floral development

食品与生物样品糖类及其衍生物检测方法研究进展

在线全文

学校读者我要写书评

暂无评论

食品安全质量检测学报 2024年第14期15卷 115-124页

作者：刘权刘雨婷霍滢肖驰骋李欣湖北工业大学生命科学与健康工程学院工业发酵省部共建协同创新中心发酵工程教育部重点实验室工业微生物湖北省重点实验室武汉430068

糖类有单糖、低聚糖、多糖3种形式,目前国内外已建立多种检测糖类及其衍生物的方法。单糖早期通过旋光法、比色法、容量法检测,但这些方法只能对糖总量进行分析;纸色谱法与薄层色谱法因灵敏度低、分离度差被淘汰;目前常用的方法有高效... 详细信息

糖类有单糖、低聚糖、多糖3种形式,目前国内外已建立多种检测糖类及其衍生物的方法。单糖早期通过旋光法、比色法、容量法检测,但这些方法只能对糖总量进行分析;纸色谱法与薄层色谱法因灵敏度低、分离度差被淘汰;目前常用的方法有高效液相色谱法、气相色谱法、高效阴离子交换色谱法及毛细管电泳法,这些方法同样适用于低聚糖、多糖和糖类衍生物的检测。糖类的分子量可通过黏度法、凝胶渗透色谱法、光散射法检测,糖类的结构可通过傅里叶变换红外光谱法、核磁共振波谱法、高分辨率质谱法检测。然而,不同样品中糖类及其衍生物的检测方法和检测条件均有所不同,且糖类及其衍生物种类繁多、组成复杂,对糖类及其衍生物的精准定量和定性研究带来了巨大的挑战。本文综述了糖类及其衍生物的前处理和检测方法,对各种方法的优缺点及适用范围进行论述,为样品中糖类及其衍生物的精准定量和定性研究提供一定的参考。

关键词：糖类及其衍生物提取纯化色谱法质谱法

在线全文

学校读者我要写书评

暂无评论

LTE网络节能降耗研究及应用

长江信息通信 2024年第6期37卷 207-210页

作者：王君李荣华蔡伟华肖驰李雅中国联合网络通信有限公司娄底市分公司湖南娄底417000 湘潭理工学院湖南湘潭411104 河海大学江苏南京210000

基于现网4/5G网络业务承载的情况,研究LTE网络节能降耗策略,在不牺牲用户体验的情况下,探索一套适宜现网场景的节能策略,降低能耗支出,提升网络运行效能。

关键词：智能关断符号关断 PRB RF

维普期刊数据库博看期刊

Inversion of Venus internal structure based on geodetic data

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2020年第8期20卷 237-251页

作者： chi xiao Fei Li Jian-Guo Yan Wei-Feng Hao Yuji Harada Mao Ye Jean-Pierre Barriot chinese Antarctic Center of Surveying and Mapping Wuhan UniversityWuhan 430079China State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China Space Science Institute Macao University of Science and TechnologyAvenida WailongTaipaMacaoChina Observatory Geodetic de Tahiti BP 657098702 Faa'aTahitiFrench Polynesia

Understanding the internal structure of Venus promotes the exploration of the evolutionary history of this ***,the existing research concerning the internal structure of Venus has not used any inversion *** this work we employed an inversion method to determine the internal structure of Venus using observational or hypothetical geodetic data;these data include mass,mean radius,mean moment of inertia and second degree tidal Love number *** determine the core state of Venus,we created two models of Venus,an isotropic 3-layer model with entire liquid core and an isotropic 4-layer model with liquid outer core and a solid inner core,assuming that the interior of Venus is spherically symmetric and in hydrostatic equilibrium.A series of the sensitivity analysis of interior structure parameters to the geodetic data considered in here shows that not all of the parameters can be constrained by the geodetic data from *** this basis,a Markov Chain Monte Carlo algorithm was used to determine the posterior probability distribution and the optimal values of the internal structure parameters of Venus with the geodetic *** found that the 3-layer model is more credible than the 4-layer model via currently geodetic *** the assumption of the 3-layer model with the k2=0.295±0.066,I/MR^2=0.33±0.0165,andρ=5242.7±2.6 kg m^-3,the liquid iron-rich core of Venus has a radius of 3294+215-261km,which suggests a larger core than previous research has *** average density of the mantle and liquid core of Venus are 4101+325-375and 11885+955-1242kg m~^-3,respectively.

关键词： planets and satellites:interiors planets and satellites:terrestrial planets planets and satellites:physical evolution planets and satellites:fundamental parameters

不同剂量左甲状腺素钠片联合放射性^(131)I治疗对甲状腺癌术后患者的影响

在线全文

学校读者我要写书评

暂无评论

中国药物经济学 2024年第8期19卷 44-47页

作者：胡小池杨玉闽陈延祺陈宸瞿锐遵义市第一人民医院(遵义医科大学第三附属医院)乳腺甲状腺外科贵州遵义563000

目的探讨不同剂量左甲状腺素钠片联合放射性^(131)I治疗对甲状腺癌术后患者的影响。方法选取2021年8月至2022年8月遵义市第一人民医院收治的120例甲状腺癌患者作为研究对象,采用随机数字表法分为常规组和负荷组,各60例。两组甲状腺全切... 详细信息

目的探讨不同剂量左甲状腺素钠片联合放射性^(131)I治疗对甲状腺癌术后患者的影响。方法选取2021年8月至2022年8月遵义市第一人民医院收治的120例甲状腺癌患者作为研究对象,采用随机数字表法分为常规组和负荷组,各60例。两组甲状腺全切或近全切术后均接受放射性^(131)I治疗,常规组采用2.0μg/kg左甲状腺素钠片,负荷组采用2.5μg/kg左甲状腺素钠片。比较两组患者治疗前后血清甲状腺激素[游离三碘甲状腺素(FT_(3))、游离甲状腺素(FT4)、促甲状腺激素(TSH)、甲状腺过氧化物酶(TPO)]、免疫功能[CD3^(+)、CD4^(+)、CD4^(+)/CD8^(+)]、不良反应发生情况、预后情况。结果治疗后两组FT_(3)、FT4水平均升高,TSH、TPO水平均降低,且负荷组变化幅度大于常规组,差异有统计学意义(P0.05);两组肿瘤复发率、转移率、死亡率比较差异无统计学意义(P>0.05)。结论2.5μg/kg剂量左甲状腺素钠片联合放射性^(131)I治疗甲状腺癌术后患者改善甲状腺激素水平效果更好,免疫功能更高,预后较好,安全性较高。

关键词：甲状腺癌甲状腺激素不同剂量左甲状腺素钠片