期刊文献+
共找到406篇文章
< 1 2 21 >
每页显示 20 50 100
速度350km/h高速铁路长大下坡地段闭塞分区设置方法研究
1
作者 张守帅 张雨洁 +2 位作者 闫海峰 田长海 骆泳吉 《铁道学报》 EI CAS CSCD 北大核心 2024年第1期72-80,共9页
通过分析长大下坡道闭塞分区长度对CTCS-3级和后备CTCS-2级列控系统的影响,指出二者对闭塞分区长度的需求完全相反,并针对CTCS-3级列控系统的行车许可回缩、速度突降等问题的产生原因进行分析。阐述坡度、闭塞分区长度与不同列控模式下... 通过分析长大下坡道闭塞分区长度对CTCS-3级和后备CTCS-2级列控系统的影响,指出二者对闭塞分区长度的需求完全相反,并针对CTCS-3级列控系统的行车许可回缩、速度突降等问题的产生原因进行分析。阐述坡度、闭塞分区长度与不同列控模式下列车运行速度、追踪间隔时间等要素之间的关系,制定闭塞分区设置的基本原则。检算典型坡度下闭塞分区长度设置的合理区间范围及相应追踪间隔时间,指出坡度超过-30‰后将无法兼顾不同列控等级下的运行速度。设计模拟退火算法,根据闭塞分区设置原则及闭塞分区取值规律,给出压缩求解空间、提高求解效率的方法。以郑万高速铁路长大下坡地段为例,对闭塞分区设置进行优化,在不考虑其他约束的前提下,与设计院优化方案相比,本求解优化方案在确保CTCS-3级控车模式下允许速度可达350 km/h的同时,将CTCS-2级控车模式下的允许速度提高30 km/h,追踪间隔时间压缩23 s。 展开更多
关键词 高速铁路 长大下坡道 CTCS-3级列控系统 闭塞分区 行车许可
下载PDF
Integration of Sequence Stratigraphic Analysis and 3D Geostatistical Modeling of Pliocene–Pleistocene Delta,F3 Block,Netherlands 被引量:1
2
作者 Haris Ahmed KHAN Ali Asghar SHAHID +3 位作者 Muhammad Jahangir KHAN Taher ZOUAGHI Maria Dolores ALVAREZ Syed Danial Mehdi NAQVI 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2023年第1期256-268,共13页
This research is focused on the analysis of the sequence stratigraphic units of F3 Block,within a wave-dominated delta of Plio–Pleistocene age.Three wells of F3 block and a 3D seismic data,are utilized in this resear... This research is focused on the analysis of the sequence stratigraphic units of F3 Block,within a wave-dominated delta of Plio–Pleistocene age.Three wells of F3 block and a 3D seismic data,are utilized in this research.The conventional techniques of 3D seismic interpretation were utilized to mark the 11 surfaces on the seismic section.Integration of seismic sequence stratigraphic interpretation,using well logs,and subsequent 3D geostatistical modeling,using seismic data,aided to evaluate the shallow hydrocarbon traps.The resulting models were obtained using System Tract and Facies models,which were generated by using sequential stimulation method and their variograms made by spherical method,moreover,these models are validated via histograms.The CDF curve generated from upscaling of well logs using geometric method,shows a good relation with less percentage of errors(1 to 2 for Facies and 3 to 4 for System Tract models)between upscaled and raw data that complements the resulted models.These approaches help us to delineate the best possible reservoir,lateral extent of system tracts(LST and/or HST)in the respective surface,and distribution of sand and shale in the delta.The clinoform break points alteration observed on seismic sections,also validates the sequence stratigraphic interpretation.The GR log-based Facies model and sequence stratigraphy-based System Tract model of SU-04-2 showed the reservoir characteristics,presence of sand bodies and majorly LST,respectively,mainly adjacent to the main fault of the studied area.Moreover,on the seismic section,SU-04-2 exhibits the presence of gas pockets at the same location that also complements the generated Facies and System Tract models.The generated models can be utilized for any similar kind of study and for the further research in the F3 block reservoir characterization. 展开更多
关键词 sequence stratigraphy facies modeling system tract modeling F3 block North Sea
下载PDF
猪圆环病毒3型Cap蛋白单克隆抗体的制备及阻断ELISA检测方法的建立 被引量:1
3
作者 张宝戈 黄雅琴 +2 位作者 蔡金双 朱晨光 李玉峰 《畜牧兽医学报》 CAS CSCD 北大核心 2024年第3期1170-1178,共9页
旨在建立检测猪圆环病毒3型(PCV3)抗体的阻断ELISA方法,本研究利用原核表达的PCV3Cap重组蛋白免疫BALB/c小鼠制备获得了一株分泌阻断效果良好抗体的杂交瘤细胞株2E6。以重组Cap蛋白作为包被抗原,以辣根过氧化物酶(HRP)标记的2E6单克隆... 旨在建立检测猪圆环病毒3型(PCV3)抗体的阻断ELISA方法,本研究利用原核表达的PCV3Cap重组蛋白免疫BALB/c小鼠制备获得了一株分泌阻断效果良好抗体的杂交瘤细胞株2E6。以重组Cap蛋白作为包被抗原,以辣根过氧化物酶(HRP)标记的2E6单克隆抗体作为检测抗体,经条件优化后建立了一种检测PCV3抗体的阻断ELISA方法。用建立的阻断ELISA方法检测50份临床阴性血清,计算阻断率(PI)的临界值,以此来确定该方法的判定标准:当PI≤28.30%时,判定结果为阴性;当PI≥35.05%时,判定结果为阳性;当28.30%<PI<35.05%时,判定为可疑,重复一次试验后如果结果仍为可疑,则判定为阳性。特异性试验表明该方法与猪圆环病毒2型(PCV2)、猪伪狂犬病病毒(PRV)、猪繁殖与呼吸综合征病毒(PRRSV)以及猪瘟病毒(CSFV)的阳性血清均无交叉反应;敏感性试验表明其检测效价可达到1:128;重复性试验表明批内与批间的变异系数均小于10%;符合性检验表明该方法与PCV检测金标准免疫过氧化物酶单层试验(IPMA)比对的Kappa值达0.9,具有高度的一致性。综上所述,本研究建立的阻断ELISA方法具有良好的特异性与较高的符合率,可用于后期进行PCV3抗体的检测,为PCV3的流行病学调查与临床诊断提供技术支持。 展开更多
关键词 猪圆环病毒3 Cap重组蛋白 单克隆抗体 阻断ELISA
下载PDF
微流控技术辅助制备多孔石墨相氮化碳(g-C3N4)块体及其性能研究
4
作者 马千驰 徐倩鑫 +2 位作者 周何 郝彬琦 常振旗 《现代化工》 CAS CSCD 北大核心 2024年第3期90-96,共7页
设计了适用于微流控系统的原位生成酸催化聚乙烯醇/戊二醛凝胶反应体系并用于g-C_(3)N_(4)多孔微球粒径与形貌的可控制备,以无机粘结剂和多孔微球为原料实现氚兼容的多孔g-C_(3)N_(4)块体的制备。考察了凝胶组成成分、煅烧模式对微球比... 设计了适用于微流控系统的原位生成酸催化聚乙烯醇/戊二醛凝胶反应体系并用于g-C_(3)N_(4)多孔微球粒径与形貌的可控制备,以无机粘结剂和多孔微球为原料实现氚兼容的多孔g-C_(3)N_(4)块体的制备。考察了凝胶组成成分、煅烧模式对微球比表面积与机械强度的影响,以及无机黏合剂质量分数、微球粒径对g-C_(3)N_(4)块体比表面积与机械强度的影响。结果表明,微球粒径对块体材料性能有显著影响,在相同成型黏合剂质量分数下,微球粒径增加79.5%块体材料的比表面积提高205%,而机械强度仅降低了42%。4.5 K低温气体吸附实验结果表明,所制备的g-C_(3)N_(4)多孔块体吸附层对氢气和氦气的选择性系数可达13.02。 展开更多
关键词 g-C_(3)N_(4)多孔微球 多孔g-C_(3)N_(4)块体 比表面积 微流控技术 低温泵
下载PDF
聚(3-己基噻吩)-聚苯乙烯嵌段共聚物的一锅法制备
5
作者 樊亚娟 刘承先 +1 位作者 李东升 刘长春 《合成树脂及塑料》 CAS 北大核心 2023年第4期19-23,共5页
采用具有聚苯乙烯高分子链为配位基团的聚合催化剂,催化2,5-二溴-3-己基噻吩单体进行Kumada缩聚反应,利用一锅法制备了聚(3-己基噻吩)-聚苯乙烯嵌段共聚物。结果表明:采用一锅法,在室温、常压条件下进行一步聚合直接生成嵌段共聚物,反... 采用具有聚苯乙烯高分子链为配位基团的聚合催化剂,催化2,5-二溴-3-己基噻吩单体进行Kumada缩聚反应,利用一锅法制备了聚(3-己基噻吩)-聚苯乙烯嵌段共聚物。结果表明:采用一锅法,在室温、常压条件下进行一步聚合直接生成嵌段共聚物,反应过程简单,聚(3-己基噻吩)与聚苯乙烯嵌段对接率接近100%;与聚(3-己基噻吩)相比,聚(3-己基噻吩)-聚苯乙烯嵌段共聚物的结晶性能更好。 展开更多
关键词 聚(3-己基噻吩) 聚苯乙烯 嵌段共聚物 Kumada缩聚反应
下载PDF
区组长为4和6的3-设计
6
作者 王建 《南通职业大学学报》 2023年第2期64-66,共3页
t-(v,K,λ)设计是一个关联结构(V,B),满足条件:(1)V是v元点集;(2)B是V的子集族(B中的元素称为设计的区组),且每一个区组b∈B有|b|∈K;(3)V中的任意一个t-元子集恰好出现在λ个区组中。Hanani给出了λ=1时3-(v,{4,6},1)存在的充分必要条... t-(v,K,λ)设计是一个关联结构(V,B),满足条件:(1)V是v元点集;(2)B是V的子集族(B中的元素称为设计的区组),且每一个区组b∈B有|b|∈K;(3)V中的任意一个t-元子集恰好出现在λ个区组中。Hanani给出了λ=1时3-(v,{4,6},1)存在的充分必要条件。文章证明3-(v,{4,6},λ)存在的充分必要条件是λv≡0(mod 2),λv(v-1)(v-2)≡0(mod 8)且v≥4。 展开更多
关键词 T-设计 3-设计 区组长为4和6
下载PDF
Multi-focus image fusion based on block matching in 3D transform domain 被引量:5
7
作者 YANG Dongsheng HU Shaohai +2 位作者 LIU Shuaiqi MA Xiaole SUN Yuchao 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第2期415-428,共14页
Fusion methods based on multi-scale transforms have become the mainstream of the pixel-level image fusion. However,most of these methods cannot fully exploit spatial domain information of source images, which lead to ... Fusion methods based on multi-scale transforms have become the mainstream of the pixel-level image fusion. However,most of these methods cannot fully exploit spatial domain information of source images, which lead to the degradation of image.This paper presents a fusion framework based on block-matching and 3D(BM3D) multi-scale transform. The algorithm first divides the image into different blocks and groups these 2D image blocks into 3D arrays by their similarity. Then it uses a 3D transform which consists of a 2D multi-scale and a 1D transform to transfer the arrays into transform coefficients, and then the obtained low-and high-coefficients are fused by different fusion rules. The final fused image is obtained from a series of fused 3D image block groups after the inverse transform by using an aggregation process. In the experimental part, we comparatively analyze some existing algorithms and the using of different transforms, e.g. non-subsampled Contourlet transform(NSCT), non-subsampled Shearlet transform(NSST), in the 3D transform step. Experimental results show that the proposed fusion framework can not only improve subjective visual effect, but also obtain better objective evaluation criteria than state-of-the-art methods. 展开更多
关键词 image fusion block matching 3D transform block-matching and 3D(BM3D) non-subsampled Shearlet transform(NSST)
下载PDF
Comparison between the seismic response of 2D and 3D models of rigid blocks 被引量:3
8
作者 Angelo Di Egidio Daniele Zulli Alessandro Contento 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2014年第1期151-162,共12页
A three-dimensional rigid body on the shape of a parallelepiped is modelled in order to rock on a side or a vertex of the base,in order to evaluate the seismic response of rigid blocks lying on a horizontal support.Th... A three-dimensional rigid body on the shape of a parallelepiped is modelled in order to rock on a side or a vertex of the base,in order to evaluate the seismic response of rigid blocks lying on a horizontal support.The center of mass of the body is considered as eccentric with respect to its geometric center.As seismic input,three Italian recorded accelerograms,with different spectral content,are used.The study is mainly conducted to highlight the differences between the seismic response of 2D and 3D models of rigid blocks,with the aim to understand if,in some cases,the use of the 3D model of rigid block is required to obtain safer results.In fact,the outcomes show that in some ranges of the geometrical and mechanical parameters that characterize the excitation and the body,a two-dimensional model,which is not able to consider the 3D rocking on a vertex,can provide unsafe results.In particular,it is found that the overturning process of the three-dimensional block can occur under excitations which are lower than those which overturn a corresponding two-dimensional block. 展开更多
关键词 seismic excitation 3D rigid block rectangular base ROCKING OVERTURNING
下载PDF
3D Identification and Stability Analysis of Key Surface Blocks of Rock Slope 被引量:4
9
作者 李明超 周四宝 王刚 《Transactions of Tianjin University》 EI CAS 2016年第4期317-323,共7页
Complicated geological structures make it difficult to analyze the stability of rock slopes, such as faults, weak intercalated layers or joint fissures. Based on 3D geological modeling and surface block identifying me... Complicated geological structures make it difficult to analyze the stability of rock slopes, such as faults, weak intercalated layers or joint fissures. Based on 3D geological modeling and surface block identifying methods, an integrated methodology framework was proposed and realized to analyze the stability of surface blocks in rock slopes. The surface blocks cut by geological structures, fissures or free faces could be identified subjected to the four principles of closure, completeness, uniqueness and validity. The factor of safety(FOS)of single key block was calculated by the limit equilibrium method. If there were two or more connected blocks, they were defined as a block-group. The FOS of a block-group was computed by the Sarma method. The proposed approach was applied to an actual rock slope of a hydropower project, and some possible instable blocks were demonstrated and analyzed visually. The obtained results on the key blocks or block-groups provide essential information for determining potential instable region of rock slopes and designing effective support scheme in advance. 展开更多
关键词 rock slope 3D model surface block block-group stability factor of safety(FOS)
下载PDF
Study on the Influence of Piloti on Mean Radiant Temperature in Residential Blocks by 3-D Unsteady State Heat Balance Radiation Calculation 被引量:1
10
作者 Tian-Yu Xi Jian-Hua Ding Hong Jin 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2014年第4期91-95,共5页
Piloti is commonly used in tropical and subtropical climate zones to get high wind velocity and create shadowed areas in order to optimize the living environment of residential blocks,but there are few studies to reve... Piloti is commonly used in tropical and subtropical climate zones to get high wind velocity and create shadowed areas in order to optimize the living environment of residential blocks,but there are few studies to reveal the influence of piloti on the radiant environment of residential blocks systematically. Taking the city of Guangzhou as an example,using 3-D Unsteady State Heat Balance Radiation Calculation Method,this paper shows that the mean radiant temperature( MRT) under piloti area increases with the increase of piloti ratio,and especially when piloti ratio is equal to 100%,the MRT increase trend becomes sharp. The MRT of exposed area decreases with the increase of piloti ratio,especially when piloti ratio reaches 100%,the decrease trend of MRT becomes sharp,which offers the reference for the study on piloti design in subtropical climate zones and further research on living environment by CFD simulation in residential blocks. 展开更多
关键词 piloti mean radiant temperature 3-D unsteady state heat balance radiation calculation residential block
下载PDF
Characterization of a 3-Phase a.c. Free Burning Arc Plasma 被引量:1
11
作者 夏维东 Laurent FULCHERI +2 位作者 Jose GONZALEZ-AGUILAR 李辉 Thomas M. GRUENBERGER 《Plasma Science and Technology》 SCIE EI CAS CSCD 2006年第2期156-163,共8页
A 3-phase a.c. arc plasma reactor with large volume plasma has been developed for the synthesis of new carbon nano-structures. One of the main characteristics of the plasma system is related to the absence of a fixed ... A 3-phase a.c. arc plasma reactor with large volume plasma has been developed for the synthesis of new carbon nano-structures. One of the main characteristics of the plasma system is related to the absence of a fixed neutral point. This gives rise to a rich and complex phenomenology related to instabilities and arc motion since the arcs are "burning" freely in the gas flow between the three electrodes. This paper is dedicated to the analysis of the behavior of such a system under typical conditions using argon and nitrogen as plasma gases. A classification of are configuration, arc commutating, arc interaction, arc motion and arc instabilities are discussed based on ultra high-speed cine camera analysis. A simple model describing the time evolution of the system is also presented and compared with the experimental measurements. The results show that an adequate control could allow the improvement of the overall system. 展开更多
关键词 3-phase AC arc plasma free arc arc motion arc commutating arc instabilities
下载PDF
基于CTCS-3/2级列控系统的高速铁路闭塞分区长度设计研究 被引量:1
12
作者 耿敬春 李建新 +2 位作者 吕苗苗 倪少权 潘金山 《铁道学报》 EI CAS CSCD 北大核心 2023年第4期8-15,共8页
根据CTCS-3级和CTCS-2级列控车载设备控车原理,提出高速铁路闭塞分区长度设计原则和约束条件。结合现行列控车载设备参数,当线路长大下坡道不大于24‰时,闭塞分区长度设计满足CTCS-3级列控车载顶棚速度350 km/h、CTCS-2级300 km/h正常... 根据CTCS-3级和CTCS-2级列控车载设备控车原理,提出高速铁路闭塞分区长度设计原则和约束条件。结合现行列控车载设备参数,当线路长大下坡道不大于24‰时,闭塞分区长度设计满足CTCS-3级列控车载顶棚速度350 km/h、CTCS-2级300 km/h正常运行。当线路长大下坡道大于24‰时,闭塞分区长度按照满足CTCS-3级列控车载顶棚速度350 km/h、CTCS-2级降速至250 km/h设计;或将CTCS-3级列控系统结合轨道电路信息定义的闭塞分区平均长度由3000 m调整为4400 m,以满足CTCS-3级列控车载顶棚速度350 km/h、CTCS-2级300 km/h运行要求。 展开更多
关键词 高速铁路 CTCS-3/2级列控系统 闭塞分区 长度 设计
下载PDF
Integrating artificial neural networks and geostatistics for optimum 3D geological block modeling in mineral reserve estimation:A case study 被引量:2
13
作者 Jalloh Abu Bakarr Kyuro Sasaki +1 位作者 Jalloh Yaguba Barrie Abubakarr Karim 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2016年第4期581-585,共5页
In this research, a method called ANNMG is presented to integrate Artificial Neural Networks and Geostatistics for optimum mineral reserve evaluation. The word ANNMG simply means Artificial Neural Network Model integr... In this research, a method called ANNMG is presented to integrate Artificial Neural Networks and Geostatistics for optimum mineral reserve evaluation. The word ANNMG simply means Artificial Neural Network Model integrated with Geostatiscs, In this procedure, the Artificial Neural Network was trained, tested and validated using assay values obtained from exploratory drillholes. Next, the validated model was used to generalize mineral grades at known and unknown sampled locations inside the drilling region respectively. Finally, the reproduced and generalized assay values were combined and fed to geostatistics in order to develop a geological 3D block model. The regression analysis revealed that the predicted sample grades were in close proximity to the actual sample grades, The generalized grades from the ANNMG show that this process could be used to complement exploration activities thereby reducing drilling requirement. It could also be an effective mineral reserve evaluation method that could oroduce optimum block model for mine design. 展开更多
关键词 Artificial Neural Network Model withGeostatistics (ANNMG)3D geological block modeling Mine designKriging
下载PDF
3-D crustal-scale gravity model of the San Rafael Block and Payenia volcanic province in Mendoza,Argentina
14
作者 Daniel Richarte Marianela Lupari +2 位作者 Agustina Pesce Silvina Nacif Mario Gimenez 《Geoscience Frontiers》 SCIE CAS CSCD 2018年第1期239-248,共10页
The San Rafael Block(SRB)is part of one of the main retroarc volcanic provinces in southern Central Andes in Mendoza,Argentina.This block is located in the Andean foothills between the orogenic front and foreland base... The San Rafael Block(SRB)is part of one of the main retroarc volcanic provinces in southern Central Andes in Mendoza,Argentina.This block is located in the Andean foothills between the orogenic front and foreland basement uplifts of late Miocene age.In order to analyze the geochronological evolution of the Quaternary volcanism in the region,several geologic and geophysical studies have been conducted.Nevertheless,the crust,where the SRB is located,has not been well characterized yet.Based on gravimetric and magnetic data,together with isostatic and elastic thickness analyses,we modeled the crustal structure of the area.Information obtained has allowed us to understand the crust where the SRB and the Payenia volcanic province are located.Bouguer anomalies indicate that the SRB presents higher densities to the North of Cerro Nevado and Moho calculations suggest depths for this block between 40 and 50 km.Determinations of elastic thickness would indicate that the crust supporting the San Rafael Block presents values of approximately 10 km,being enough to support the block loading.However,in the Payenia region,elastic thickness values are close to zero due to the regional temperature increase. 展开更多
关键词 SAN Rafael block Payenia 3-D CRUSTAL model Asthenospheric wedge
下载PDF
Comparison between Plane and Stereo Block Adjustment for ZY-3 Satellite Images 被引量:1
15
作者 Taoyang WANG Guo ZHANG +3 位作者 Deren LI Wanshou JIANG Xinming TANG Xuelin LIU 《Journal of Geodesy and Geoinformation Science》 2018年第1期53-60,共8页
Block adjustment for satellite images cannot be solved with weak convergence geometric conditions,therefore a plane block adjustment method to improve the targeting precision of images is proposed utilizing DEM as hei... Block adjustment for satellite images cannot be solved with weak convergence geometric conditions,therefore a plane block adjustment method to improve the targeting precision of images is proposed utilizing DEM as height constraint plane block adjustment method.First,a rational function model with affine transformation is selected as the mathematical model of the satellite image plane block adjustment.Second,to update the ground coordinates of tie points(TPs),the plane coordinates of TPs are only solved in the adjustment process.Elevation values are obtained by using DEM interpolation.Finally,the plane coordinates of all TPs and orientation parameters of all satellite images are solved through plane block adjustment with a few ground control points ZY-3 nadir images for two regions are tested for plane block adjustment while ZY-3 forward-nadir-back images of the same two regions are tested for stereo block adjustment.A comparison indicates that almost the same accuracy can be obtained with plane block adjustment support using a 1∶50 000 DEM and stereo block adjustment for ZY-3 images.For ZY-3 nadir images,almost no loss of plane block adjustment accuracy occurred when global DEM with 1 km grid and SRTM with 90 m grid replaced the 1∶50 000 DEM as elevation control,.Test results demonstrate the effectiveness and feasibility of the plane block adjustment method. 展开更多
关键词 ZY-3 SATELLITE IMAGES STEREO block adjustment PLANE block adjustment ACCURACY
下载PDF
SYNTHESIS OF NOVEL BLOCK COPOLYMERS OF POLY(3-HYDROXYBUTYRIC ACID)WITH POLY(ETHYLENE GLYCOL)THROUGH ANIONIC POLYMERISATION
16
作者 Xin-tao Shuai Zbigniew Jedlinski +1 位作者 Qiang Luo Nozirow Farhod Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China Institute of Polymer Chemistry, Polish Academy of Sciences, 41-800 Zabrze, Poland Institute of Synthetic Fibre, Chinese Academy of Textile Sciences, Beijing 100025, China 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2000年第1期19-23,共5页
A novel kind of copolymer with ABA-type block structure was synthesized by anionic ring-opening polymerization of beta-butyrolactone (beta-BL) in the presence of a PEG-based dicarboxylates as macroinitiators which wer... A novel kind of copolymer with ABA-type block structure was synthesized by anionic ring-opening polymerization of beta-butyrolactone (beta-BL) in the presence of a PEG-based dicarboxylates as macroinitiators which were prepared by the esterification of aliphatic cyclic anhydride and poly(ethylene glycol) (PEG) oligomers (M-n = 2000, 4000 and 6000) and conversion of potassium dicarboxylates. The resultant copolymers as well as the intermediates were characterized by IR, H-1-NMR and GPC. 展开更多
关键词 block copolymer poly(ethylene glycol) poly(3-hydroxybutyric acid)
下载PDF
A new design of stator magnetic system for 3-phase & 12-pole HB stepper
17
作者 任雷 史敬灼 王宗培 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 1999年第3期52-56,共5页
A new design of stato magnetic System is Proposed for 3-phase & 12-pole HB stepper, and it features bet-ter distribution of magntic lield to incare Pullou tope and bopmve Operaonal stability of moor and minimummut... A new design of stato magnetic System is Proposed for 3-phase & 12-pole HB stepper, and it features bet-ter distribution of magntic lield to incare Pullou tope and bopmve Operaonal stability of moor and minimummutual inductance between phase windimp to make design of control circuit easier, and application proved it is as good as expected. 展开更多
关键词 HB STEPPER STATOR MAGNETIC system 3-phase STEPPER
下载PDF
Improvement of β-phase crystal formation in a BaTiO3-modified PVDF membrane
18
作者 Lin SHEN Lei GONG +3 位作者 Shuhua CHEN Shiping ZHAN Cheng ZHANG Tao SHAO 《Plasma Science and Technology》 SCIE EI CAS CSCD 2018年第6期144-151,共8页
In this paper,low temperature plasma is used to modify the surface of barium titanate(BaTiO3)nanoparticles in order to enhance the interfacial compatibility between ferroelectric poly(vinylidene fluoride)(PVDF) ... In this paper,low temperature plasma is used to modify the surface of barium titanate(BaTiO3)nanoparticles in order to enhance the interfacial compatibility between ferroelectric poly(vinylidene fluoride)(PVDF) and BaTiO3 nanoparticles.The results demonstrate that oxygenic groups are successfully attached to the BaTiO3 surface,and the quantity of the functional groups increases with the treatment voltage.Furthermore,the effect of modified BaTiO3 nanoparticles on the morphology and crystal structure of the PVDF/BaTiO3 membrane is investigated.The results reveal that the dispersion of BaTiO3 nanoparticles in the PVDF matrix was greatly improved due to the modification of the BaTiO3 nanoparticles by air plasma.It is worth noting that the formation of a β-phase in a PVDF/modified BaTiO3 membrane is observably promoted,which results from the strong interaction between PVDF chains and oxygenic groups fixed on the BaTiO3 surface and the better dispersion of BaTiO3 nanoparticles in the PVDF matrix.Besides,the PVDF/modified BaTiO3 membrane at the treatment voltage of 24 k V exhibits a lower water contact angle(≈68.4°) compared with the unmodified one(≈86.7°).Meanwhile,the dielectric constant of PVDF/BaTiO3 nanocomposites increases with the increase of working voltage. 展开更多
关键词 PVDF BaTiO3 NANOCOMPOSITE non-thermal plasma β-phase ferroelectric
下载PDF
3-Phase Modeling for the Origin of Chinese Lithium-Rich Brines
19
作者 HUANG Wenbin WU Xishun +1 位作者 DU Xiaohui LI Li 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第S1期339-340,共2页
There are significantly different origins and mineralizations among various lithium-rich brines of the world.As for Clayton Valley,Nevada,the data and interpretations recently presented suggest that the model
关键词 3-phase modeling lithium brine origin Qaidam Basin
下载PDF
Fault diagnosis algorithm for 3-phase passive rectifiers based on frequency-domain analysis for acceleration grid power supply in CFETR NBI system
20
作者 Bangyou ZHU Shaoxiang MA +3 位作者 Hongqi ZHANG Zhiheng LI Ming ZHANG Yuan PAN 《Plasma Science and Technology》 SCIE EI CAS CSCD 2022年第12期40-54,共15页
The acceleration grid power supply(AGPS) is a crucial part of the Negative-ion Neutral Beam Injection system in the China Fusion Engineering Test Reactor,which includes a 3-phase passive(diode) rectifier.To diagnose a... The acceleration grid power supply(AGPS) is a crucial part of the Negative-ion Neutral Beam Injection system in the China Fusion Engineering Test Reactor,which includes a 3-phase passive(diode) rectifier.To diagnose and localize faults in the rectifier,this paper proposes a frequencydomain analysis-based fault diagnosis algorithm for the rectifier in AGPS.First,time-domain expressions and spectral characteristics of the output voltage of the TPTL-NPC inverter-based power supply are analyzed.Then,frequency-domain analysis-based fault diagnosis and frequency-domain analysis-based sub-fault diagnosis algorithms are proposed to diagnose open circuit(OC) faults of diode(s),which benefit from the analysis of harmonics magnitude and phase-angle of the output voltage.Only a fundamental period is needed to diagnose and localize exact faults,and a strong Variable-duration Fault Detection Method is proposed to identify acceptable ripple from OC faults.Detailed simulations and experimental results demonstrate the effectiveness,quickness,and robustness of the proposed algorithms,and the diagnosis algorithms proposed in this article provide a significant method for the fault diagnosis of other rectifiers and converters. 展开更多
关键词 fault diagnosis 3-phase passive rectifier acceleration grid power supply(AGPS) fault localization
下载PDF
上一页 1 2 21 下一页 到第
使用帮助 返回顶部