首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   34篇
  免费   0篇
电工技术   2篇
化学工业   17篇
轻工业   1篇
无线电   1篇
一般工业技术   6篇
冶金工业   1篇
自动化技术   6篇
  2021年   3篇
  2019年   2篇
  2016年   1篇
  2013年   12篇
  2012年   3篇
  2009年   1篇
  2008年   1篇
  2007年   4篇
  2006年   1篇
  2005年   1篇
  2003年   1篇
  2002年   1篇
  2000年   2篇
  1998年   1篇
排序方式: 共有34条查询结果,搜索用时 15 毫秒
31.
Bi-articular actuators – actuator spanning two joints – play fundamental role in robot arms designed under the human musculoskeletal actuation paradigm. Unlike kinematic redundancy, actuator redundancy resulting from bi-articular actuation brings advantages such as increasing stability, reducing link's inertia, and decreasing non-linearity of the end-effector force with respect to the force direction. The traditional phase different control (PDC) resolves actuator redundancy on the basis of a linearized model derived from measured human muscle activity. Such linear model produces a non-zero error in calculation between a desired output force and necessary inputs. In this paper, the non-linear phase different control (NLPDC) is proposed to resolve actuator redundancy with no error. The maximum end-effector force of BiWi, bi-articularly actuated, and wire-driven arm, is measured using both PDC and NLPDC. When the robot arm moves towards singular configurations, the measured error in output force remains within the modeling error if using NLPDC, while such error increases significantly for PDC. Furthermore, unlike PDC, the proposed NLPDC allows design of joint stiffness and torque independently, reduction of necessary total muscle input force, and precise calculation of maximum output force.  相似文献   
32.
The discovery of novel melanoma markers for not only early detection but also monitoring disease status is promising to improve the clinical outcome of patients. In the present study, we performed proteomic comparative analysis of plasma proteins between healthy volunteers and melanoma patients using NanoLC and MALDI‐TOF‐MS. As a result, we were successful in identifying nine proteins that were specifically expressed in melanoma plasma compared with healthy plasma, most of which had not previously been identified as plasma markers of melanoma. The mRNA expression levels of four proteins [pro‐platelet basic protein precursor (PPBP), serum amyloid A2 (SAA2), complement factor H‐related protein 1 precursor (FHR1), inter‐alpha‐trypsin inhibitor heavy chain H4 precursor (IAIH4)] were prominently up‐regulated in several melanoma cell lines compared with melanocytes. Moreover, two proteins (PPBP, SAA) were shown to be expressed in tumor specimens from melanoma patients. In the survival time analysis regarding melanoma patients, the semi‐quantified plasma PPBP levels were statistically negatively correlated with the survival time. Most interestingly, the significant survival benefit was seen in low PBPP level group (< index 20) versus high level (≥ index 20) group. The results suggest that PPBP might be a novel promising serological marker and a prognostic factor specific to melanomas.  相似文献   
33.
Hexabenzo[a,cd,f,j,lm,o]perylene (HBP), an undecacyclic condensed polycyclic aromatic hydrocarbon with two severely crowded fjord regions, was synthesized by Clar's method; the starting material 8H-benzo[fg]-naphthacene-8-one was newly prepared by the glycerol condensation of 5,12-dihydro-naphthacene-5,12-dione. 1H and 13C NMR spectra of HBP were measured and the chemical shifts were completely assigned. Absorption and fluorescence spectra of HBP were also measured and the effects of nonplanarity on its spectroscopic properties was discussed.  相似文献   
34.
Carnitine and acetylcarnitine are important for the acquisition of motility and maturation of spermatozoa in the epididymis. In this study, we examined the involvement of carnitine/organic cation transporter (OCTN) in carnitine and acetylcarnitine transport in epididymal spermatozoa of mice. Uptake of both compounds by epididymal spermatozoa was time-dependent and partially Na(+)-dependent. Kinetic analyses revealed the presence of a high-affinity transport system in the spermatozoa, with K(m) values of 23.6 and 6.57 muM for carnitine and acetylcarnitine respectively in the presence of Na(+). Expression of OCTN2 and OCTN3 in epididymal spermatozoa was confirmed by immunofluorescence analysis. The involvement of these two transporters in carnitine and acetylcarnitine transport was supported by a selective inhibition study. We conclude that both Na(+)-dependent and -independent carnitine transporters, OCTN2 and OCTN3, mediate the supply of carnitine and acetylcarnitine to epididymal spermatozoa in mice.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号