Showing papers by "Zhen Li published in 2000"

The planning and control of robot dextrous manipulation

Abstract: Dextrous manipulation is a fundamental problem in the study of multifingered robotic hands. Given a robotic hand and an object to be manipulated by the hand in an environment filled with obstacles, the main objectives of dextrous manipulation are to have the hand grasp the object and transfer it from a start configuration to a goal configuration without collision. To fulfill such a task in general, we will need: (a) a manipulation planner to generate a feasible path for the hand; and (b) a controller to implement the planned path. In this overview paper, we define the manipulation planning problem and present a unified control system architecture for multifingered manipulation (CoSAM/sup 2/). By incorporating the various kinematic and static relationships of a multifingered robotic hand system with proper sensory data inputs at different stages, CoSAM/sup 2/ achieves the various objectives of dextrous manipulation. Theoretical background of the control system design along with real-time experimental results are described.

Novel polyphosphazenes containing charge-transporting agent and chromophore as pendant groups

Abstract: Two novel functionalized polyorganophosphazenes containing charge-transporting agent and electro-optical chromophore as side chains for the photorefractive application are synthesized. The structure characterization was carried out by 1H-NMR, IR and UV-Visble spectra, gel permeation chromatograply and differential scanning calorimetry. Due to the good flexibility of the backbone and the high degree of functionalization, polyphosphazenes are expected to be a good candidate for photorefractive polymeric materials.

Estimation of snow density with L-band polarimetric SAR data

Abstract: The areas covered by snow are important factors in climatological and hydrological investigations, particularly in alpine regions Snow density is an important index for indicating snow statutes and calculating snowmelt-runoff Active microwave sensors can discriminate snow and glacier from other surfaces and are all weather use The radar polarization signature of an object permits a more accurate description of the object of interest than single-polarization measurements In this paper, the polarimetric backscattering characteristics of dry snow at L-band are analyzed, and the algorithm for estimation of snow density by using L-band SAR measurements data are used in experiment field The results showed that L-band polarimetric SAR data are fairly good use to snow density estimation in alpine areas, through comparing snow density in study site from L-band polarimetric SAR data with in situ data

Synthesis, Characterization, and Fluorescence of Copolymers of N-Alkylcarbazole and trans-Stilbene Obtained by an Oxidative-Coupling Reaction

Abstract: A novel kind of conjugated polymer was prepared by an oxidative-coupling polymerization of N-alkylcarbazole and trans-stilbene. The structure of the copolymers was characterized by elemental analysis, 1H NMR, UV−vis, and FTIR spectra. The copolymers have good solubility in common organic solvents and are thermally stable. Fluorescence spectra showed that these polymers are blue-light-emitting materials.

[Study on the relations between HLA-DRB 1 alleles and Helicobacter pylori infection].

Abstract: OBJECTIVE In order to study the relation between human leukocyte antigen (HLA) DRB1 alleles and Helicobacter pylori (Hp) infection. METHODS Hp-IgG antibody from 46 gastric cancer (GC), 75 esophageal cancer and 100 population-based controls were identified by Hp-IgG quantitative enzyme immunoassay. Biotest HLA-DRB enzyme linked probe hybridization assay kit (low resolution) was used to identify DRB1 alleles. RESULTS (1) Frequency of DRB1 * 08 was significantly higher in Hp-IgG positive group than in Hp-IgG negative group (13.1% vs 4.4%, chi(2) = 11.14, P < 0.001). Frequency of DRB1 * 12 was significantly lower in Hp-IgG positive group than in Hp-IgG negatives (5.4% vs 11.3%, chi(2) = 4.49, P < 0.05). (2) Frequency of DRB1 * 02 in GC was significantly higher than that of controls. Frequency of DRB1 * 07 in GC was significantly lower than that of controls. However, neither the frequency of DRB1 * 02 between Hp-IgG positive and Hp-IgG negative groups nor the frequency of DRB1 * 07 between Hp-IgG positive and Hp-IgG negative groups showed significant differences in GC and controls. CONCLUSIONS (1) HLA-DRB1 * 08 might serve a genetic risk factor for Hp infection while DRB1 * 12 might play a role of protecting effect against Hp infection. (2) DRB1 * 02 might be a genetic risk factor for GC while DRB1 * 07 might play a role of protecting effect against GC. However, the relations between DRB1 * 02, DRB1 * 07 and GC were not associated with Hp infection.