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21.
This paper presents a dynamic compensation concept to grapple with the dynamic defects of a traditional robot arm, especially while performing high-speed endpoint regulations. The proposed high-speed dynamic compensation concept offers a new point of view for cooperating with a traditional manipulator to realize highly dexterous performance of manipulations. The concept is realized through adoption of a high-speed light-weight actuator as well as endpoint closed loop configured high-speed cameras. The dynamic compensation is analyzed experimentally with 1000 Hz visual feedback and a high-speed finger for a robot arm in the case of one degree of freedom. The advantage of the proposed approach is that the modeling for the robot system’s dynamics is not needed, whereas it is necessary and trivial in order to realize high-speed regulations by traditional approaches. Thus, the control issue becomes easier with the proposed approach. As an application for this concept, fast peg-and-hole alignment with large position and attitude uncertainty is studied. The alignment algorithm is based on a visual compliance strategy. Alignment experiments show that with the proposed concept of dynamic compensation as well as visual compliant motion control, robust and fast convergence was realized for most cases. 相似文献
22.
Temperature dependence of cyclic creep behavior has been studied using a Cu bicrystal containing dispersed SiO2 particles and a [0 1 1] 20° twist boundary. Failure occurred at shorter times with increasing temperature and stress amplitude. The fracture-mode of the bicrystals changed sharply from transgranular to intergranular at a certain critical stress amplitude. The brittle intergranular fracture that occurred below the critical stress amplitude caused discontinuous life shortening. The observed fracture-mode change at the critical stress amplitude is discussed in relation to grain-boundary sliding and grain-boundary cracking. 相似文献
23.
Kazuaki Shibuki Taku M. Aida Hiromichi Hayashi 《The Journal of Supercritical Fluids》2010,54(2):266-271
Sub-micron sized Zn2SiO4:Mn2+ phosphors particles were continuously synthesized in supercritical water with a flow reactor. Colloidal silica or sodium silicate was used as the Si source. Zn and Mn sources were chosen from their nitrates, sulfates, and acetates. The syntheses were carried out at temperatures from 400 to 500 °C, at pressures from 30 to 35 MPa, at NaOH concentrations from 0.014 to 0.025 M, and for residence times from 0.025 to 0.18 s. Sodium silicate formed α- and β-Zn2SiO4:Mn2+ phases regardless of the Zn and Mn sources, while colloidal silica formed phases dependent on the type of Zn and Mn sources used in addition to the use of alkali. As the reaction temperature increased, the crystallinity of α-Zn2SiO4:Mn2+ phase increased and the Mn substitution into the Zn sites of the α-Zn2SiO4 phase decreased. Of the conditions studied, the most highly crystalline α-Zn2SiO4:Mn2+ was produced at a temperature of 400 °C, a pressure of 30 MPa, a NaOH concentration of 0.14 M, and a residence time of 0.13 s with Zn and Mn sulfates and colloidal silica as starting materials. The α-Zn2SiO4:Mn2+ fine particles synthesized were round in shape, had an average diameter of 268 nm, and exhibited a green-emission with a peak wavelength of 524 nm. 相似文献
24.
Kitako Tabata Eriko Sugano Akito Hatakeyama Yoshito Watanabe Tomoya Suzuki Taku Ozaki Tomokazu Fukuda Hiroshi Tomita 《International journal of molecular sciences》2021,22(13)
The death of photoreceptor cells is induced by continuous light exposure. However, it is unclear whether light damage was induced in retinal ganglion cells with photosensitivity by transduction of optogenetic genes. In this study, we evaluated the phototoxicities of continuous light exposure on retinal ganglion cells after transduction of the optogenetic gene mVChR1 using an adeno-associated virus vector. Rats were exposed to continuous light for a week, and visually evoked potentials (VEPs) were recorded. The intensities of continuous light (500, 1000, 3000, and 5000 lx) increased substantially after VEP recordings. After the final recording of VEPs, retinal ganglion cells (RGCs) were retrogradely labeled with a fluorescein tracer, FluoroGold, and the number of retinal ganglion cells was counted under a fluorescent microscope. There was no significant reduction in the amplitudes of VEPs and the number of RGCs after exposure to any light intensity. These results indicated that RGCs were photosensitive after the transduction of optogenetic genes and did not induce any phototoxicity by continuous light exposure. 相似文献
25.
Taku Matsushita Mitsunori Hieda Nobuo Wada 《Journal of Low Temperature Physics》2011,162(5-6):536-543
To examine whether one-dimensional (1D) helium quantum fluid is realized in narrower channels than those studied previously, we have measured heat capacities of 4He adsorbed in nanoporous material FSM with straight 1D channels 1.5 nm in diameter. From the heat of desorption for adsorbed 4He, the coverage n f, up to which 4He film grows in the channels, is determined to be 15.4 ??mol/m2 using the Frenkel-Halsey-Hill model. At coverages sufficiently below n f, the temperature dependence of the 4He heat capacity has a shoulder, above which adsorbed 4He is delocalized from the substrate. On the other hand, the depression of the heat capacity indicating quantum effects has not been observed up to n f, which suggests that 4He film in the channels remains amorphous-like normal fluid. Just above n f, the quantum effect is observed in 4He adatoms on the grain surface of FSM powder, which indicates that 1.5 nm channels are slightly below the limit required to realize quantum effect in the inside 4He fluid. 相似文献
26.
Kazufumi Yogo Ryoichi Shinkuma Taku Konishi Satoko Itaya Shinichi Doi Keiji Yamada Tatsuro Takahashi 《International Journal of Network Management》2012,22(1):1-11
We have developed an incentive‐rewarding mechanism that stimulates activities in social networking services (SNSs), including content uploading and link establishment. We particularly focus on changing the reward assignment ratio based on the different risks users perceive when uploading content with different privacy settings: public‐open and friend‐limited. Learning‐based simulation allowed us to observe that SNS activity, which we measured as the amount of browsed content within a certain period, can be controlled by a rewarding assignment ratio. We then analyzed how the amount of uploaded content and the increase of established links affect SNS activity. Results suggested that the optimal reward assignment ratio to maximize SNS activity changes depending on the total amount of available reward resources. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
27.
Prihardi Kahar Kazuo Taku Shuzo Tanaka 《Journal of Bioscience and Bioengineering》2010,110(4):453-458
In this study, the effect and the optimum pretreatment condition of corncobs using low strength of H2SO4 were investigated, in which H2SO4 was used to improve the enzymatic digestibility of corncobs for saccharification without degradation of sugars released. The optimum pretreatment condition was found to be the addition of 0.5% (vol./vol.) H2SO4 and autoclaving at 122 °C for 20 min. Under this condition, the structural integrity of corncob was altered to make cellulose microfibrils more accessible for cellulase enzymes, and the enzymatic digestion of corncobs could be significantly enhanced. A high yield of sugar, 80% (wt./wt.), could be obtained at a low enzyme dosage of 0.024 g enzymes/g cobs, when pretreated. As a result, the ethanol production was obviously improved by the pretreatment, i.e., the ethanol yield of 77% (wt./wt.) was obtained within 36 h in the SSF fermentation using Saccharomyces cerevisiae NBRC2114. 相似文献
28.
Frictional anisotropy of oblique Ti nanocolumns grown by glancing angle deposition (GLAD) was investigated by ramp-scratch
experiments in forward (in the direction of the column tilt) and reverse (against the column tilt) directions using rectangular
and conical loading tips. Strong anisotropy in friction was generally observed, wherein the resistance or friction coefficient
in reverse scratching was higher than that in forward scratching, and the reverse resistance was sensitive to the tip shape.
In forward scratching, the nanocolumns bend with the column tilt direction, designated as the W-mode deformation. On the other
hand, in reverse scratching, the nanocolumns deflect against the column tilt in high normal force, designated as the A-mode
deformation. The deformation mode changes from the W-mode to the A-mode as the normal force increases in reverse scratching.
The mechanism of the frictional anisotropy was discussed on the basis of a simple deformation model of column by finite element
method. The anisotropy can be explained by the difference in the deformation mode. That is, compressive deformation in the
longitudinal direction and large deflection against the column tilt induce higher friction resistance in reverse scratching
than in forward scratching brought about by compliant bending deformation with the column tilt. 相似文献
29.
在形变温度为1133K、形变速率为2×10~(-3)s~(-1)的试验条件下,采用两段加载拉伸试验方法研究了0.4%C-1.5%Mn钢高温变形后的静态软化行为.调查了由两次加载拉伸变形时的屈服应力求得的静态软化率以及相对峰值应力比和峰值应变比随等温保持时间的变化.详细讨论了动态回复组织和动态再结晶组织对高温变形后的静态软化过程的影响. 相似文献
30.
Taku Watanabe James S. Tulenko Patrick K. Schelling 《Journal of Nuclear Materials》2008,375(3):388-396
The thermal conductivities of single crystal and polycrystalline UO2 are calculated using molecular dynamics simulations, with interatomic interactions described by two different potential models. For single crystals, the calculated thermal conductivities are found to be strongly dependent on the size of the simulation cell. However, a scaling analysis shows that the two models predict essentially identical values for the thermal conductivity for infinite system sizes. By contrast, simulations with the two potentials for identical fine polycrystalline structures yield estimated thermal conductivities that differ by a factor of two. We analyze the origin of this difference. 相似文献