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Four-Leg Object Recognition for Service Robot Based on Top-hat Transformation
Hao Wu,Guohui Tian,Xinran Wang,Fei Lu 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.12
A method of object recognition for objects with special topological structure is developed based on top-hat transformation for service robot. The objects with four legs are easily detected and recognized by service robot with laser ranger array by this method. First, the top-hat transformation in one dimension is reviewed, then the recognition strategy of self-adapting threshold for objects with special topological structure is proposed, and the general data process for object recognition and position is proposed and analyzed. Experimental results show that the process of object recognition based on top-hat transformation proposed in this article is an effective and accurate application.
Mobile Robot Navigation based on Human Walking Trajectory in Intelligent Space
Peng Duan,Guohui Tian,Hao Wu 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.11
This paper presents a mobile robot navigation method based on human walking trajectory in intelligent space. Unlike the traditional navigation methods, the proposed method enables the robot to walk a meaningful path, which reflects human activity patterns in daily life. Human walking trajectories are extracted using multiple distributed vision cameras in intelligent space. To group trajectories with the same direction, trajectory similarity measurement is implemented. Key points on human walking trajectories and typical transfer points are utilized to build a topological map. To navigate a mobile robot to walk along the trajectory of human walking, global path planning based on the topological map and local path planning based on gird map are carried out with the spared information in intelligent space. Experimental results illustrate the performance of the proposed navigation method.
^(64)Zn and ^(67)Zn (n,α) Reactions in the MeV Neutron Energy Region
Guohui Zhang,Jiaguo Zhang,Hao Wu,Jiaming Liu,Jinxiang Chen,Yuri Gledenov,Milana Sedysheva,Gonchigdorj Khuukhenkhuu,Pavel Szalanski 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
Nuclear reactions of ^(64)Zn(n,α)^(61)Ni and ^(67)Zn(n,α)^(64)Ni are important because they are gas pro-duction reactions and zinc is a reactor constituent element with a signicant fraction. But the cross section data of these reactions are scanty because the residual nuclei ^(61)Ni and ^(64)Ni are stable and the commonly used activation method is not feasible. In the present work, differential cross sections and angleintegrated cross sections were measured for the ^(64)Zn(n,α)^(61)Ni reaction at neutron energies of 2.5, 4.0, 5.0, 5.5, and 6.0 MeV and cross sections of the ^(67)Zn(n,α)^(64)Ni reaction were measured at 4.0, 5.0, and 6.0 MeV. A twin gridded ionization chamber was employed as alpha particle detector. Experiments were performed at the 4.5 MV Van de Graaff accelerator of Peking University. Monoenergetic neutrons of 2.5 MeV were produced through the T(p, n)^3He reaction with a solid Ti-T target, and those of other energies were produced through the D(d, n)^3He reaction with a deuterium gas target. Absolute neutron fluxes were determined through the ^(238)U(n, f) reaction and a BF^3 long counter was used as the neutron flux monitor. Present results are compared with other measurements and evaluations.
Wind tunnel investigation on wind characteristics of flat and mountainous terrain
Jia-Wu Li,Jun Wang,Shucheng Yang,Feng Wang,Guohui Zhao 한국풍공학회 2022 Wind and Structures, An International Journal (WAS Vol.35 No.4
Wind tunnel test is often adopted to assess the site-specific wind characteristics for the design of bridges as suggested by current design standards. To investigate the wind characteristics of flat and mountainous terrain, two topographic models are tested in a boundary layer wind tunnel. The wind characteristics, including the vertical and horizontal mean wind speed distributions, the turbulence intensity, and the wind power spectra, are presented. They are investigated intensively in present study with the discussions on the effect of wind direction and the effect of topography. It is indicated that for flat terrain, the wind direction has negligible effect on the wind characteristics, however, the assumption of a homogenous wind field for the mountainous terrain is not applicable. Further, the non-homogeneous wind field can be defined based on a proposed approach if the wind tunnel test or on-site measurement is performed. The calculated turbulence intensities and wind power spectra by using the measured wind speeds are also given. It is shown that for the mountainous terrain, engineers should take into account the variability of the wind characteristics for design considerations
A flow rate on-line monitoring method for piezoelectric pump based on self-sensing circuit
Hong Jiang,Guohui Wu,Lipeng He,Yuecheng Wang,Dianbin Hu,Zheng Zhang,Guangming Cheng 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.5
This paper presents a new flow rate monitoring method for a piezoelectric micropump based on a self-sensing circuit. Utilizing the voltage generated by the secondary direct piezoelectric effect as the sensing voltage, a soft sensor of the piezoelectric actuator can be implemented onto the piezoelectric micropump. A bridge-type circuit is proposed as the selfsensing circuit, the piezoelectric micropump is fabricated with a circular piezoelectric actuator, the characteristics of the self-sensing voltage and the flow rate are experimentally investigated under different excitation voltages and frequencies. The results show that the method can accurately determine optimal frequency of the micropump (100 Hz, 280 Hz), and for a fixed frequency of 100 Hz and a voltage range of 50-180 V, the correlation between the self-sensing voltage and the flow rate is 0.9732. As a result, the method demonstrated in this paper allows precise monitoring of the flow rate of the piezoelectric micropump without using external sensors.
Investigation of (n,α) Reaction for Rare-earth Elements in the MeV Neutron Energy Region
Y. Gledenov,M. Sedysheva,Guohui Zhang,Jiaguo Zhang,Hao Wu,Jiaming Liu,Jinxiang Chen,P. Koehler,G. Khuukhenkhuu,P. Szalanski 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
Cross sections and forward/backward ratios in the laboratory reference system were measured for ^(143)Nd(n,α)^(140)Ce at 4.0, 5.0, and 6.0 MeV, ^(147)Sm(n,α)^(144)Nd at 5.0 and 6.0 MeV, and ^(149)Sm(n,α)^(146)Nd at 6.0 MeV. A twin gridded ionization chamber and large-area back-to-back ^(143)Nd^2O^3 and ^(147,149)Sm^2O^3 samples were employed. Experiments were performed at the 4.5 MV Van de Graaff of Peking University, China. Fast neutrons were produced through the D(d, n)^3He reaction by using a deuterium gas target. A small ^(238)U fission chamber was employed for absolute neutron flux determination and a BF_3 long counter was used as neutron flux monitor. Present experimental data are compared with previous measurements, evaluations, and model calculations.
Lin Ze,Xiong Yuan,Sun Yun,Zeng Ruiyin,Xue Hang,Hu Yiqiang,Chen Lang,Liu Guodong,Panayi Adriana C.,Zhou Wu,Cao Faqi,Gao Fei,Mi Bobin,Liu Guohui 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-
Fracture combined with traumatic brain injury (TBI) is one of the most common and serious types of compound trauma in the clinic and is characterized by dysfunction of cellular communication in injured organs. Our prior studies found that TBI was capable of enhancing fracture healing in a paracrine manner. Exosomes (Exos), as small extracellular vesicles, are important paracrine vehicles for noncell therapy. However, whether circulating Exos derived from TBI patients (TBI-Exos) regulate the prohealing effects of fractures remains unclear. Thus, the present study aimed to explore the biological effects of TBI-Exos on fracture healing and reveal the potential molecular mechanism. TBI-Exos were isolated by ultracentrifugation, and the enriched miR-21-5 p was identified by qRT‒PCR analysis. The beneficial effects of TBI-Exos on osteoblastic differentiation and bone remodeling were determined by a series of in vitro assays. Bioinformatics analyses were conducted to identify the potential downstream mechanisms of the regulatory effect of TBI-Exos on osteoblasts. Furthermore, the role of the potential signaling pathway of TBI-Exos in mediating the osteoblastic activity of osteoblasts was assessed. Subsequently, a murine fracture model was established, and the effect of TBI-Exos on bone modeling was demonstrated in vivo. TBI-Exos can be internalized by osteoblasts, and in vitro, suppression of SMAD7 promoted osteogenic differentiation, whereas knockdown of miR-21-5 p in TBI-Exos strongly inhibited this bone-beneficial effect. Similarly, our results confirmed that preinjection of TBI-Exos led to enhanced bone formation, whereas knockdown of exosomal miR-21-5 p substantially impaired this bone-beneficial effect in vivo.