The Method of Aiming towards the Normal Direction for Robotic Drilling

Yuhao Gao,Dan Wu,Yunfei Dong,Xinguo Ma,Ken Chen 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.6

During the robotic drilling of an aircraft assembly, the normal directions of the workpieces are to be measured to guide the robot by aiming the spindle at the real normal directions of the curved surfaces. This paper describes the development of a method of using four laser displacement sensors to measure the normal direction and the implementation of the proposed method in a robotic drilling system to meet industrial application requirements. First, a novel mechanical structure is introduced to achieve a higher installation accuracy for the laser displacement sensors with a micro adjusting method. Next, the hardware structures and a convenient method of calibrating the sensors are introduced. To accommodate the complexity of the industrial circumstance, a procedure of measuring and adjusting is developed with consideration of both an angular deviation threshold and a limited adjusting iteration. Finally, the experiments of measuring and adjusting iteratively show that two iterations can achieve a satisfactory angular deviation of 0.1° for planar workpieces and three iterations are required for curved workpieces, with the perpendicularity errors of the drilled holes being less than 0.3°. The results can meet the required perpendicularity accuracy of 0.5°.

FePO4-coated Li5Cr7Ti6O25 nanocomposites as anode materials for high-performance lithium-ion batteries

Hui Chang,Yuhao Chen,Nan Zhang,Yan-Rong Zhu,Ting-Feng Yi 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.105 No.-

FePO4 coated Li5Cr7Ti6O25 nanocomposites are synthesized according to a simple sol–gel method followingby a calcination procedure. XRD and Rietveld refinement result indicate that FePO4 decorating doesnot change the crystal structure and lattice parameters of Li5Cr7Ti6O25. SEM and TEM prove that the particlesize of all sample are evenly distributed in the 50–100 nm range. Both energy dispersion spectroscopymapping and HRTEM indicate the existence of FePO4 on the surface of Li5Cr7Ti6O25, whichprovides a good conductive contact. CV and EIS exhibit that FePO4 (3 wt%) coated Li5Cr7Ti6O25 materialhas lower polarization, larger Li+ diffusion coefficient and higher conductivity than other pureLi5Cr7Ti6O25 and other FePO4 coated Li5Cr7Ti6O25 composites. Therefore, FePO4 (3 wt%) coatedLi5Cr7Ti6O25 anode material displays the highest charge and discharge capacity at each rate. Theenhanced electrochemical performance of FePO4-coated Li5Cr7Ti6O25 result from the enhanced lithiumion and electron transfer kinetics. The pristine Li5Cr7Ti6O25 only shows a specific capacity of197 mAh g 1 at 500 mA g 1 after 100 cycles, but FePO4 (3 wt%)-coated Li5Cr7Ti6O25 achieves a highcapacity of 237.9 mAh g 1. Therefore, the FePO4 coating can be regarded as a promising strategy toimprove the electrochemical properties of Li5Cr7Ti6O25.

Polymer composite microspheres loading 177Lu radionuclide for Interventional Radioembolization therapy and Real-time SPECT imaging of Hepatic Cancer

Liu Xiao,Yuhao Li,Ruiman Geng,Lihong Chen,Peng Yang,Mingyu Li,Xia Luo,Yuchuan Yang,Lin Li,Huawei Cai 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Transarterial radioembolization (TARE) with 90Y-labeled glass and resin microspheres is one of the primary treatment strategies for advanced-stage primary and metastatic hepatocellular carcinoma (HCC). However, difficulties of real-time monitoring post administration and embolic hypoxia influence treatment prognosis. In this study, we developed a new biodegradable polymer microsphere that can simultaneously load 177Lu and MgO nanoparticle, and evaluated the TARE therapeutic efficacy and biosafety of 177Lu-PDA-CS-MgO microspheres for HCC treatment. Methods Chitosan microspheres were synthesized through emulsification crosslink reaction and then conducted surface modification with polydopamine (PDA). The 177Lu and nano MgO were conjugated to microspheres using active chemical groups of PDA. The characteristics of radionuclide loading efficiency, biodegradability, blood compatibility, and anti-tumor effectwere evaluated both in vitro and in vivo. SPECT/CT imaging was performed to monitor bio-distribution and bio-stability of 177Lu-PDA-CS-MgO after TARE treatment. The survival duration of each rat was monitored. HE analysis, TUNEL analysis, immunohistochemical analysis, and western blot analysis were conducted to explore the anti-tumor effect and mechanism of composited microspheres. Body weight, liver function, blood routine examination were monitored at different time points to evaluate the bio-safety of microspheres. Results The composite 177Lu-PDA-CS-MgO microsphere indicated satisfactory degradability, biocompatibility, radionuclide loading efficiency and radiochemical stability in vitro. Cellular evaluation showed that 177Lu-PDA-CS-MgO had significant anti-tumor effect and blocked tumor cell cycles in S phase. Surgical TARE treatment with 177Lu-PDACS- MgO significantly prolonged the medial survival time from 49 d to 105 d, and effectively inhibited primary tumor growth and small metastases spreading. Moreover, these microspheres indicated ideal in vivo stability and allowed real-time SPECT/CT monitoring for up to 8 weeks. Immunostaining and immunoblotting results also confirmed that 177Lu-PDA-CS-MgO had potential in suppressing tumor invasion and angiogenesis, and improved embolic hypoxia in HCC tissues. Further evaluations of body weight, blood test, and pathological analysis indicated good biosafety of 177Lu-PDA-CS-MgO microspheres in vivo. Conclusion Our study demonstrated that 177Lu-PDA-CS-MgO microsphere hold great potential as interventional brachytherapy candidate for HCC therapy. Graphical Abstract Polymer composite microspheres loading 177Lu radionuclide and MgO nanoparticles for interventional radioembolization therapy and real-time SPECT imaging of hepatic cancer.

Robust Secure UAV Relay-Assisted Cognitive Communications with Resource Allocation and Cooperative Jamming

Zhen Wang,Jichang Guo,Zhiqiong Chen,Zhiqiong Chen,Lisu Yu,Yuhao Wang,Hong Rao 한국통신학회 2022 Journal of communications and networks Vol.24 No.2

This paper considers a novel scenario, where a physicallayer security issue is studied in unmanned aerial vehicles(UAVs)-assisted cognitive relay system. A secondary unmannedaerial vehicle (SUAV) relay delivers information from multiplesecondary Internet of things (IoT) devices to a secondary user(SU) under the spectrum sharing with primary users (PUs). Inthe processing of the information transmission of the SUAV relay,a secondary eavesdropper (SE) wiretaps the information transmittedby the UAV relay with imperfect location information. Inorder to confuse the SE, a friendly SUAV jammer is employedto transmit jamming signals to the SE. To prevent the SEwiretapping information as much as possible, we aim to maximizeaverage worst-case secrecy rate of the secondary relay networkby jointly optimizing robust trajectories and power of the SUAVrelay and jammer under the power, trajectories, informationcausality and multiple interference temperature (IT) thresholdconstraints. Thus, we formulate the original problem whichis a challenging non-convex problem. We propose an effectivealgorithm to solve the original problem and attain locally optimalsolution based on the successive convex approximation (SCA)technology and the alternate optimization method. Simulationsare offered to demonstrate that our proposed resource allocationscheme can effectively improve the security performance ofthe SUAV relay network in comparison with other benchmarkschemes.

Molecular Characterization and Expression Analysis of Ribosomal Protein S6 Gene in the Cashmere Goat (Capra hircus)

Bao, Wenlei,Hao, Xiyan,Zheng, Xu,Liang, Yan,Chen, Yuhao,Wang, Yanfeng,Wang, Zhigang Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.11

Ribosomal protein (rp) S6 is the substrate of ribosomal protein S6K (S6 kinase) and is involved in protein synthesis by mTOR/S6K/S6 signaling pathway. Some S6 cDNA have been cloned in mammals in recent years but has not been identified in the goat. To facilitate such studies, we cloned the cDNA encoding Cashmere goat (Capra hircus) S6 (GenBank accession GU131122) and then detected mRNA expression in seven tissues by real time PCR and protein expression in testis tissue by immunohistochemisty. Sequence analysis indicated that the obtained goat S6 was a 808 bp product, including a 3' untranslated region of 58 bp and an open reading frame of 750 bp which predicted a protein of 249 amino acids. The predicted amino acid sequence was highly homologous to cattle, human, mouse and rat S6. Expression analysis indicated S6 mRNA was expressed extensively in detected tissues and S6 protein was expressed in testis tissue.