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Unequal Forced-Intra-Refresh for robust video streaming

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第10期7卷 1695-1701页

作者： LIU hao ZHANG wen-jun YANG Xiao-kang Institute of lmage Communication and Information Processing Shanghai Jiao Tong University Shanghai 200240 China

For video streaming over lossy channels, intra refresh can mitigate the error-propagation effect caused by packet losses Besides some intra-mode macroblocks （MBs） generated by the ＂Lagrangian rate-distortion＂ or ＂Sum of absolute difference＂ mode decision, the encoder or transcoder possibly needs to increase some ＂forced＂ intra-mode MBs for robust video streaming. Based on the error-propagation analysis in a group of pictures （GOP）, we propose an unequal Forced-Intra-Refresh （FIR） scheme to improve packet loss resilience of video streaming. According to a GOP-level error-propagation model, the proposed unequal FIR scheme can optimally increase the unequal number of forced intra-mode MBs for different frames in a GOP. Simulation results showed that the proposed scheme can effectively enhance the robustness of video streaming under different channel conditions, and achieve about 0. 1-0.9 dB gains over the average FIR scheme in H.264/AVC tools.

关键词： Video streaming Error propagation Intra refresh Packet loss resilience Group of pictures (GOP)

Experiment on Boiling Heat Transfer of Refrigerant R134a in Mini-channels

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Transactions of Nanjing University of Aeronautics and Astronautics 2019年第1期36卷 80-87页

作者： ZHAN Hongbo SHEN hao wen Tao ZHANG Dalin College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics Shanghai Aircraft Airworthiness Certification Center of CAAC

The flow boiling heat transfer characteristics of refrigerant R134 a flowing inside two different kinds of minichannels are investigated. One channel is multi-port extruded with the hydraulic diameter of 0.63 mm,and the other one is rectangular with offset fins and a hydraulic diameter of 1.28 mm. The experiments are performed with a mass flow rate between 68 and 630 kg/(m^2·s),a heat flux between 9 and 64 kW/m^2,and a saturation pressure between 0.24 and 0.63 MPa,under the constant heat flux heating mode. It is found that the effect of mass flow rate on boiling heat transfer is related to heat flux,and that with the increase of heat flux,the effect can only be efficient in higher vapor quality region. The effects of heat flux and saturation pressure on boiling heat transfer are related to a threshold vapor quality,and the value will gradually decrease with the increase of heat flux or saturation pressure. Based on these analyses,a new correlation is proposed to predict the boiling heat transfer coefficient of refrigerant R134 a in the mini-channels under the experimental conditions.

关键词： flow boiling heat transfer two-phase flow refrigerant R134a channels with offset fins multi-portchannel

Analytical libration control law for electrodynamic tether system with current constraint

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Astrodynamics 2024年第2期8卷 237-246页

作者： Shidong Xu Ti Chen hao wen Dongping Jin State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing210016China

This study focuses on stabilizing the libration dynamics of an electrodynamic tether system(EDTS)using generalized torques induced by the Lorentz *** contrast to existing numerical optimization methods,a novel analytical feedback control law is developed to stabilize the in-plane and out-of-plane motions of a tether by modulating the electric current *** saturation constraint on the current is accounted for by adding an auxiliary dynamic system to the *** enhance the robustness of the proposed controller,multiple perturbations of the orbital dynamics,modeling uncertainties,and external disturbances are approximated using a neural network in which the weighting matrix and approximation error are estimated simultaneously,such that these perturbations are well compensated for during the control design of the ***,a dynamically scaled generalized inverse is utilized to address the singular matrix in the control *** closed-loop system is proven to be ultimately bounded based on Lyapunov stability ***,numerical simulations are performed to demonstrate the effectiveness of the proposed analytical control law.

关键词： electrodynamic tether system(EDTS) libration dynamics analytical control current constraint

New method to implement digital down converter in radar system

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Journal of Systems Engineering and Electronics 2005年第4期16卷 775-780页

作者： Ma Zhigang wen Biyang Zhou hao Bai Liyun Radio Propagation Lab Electronics and informations school Wuhan Univ. Wuhan 430079 P. R. China

Digital down converter （DDC） is the main part of the next generation high frequency （HF） radar. In order to realize the single chip integrations of digital receiver hardware in the next generation HF Radar, a new design for DDC by using FPGA is presented. Some important and practical applications are given in this paper, and the result can prove the validity. Because we can adjust the parameters freely according to our need, the DDC system can be adapted to the next generation HF radar system.

关键词： high frequency radar FPGA DDC decimation.

Review of attitude consensus of multiple spacecraft

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Astrodynamics 2022年第4期6卷 329-356页

作者： Ti Chen Jinjun Shan hao wen Shidong Xu State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing210016China Department of Earth and Space Science and Engineering York UniversityToronto M3J 1P3Canada

A group of cooperative agents can finish complicated missions that are difficult for a large *** the past two decades,spacecraft attitude coordination has attracted significant research attention owing to its wide potential *** paper presents a survey of recent research progress on the spacecraft attitude consensus problem,paying particular attention to the papers published in major aerospace,dynamics,automation,and robotics journals since *** consensus concepts for centralized,decentralized,and distributed cases are *** overview summarizes results on system dynamics and consensus algorithms based on frequently used attitude representations,such as Euler angles,modified Rodrigues parameters,unit quaternions,and rotation *** conducted under complicated operating conditions are also *** results on attitude consensus are *** the final section,the main conclusions are drawn and several potential research directions are provided.

关键词： attitude consensus networked spacecraft communication graph multi-agent systems(MAS) attitude synchronization

Model and experiment-based evaluation of seawater-based urine phosphorus recovery (SUPR) process

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FRONTIERS OF ENVIRONMENTAL SCIENCE & ENGINEERING 2024年第11期18卷 141页

作者： Tang, wen-Tao Xiao, Yihang Deng, Yang-Fan Tan, Yunkai Chen, Guang-hao hao, Tianwei Zhuhai UM Sci & Technol Res Inst Zhuhai 519031 Peoples R China Hong Kong Univ Sci & Technol Dept Civil & Environm Engn Hong Kong 999077 Peoples R China Univ Macau Fac Sci & Technol Dept Civil & Environm Engn Taipa 999078 Macao Peoples R China

Leveraging seawater toilet flushing system in Hong Kong, China, a Seawater-based Urine Phosphorus Recovery (SUPR) process that integrates ureolysis and phosphorus (P) recovery was proposed in our earlier work. In this study, a thermodynamic model was applied to evaluate the effects of ureolysis and the seawater-to-urine mixing ratio (S/U ratio) on P precipitation in the SUPR system. The results suggested that effective P recovery was thermodynamically feasible across a wide range of S/U ratios, with elevated pH levels resulting from ureolysis being critical for P precipitation. Furthermore, a SUPR reactor was developed to validate this process. When the hydraulic retention time (HRT) exceeded 3 h and the S/U ratio was lower than 3:1, more than 98% of P could be recovered without urine storage, chemical dosage, or external mixing. Further decrease in the HRT and increase in S/U ratio caused flushing out of fine precipitates, resulting in a relatively low P recovery efficiency. However, this could be advantageous when downstream urine nitrification is implemented, as dilution of urine can alleviate the inhibitory effects of free ammonia and free nitrous acid, as well as overcome the P limitation problem, thus facilitating urine nitrification. Consequently, there is a trade-off between optimizing P recovery and nitrification efficiencies.

关键词： Phosphorus recovery Struvite Urine nitrification Source separation Seawater toilet flushing

Multiple clear-cell sarcomas of small intestine with parotid gland metastasis: A case report

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World Journal of Gastroenterology 2017年第12期23卷 2258-2265页

作者： hao Su wen-Sheng Liu wen-hao Ren Peng Wang Lei Shi Hai-Tao Zhou Department of Colorectal Surgery National Cancer Center/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical College Department of Head and Neck Surgery National Cancer Center/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical College Department of Pathology National Cancer Center/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical College

Clear-cell sarcoma is a rare, malignant soft tissue tumor that displays melanocytic differentiation with a distinct molecular profile. It is rarely localized in the gastrointestinal tract. Herein we reported a case of multiple synchronous clear-cell sarcomas of the gastrointestinal tract with parotid gland metastasis. A 51-year-old male patient presented with a growing painless mass under the right ear. A preoperative positron emission tomography/computed tomography showed multiple intestinal masses and a mass in the right parotid with increased glucose uptake, and he underwent operative treatment with resection of three tumors in the jejunum and ileum and then received a right parotidectomy. Postoperative pathological examination showed that cells in the intestinal tumor were consistent with clear-cell sarcoma of the gastrointestinal tract, and the malignant cells in the parotid gland were similar to the intestinal tumor. Immunohistochemical studies revealed positive expression of HMB-45, Melan-A, and S-100. EWSR1 gene fusion transcripts were undetectable by fluorescence in situ hybridization.

关键词： Clear-cell sarcomas Clear-cell sarcomas of the gastrointestinal tract Parotid gland metastasis Immunohistochemistry

Analysis of the SiO_(x) Film Microstructure on Al Substrate by APC VD Process

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材料热处理学报 2004年第05B期25卷 847-850页

作者： ZHANGJi-liang LIJian WOYin-hua WANGYou-wen GANZheng-hao MaterialScienceandEngineeringDepartment ZhejiangUniversityHangzhouPR.China SchoolofElectricat＆ElectronicEngineeringNanyangTechnotogicalUniiversity Singapore

A new kind of SiOx film on Al substrate,prepared by Ambient Pressure Chemical Vapor Deposition (APCVD) is reported in this paper. It is proposed that the SiOx particles as products of SiH4 and O2 reaction deposited on the heated Al surface, followed by close packing and further growth to form the thin film. The morphology, composition and microstructure of the film are characterized by SEM, XPS, XRD and HRTEM. The results show that the SiO, film comprises a majority of uncrystalline structure with a fraction of dispersed ordered zones and the atomic ratio of Si/O in the film is 1:1.60-1:1.75. The tests show that the film is well-bonded with the substrate.

关键词： SiOx薄膜显微结构 APCVD 铝衬底

Relapsing polychondritis causing breathlessness: Two case reports

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World Journal of Clinical Cases 2022年第23期10卷 8360-8366页

作者： Song-Yu Zhai Yu-hao Zhang Ru-Yan Guo Jie-wen hao Shu-Xin wen Department of Otorhinolaryngology Head and Neck Surgery Xi’an Fourth HospitalXi’an 710004Shaanxi ProvinceChina Department of Otorhinolaryngology Head and Neck Surgery Shanxi Bethune HospitalTaiyuan 030000Shanxi ProvinceChina Department of Otorhinolaryngology Head and Neck Surgery The First People's Hospital of NanyangNanyang 473000Henan ProvinceChina Department of Otorhinolaryngology Head and Neck Surgery The Third Clinical College of Shanxi Medical UniversityTaiyuan 030000Shanxi ProvinceChina

BACKGROUND Relapsing polychondritis is a rare multisystem autoimmune disease that mainly involves systemic cartilage and proteoglycan-rich *** the larynx and trachea are involved,the patient’s condition deteriorates *** relapsing polychondritis becomes more advanced,the airways collapse and treatment is difficult,rendering a poor ***,the diagnosis method,treatment strategy and prognosis of relapsing polychondritis with larynx and trachea involvement need to be elucidated to improve clinicians’awareness of the *** SUMMARY A man and a woman were admitted because of *** polychondritis was diagnosed after a series of accessory *** were both treated with glucocorticoids and immunosuppressants,and underwent tracheotomy as their breathing difficulties could not be relieved by the *** The two cases highlight the importance of the timely diagnosis,full evaluation and initiating individualized treatment of relapsing polychondritis with larynx and trachea ***,bronchoscopy and pathological examination are helpful in diagnosis of this disease.

关键词： Relapsing polychondritis Larynx Trachea Case report