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Recovery of waste rare earth fluorescent powders by two steps acid leaching

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Rare Metals 2013年第6期32卷 609-615页

作者： Shen-Gen Zhang Min Yang Hu Liu De-An Pan Jian-Jun tian Institute of Advanced Materials and Technology School of Materials Science and Engineering University of Science and Technology Beijing

The effects of the acid leaching and alkali fusion on the leaching efficiency of Y,Eu,Ce,and Tb from the waste rare earth fluorescent powders were investigated in this *** results show that hydrochloric acid is better than sulfuric acid in the first acid leaching,and NaOH is better than Na2CO3in the alkali *** the first acid leaching,the Wloss is 20.94%when the waste rare earth fluorescent powders are acid leached in H?concentration 3 mol L-1and S/L ratio 1:3 for 4 h due to red powders *** better results of the alkali fusion can be got at 800℃ for 2 h when the NaOH is *** blue powders and the green powders can be dissolved into NaAlO2and oxides such as rare earth oxide(REO).The REO can be dissolved in H?concentration 5 mol L-1,S/L1:10 for 3 h in the second acid *** leaching rates of the Y,Eu,Ce,and Tb are 99.06%,97.38%,98.22%,and 98.15%,*** leaching rate of the total rare earth is 98.60%.

关键词： Waste rare earth fluorescent powders Two steps acid leaching Alkali fusion

Clinical significance of stanniocalcin expression in tissue and serum of gastric cancer patients

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Chinese Journal of Cancer Research 2014年第5期26卷 602-610页

作者： Zheng Fang Zhiqiang tian Kunlun Luo Haizhu Song Jun Yi Department of General Surgery 101th Hospital of People’s Liberation Army Department of Medical Oncology Jinling HospitalMedical School of Nanjing University Department of Cardiothoracic Surgery Jinling HospitalMedical School of Nanjing University

Purpose： Stanniocalcin（STC） has been recognized as a potential biomarker in a variety of cancers. The aim of this study was to examine STC1 and STC2 expression in tumor and serum samples from gastric cancer（GC） patients.Methods： A total of 83 GC patients treated with radical resection were enrolled in this study. Immunohistochemistry was used to detect STC protein expression in paired tumor and adjacent normal tissues. Serum STC levels were determined by enzyme-linked immunosorbent assay（ELISA）. The receiver operating characteristics（ROC） curve was constructed to describe diagnostic specificity and sensitivity. Results： Both of STC1 and STC2 protein expression were upregulated in GC tissues compared with that in normal ones. Moreover, the high/moderate of STC1 protein was significantly associated with lymph metastasis, clinical stage and adverse 3-year progression-free survival（PFS）. In addition, serum STC1 and STC2 expression in GC patients were much higher than that in patients with benign gastric disease, which decreased at postoperative 7-10 days. The sensitivity of serum STC protein also showed superiority over CEA and CA19-9. Conclusions： STC upregulation plays an important role in GC development, and serum STC1 and STC2 might function as promising tumor markers for GC diagnosis and prognosis.

关键词： Gastric cancer(GC) stanniocalcin(STC) immunohistochemistry diagnosis prognosis

An Estimation of the daily Intake of Di(2-ethlhexyl) Phthalate(DEHP) among Workers in Flavoring Factories

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Biomedical and Environmental Sciences 2014年第6期27卷 419-425页

作者： LU Jie ZHANG Jing WANG Zhu tian FAN Yong Xiang Key Laboratory of Food Safety Risk Assessment Ministry of Health China National Center For Food Safety Risk Assessment Division of Food Safety Standard Ministry of Health China National Center For food Safety Risk Assessment

Objective To estimate the daily intake of DEHP among workers in flavoring factories. Methods 71 workers in two flavoring manufacturers, 27 administrators in those factories and 31 laboratory technicians in a research institute were recruited and assigned to exposure group, control group 1 and control group 2 respectively. Their urinary DEHP metabolites, mono（2-ethylhexyl） phthalate （MEHP）, mono-（2-ethyl-5-hydroxyhexyl） phthalate （MEHHP）, mono-（2-ethyl-5-oxohexyl） phthalate （MEOHP）, were detected by isotope dilution-ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）. The urinary metabolites concentrations were converted into DEHP intake levels using two pharmacokinetic models： the urine creatinine-excretion （UCE） one and the urine volume （UV） one. Results No significant differences were found among the three groups. Based on the urinary concentrations of Z3MEHP, we got a median daily DEHP intake of 3.22 or 1.85 μg/kg body-weight/day applying the UV or UCE models respectively. Depending on the UV model, three subjects （2.34%） exceeded the RfD value given by US EPA and the P50 of estimate daily DEHP intakes accounted for 16.10% of the RfD value. No subjects exceeded the limitation depending on the UCE model. Conclusion The workers in flavoring factories were not supposed to be the high DEHP exposure ones and their exposure level remained at a low risk.

关键词： Di (2-ethylhexyl) phthalate (DEHP) Estimate daily intake Biomonitoring Occupationa exposure

Leakage research on supercritical carbon dioxide fluid in rolling piston expander

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Science China(Technological Sciences) 2012年第6期55卷 1711-1718页

作者： tian Hua MA YiTai LI MinXia LIU ShengChun WANG KaiYang State Key Laboratory of Engine Tianjin UniversityTianjin 300072China Thermal Energy Research Institute Tianjin UniversityTianjin 300072China tianjin Key Laboratory of Refrigeration Technology Tianjin University of CommerceTianjin 300134China

The leakage research on supercritical carbon dioxide fluid in rolling piston expander was investigated *** expander instead of throttle valve is an important way to improve the efficiency of carbon dioxide refrigeration ***,the supercritical fluid leakage in expander is serious and is the main factor affecting the expander's *** paper presented and compared four classic leakage *** analysis indicated that laminar leakage model is suitable in leakage simulation of expander.A leakage test system,including the leakage test part which has two types of leakage specimens with different gaps ranging from 5 to 15 m,was *** experimental results indicated that lubricant film played an important *** the leakage clearance of cylindrical specimen was 5 m,the mass flow rate of leakage was about 0.88 g *** data was 3.638 g s-1 with leakage clearance being 10 m and 7.11g s-1 with leakage clearance being 15 m.A modified leakage model was developed,whose average deviation was within 10% compared with the experimental *** last,this paper simulated the leakage in rolling piston expander presented by tian et al.(2010).The leakage between rolling piston and cylinder was the most serious part with the value up to 0.04 kg s-1.

关键词： leakage supercritical carbon dioxide liquid rolling piston expander leakage model

An Efficient Bar Code Image Recognition Algorithm for Sorting System

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Computers, Materials & Continua 2020年第9期64卷 1885-1895页

作者： Desheng Zheng Ziyong Ran Zhifeng Liu Liang Li Lulu tian School of Computer Science Research Center for Cyber SecuritySouthwest Petroleum UniversityChengdu610500China College of Information and Software Engineering UESTCChengdu611731China Brunel University London UxbridgeMiddlesex UB83PHUK

In the sorting system of the production line,the object movement,fixed angle of view,light intensity and other reasons lead to obscure blurred *** results in bar code recognition rate being low and real time being *** at the above problems,a progressive bar code compressed recognition algorithm is ***,assuming that the source image is not tilted,use the direct recognition method to quickly identify the compressed source *** indicates that the compression ratio is improper or the image is ***,the source image is enhanced to identify the source image ***,the inclination of the compressed image is detected by the barcode region recognition method and the source image is corrected to locate the barcode information in the barcode region recognition *** results of multitype image experiments show that the proposed method is improved by 5+times computational efficiency compared with the former methods,and can recognize fuzzy images better.

关键词： Bar code recognition Hough transformation binarization image processing

DC fault analysis for modular multilevel converter-based system

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Journal of Modern Power Systems and Clean Energy 2017年第2期5卷 275-282页

作者： Bin LI Jiawei HE Jie tian Yadong FENG Yunlong DONG Key Laboratory of Smart Grid of Ministry of Education Tianjin UniversityTianjinChina NR Electric NanjingChina

DC fault protection is the key technique for the development of the DC distribution and transmission system. This paper analyzes the transient characteristics of DC faults in a modular multilevel converter(MMC) based DC system combining with the numerical method. Meanwhile,lots of simulation tests based on MATLAB/Simulink are carried out to verify the correctness of the theoretical analysis. Finally, the technological difficulties of and requirements for the protection and isolation are discussed to provide the theoretical foundation for the design of dc fault protection strategy.

关键词： DC system DC fault analysis DC fault protection Modular multilevel converter

Blunt myocardial injury and gastrointestinal hemorrhage following Heimlich maneuver:A case report and literature review

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World Journal of Emergency Medicine 2022年第3期13卷 248-250页

作者： Chu Wang Zhen-zhou Wang tian-bing Wang Trauma Medicine Center Peking University People's HospitalBeijing 100044China

Dear editor,In 1975,*** Heimlich introduced the Heimlich maneuver[2],which has become the initial treatment for emergency foreign-body airway *** is recommended by American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.[2]During thrusts,airway pressure increases,thereby expelling foreign bodies.

关键词： airway obstruction gastrointestinal

Electrochemical and spectroscopic characteristics of dissolved organic matter in a forest soil profile

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Journal of Environmental Sciences 2013年第10期25卷 2093-2101页

作者： Ran Bi Qin Lu tian Yuan Shungui Zhou Yong Yuan Yanfei Cai Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangdong Institute of Eco-Environmental and Soil Sciences College of Resources and Environment SouthChina Agricultural University

Dissolved organic matter （DOM） represents one of the most mobile and reactive organic compounds in ecosystem and plays an important role in the fate and transport of soil organic pollutants, nutrient cycling and more importantly global climate change. Electrochemical methods were first employed to evaluate DOM redox properties, and spectroscopic approaches were utilized to obtain information concerning its composition and structure. DOM was extracted from a forest soil profile with five horizons. Differential pulse voltammetry indicated that there were more redox-active moieties in the DOM from upper horizons than in that from lower horizons. Cyclic voltammetry further showed that these moieties were reversible in electron transfer. Chronoamperometry was employed to quantify the electron transfer capacity of DOM, including electron acceptor capacity and electron donor capacity, both of which decreased sharply with increasing depth. FT-IR, UV-Vis and fluorescence spectra results suggested that DOM from the upper horizons was enriched with aromatic and humic structures while that from the lower horizons was rich in aliphatic carbon, which supported the findings obtained by electrochemical approaches. Electrochemical approaches combined with spectroscopic methods were applied to evaluate the characteristics of DOM extracted along a forest soil profile. The electrochemical properties of DOM, which can be rapidly and simply obtained, provide insight into the migration and transformation of DOM along a soil profile and will aid in better understanding of the biogeochemical role of DOM in natural environments.

关键词： dissolved organic matter electrochemical characteristics soil profile spectroscopic characteristics

Distributed Robust UAVs Formation Control Based on Semidefinite Programming

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Tsinghua Science and Technology 2024年第5期29卷 1341-1354页

作者： Peiyu Zhang Jianshan Zhou daxin tian Xuting Duan Dezong Zhao Kan Guo School of Transportation Science and Engineering Beihang UniversityBeijing 100191China James Watt School of Engineering University of GlasgowGlasgowG128QQUK

The formation control of unmanned aerial vehicle(UAV)swarms is of significant importance in various fields such as transportation,emergency management,and environmental ***,the complex dynamics,nonlinearity,uncertainty,and interaction among agents make it a challenging *** this paper,we propose a distributed robust control strategy that uses only local information of UAVs to improve the stability and robustness of the formation system in uncertain *** establish a nominal control strategy based on position relations and a semi-definite programming model to obtain control ***,we propose a robust control strategy under the rotation setΩto address the noise and disturbance in the system,ensuring that even when the rotation angles of the UAVs change,they still form a stable ***,we extend the proposed strategy to a quadrotor UAV system with high-order kinematic models and conduct simulation experiments to validate its effectiveness in resisting uncertain disturbances and achieving formation control.

关键词： multi-unmanned aerial vehicle(UAV)systems formation control uncertain perturbation robust distributed control