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Contamination of Prohibited Substances in various Food Products in Guangzhou, China

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Biomedical and Environmental Sciences 2020年第1期33卷 68-71页

作者： MHUNGU Florence HU Ke Qi ZHANG Wei Wei ZHOU Zhi Feng SHI Ming LIU Yun Gang School of Public Health Southern Medical UniversityGuangzhou 510515GuangdongChina Guangzhou Centre for Disease Control and Prevention Guangzhou 510440GuangdongChina Department of Environmental and Occupational Health School of Public HealthGuangdong Medical UniversityDongguan 523808GuangdongChina

The use of antibiotics to maintain animal health has widely been practiced,for both therapeutic and prophylactic purposes.Along with the identification of serious adverse effects of some antibiotics on human and domes... 详细信息

关键词： Contamination of Prohibited Substances various Food Products Guangzhou China

Exact quantum mechanical vibration-rotation kinetic energy operator of four-particle system in various coordinates

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Science China Chemistry 1996年第6期39卷 627-637页

作者：陈光巨刘若庄 Department of Chemistry Beijing Normal University Beijing 100875 China

The vibration-rotational kinetic energy operators of four-particle system in various coordinates are derived using a new and simple angular momentum method. The operators are respectively suitable for studying the systems described by scattering coordinate, valence coordinate, Radau coordinate, Radau/Jacobi and Jacobi/valence hybrid coordinates and so on. Certain properties of these operators and their possible applications are discussed.

关键词： vibration rotation kinetic energy operator four-particle system various coordinates.

Electron Cloud in various Kinds of Magnetic Field of BEPCⅡ

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Chinese Physics Letters 2006年第2期23卷 336-339页

作者：刘瑜冬国智元秦庆王九庆 Institute of High Energy Physics Chinese Academy of Sciences PO Box 918 Beijing 100049

Electron cloud instability （ECI） may take place in a positron storage ring when the machine is operated with a multl-bunch positron beam. According to the actual shape of the vacuum chamber in the BEPCII, a programme which is different from the other simulation codes has been developed. Because of the distance between dipole magnet and sextupole, the quadrupote magnet of BEPCII is very short, much of the photoelectrons can be produced and can move in magnetic fields. The motion of electrons in various kinds of magnetic fields is studied in detail, especially for the solenoid field which will be wound in the vacuum pipe of BEPCII. Simulation shows that the solenoid field is very effective to confine the electrons to the vicinity of the vacuum chamber wall and to make an electron free region at the vacuum pipe centre.

关键词： Magnetic BEPCII various ECI

Performance Analysis of a Multistage Centrifugal Pump Used in an Organic Rankine Cycle(ORC) System under various Condensation Conditions

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Journal of Thermal Science 2019年第4期28卷 621-634页

作者： YANG Yuxin ZHANG Hongguang TIAN Guohong XU Yonghong WANG Chongyao GAO Jianbing College of Environmental and Energy Engineering MOE (Ministry of Education) Key Laboratory of Enhanced Heat Transfer and Energy ConservationBeijing Key Laboratory of Heat Transfer and Energy ConversionBeijing University of TechnologyBeijing 100124China Collaborative Innovation Center of Electric Vehicles in Beijing Beijing 100124China Department of Mechanical Engineering Sciences University of SurreyGuildford GUI 2LJUK School of Electrical and Mechanical Engineering Beijing Information Science and Technology UniversityBeijing 100192China

In an organic Rankine cycle(ORC)system,the working fluid pump plays an important role in the system performance.This paper focused on the operating characteristics of a multistage centrifugal pump at various speeds and condensation conditions.The experimental investigation was carried out to assess the influence of the performance of the pump by the ORC system with special attention to actual net power output,thermal efficiency as well as back work ratio(BWR).The results showed that an increase in the pump speed led to an increase in the mass flow rate and expand in the operating range of the outlet pressure.The mass flow rate decreased nonlinearly with the increase of the outlet pressure from 0.22 to 2.41 MPa;the electric power consumption changed between 151.54 and 2409.34 W and the mechanical efficiency of the pump changed from 7.90%to 61.88%when the pump speed varied from 1160 to 2900 r/min.Furthermore,at lower pump specific speed the ORC system achieved higher thermal efficiency,which suggested that an ultra-low specific speed pump was a promising candidate for an ORC system.The results also suggested that the effects of condensation conditions on the pump performance decreased with the pump speed increasing and BWR was relatively sensitive to the condensation conditions,especially at low pump speed.

关键词： waste heat recovery organic Rankine cycle multistage centrifugal pump operating characteristics various condensation conditions back work ratio(BWR)

Effects of various donor:acceptor blend ratios on photophysical properties in non-fullerene organic bulk heterojunctions

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Chinese Chemical Letters 2019年第5期30卷 995-999页

作者： Zhenchuan Wen Xuejian Ma Xiaoyu Yang Pengqing Bi Mengsi Niu Kangning Zhang Lin Feng Xiaotao Hao School of Physics State Key Laboratory of Crystal MaterialsShandong UniversityJi'nan 250100China ARC Centre of Excellence in Exciton Science School of ChemistryThe University of MelbourneParkvilleVictoria3010Australia

The composition ratio of donor and acceptor materials in organic bulk heterojunction (BHJ) is one of the key parameters to govern the performance in organic solar cells (OSCs). Therefore, high-performance non-fullerene organic bulk heterojunction consisting of poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b' ]dithiophene))-co-(1,3-di(5-thiophene-2-yl)–5,7-bis(2-ethylhexyl) benzo[1,2-c:4,5-c']dithiophene-4,8-dione)] (PBDB-T) and 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))–5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2' ,3'-d' ]-s-indaceno[1,2-b:5,6-b' ]-dithio-phene (ITIC) are used to investigate the correlation among various donor: acceptor (D:A) ratios, photophysical properties and photovoltaic performance. Interestingly, the function of short-circuit current (Jsc) and D:A ratios demonstrates an axisymmetric trend. When the blending ratio of D:A deviates from the optimal ratio, the symmetrically decreased Jsc is derived from a reduction in the D:A interface or amorphous region. Research on the steady-state photoluminescence (PL), the time-resolved fluorescence spectroscopy measurements, atomic force microscopic (AFM) and grazing-incidence small angle X-rays scattering (GIWAXS) indicates no significant variation in energy loss in the process of changing D:A ratios in BHJs. With high donor or acceptor content, the domain size improves significantly, but the distance of π-π stacking corresponding to molecular packing has not changed significantly, and the bi-continuous percolation pathways were not obviously influenced.

关键词： Photophysical properties Non-fullerene Bulk heterojunctions various blend ratios Organic solar cells

Study　on　the　Singlet　and　Triplet　StateElectron　Transfer　between　Hypocrellin　A　and　Aromatic　Amines　in　Solvents　of　various　Polarity

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Chinese Chemical Letters 1996年第10期7卷 924-927页

作者： Min WENG ManHua ZHANG Tao SHEN(Institute of Photographic Chemistry, Academia Sinica, P.O.Box 772,Beijing 100101) Institute of Photographic Chemistry Academia Sinica P.O.Box 772 Beijing 100101

In this paper, the singlet and triplet state electron transfer processes between hypocrellin A(HA) and aromatic amines in solvents of various polarity have been studied by fluorescence and time-resolved transient absorption spectra. The results show,in.polar solvent, the quenching of HA fluorescence by aromatic amines results in Stern-Volmer plot, the investigation of transient absorption indicated that triplet-state electron transfer process from 3HA to the ground-state of amines occured, and the wines of the singlet and triplet state electron transfer rate constant were calculated, however in weak polar solvent, only the triplet-triplet absorption of HA was observed.

关键词： StateElectron Transfer Triplet Solvents various Hypocrellin

Study of total phenol,flavonoids contents and phytochemical screening of various leaves crude extracts of locally grown Thymus vulgaris

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Asian Pacific Journal of Tropical Biomedicine 2013年第9期3卷 705-710页

作者： Mohammad Amzad Hossain Khulood Ahmed Salim AL-Raqmi Zawan Hamood AL-Mijizy Afaf Mohammed Weli Qasim Al-Riyami School of Pharmacy College of Pharmacy and NursingUniversity of Nizwa

Objective:To prepare various crude extracts using different polarities of solvent and to quantitatively evaluate their total phenol,flavonoids contents and phytochemical screening of Thymus vulgaris collected from Al Jabal Al Akhdar,Nizwa.Sultanate of Oman.Methods:The leave sample was extracted with methanol and evaporated.Then it was defatted with water and extracted with different polarities organic solvents with increasing polarities.The prepare hexane,chloroform,ethyl acetate,hutanol and methanol crude extracts were used for their evaluation of total phenol,flavonoids contents and phytochemical screening study.The established conventional metliods were used for quantitative determination of total phenol,flavonoids contents and phytochemical screening.Results:Phytochemical screening for various crude extracts were tested and shown positive result for flavonoids,saponins and steroids compounds.The result for total phenol content was the highest in hutanol and the lowest in methanol crude extract whereas the total flavonoids contents was the highest in methanol and the lowest hexane crude extract.Conclusions:The crude extracts from locally grown Thymus vulgaris showed high concentration of flavonoids and it could be used as antibiotics for different curable and uncurable diseases.

关键词： Thymus vulgaris L., various crude extracts Phytochemical screening Soxhlet extractor Total phenol Flavonoids contents.

Extraction of various Sulfurs in Coal and Sedimentary Rock and Preparation of Samples for Sulfur Isotopic Analysis

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Chinese Science Bulletin 1994年第2期39卷 140-145页

作者：储雪蕾赵瑞臧文秀雷加锦唐跃刚 Institute of Geology Academia Simca Beijing 100029 PRC Beijing Graduate School China University of Mining and Technology Beijing 100083 PRC

Studies of sulfur isotopes of coal or sedimentary rock may not only providesources of sulfur, but also provide some information about sedimentary environment,coalification and diagenesis. Many samples of coal and organic-rich sediments, suchas black shale, contain a considerable content of sulfur that exists in several forms,such as pyrite, monosulfides, sulfates and organic sulfurs. For the various sulfurs,their isotopic compositions can be different in a single sample, for example, theisotopic ratios varied by as many as 30‰ in a sample of coal. To

关键词： coal and sedimentary rock separation and extraction of various sulfurs preparation of isotopic samples.

Malaysia Promotes various Convenient Measures to Attract More Chinese Tourists——Interview with Zalizam Zakaria, Tourism Minister of Malaysia Embassy

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China's Foreign Trade 2019年第3期 17-19页

作者： Guo Yan 不详

Malaysia has many worldclass tourist spots,like Kuala Lumpur,Malacca,Pulau Langkawi and Sabah.Malaysia’s musang king is the top delicious’food for world gourmets.According to the recent data released by Malaysia’s Ministry of Tourism,China ranked the third in terms of number of tourists visiting Malaysia in 2018,with about 2.94 million tourists in all.This year marks the 45th anniversary of the establishment of diplomatic relations between China and Malaysia.

关键词： Interview with Zalizam Zakaria Malaysia Promotes various Convenient Measures to Attract More Chinese Tourists Tourism Minister of Malaysia Embassy