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AEROSOL SIZE DISTRIBUTION AND ELEMENTAL COMPOSITION IN URBAN AREAS OF NORTHERN CHINA
ZHONG, LIANG-XI,CHUNG,YONG-SEUNG,NING,DA-TONG 한국교원대학교 환경과학연구소 1996 환경연구논문집 Vol.- No.3
Based on monitoring data collected in the northern cities of China since 1980, the particle size spectra, distribution modes and the elements distribution features are dicussed in this article. It is found that the major aerial contaminant in urban aerosol of northern China is fine dust. It makes up about 70% of the total suspended particulate matter by mass concentration. The spectra of aerosol particles in the range 0.5-15.0㎛ are all unimodal structures. Regardless of narrow or broad profiles, their peak values fall between 0.5 and 1.0㎛, while their surface area spectra present a trimodal structure. The three peaks are in the range 0.5-1.8, 2-8 and 10.20 ㎛, respectively. Of these peaks the surface area concentration of particulates had made a large contribution to the first and the second peaks. The shape of mass distribution also presents a trimodal structure, and the positions of the three peaks are the same as those found in the surface area pattern. Mineral elements mainly exist in large size particles. The anthropogenic pollution elements, however, are contained in corpuscles (<2.0㎛). Compared to the situation in winter, some element concentrations of particulates in summer are found to have generally decreased. Copyright ⓒ 1996 Elsevier Science Ltd.
Zhong, Zhi-Rong,Zhang, Zhi-Rong,Liu, Ji,Deng, Yong,Zhang, Hong-Wei,Fu, Yao,Song, Qing-Guo,He, Qin 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.1
A novel non-viral gene delivery system, Procationic-Liposome-Protamine-DNA complexes (PLPD) which could further adsorb transferrin on the surface as a targeting ligand to form Tf-PLPD, was prepared and characterized before and after lyophilization. The size distribution of Tf-PLPD was in the range of $240{\pm}12nm$ and the zeta potential was $-24.10{\pm}2.5mV$. The transfection efficiencies of PLPD and Tf-PLPD were $12.18{\pm}3.8\;and\;24.26{\pm}2.6mU\;{\beta}-galactosidase/mg$ protein respectively. The lyophilization and the presence of serum didn't affect the tansfectivities of PLPD or Tf-PLPD. Compared to $Lipofectamine^{TM}$ 2000 (Invitrogen, U.S.A.), the procationic liposomes had less cytotoxicity to cells. In summary the procationic lipoplex described here, combining the condensing effect of protamine and the targeting capability of Tf, was a perspective non-viral vector for gene delivery system.
Predicting connection integrity with consideration of thermo stress
Yong Qin Cheng,Shuo Qiong Liu,Feng Zhong Qi,Hui Ting Liu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.8
In the conventional gas seal analysis of special threaded joints, the influence of temperature stress caused by the difference between formation temperature and fluid temperature in casing is often neglected. However, the influence mechanism of temperature stress is prerequisite information for accurately predicting the safe operating conditions that prevent a premium connection from being damaged. In this paper, we propose a model that includes these effects to predict the safe operating pressures and temperatures that will prevent seal failure. For the temperature stress, we propose a finite element model of thermal solid coupling. Subsequent stress changes are evaluated by a fully coupled model of thermal solid coupling to analyze the mechanical behavior of the premium connection. We predict the safe operating envelope (SOE) for premium connection failures caused by pressure and temperature perturbations after make-up. Our model predicts that radial pressure is a key factor for connection failure, especially for rapid temperature changes. If the formation temperature is high and the casing fluid temperature is low, the influence of temperature stress will increase under this working condition, resulting in an increase in the probability of failure of premium connections. Compared with conventional premium connection models, the model of thermal solid coupling predicts a smaller SOE when heating the internal casing fluid and a larger envelope when cooling the internal casing fluid. Finally, the heating rate was considered with respect to field applications. The heating rate was also considered, and slower heating/cooling rates can prevent damage to the seal integrity. Finally, the model was applied to explain several laboratory and field experiments and achieved good matches.
Inertia Parameter Selection Method for HVDC Converter Station Based on VSG Control
Yong Shi,Ce Fang,Lei Chen,Meiqing Mao,Zhong Chen 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.2
With the purpose of improving the frequency support capability of high voltage direct current (HVDC) transmission equipment and ensuring the stable and reliable operation for the receiving end power grid, a virtual synchronous generator (VSG) control algorithm for high voltage direct current converter was proposed in this paper. The virtual synchronous generator control method is analyzed in detail, and the small-signal model of grid-tied high voltage direct current converter is established, and further established the small signal-model of the three-area power system. On the basis of the proposed models, considering the factors such as diff erent short circuit ratios, decoupling performance, stability, dynamics, the selection principle of inertia factor J and damping factor D of virtual synchronous generator is proposed. Finally, the eff ectiveness of the proposed inertia and damping coeffi cient selection method is verifi ed by simulation.
Zhong Zaimin,Shao Zhongshu,Bao Yong 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.6
The real-time simulation platform of constant d–q axis inductance parameter permanent magnet synchronous motor model only considers the fundamental wave of magnetic fi eld and it cannot accurately describe the spatial harmonic characteristics of the motor. Thus, this platform is not applicable in the developing and testing of control algorithms suppressing torque ripple and harmonic current. Aiming at this problem, a hardware-in-the-loop platform is built using an analytical motor model called “distributed parameter model” based on magnetic co-energy reconstruction. This model describes the variation of magnetic co-energy, fl ux linkage, voltage and torque with reference to rotor spatial position. So, it can accurately refl ect the nonlinear characteristics including saturation, slotting eff ects and non-sinusoidal back-EMF. The model is numerically discretized and compiled by Verilog hardware language in FPGA, then tested with closed-loop FOC control algorithm. The real-time simulation can verify the control algorithm with real controller and the simulation step of the motor model is 1 μs. Compared with the bench test results of the actual motor, the spatial harmonic characteristics of the motor in the real-time simulation platform are verifi ed.
( Zhong Wen Chen ),( Yin Bing Zhang ),( Xaing Jun Chen ),( Xiao Liu ),( Zhen Wang ),( Xi Kun Zhou ),( Ji Qiu ),( Nan Nan Zhang ),( Xiu Teng ),( Yong Qiu Mao ),( Chang Yong Liu ),( Yu Quan Wei ),( Jion 대한피부과학회 2015 Annals of Dermatology Vol.27 No.3
Background: Psoriasis is an autoimmune disease that is caused by a shift in the Th1/Th2 balance toward Th1- dominant immunity. It has been established as an effective treatment to counteract psoriasis by subcutaneous injection of recombinant interleukin (IL)-4, and IL-4 gene therapy by topical transdermal penetration has shown its antipsoriatic effect in mice. Retinoic acid (RA) and dimethylsulfoxide can increase the efficiency of gene transfection in the topical transdermal delivery system. Objective: We investigated whether RA could improve anti-psoriasis efficiency using IL-4 expression plasmid pORF-mIL-4 (pIL-4) via transdermal delivery system in K14-vascular endothelial growth (K14- VEGF) factor transgenic mice. Methods: After pretreatment with RA, plasmid pIL-4 in 10% dimethylsulfoxide was applied to the ear skin by topical transdermal penetration. Hematoxylin- eosin staining and immunohistochemistry were performed with ear samples to evaluate anti-psoriasis efficiency in mice. Results: The psoriasis pathological features were relieved and psoriasis-associated factors were significantly reduced. Conclusion: Our results reveal that topical application of pIL-4 in dimethylsulfoxide by transdermal delivery with RA pretreatment can improve psoriasis significantly. (Ann Dermatol 27(2) 121∼127, 2015)
( Zhong Wen Chen ),( Yin Bing Zhang ),( Xaing Jun Chen ),( Xiao Liu ),( Zhen Wang ),( Xi Kun Zhou ),( Ji Qiu ),( Nan Nan Zhang ),( Xiu Teng ),( Yong Qiu Mao ),( Chang Yong Liu ),( Yu Quan Wei ),( Jion 대한피부과학회 2015 Annals of Dermatology Vol.27 No.2
Background: Psoriasis is an autoimmune disease that is caused by a shift in the Th1/Th2 balance toward Th1- dominant immunity. It has been established as an effective treatment to counteract psoriasis by subcutaneous injection of recombinant interleukin (IL)-4, and IL-4 gene therapy by topical transdermal penetration has shown its antipsoriatic effect in mice. Retinoic acid (RA) and dimethylsulfoxide can increase the efficiency of gene transfection in the topical transdermal delivery system. Objective: We investigated whether RA could improve anti-psoriasis efficiency using IL-4 expression plasmid pORF-mIL-4 (pIL-4) via transdermal delivery system in K14-vascular endothelial growth (K14- VEGF) factor transgenic mice. Methods: After pretreatment with RA, plasmid pIL-4 in 10% dimethylsulfoxide was applied to the ear skin by topical transdermal penetration. Hematoxylin- eosin staining and immunohistochemistry were performed with ear samples to evaluate anti-psoriasis efficiency in mice. Results: The psoriasis pathological features were relieved and psoriasis-associated factors were significantly reduced. Conclusion: Our results reveal that topical application of pIL-4 in dimethylsulfoxide by transdermal delivery with RA pretreatment can improve psoriasis significantly.(Ann Dermatol 27(2) 121∼127, 2015)
The Use of Molecular Markers to Certify Clubroot Resistant Cultivars of Chinese Cabbage
Zhong Yun Piao,Su Ryun Choi,Young Mi Lee,Hong Gi Kim,Yong Pyo Lim 한국원예학회 2007 Horticulture, Environment, and Biotechnology Vol.48 No.3
Chinese cabbage cultivated in most area of Korea is subjected to the most serious clubroot disease caused by Plasmodiophora brassicae Wor. A number of clubroot resistant (CR) cultivars were released or in development. We have previously tagged CR locus (CRb) within 3 cM flanked by two co-dominant markers (TCR01 and TCR05) and one dominant marker (TCR09). Thirty-seven CR cultivars and ten non-CR cultivars were collected to study the utility of these DNA markers. In addition, markers (BRMS096, BRMS088, and OPC11-2S) linked to Crr1, Crr2, and Crr3, respectively, were evaluated. Of the surveyed CR cultivars, 18 carried marker fragment TCR01₂?? and TCR05₂?? linked to CRb in coupling. Evaluation of these cultivars to race 4 of clubroot revealed that all of them conferred resistance. Other CR cultivars absent of TCR01₂?? and TCR05₂?? were either resistant or susceptible. Only OPC11-2S linked to Crr3 can explain the two CR cultivars showing susceptible, while others cannot. Analysis of European Clubroot Differential set 01 to 04 indicate that marker fragment TCR05₂?? with the CRb locus, possibly also TCR01₂??, was introgressed from CR turnip into partial CR cultivars of Chinese cabbage. The usefulness of these markers in marker-assisted selection was also discussed.