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Improved analytical performance estimation and preliminary design of 50 W-class RF Ion Engine
Pham Tran Dang Quang,Jichul Shin(신지철) 한국추진공학회 2018 한국추진공학회 학술대회논문집 Vol.2018 No.5
A 0-D analytical model of the plasma discharge was previously developed without magnetic ring-cusp ion engine based on energy and particles balance equations for predicting RIT thruster discharge chamber performance and thruster efficiency improvement which are affected by the design process including geometry of the discharge chamber, Ion optic, RF coil and Gas inlet. The improved analytical model plays a critical role in estimating performance of UOU-RF Ion Thruster. The present model is expanded by covering the secondary electron emission from the wall and the screen grid, double ionization xenon, Clausing factor and ion confinement factor produced by the induced electromagnetic field. In sum, several factors lead to a better calculation results that are verified by experiment data. By doing so, UOU-RF Ion Thruster is expected to produce a thrust and Isp of about 5 mN and 2600s at 2 sccm and 50 w of power loss.
Pham, Duong Quang,Ba, Duong Thi,Dao, Nga Thu,Choi, Gyung Ja,Vu, Thuy Thu,Kim, Jin-Cheol,Giang, Thi Phuong Ly,Vu, Hoang Dinh,Le Dang, Quang Elsevier 2017 INDUSTRIAL CROPS AND PRODUCTS Vol.108 No.-
<P><B>Abstract</B></P> <P>The antimicrobial efficacies of extracts and constituents fractionated from <I>Rheum tanguticum</I> rhizomes were evaluated by using <I>in vitro</I> and <I>in vivo</I> bioassay against seven phytopathogenic fungi and ten pathogenic bacteria, respectively. Dichloromethane and ethyl acetate soluble extracts derived from <I>R. tanguticum</I> rhizomes effectively controlled plant diseases caused by five fungi <I>Magnaporthe oryzae</I>, <I>Blumeria graminis</I> f. sp<I>. hordei, Colletotrichum coccodes, Phytophthora infestans,</I> and <I>Puccinia recondita</I> in <I>in vivo</I> whole plant bioassay. In addition, these extracts showed strong inhibitory activity against the bacterial growth of <I>Acidovorax avenae</I> subsp. <I>cattlyae</I> (Aac), <I>Clavibacter michiganensis</I> subsp. <I>michiganensis</I>, <I>Xanthomonas arboricola</I> pv. <I>pruni</I> (Xap), and <I>Pseudomonas syringae</I> pv. <I>actinidiae</I> (Psa), with MIC values ranging from 125 to 250μg/mL. The active extracts of <I>R. tanguticum</I> rhizomes were fractionated by using various and repeated chromatographic techniques to yield seven constituents that included three anthraquinones and four stilbenes. Notably, at concentrations ranging from 75 to 300μg/mL, physcion (<B>DH03</B>) and chrysophanol (<B>DH04</B>) were significantly effective in suppressing the development of barley powdery mildew (BPM) caused by <I>B. graminis</I> f. sp. <I>hordei,</I> with control values from 80 to 96.7%. Moreover, stilbenes rhapontigenin (<B>DH02</B>) and desoxyrhapontigenin (<B>DH05</B>) had a broad spectrum and potent activity against phytopathogenic bacteria; <B>DH05</B> effectively inhibited the bacterial growth of Aac, <I>Burkholderia glumae</I> and Psa at MICs ranging from 38 to 150μg/mL. In this paper, we report their antibacterial activity for the first time. The botanical materials containing anthraquinones and stilbenes were active against both phytopathogenic fungi and bacteria. These results suggested that <I>R. tanguticum</I> rhizomes could be used as a new source of antimicrobial substances for developing a botanical fungicide and bactericide to control plant diseases.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>R. tanguticum</I> extracts exhibited activity against phytopathogenic fungi and bacteria. </LI> <LI> Seven anthraquinones and stilbenes from <I>R. tanguticum</I> were isolated and identified. </LI> <LI> <I>In vivo</I> antifungal activity of botanicals was evaluated by the whole plant bioassay. </LI> <LI> The isolated stilbenes effectively inhibited the growth of phytopathogenic bacteria. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Quang Vang DANG(Quang Vang DANG ),Viet Thanh Truc TRAN(Viet Thanh Truc TRAN ),Hieu PHAM(Hieu PHAM ),Van Nam MAI(Van Nam MAI ),Quoc Duy VUONG(Quoc Duy VUONG ) 한국유통과학회 2023 The Journal of Asian Finance, Economics and Busine Vol.10 No.2
This paper investigates the determinants of credit accessibility and the effect of credit on the income of farm households borrowing from Vietnam Bank for Agriculture and Rural Development, Giong Rieng District Branch, Kien Giang Province. Based on the primary data of 200 farming households who are the customer of the bank, the study applied the Probit regression model to examine determinant factors of credit accessibility of farm households and employed the Propensity score matching method to investigate the impact of credit on households’ income. The findings of the Probit regression shown that three independent variables that significantly influence the access to credit of households are household size, income source, and farm size. Besides that, the Propensity score matching method results showed a difference of 23.799 million VND/year between the income of borrowing households and that of non-borrowing households at the significance level of 1%. The difference in the imcome from the interval and central matching methods are VND 24.700 million VND/year and VND 24.633 million VND/year, respectively. Given empirical findings suggetsted that several recommendations to increase the credit accessibility of farm households, thereby creating favorable conditions for improving their income.
Dang, Ngoc-Loi,Pham, Quang-Quang,Kim, Jeong-Tae Techno-Press 2022 Structural monitoring and maintenance Vol.9 No.2
In this study, parametric analyses on a hoop-type PZT (lead-zirconate-titanate) interface are performed to estimate the effects of the PZT interface's materials and geometries on sensitivities of impedance responses under strand breakage. The paper provides a guideline for installing the PZT interface suitable in tendon anchorages for damage-sensitive impedance signatures. Firstly, the concept of the PZT interface-based impedance monitoring technique in prestressed tendon anchorage is briefly described. A FE (finite element) analysis is conducted on a multi-strands anchorage equipped with a hoop-type PZT interface for analyzing materials and geometric effects. Various material properties, geometric sizes of the interface, and PZT sensor are simulated under two states of prestressing force for acquiring impedance responses. Changes in impedance signals are statistically quantified to analyze the effect of these factors on damage-sensitive impedance monitoring in the tendon anchorage. Finally, experimental analyses are performed to demonstrate the effects of materials and geometrical properties of the PZT interface on damage-sensitive impedance monitoring.
EQCM studies of the effect of sulfamic acid on the formation Cu-Se compounds
Dang Thi Bich Hop,Pham Hong Quang,Duc H. Tran,Do Thi Kim Anh,Do Phuc Quan,Ngo Dinh Sang,W. B. K. Putri 한양대학교 세라믹연구소 2015 Journal of Ceramic Processing Research Vol.16 No.1
A combination of Cyclic Voltammetry (CV) and Electrochemical Quartz Crystal Microbalance (EQCM) has been used to study the effect of sulfamic acid as a complexing agent on the formation of Cu-Se compounds. The values of the equivalent atomic mass (M/z) grown at the gold EQCM sensor during electrodeposition at varying potentials and constant potentials were analyzed to understand the mechanism of the growing process. It was found that sulfamic acid does not affect so much the deposition of Cu in the absence of Se. However, when Cu and Se are present simultaneously, sulfamic acid causes and facilitates the formation of Cu-Se compounds. Furthermore, at a high concentration, sulfamic acid causes a mass-loss process, leading to a change of composition. A suitable concentration of sulfamic acid can be concerned from these studies.
( Minh Hai Pham ),( Quan Anh Tuan Le ),( Hoang Bac Nguyen ),( Quang Hung Vu ),( Thai Ngoc Huy Tran ),( Hang Dang Khoa N Guyen ),( Thi Ngoc Sang Duong ),( Van Toan Tran ) 대한간학회 2020 춘·추계 학술대회 (KASL) Vol.2020 No.1
Aims: Laparoscopic pancreaticoduodenectomy (LPD) is considered as a safe and effective procedure in well - selected patients and appropriate surgical technique. Our aim is to evaluate suitability of using protocol for LPD in treatment of periampullary cancer at a single team. Methods: case series Results: Indication for LPD included 37 cases with resectable tumors which were classified basing on NCCN. All witness evaluation risk of complications with PREPARE score, ASA and evaluation risk of postoperative pancreatic fistula (POPF) with FRS classification. There were 2 open conversions because of vein resections, accounting for 5.4%. Standard lymphadenectomy was performed in all of 37 cases. In term of PREPARE score, major complications (Clavien - Dindo >= III) were 17.8%, 0% and 0% (5/28, 0/5 and 0/2 cases) in low risk, intermediate risk and high risk group, respectively. All of cases had ASA I or II. POPF happened 11.1% (1/9), 4.1% (1/24) and 50% (1/2) in low risk, intermediate risk and high risk group, respectively. Frozen section was needed for R0 margin. Retrieved lymph nodes was 8 - 18 with 12 lymph nodes in average. Conclusions: Indication for LPD with resectable tumors is acceptable. ASA I or II is a safe measure to select patient for LPD. FRS classification shows appropriation to evaluate risk of POPF.