Relaxor characteristics of PSLZT-BMT-based ferroelectric material ceramics

Nguyen Van Thinh,Le Dai Vuong,Do Viet On,Truong Van Chuong,Le Vu Truong Son,Trinh Ngoc Dat,Le Van Thanh Son,Vo Thanh Tung 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.3

(1-x)[(Pb0.94Sr0.05La0.01)(Zr0.54Ti0.46)0.9975O3]-x[Bi(Mn1/2Ti1/2)O3] (PSLZT-BMT) ferroelectric material ceramics with x in therange of 0-0.05 mol were successfully synthesized following the conventional solid-phase route. The materials were thoroughlyinvestigated to study their structural phase, microstructure, ferro-piezoelectric characteristics, and dielectric behavior. Theexperimental results show that the density of the samples decreased from 7.75 to 7.58 g/cm3, and the relative density decreasedin the range of 98.48%-96.28%. However, with increasing contents of BMT, the dielectric and ferroelectric properties ofPSLZT-BMT ceramics tend to decrease, specifically the maximum dielectric constant (εmax) of PSLZT-BMT decreased in therange of 23579-9991 and the residual polarization (Pr) decreases in the range of 22.54-7.87 μC/cm2 when the doping contentincreased in the range of 0.0-0.05 mol. The diffusivity values (γ) of the PSLZT-BMT material are 1.74, 1.78, 1.82, 1.84, 1.79,and 1.77 when the doping content x varies as 0.0, 0.01, 0.02, 0.03, 0.04, and 0.05 mol, respectively, which is characteristic ofrelaxor ferroelectric materials. Besides, the Tm, TB, TC-W, and C values depend on BMT concentration, and the trend decreases.

Antioxidant C-glycosylflavones of Drymaria cordata (Linn.) Willd

Raymond N. Nono,Laurence K. Nzowa,Beaudelaire K. Ponou,Re´my B. Teponno,Te´lesphore B. Nguelefack,Luciano Barboni,Le´on A. Tapondjou,박희준 대한약학회 2016 Archives of Pharmacal Research Vol.39 No.1

A new C-glycosylflavone, drymaritin E (6-C- (3-keto-b-digitoxopyranosyl)-40-O-(b-D-glucopyranosyl)- 7-methoxyl-5,40-dihydroxylflavone) 1 was isolated from the oily upper phase (SU) of the MeOH extract from aerial parts of Drymaria cordata together with two known compounds (cassiaoccidentalin A 2 and anemonin 3) and an inseparable mixture of two known C-glycosylflavones 5,40- dihydroxy-7-methoxyflavone-6-C-(200-O-a-L-rhamnopyranosyl)- b-D-glucopyranoside 4a and 5,7,30,40-tetrahydroxyflavone- 6-C-(200-O-a-L-rhamnopyranosyl)-b-D-glucopyranoside 4b. The alkaline hydrolysis of 3 led to a new hemisynthetic derivative, sodium anemonate (sodium 2-((1’E) 20-sodium-carboxylate-vinyl)-5-oxo-cyclohex- 1-ene carboxylate) 3a. The chemical structures were determined by spectroscopic methods (1H NMR, 13C NMR, 1H-1H COSY, HMBC, HSQC, and NOESY) and mass spectrometry (ESI–MS). C-glycosylflavones had significant free radical-scavenging activities on the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). However, SU and compounds 3 and 3a exhibited no activity. In particular, compound 1 exhibited a concentration-dependent radical scavenging activity on DPPH with EC50 of 31.43 lg/mL.

터널형 방음벽의 소음저감 효과 연구 : 설계방향

김태민 ( Tae-min Kim ),김정태 ( Jeung-tae Kim ),박광현 ( Gwang-hyun Park ),손정곤 ( Jung-gon Son ),류래언 ( Le-on Ryu ),고효인 ( Hyo-in Koh ) 한국환경기술학회 2015 한국환경기술학회지 Vol.16 No.2

철도 차량의 주행 소음은 철도 변 인근 지역에 소음피해를 발생시킨다. 발생된 철도 소음 전파를 저감시키기 위해 직접음 차단의 방안으로 방음시설이 설치되고 있다. 터널형 방음벽은 방음시설의 일종으로 벽면과 지붕까지 방음재료로 구성되어 있기 때문에 상부로 전파되는 직접음을 차단할 수 있어 고층에서의 소음 저감 효과가 우수하다. 하지만, 터널형 방음벽을 철도교량 위에 설치하기 위해서는 구조적 안정성이 고려되어야 하며, 필요시 보강 작업이 요구 된다. 또한, 풍하중, 유지보수 문제도 고려되어야 한다. 본 연구에서는 하중 및 풍하중 저감과 더불어 고층 건물에 대하여 효과적인 소음대책이 이루어지기 위한 터널형 방음벽 설계방안을 제시한다. 터널형 방음벽의 측면부분 개방을 통해 방음효과는 유지하며 외부 유동에 의한 풍하중 저감 설계 방안을 함께 고려하였다. 풍하중 저감을 위한 구조 설계 검토 시 교량 위에 선로가 존재하는 조건 하에서 풍하중에 의한 구조 검토를 수행하여 풍하중 저감 및 경량화가 가능한 터널형 방음벽 설계 방향을 제시하였다. Railway noise problems generates social issues in residential areas around railway. In order to reduce noise, soundproof facilities is considered as a way to block the direct noise path which is the main noise sources. Tunnel type soundproof walls that protects direct train noise path by applying sound materials on sides and roof provide an advantage to reduce noise more effectively than noise barriers that have only walls. Especially, it is effective from high-rise apartments because it is able to cut the direct sound by middle and upper floors. In a case of railway on bridge, however, there are constraints such as economic cost, weight requirement and wind load effect. Also maintenance problem is another concern, too. In this study, a design concept of tunnel type soundproof walls for its weight, wind load and noise reduction applying to railway is proposed. The side part that has loading effect due to wind turns out to be a main target of this tunnel type soundproof walls design. A partial opening is the proposed design concept since it reduces the wind loading effect remaining the noise reduction level to high-rise building residents.

경량화 철도 방음시설 설치에 따른 소음저감 효과 연구

김다래(Da Rae Kim),김태민(Tae Min Kim),김정태(Jeung Tae Kim),손정곤(Jung Gon Son),류래언(Le On Ryu) 한국철도학회 2014 한국철도학회 학술발표대회논문집 Vol.2014 No.10

철도 소음은 철도 변 주거지역에 심각한 소음피해를 발생하게 된다. 따라서 주변지역으로 전달되는 소음 전파를 감소시키기 위해 방음벽 또는 방음터널을 설치하여 소음전파 현상을 차단하고자 한다. 그래서 기술 발전에 따른 철도 차량의 고속화, 공동주택의 고층화 등으로 인하여 기존 방음시설 적용 가능 여부 및 재료 선정에 대한 연구가 요구된다. 특히 교량 위의 철로 변의 경우, 일반 지반의 철도 변보다 교량 진동에 의한 소음이 상대적으로 크게 발생되며 방음 시설 설치에 따른 많은 경제적 비용이 요구되기 때문에 방음시설의 효과에 알아 볼 필요가 있다. 본 연구에서는 광음향 기법을 이용하여 교량 위방음 시설의 종류 및 재질에 따른 소음 저감 효과를 분석하였다. 그 결과, 방음벽보다 방음 터널 설치 시 공동주택 고층부 소음 저감 효과를 보였으며, 기존 방음 터널 대비 경량화된 루버를 사용했을 때 철도 소음을 전반적으로 3 ~ 8 dB 저감해주는 것으로 나타났다. Railway noise takes place in critical noise damages to residential area around railway. In order to reduce noise propagation transferred into the surrounding area, we attempt to block noise propagation establishing soundproof walls or soundproof tunnel. So caused by high speed railroad car and high-rise apartment with development of railway technology, it is demanded study on whether it is able to apply to existing sound proof facilities and selection of materials. In a case of railroad on bridge, especially, it comes about relatively louder noises than ones of railroad on ordinary ground. And it is demanded lots of economic cost by establishing sound proof facilities. That’s why we studied that is the way on noise propagation with sound proof wall or sound proof tunnel around railroad. As result, establishing sound proof tunnel is more effective on noise reduction of high floors than sound proof walls, and in a case about using louver which is lightening than existing sound proof tunnel, it is reduced by 3 ~ 8 dB at the whole floors.

소형 잔향실을 이용한 재료의 차음 성능 민감도 연구

김다래(Da-Rae Kim),김태민(Tae-Min Kim),김정태(Jeung-Tae Kim),박광현(Gwang-Hyun Park),류래언(Le-On Ryu) 한국소음진동공학회 2015 한국소음진동공학회 학술대회논문집 Vol.2015 No.4

Reverberation chambers have been used to evaluate structural sound transmission characteristics. However, due to economic cost and spatial problems, scaled transmission chamber is a alternative. Scaled reverberation chamber needs correction factor to satisfy to have formation of complete diffuse field. This study is to draw correction factor to fit diffuse field in scaled reverberation chamber on frequency range satisfied with mass law. In order to draw correction factor, transmission loss is measured using two different specimens have over a certain stiffness. As a result, correction factor as one specimen have a limitation caused by altering frequency range to satisfy the masslaw of each plate that have different stiffness. And, in critical frequency range of specimen having bigger stiffness, corrected value of transmission loss is inappropriate to having a correction effect. Also it is considered that correction factor is more similar to based on the masslaw than on the numerical analysis. Therefore, it is possible to be obtainable from more approximate results of transmission loss on scaled reverberation chamber as a combination of correction factor by frequency using more than one specimen. Into additional study, it is supposed to verify improved correction factor by applying it to a variable of specimen and comparing results from real-scaled reverberation chamber.

A New Ceanothane-Type Triterpenoid Saponin Isolated from Gouania leptostachya DC. var. tonkinensis Pit. and Its Underlying Anti-Inflammatory Effects

( Nguyen Thi Hang ),( Nguyen Thi Bich Thu ),( Le Ba Vinh ),( Nguyen Viet Phong ),( Tran Van On ),( Ki Yong Lee ) 한국미생물생명공학회 2023 Journal of microbiology and biotechnology Vol.33 No.7

Metabolites from medicinal plants continue to hold significant value in the exploration and advancement of novel pharmaceuticals. In the search for plants containing compounds with anti-inflammatory effects, we observed that the ethanol (EtOH) extract obtained from the aerial components of Gouania leptostachya DC. var. tonkinensis Pit. exhibited substantial suppression of nitric oxide (NO) in vitro. In a phytochemical study on an EtOH extract of G. leptostachya, 11 compounds were purified, including one unreported compound namely gouanioside A (1). Their chemical structures were unambiguously determined through the use of various spectroscopic techniques, such as 1 and 2D NMR, IR, and HR-ESI-MS, and by producing derivatives via chemical reactions. The EtOH extract, fractions, and a new compound exerted inflammatory effects by altering NO synthesis in murine RAW264.7 macrophage cells stimulated with lipopolysaccharide. The underlying inflammatory mechanism of the new compound 1 was also explored through various in vitro experiments. The results of this study indicate the potential usefulness of new compound 1 from G. leptostachya as a treatment for inflammatory diseases.

Antiangiogenic-Like Properties of Fermented Extracts of Ayurvedic Medicinal Plants

Che´rif Rabhi,Guillaume Arcile,Le´on Cariel,Christine Lenoir,Je´rome Bignon,Joanna Wdzieczak-Bakala,Jamal Ouazzani 한국식품영양과학회 2015 Journal of medicinal food Vol.18 No.9

The three ayurvedic medicinal plants, Withania somnifera, Emblica officinalis, and Bacopa monnieri, were extracted by high-pressure static extraction using the Zippertex® technology. The extracts were mixed to reach quantifiable amounts of active compounds identified by high-pressure liquid chromatography-mass spectrometry (HPLC-MS) analysis. The mixture of extracts was incubated with resting cells of the fungus Beauveria bassiana ATCC 7159. The fermentation promoted the fluidization of the starting dense mixture, while HPLC monitoring evidenced the disappearance of glucogallin from E. officinalis extract and the concomitant increase in gallic acid content. Topical exposure of the chick embryo chorioallantoic membrane (CAM) to the nonfermented extract led to the extensive necrosis and destruction of the treated membrane. However, the fermented extract was shown to be free of any toxicity. Furthermore, compared with the untreated CAM, the fermented sample reduced CAM vascularization, suggesting its antiangiogenic potency. The innocuity of the fermented extract was demonstrated using the in vivo LD50 test, the morphological examination of internal organs of treated rats, as well as the evaluation of blood biomarkers of liver damage (aspartate aminotransferase and alanine aminotransferase). The fermented extract was developed as a nutraceutical antiangiogenic treatment of age-related macular degeneration and commercialized in an oral form named Ethnodyne-Visio™.

Side-by-Side Comparison of DNA Damage Induced by Low-Energy Electrons and High-Energy Photons with Solid TpTpT Trinucleotide

Park, Yeunsoo,Peoples, Anita R.,Madugundu, Guru S.,Sanche, Lé,on,Wagner, J. Richard American Chemical Society 2013 The journal of physical chemistry. B, Condensed ma Vol.117 No.35

<P>The genotoxic effects of high-energy ionizing radiation have been largely attributed to the ionization of H<SUB>2</SUB>O leading to hydroxyl radicals and the ionization of DNA leading mostly to damage through base radical cations. However, the contribution of low-energy electrons (LEEs; ≤ 10 eV), which involves subionization events, has been considered to be less important than that of hydroxyl radicals and base radical cations. Here, we compare the ability of LEEs and high-energy X-ray photons to induce DNA damage using dried thin films of TpTpT trinucleotide as a simple and representative model for DNA damage. The main radiation-induced damage of TpTpT as measured by high-performance liquid chromatography (HPLC) with UV detection and HPLC coupled to tandem mass spectrometry analyses included thymine release (-Thy), strand breaks (pT, Tp, pTpT, TpTp, and TpT), and the formation of base modifications [5,6-dihydrothymine (5,6-dhT), 5-hydroxymethyluracil (5-hmU), and 5-formyluracil (5-fU)]. The global profile of products was very similar for both types of radiation indicating converging pathways of formation. The percent damage of thymine release, fragmentation, and base modification was 20, 19, and 61 for high-energy X-rays, respectively, compared to 35, 13, and 51 for LEEs (10 eV). Base release was significantly lower for X-rays. In both cases, phosphodiester bond cleavage gave mononucleotides (pT and Tp) and dinucleotides (pTpT and TpTp) containing a terminal phosphate as the major fragments. For base modifications, the ratio of reductive (5,6-dhT) to oxidative products (5-hmU plus 5-fU) was 0.9 for high-energy X-rays compared to 1.7 for LEEs. These results indicate that LEEs give a similar profile of products compared to ionizing radiation.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpcbfk/2013/jpcbfk.2013.117.issue-35/jp405397m/production/images/medium/jp-2013-05397m_0009.gif'></P>

Air-stable Fe@Au Nanoparticles Synthesized by the Microemulsion’s Methods

Jos´e Rivas,Yolanda Pi˜neiro Redondo,Esther Iglesias-Silva,J. M. Vilas-Vilela,L. M. Le´on,Manuel Arturo L´opez-Quintela 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.10

Magnetic particles covered by gold are very important in many biological applications. However,there are not simple methods to produce small (< 5-10 nm) nanoparticles. One of the main reasons for that is the general use of iron oxides as magnetic cores, which have a large crystalline mismatch with gold. The use of Fe would be more appropriate, but its high tendency to oxidation has largely precluded it from being used as a core. Here, we will show that using a simple “one-pot” successive reaction method in microemulsions, can avoid such problems and is able to produce very stable core-shell Fe@Au nanoparticles. With this procedure, nanoparticles of ∼ 6 nm with a Fe core of 3nm can easily be obtained. These Fe@Au nanoparticles, with a saturation magnetization of 1.13emu/g, are very stable even in air after magnetic separation from the solution, which shows the good covering of the Fe core by the Au shell. In this contribution we will report the key parameters, which have to be taken into account, to prepare such stable Fe@Au dispersions and analyze their optical and magnetic properties, as well as their possible applications as biosensors, targeted magnetic separation, etc.

Evaluation of genetic diversity of Asian landrace wheat based on HMW glutenin subunit and maturity

Sukyeung Lee,Yu-mi Choi,Do yoon Hyun,Myung-chul Lee,Sejong Oh,On sook Hur,Hocheol Ko,Na-Young Ro 한국육종학회 2015 한국육종학회 심포지엄 Vol.2015 No.07

Glutenin is the major factor responsible for the unique viscoelastic dough characterisitcs of wheat flour, which determine mixing and bread baking performance(X.Shan et al, 2007). And early maturity is one of the most important cultural characteristic in Korea because of its winter cropping system. This study is to reveal the genetic properties of Asian wheat landrace collection originated from 6 separate regions such as Korea, China, Japan, Afganistan, Iran, Pakistan, Caucasus, and Middle East. Using germplasms maintained in National Agrobiodiversity Center, RDA, Korea, the variations in morphological character and HMW glutenin subunit composition were investigated. In this study, Glu-A1c(null), Glu-B1b(7+8) and Glu-D1a(2+12) alleles are the most frequent in Asian landrace wheats. When it comes to unique composition, Glu-B1aj(8) and Glu-D1q(2+11) subunits are only in Afghanistan wheat. And Glu-B1k(22), Glu-D1l(12), Glu-D1m(10) subunits are only in accessions from Pakistan, Korea, and China, respectively. The accessions from Iran and Caucasus have the highest PIC value(0.57), which shows wheat origin region has high genetic diversity. Grouping by UPGMA anlysis of combination of Glu-1 allele, most accessions from Afghanistan, Korea, and Japan were in the same group despite of geological distance. Contrasively, many germplasms originated from China, Caucasus, and Middle East were in the other same group. The evaluation of bread baking quality by Glu-1 scoring system, 34 accessions are perfect 10. 16 samples from China and 1 Afghanistan among them were also matured before early June, suitable to Korean cropping system. Especially, 3 accessions(K151847, K151865, K151962) had extremely early maturity, ripened before late May. These genetic resources having good gluten quality and early maturity are expected to be used for Korea wheat breeding system.