Nanoporous metallic thin films prepared by dry processes

Tran, Hieu Trung,Byun, Ji Young,Kim, Sang Hoon Elsevier 2018 JOURNAL OF ALLOYS AND COMPOUNDS Vol.764 No.-

<P><B>Abstract</B></P> <P>Nanoporous Pt and Au thin films were prepared by dry etching methods and compared to those prepared by conventional wet etching (dealloying). While reactive ion etching (RIE) and deep RIE methods did not yield nanoporous structures with high roughness factors (<5), gentle XeF<SUB>2</SUB> dry etching yielded thin metallic nanoporous films (∼200 nm) with high enough roughness factors (∼40). The nanoporous films were as good as those prepared by wet etching using 3% HF solution in terms of thickness and roughness factors. Sensing performance of nanoporous Pt films prepared by XeF<SUB>2</SUB> dry etching was as good as that of wet-chemically dealloyed nanoporous Pt films for glucose sensing.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Nanoporous Pt and Au thin films 100–200 nm thick were fabricated by all dry processes from Pt-Si and Au-Si alloy films. </LI> <LI> Alloy films were prepared by cosputtering metal and Si targets at the same time. </LI> <LI> Si etching was carried out by XeF<SUB>2</SUB>, RIE and deep RIE dry etchings. </LI> <LI> Dry etched nanoporous thin films showed sensing performance as good as that of wet etched nanoporous films. </LI> </UL> </P>

Visualization of Dolichopteryx longipes spookfish mirror eye

Hieu Tran Doan Trung,Donguk Lee,Tung Lam Nguyen,Hocheol Lee 한국생산제조학회 2020 한국생산제조시스템학회 학술발표대회 논문집 Vol.2020 No.12

Vapor Phase Repellency and Toxicity of Zanthoxylum piperitum Pericarp Steam Distillate, Zanthoxylum amartum Seed Oil, and their Constituents to Stomoxys calcitrans Orientation Responses

Tran Trung Hieu,Soon-Il Kim,Hyung Wook Kwon,Young-Joon Ahn 한국응용곤충학회 2010 한국응용곤충학회 학술대회논문집 Vol.2010 No.05

The vapor phase repellency and toxicity of Zanthoxylum piperitum pericarp steam distillate (ZP-SD), Z. armatum seed oil (ZA-SO), and their 29 constituents to the adult female stable fly, Stomoxys calcitrans (Diptera: Muscidae), were examined using filter paper fumigation bioassay. Results were compared with those of the currently used repellent: DEET. Both of ZP-SD and ZA-SO exhibited vapor phase repellency and toxicity to female flies at 5 to 40 mg/filter paper (0.23 to 1.82 mg/cm3 air) during a 120-min exposure, whereas DEET exhibited neither repellency nor toxicity to the stable fly. At 5 mg/filter paper, vapor phase of ZP-SD and ZA-SO repelled 50 to 67% and 61 to 51% flies, respectively, to control area during 30 to 120 min. At 40 mg/filter paper, vapor phase of ZP-SD and ZA-SO caused 100% and 81% mortality, respectively, after 120 min of exposure. Among the tested volatile constituents, cuminaldehyde was the strongest repellent and toxic compound to the fly and was four times more toxic than ZP-SD and ZA-SO. Cuminaldehyde vapor phase repelled 62% flies to control area after 30 min at 2.5 mg/filter paper and caused 100% mortality after 120 min at 10 mg/filter paper. Based on the structure-activity relationships, the toxicity and repellency of constituents having aldehyde moiety were better than those of alcohol or ether one. Overall, ZP-SD, ZA-SO, and their bioactive constituents could be useful as potential vapor repellents to control stable fly population.

Behavioural and electroantennogram responses of the stable fly (<i>Stomoxys</i> <i>calcitrans</i> L.) to plant essential oils and their mixtures with attractants

Hieu, Trung Tran,Jung, JeWon,Kim, Soon‐,Il,Ahn, Young‐,Joon,Kwon, Hyung Wook John Wiley Sons, Ltd 2014 Pest Management Science Vol.70 No.1

<P><B>Abstract</B></P><P><B>BACKGROUND</B></P><P><B>Insect olfactory organs possess many olfactory receptor neurons, which detect many different sets of odorants in nature. In order to feed on blood meals, stable flies locate host animals and humans using chemical cues such as 1‐octen‐3‐ol and butyric acid. In the present study, behavioural and electroantennogram (EAG) response patterns to repellent volatiles from essential oils (EOs) of <I>Zanthoxylum piperitum</I> and <I>Z. armatum</I> in combination with the attractants were investigated</B>.</P><P><B>RESULTS</B></P><P><B>Components of the EOs such as cuminaldehyde, citronellal, neral, linalool, linalool oxide, terpinen‐4‐ol, 1,8‐cineole, and piperitone induced remarkable repellent behaviours in the stable fly. EAG responses in the fly antenna to these chemicals showed a dose‐dependent manner. The patterns of behavioural and EAG responses were significantly altered depending on the ratios of 1‐octen‐3‐ol or butyric acid to the EOs or compounds in the air mixtures</B>.</P><P><B>CONCLUSION</B></P><P><B>The present study demonstrated that the <I>Zanthoxylum</I> EOs decreased the levels of response of flight behaviours of the stable fly towards host volatile compounds. The combinations of odorant mixtures of the attractants with the EOs and their components affect the representation of behavioural and EAG responses of the flies. The summation and integration patterns of olfactory responses measured by the EAG indicated that the peripheral olfactory networks in antennae could process the odorant complexity of different odorant mixtures between attractants and repellents. © 2013 Society of Chemical Industry</B></P>

Enhanced repellency of binary mixtures of <i>Calophyllum inophyllum</i> nut oil fatty acids or their esters and three terpenoids to <i>Stomoxys calcitrans</i>

Hieu, Tran Trung,Choi, Won Sil,Kim, Soon‐,Il,Wang, Mo,Ahn, Young‐,Joon John Wiley Sons, Ltd 2015 Pest Management Science Vol.71 No.9

<P><B>Abstract</B></P><P><B>BACKGROUND</B></P><P>An assessment was made of the repellency to female stable flies of tamanu nut oil fatty acids or their esters alone (each 0.5 mg cm<SUP>−2</SUP>) or in combination with cuminyl alcohol, cuminaldehyde and <I>α</I>‐phellandrene (each 0.25 mg cm<SUP>−2</SUP>), using an exposed human hand bioassay. Results were compared with those of synthetic repellent DEET (0.25 mg cm<SUP>−2</SUP>).</P><P><B>RESULTS</B></P><P>Based upon protection time (PT) (time to first bite of stable fly), oleic acid, linoleic acid, methyl oleate or methyl linoleate synergised the repellency of each monoterpenoid and DEET. For example, the binary mixture of oleic acid and cuminyl alcohol (PT 2.05 h) resulted in significantly greater repellency than either oleic acid (0.55 h), cuminyl alcohol (0.70 h) or DEET alone (1.50 h). The binary mixtures of oleic acid and cuminyl alcohol or DEET (PT 2.10 h) did not differ significantly in repellency. The structure–activity relationship indicates that the degree of saturation, the side chain length and the functional group of fatty acids appear to play a role in determining the fatty acid repellency to stable flies.</P><P><B>CONCLUSION</B></P><P>Mixtures formulated from fatty acid and monoterpenoid could be useful as potential repellents for protecting humans and possibly domestic animals from bites caused by stable fly. © 2014 Society of Chemical Industry</P>

Performance Enhancement of Motion Estimation Using SSE2 Technology

Trung Hieu Tran,Hyo-Moon Cho,Sang-Bock Cho 대한전자공학회 2008 ICEIC:International Conference on Electronics, Inf Vol.1 No.1

Motion estimation is the most computationally intensive part in video processing. Many fast motion estimation algorithms have been proposed to decrease the computational complexity by reducing the number of candidate motion vectors. However, these studies are for fast search algorithms themselves while almost image and video compressions are operated with software based. Therefore, the timing constraints for running these motion estimation algorithms not only challenge for the video codec but also overwhelm for some of processors. In this paper, the performance of motion estimation is enhanced by using Intel's Streaming SIMD Extension 2 (SSE2) technology with Intel Pentium 4 processor.

곤충 겹눈 구조의 카메라 모사 설계 위한 가시화 평가 방법 연구

Hieu Tran Doan Trung,Tung Lam Nguyen,이호철(Hocheol Lee) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.6

Maneuvering flight of beetle (Allomyrina Dichotoma)

Trung-Hieu Tran,Tien Van Truong,Tuyen Quang Le,Hoon Cheol Park,Doyoung Byun 한국항공우주학회 2009 한국항공우주학회 학술발표회 논문집 Vol.2009 No.11

Maneuvering flight has been recognized as an important characteristic of insects and animals where these species frequently use. Here we investigate kinematics and role of flexibility of hind wing of Allomyrina Dichtoma in which body and wing kinematics were reconstructed into three?dimensional through DLT method. Result shows that a flexibility of hind wing can increase performance significantly in turning and stability control of beetle especially in supination and pronation phases. In the downstroke phase, hindwing has positive wing camber, inversely, it is passive deformed into negative wing camber in chordwise as well as in span wise direction at begin of upstroke. These mechanisms can create a large variant of force and moment In magnitude and direction which can change direction and altitude of beetle in maneuvering.

Repellency to Stomoxys calcitrans (Diptera: Muscidae) of Plant Essential Oils Alone or in Combination with Calophyllum inophyllum Nut Oil

Tran Trung Hieu,Soon-Il Kim,Sang-Gye Lee,Young-Joon Ahn 한국응용곤충학회 2009 한국응용곤충학회 학술대회논문집 Vol.2009 No.05

The repellency to female Stomoxys calcitrans (L.) of 21 essential oils alone or in combination with Calophyllum inophyllum nut oil (tamanu oil) was examined using a skin bioassay. Results were compared with those following treatment with the commonly used repellent DEET (N,N-diethyl-3-methylbenzamide). As judged by the protection time (PT) to first bite at 0.5 mg cm-2, patchouli (3.67 h) was the most effective essential oil, followed by clove bud, lovage root, clove leaf and thyme white essential oils (3.50-2.12 h). Thyme red, oregano and geranium essential oils exhibited moderate protection time (PT, 1.24-1.11 h). At 0.25 mg cm-2, effective protection time of clove bud, clove leaf and lovage root essential oils was about 1 h. The protection times of DEET were 4.47 and 2.17h at 0.5 and 0.25 mg cm-2 respectively. The remarkable increase in the protection time were produced by binary mixtures of five essential oils (clove bud, clove leaf, thyme white, patchouli and savory) and tamanu oil (0.25:2.0 mg cm-2) compared with those of either the constituted essential oil, tamanu oil or DEET alone, indicating the involvement in synergy. These essential oils, tamanu oil and binary mixtures did not cause any adverse effects on the human volunteers at 0.5 mg cm-2 except savory oil. Thus binary mixtures of essential oils and tamanu oil described merit further study as potential insect repellents for protection from humans and domestic animals from biting and nuisance caused by S. calcitrans.

Local Gradient와 Median Filter에 근거한 초해상도 이미지 재구성

Tran Trung Hieu,조상복(Sang-Bock Cho) 大韓電子工學會 2010 電子工學會論文誌-SP (Signal processing) Vol.47 No.1

본 논문은 높은 품질 SR 이미지를 획득하기 위해 국소 그라디언트를 기반으로 적응형 보간법을 이용하는 SR 방법을 제공한다. 이 방법에서, 내삽 화소와 인접하는 유효한 화소 사이에 거리는 국소 그라디언트 특징을 이용하여 고려되며, 보간 계수는 LR 이미지의 국소 그라디언트를 고려한다. 픽셀의 국소 그라디언트는 더 작을수록, 그리고 메디안 필터는 보간된 HR 이미지의 블러링과 노이즈를 감소시키기 위해 적용된다. 실험 결과는 특히 이미지의 에지 부분에서, 다른 방법과 비교하여 제안된 방법의 유효성을 보여준다. This paper presents a SR method using adaptive interpolation based on local gradient features to obtain a high quality SR image. In this method, the distance between the interpolated pixel and the neighboring valid pixel is considered by using local gradient properties. The interpolation coefficients take the local gradient of the LR images into account. The smaller the local gradient of a pixel is, the more influence it should have on the interpolated pixel. And the median filter is finally applied to reduce the blurring and noise of the interpolated HR image. Experiment results show the effectiveness of the proposed method in comparison with other methods, especially in the edge areas of the images.