Unipolar Resistance Switching Characteristics in a Thick ZnO/Cu/ZnO Multilayer Structure

Tran Le,Hoang Cao Son Tran,Van Hieu Le,Tuan Tran,Cao Vinh Tran,Thanh Tan Vo,Mau Chien Dang,김상섭,이재찬,Bach Thang Phan 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.7

The resistance switching mechanism and the electrical conduction of thick Cu/ZnO/Cu/ZnO/Cu structures were investigated for various ZnO thicknesses (40, 80, 160, and 320 nm) when the thickness of the middle Cu layer was 2 nm. The ZnO films had a microstructure with columnar grains normal to the substrate. The switching voltages (VSET and VRESET) varied with the thickness of the ZnO layer. A symmetric electrode structure exhibited a unipolar resistance switching. The electrical transport of both high-resistance state (HRS) and low-resistance state (LRS) was Ohmic conduction, and the resistance switching mechanism was driven by the formation and the rupture of Cu conducting paths.

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.

Toll-like receptor-targeted particles: A paradigm to manipulate the tumor microenvironment for cancer immunotherapy

Tran, Tuan Hiep,Tran, Thi Thu Phuong,Truong, Duy Hieu,Nguyen, Hanh Thuy,Pham, Tung Thanh,Yong, Chul Soon,Kim, Jong Oh Elsevier Science B.V. Amsterdam 2019 ACTA BIOMATERIALIA Vol. No.

<P><B>Abstract</B></P> <P>The expression of Toll-like receptors (TLRs) on antigen presenting cells, especially dendritic cells, offers several sensitive mediators to trigger an adaptive immune response, which potentially can be exploited to detect and eliminate pathogenic objects. Consequently, numerous agonists that target TLRs are being used clinically either alone or in combination with other therapies to strengthen the immune system in the battle against cancer. This review summarizes the roles of TLRs in tumor biology, and focuses on relevant TLR-dependent antitumor pathways and the conjugation of TLR agonists as adjuvants to nano- and micro-particles for boosting responses leading to cancer suppression and eradication.</P> <P><B>Statement of Significance</B></P> <P>Toll-like receptors (TLRs), which express on antigen presenting cells, such as dendritic cells and macrophages, play an important role in sensing pathogenic agents and inducing adaptive immunity. As a result, several TLR agonists have been investigating as therapeutic agents individually or in combination with other treatment modalities for cancer treatment through boosting the immune system. This review aims to focus on the roles of TLRs in cancer and TLR-dependent antitumor pathways as well as the use of different nano- or micro-particles bearing TLR agonists for tumor inhibition and elimination.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Facile titanium(IV) chloride and TBD-mediated synthesis of N-aryl-substituted azacycles from arylhydrazines

Tran Van Hieu,Hong Wan Pyo,Kim Hee‐Kwon 대한화학회 2022 Bulletin of the Korean Chemical Society Vol.43 No.6

A novel practical synthesis of N-aryl-substituted azacycles from arylhydrazines is described. In this method, target azacycles were prepared via reaction of arylhydrazines with cyclic ethers in the presence of both titanium(IV) chloride and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as key combined reagents. Using this synthetic protocol with titanium(IV) chloride and TBD, reaction of arylhydrazines with cyclic ethers successfully afforded various N-aryl-substituted azacycles in high yield. This facile synthetic method using arylhydrazines will be a promising guide for the synthesis of azacycles from arylhydrazines.

Kalman filter-based ARAIM algorithm for integrity monitoring in urban environment

Hieu Trung Tran,Letizia Lo Presti 한국통신학회 2019 ICT Express Vol.5 No.1

This work proposes an adaptation of Advanced Receiver Autonomous Integrity Monitoring (ARAIM) algorithm for snapshot integrity monitoring in urban environment, using Kalman Filter (KF) as underlying positioning method. This new method can follow the changes of signal quality, maintaining good performance under the effect of multipath which is always presents in urban areas. Performance analysis using both simulated and real data validates the method, and comparison with conventional ARAIM algorithm (which was developed for aviation) further consolidates the suitability of the proposed method for urban scenario.

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>

Olfactory Responses of Stomoxys calcitrans to Zanthoxylum piperitum Pericarp Steam Distillate, Zanthoxylum armatum Seed Oil, and their Volatile Constituents Alone or in Combination with 1-Octen-3-ol

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

Electroantennogram techniques (EAGs) were employed to record olfactory responses in the antennae of the adult female stable fly, Stomoxys calcitrans (Diptera: Muscidae), to Zanthoxylum piperitum pericarp steam distillate (ZP-SD), Z. armatum seed oil (ZA-SO) and their 29 volatile constituents alone as well as binary mixture of the ZP-SD and ZA-SO with 1-octen-3-ol. The electrophysiological responses of the test materials were compared with those of DEET and 1-octen-3-ol. At concentration of 10-1 (v/v) in mineral oil, ZP-SD, ZA-SO, and all volatiles elicited EAG responses in the fly antennae except for DEET, which is extremely low volatile. ZP-SD, ZA-SO, and some of the test volatiles elicited EAG responses rather lower than 1-octen-3-ol, which showed vapor phase repellency and toxicity to the fly in our previous behavioral research. This suggests that the stable fly possesses olfactory receptor neurons responding to given repellent compounds per se. In binary mixture with 1-octen-3-ol at concentration of 10-1, ZP-SD and ZA-SO elicited 16±0.55 and 18±0.63 mV while ZP-SD, ZA-SO, and 1-octen-3-ol alone elicited responses of 14±0.45, 15.8±0.37 and 16.2±0.58 mV, respectively. Among the volatile compounds, terpinen- 4-ol, β-myrcene, α-phellanderene, citronellal, and limonene oxide elicited 80 – 96% relative EAG amplitude compared to 1-octen-3-ol as a reference (100%). Based on structure-activity relationships, constituents having aldehyde moiety elicited bigger EAG responses than those of alcohol or ether one. The perception in the fly antenna to plant volatile compounds exhibited complicated patterns of olfactory responses. Current and future directions of this study on sensory processing mechanisms underlying repellent behaviors will be discussed.

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>

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.

Cu₂O/ZnO heterojunction thin-film solar cells: the effect of electrodeposition condition and thickness of Cu₂O

Tran, Man Hieu,Cho, Jae Yu,Sinha, Soumyadeep,Gang, Myeng Gil,Heo, Jaeyeong Elsevier 2018 THIN SOLID FILMS - Vol.661 No.-

<P><B>Abstract</B></P> <P>The electrodeposited Cu<SUB>2</SUB>O thin films, with a controlled morphology, were obtained by varying the deposition parameters, such as the solution temperature, applied current and charge. An optimal deposition condition was achieved for a better quality Cu<SUB>2</SUB>O film which was favorable as an absorber layer for thin-film solar cell application. The effect of applied negative charge on the as-deposited Cu<SUB>2</SUB>O films was investigated, resulting in an increase in film thickness with increasing applied charge. The performance of the Cu<SUB>2</SUB>O/ZnO heterojunction solar cells with different Cu<SUB>2</SUB>O absorber thickness exhibited the highest power-conversion efficiency of 0.52%. Thicker Cu<SUB>2</SUB>O was beneficial for the decreased shunt conductance, but it also led to the increased series resistance. The optimal thickness of Cu<SUB>2</SUB>O absorber was ~3.3 μm.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Electrodeposited Cu<SUB>2</SUB>O absorber layer with controlled morphology is achieved. </LI> <LI> An optimized deposition temperature exhibits highly uniform film deposition. </LI> <LI> ALD-ZnO films are used to from the Cu<SUB>2</SUB>O/ZnO TFSCs. </LI> <LI> Performance of TFSCs is highly dependent on the thickness of Cu<SUB>2</SUB>O absorber. </LI> <LI> A maximum PCE of 0.52% is achieved with optimal Cu<SUB>2</SUB>O thickness of 3.3 μm. </LI> </UL> </P>