Water and air friendly alkali metals synthesis of the h-BN-C QDTs and the utilization in the non-volatile resistive switching memory devices

Adila Rani,박현권,송다솜,최철종,임종선,부상돈 한국물리학회 2020 Current Applied Physics Vol.20 No.9

A novel and facile hydrothermal route was designed to produce h-BN-C quantum dots (h-BN-C QDTs) using h-BN powder as a precursor and Potassium Sodium Tartare as an intercalant. The resulting yellow solution possessed mono or few-layers of quantum dots with an average size of ~2.5 nm. Due to the incorporation of functional groups (carbon, oxygen) on the surface of h-BN, an enhancement of photo luminescent magnitude and a blue shift were observed in photoluminescence spectra from h-BN-C QDTs solution. Further, h-BN-C QDTs exhibits a bright blue fluorescence under the irradiation by a 365 nm UV light. Next, h-BN QDTs was utilized as the dielectric active layer by using simple drop casting method between the electrodes and fabricated the nonvolatile resistive switching devices. The fabricated devices exhibited the nonvolatile bipolar resistive switching characteristics with 103 ON/OFF ratio and turned ON and OFF threshold voltages of 1.9 V and þ1.4 V, respectively. Further, the switching mechanisms of h-BN-C QDTs were found to be space charged trapping. It provides a route toward tailoring the optical and electrical properties of the h-BN materials and can be utilized in the future potential applications.

Modelling contraction flows of bi-disperse polymer blends using the Rolie-Poly and Rolie-Double-Poly equations

Adila A. Azahar,Oliver G. Harlen,Mark A. Walkley 한국유변학회 2019 Korea-Australia rheology journal Vol.31 No.4

The flow of a bi-disperse polymer melt through a hyperbolic contraction is simulated using the recently proposed Rolie-Double-Poly constitutive model (Boudara et al., 2019). This simplified tube model takes account of the nonlinear coupling between the dynamics of the long and short-chains in a bi-disperse blend, in particular it reproduces the enhancement of the stretch relaxation time that arises from the coupling between constraint release and chain retraction. Flow calculations are performed by implementing both the Rolie-Double-Poly and multimode Rolie-Poly models in OpenFOAM® using the RheolTool library. While both models predict very similar flow patterns, the enhanced stretch relaxation of the Rolie-Double-Poly models results in an increase in the molecular stretch of the long chain component in the pure extensional flow along the centre-line of the contraction, but a decrease in the stretch in shear-flow near the channel walls.

Electrical Conductivity of Chemically Reduced Graphene Powders under Compression

Adila Rani,Seung-Woong Nam,Kyoung-Ah Oh,Min Park 한국탄소학회 2010 Carbon Letters Vol.11 No.2

Carbon materials such as graphite and graphene exhibit high electrical conductivity. We examined the electrical conductivity of synthetic and natural graphene powders after the chemical reduction of synthetic and natural graphite oxide from synthetic and natural graphite. The trend of electrical conductivity of both graphene (synthetic and natural) was compared with different graphite materials (synthetic, natural, and expanded) and carbon nanotubes (CNTs) under compression from 0.3 to 60 MPa. We found that synthetic graphene showed a marked increment in electrical conductivity compared to natural graphene. Interestingly, the total increment in electrical conductivity was greater for denser graphite; however, an opposite behavior was observed in nanocarbon materials such as graphene and CNTs, probably due to the differing layer arrangement of nanocarbon materials.

Layer-by-layer self-assembled graphene multilayers as pt-free alternative counter electrodes in dye-sensitized solar cells

( Adila Rani ),( Kyungwha Chung ),김동하 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0

The neat rGO-based counter electrodes were developed via two types of layer-by-layer (LBL) self-assembly (SA) methods: spin coating and spray coating methods. In spin coating method, two sets of multilayer counter electrodes were fabricated on poly(diallyldimethylammonium chloride) (PDDA) coated fluorine-doped tin oxide (FTO) substrates using [GO(-)] combined with [N-GO(+)] ([rGO(-)/N-rGO(+)]n) or with [NS-GO(+)] ([rGO(-)/NS-rGO(+)]n). The DSSCs employing new types of counter electrodes exhibited ~7.0 and ~6.2% power conversion efficiency (PCE) based on ten bilayers of [rGO(-)/N-rGO(+)]10 and [rGO(-)/NS-rGO(+)]10, respectively. The DSSCs equipped with blend of one bilayer of PDDA[rGO(-):N-rGO(+)] and [rGO(-):NS-rGO(+)]prepared from spray coating showed ~ 6.4 and ~ 5.6% PCE, respectively,with ~ 56% fill factor value. This work indicates that combination of un-doped, nitrogen-doped and/or nitrogen sulfur dual-doped reduced graphene oxides can be used as a new class of electro catalysts as alternative electrodes in conventional photovoltaic devices.

Layer-by-Layer Self-Assembled Graphene Multilayers as Pt-Free Alternative Counter Electrodes in Dye-Sensitized Solar Cells

Rani, Adila,Chung, Kyungwha,Kwon, Jeong,Kim, Sung June,Jang, Yoon Hee,Jang, Yu Jin,Quan, Li Na,Yoon, Minji,Park, Jong Hyeok,Kim, Dong Ha American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.18

<P>Low cost, charged, and large scale graphene multilayers fabricated from nitrogen-doped reduced graphene oxide N-rGO(+), nitrogen and sulfur codoped reduced graphene oxide NS-rGO(+), and undoped reduced graphene oxide rGO(-) were applied as alternative counter electrodes in dye-sensitized solar cells (DSSCs). The neat rGO-based counter electrodes were developed via two types of layer-by layer (LBL) self-assembly (SA) methods: spin coating and spray coating methods. In the spin coating method, two sets of multilayer films were fabricated on poly(diallyldimethylammonium chloride) (PDDA)-coated fluorine-doped tin oxide (FTO) substrates using GO(-) combined with N-GO(+) followed by annealing and denoted as [rGO(-)/N-rGO(+)](n) or with NS-GO(+) and denoted as [rGO(-)/NS-rGO(+)](n) for counter electrodes in DSSCs. The DSSCs employing new types of counter electrodes exhibited similar to 7.0% and similar to 6.2% power conversion efficiency (PCE) based on ten bilayers of [rGO(-)/N-rGO(+)](10) and [rGO(-)/NS-rGO(+)](10), respectively. The DSSCs equipped with a blend of one bilayer of [rGO(-):N-rGO(+)] and [rGO(-):NS-rGO(+)] on PDDA-coated FTO substrates were prepared from a spray coating and showed similar to 6.4% and similar to 5.6% PCE, respectively. Thus, it was demonstrated that a combination of undoped, nitrogen-doped, and nitrogen and sulfur codoped reduced graphene oxides can be considered as potentially powerful Pt-free electrocatalysts and alternative electrodes in conventional photovoltaic devices.</P>

Effects of the Intercalant and the Temperature in Hybrid-MoS2 Nanodots Fabrication and Their Photoluminescence Enhancement

Rani Adila,Kim Eun-Young,Song Da Som,Lim JongSun,부상돈 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.76 No.11

In this study, we have proposed a simple method to produce temperature-dependent variable-size of MoS2 nanodots (NDTs) by using MoS2 powder as a pre-cursor and KNa-tartrate as the intercalant. Due to defects in MoS2, the optical properties are strongly modified and show blue luminescence under UV irradiation of MoS2 NDTs. The temperature variable is used to gradually introduce defects in 2D materials to obtain nanodots with different particle sizes. When the synthesis temperature is increased from 120 °C to 200 °C, the particle size is reduced from ~ 120 nm to ~ 2.5 nm. Next, an enhancement of photoluminescent magnitude and a red shift were observed in photoluminescence spectra from MoS2 NDTs solutions. These results offer a route toward tailoring the optical properties of 2D nanomaterials by controlling the size/temperature/synthesis method.

Common bacterial blight (Xanthomonas axonopodis pv. phaseoli) resistance reaction in common bean genotypes and their agronomic performances in Southern Ethiopia

Wondimu Adila,Habtamu Terefe,Agdew Bekele 한국작물학회 2021 Journal of crop science and biotechnology Vol.24 No.4

Common bacterial blight (CBB) is an economically important disease of common beans and causes signifcant yield losses worldwide, including Ethiopia. Therefore, development and use of resistant cultivars are important options to manage the disease. Thus, feld reactions of common bean genotypes to CBB and their agronomic performances were conducted at two locations in Southern Ethiopia, during 2018/2019. The experiment was arranged in a randomized complete block design with three replications. Analysis of variance revealed signifcant (P<0.01) genotypic variation for disease and yield parameters at both locations. The results showed wide ranges of variation in incidence (26.05–82.75%), severity (23.75–70.70%), AUDPC (773.9–2544%-days) and disease progress rate (0.024–0.142 unit day−1) on average for both locations. And also, remarkable genotypic variation for quantitative growth and yield characters such as plant height, days to 50% fowering, days to 90% maturity, number of pods, number of seeds, seed weight and grain yield were observed. Based on mean severity and R8_severity score, genotypes were grouped as 20% resistant, 55% moderately resistant and 25% susceptible at JARC, and 15% resistant, 80% moderately resistant and only 5% susceptible at Debub Ari. Variable relationships were found among and between parameters studied. The overall results indicated that SER119 and MALB135 showed consistent resistance reaction to CBB, and SER119 also gave high yield across felds. It is recommended to use SER119 with proper management practices for bean production and MALB135 as parent for CBB resistance development in plant breeding programs of the country

기능주도개발 Agile 방법을 사용할 때의 안전한 소프트웨어 개발에 관한 문헌연구

아딜라알바인 ( Adila Firdaus Arbain ),임란가니 ( Imran Ghani ),정승렬 ( Seung Ryul Jeong ) 한국인터넷정보학회 2014 인터넷정보학회논문지 Vol.15 No.1

Agile 방법론은 시간적 제약하에서도 효율적인 개발 프로세스로 빠르게 제품을 완성할 수 있는 방법으로 알려져 있다. 하지만 scrum, XP, DSDM 등과 같은 여타 Agile 방법들처럼 기능주도개발 (FDD) Agile 방법도 보안요소의 불가용성으로 인해 비판을 받고 있다. 이러한 이슈를 보다 자세히 살펴보기 위해 본 연구는 2001년부터 2012년사이에 나타난 연구들에 대한 체계적인 문헌연구를 수행하였다. 본 연구 결과, 현재 FDD 방법은 안전한 소프트웨어 개발을 부분적으로 지원하고 있는 것으로 나타났다. 하지만 안전한 소프트웨어 사용에 관한 상세한 정보가 문헌에 거의 나타나고 있지 않은 것으로 보아 이 분야에 대한 연구 노력은 거의 없어 보인다. 따라서 현재의 5단계 FDD 방법은 안전한 소프트웨어 개발에 충분하지 않음을 알 수 있고 결국, 본 연구는 FDD 방법에서 보안에 기반을 둔 새로운 수행 단계와 프랙티스가 제안될 필요가 있음을 보여준다. Agile methodologies have gained recognition as efficient development processes through their quick delivery of software, even under time constraints. However, like other agile methods such as Scrum, Extreme Programming (XP) and The Dynamic Systems Development Method (DSDM), Feature Driven Development (FDD) has been criticized due to the unavailability of security elements in its twelve practices. In order to examine this matter more closely, we conducted a systematic literature review (SLR) and studied literature for the years 2001-2012. Our findings highlight that, in its current form, the FDD model partially supports the development of secure software. However, there is little research on this topic, as detailed information about the usage of secure software is rarely published. Thus, we have been able to conclude that the existing five phases of FDD have not been enough to develop secure software until recently. For this reason, security-based phase and practices in FDD need to be proposed.

Amphiphilic Star Block Copolymers with Photosensitive Core by Living Radical Polymerization

백경열,Adila Rani,황승상,JEAN M. J. FRECHET 한국고분자학회 2008 한국고분자학회 학술대회 연구논문 초록집 Vol.33 No.1

Experimental and calculation studies on graphene plasmon induced sensitivity enhancement in surface plasmon resonance sensors

정경화,( Adila Rani ),김동하 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1

A simple strategy for the sensitivity enhancement of SPR sensors was demonstrated with layer-by-layer self-assembled graphene oxide on Au film. Refractive index sensitivity was estimated by calculating Fresnel equation and RI sensing was performed with glycerin solution of different concentrations. The experimental results were compared with calculation study. In both studies, graphene deposition resulted in the higher sensitivity. Graphene with unique optical properties contributed to improve the refractive index sensitivity of SPR sensor chip through the coupling of surface plasmon polariton and graphene plasmons.