내변형 폴리머 개질 아스팔트 혼합물의 개발

김광우,도영수,정규동,조희원,안경애,이상범 강원대학교 석재복합신소재제품연구센터 1997 석재연 논문집 Vol.2 No.-

본 연구에서는 국내산 LDPE 및 SBS 폴리머를 아스팔트 함량의 3%, 4%, 5%와 카본블랙을 10% 사용하여 AP-3 아스팔트를 개질한 화강암, 편마암, 석회암 혼합물을 제조하고 그 특성의 변화를 고찰하였다. 폴리머는 3가지 골재 혼합물 모두에 전반적으로 인장강도와 강성의 증가를 가져오는 것으로 나타났다. 그러나 그중 편마암에서는 그 효과가 비교적 적고 화강암과 석회암에 더 큰 것으로 나타났다. 또한 두 폴리머간 개질효과의 차이는 거의 없었으나 LDPE가 약간 높게 나타나 보였다. 카본 블랙의 사용은 폴리머 개질 혼합물의 경우에는 별로 효과적이지 못하였으나, 일반혼합물의 경우는 아스팔트의 강도특성에 영향을 미침임을 알 수 있었다. SBS and LDPE polymers with contents of 3%, 4%, 5% and a carbon black with content of 10% by wt. of asphalt were used in three aggregate mixtures, a gneiss, a granite and a limestone waste aggregates. Indirect tensile strength and stiffness index were evaluated for each mixture. The two polymers were effective on improving those strength characteristics for all three aggregate mixtures. Especially, limestone and granite aggregates were improved more than gneiss. Among two polymers, there were almost no difference in performance even though LDPE showed a little higher values. Carbon black improved the properties of plain asphalt mixtures, although it was not the case for the PMA mixtures.

The New Ecosystem of Cross-border E-Commerce among Korea, China and Japan Based on Blockchain

Xiang-Dong Shen,Xi Chen,Ran Ji,Ren-Hong Wu 한국무역학회 2020 Journal of Korea trade Vol.24 No.5

Purpose - The purpose of the study is to propose a theoretical framework of cross-border e-commerce ecosystems based on blockchain technology. The ecosystem includes five systems, namely, crossborder supply chain intelligent system, cross-border logistics system, cross-border payment system, cross-border product quality traceability system and cross-border customs supervision system. Design/methodology - This study firstly derived the main improvement factors for the new ecosystem based on blockchain through prior research and expert interviews on cross-border e-commerce. Then explored the use of virtue of decentralization, anti-counterfeiting traceability, consensus mechanism, smart contract and other means of the core technology of blockchain to overcome the bottleneck of cross-border e-commerce development among Korea, China, and Japan. Finally, proposed valuable implications in both theoretical and practical perspectives. Findings - As a result, we combined with the problems existing in cross-border e-commerce among Korea, China and Japan, this paper proposes a solution based on blockchain. On this basis, it constructs a cross-border e-commerce ecosystem among these three countries, including five systems. In addition, we discuss the main problems existing in the current blockchain, such as low transaction concurrency, security loopholes, and inconsistent standards, the corresponding countermeasures are proposed from the technical level, security level and industry standards. Originality/value - This study is the first to apply the blockchain technology to solve the cross-border e-commerce problems in Korea, China and Japan, which is of pioneering significance in both literature and practice. Block chain technology is in the ascendency. This study provides technical solutions for promoting the development of cross-border e-commerce import and export trade between Korea, China and Japan.

Sequential Polyadenylation to Enable Alternative mRNA 3’ End Formation

Xiang-Dong Fu,Yajing Hao,Ting Cai,Chang Liu,Xuan Zhang 한국분자세포생물학회 2023 Molecules and cells Vol.46 No.1

In eukaryotic cells, a key RNA processing step to generate mature mRNA is the coupled reaction for cleavage and polyadenylation (CPA) at the 3′ end of individual transcripts. Many transcripts are alternatively polyadenylated (APA) to produce mRNAs with different 3′ ends that may either alter protein coding sequence (CDS-APA) or create different lengths of 3′UTR (tandem-APA). As the CPA reaction is intimately associated with transcriptional termination, it has been widely assumed that APA is regulated cotranscriptionally. Isoforms terminated at different regions may have distinct RNA stability under different conditions, thus altering the ratio of APA isoforms. Such differential impacts on different isoforms have been considered as post-transcriptional APA, but strictly speaking, this can only be considered “apparent” APA, as the choice is not made during the CPA reaction. Interestingly, a recent study reveals sequential APA as a new mechanism for post-transcriptional APA. This minireview will focus on this new mechanism to provide insights into various documented regulatory paradigms.

Identifying a Cinnamoyl Coenzyme A Reductase (CCR) Activity with 4-Coumaric Acid: Coenzyme A Ligase (4CL) Reaction Products in Populus tomentosa

Dong-Dong Wang,Hua Bai,Wei-Qi Chen,Hai Lu,Xiang-Ning Jiang 한국식물학회 2009 Journal of Plant Biology Vol.52 No.5

A cinnamoyl coenzyme A reductase (CCR, EC 1.2.1.44), one of the key enzyme involved in lignin biosynthesis, was cloned from Populus tomentosa (Chinese white poplar). At the same time, a 4CL1 gene was cloned from P. tomentosa, too. The two genes were subcloned in pQE31 vector and expressed in Escherichia coli M15. Both of them were purified by Ni-NTA. Purified CCR protein was digested by trypsin and analyzed by HPLC-MS; the peptide segments had 27% similarity with the sequence of the CCR protein. 4CL was thought to be a neighbor enzyme of CCR in lignin biosynthesis. In this paper, a 4CL1 from P. tomentosa was cloned, and its enzyme reaction products were extracted for the substrates of CCR. Three 4CL1 enzyme reaction products were monitored by HPLC-MS and then the CCR enzyme reaction was detected by GC-MS. In the CCR reaction, the three corresponding aldehyde (p-coumaraldehyde, caffealdehyde, and coniferaldehyde) were detected and identified by Frontier3 software. The results showed that the CCR that we cloned from P. tomentosa had affinities with 4CL1 enzyme reaction products and a ptCCR that was cloned from aspen (Li et al., Plant Cell Physiol 46(7):1073–1082, 2005) only had affinity with feruloyl-CoA. The different results maybe depend on the different study method. The method of exacting 4CL enzyme products as the substrates of CCR in the paper was reliable and can be used in lignin biosynthesis network to detect the enzymes in the neighborhood that depended on the polarity of the substrates and products. This CCR gene had eight homology sequence CCR gene when a BLAST was conducted in Populus trichocarpa genome database. The CCR homology genes in Populus suggested that some CCRs may take part in the lignin biosynthesis, too. The gene family would be the hot spot in the future study.

IoT Makes Life Simpler: How to Improve the Chinese Consumer’s Intention to Use of LG HomNet Smart Home

Xiang-Dong Shen,Xi Chen,Yuting Jiang,Haixin Ji 한국무역학회 2022 Journal of Korea trade Vol.26 No.8

Purpose – The paper aims to develop the theory of TAM and perceived risk through a more comprehensive and rigorous understanding of the influencing factors of the consumer’s adoption of LG HomNet smart home from the perspective of trade-offs. Design/methodology – Based on the TAM and perceived risk theory, combined with the individual characteristics of consumers in the context of information technology as the external factors of the technology acceptance model, this paper constructs a theoretical model of the factors affecting the use intention of the consumer. It was empirically tested by using SEM, and survey data was collected from 458 respondents. Findings – The research results show that 9 hypotheses of the research model are supported and have reliable prediction accuracy. Consumers’ perceived interest, perceived connectivity and perceived controllability have a significant positive impact on their intention to use. In addition, this paper also confirmed the mediating effect of perceived usefulness and perceived ease of use. Originality/value – Consumers are very concerned about gains and losses. Low-level performance risks, security risks, and financial risks will drive the consumer to have a stronger intention to use, and financial risks have the strongest impact. This research provides a useful implication and guidance for smart home equipment manufacturers and service providers in product and service innovation and marketing and promotion strategies.

Default Prediction for Real Estate Companies with Imbalanced Dataset

Dong, Yuan-Xiang,Xiao, Zhi,Xiao, Xue Korea Information Processing Society 2014 Journal of information processing systems Vol.10 No.2

When analyzing default predictions in real estate companies, the number of non-defaulted cases always greatly exceeds the defaulted ones, which creates the two-class imbalance problem. This lowers the ability of prediction models to distinguish the default sample. In order to avoid this sample selection bias and to improve the prediction model, this paper applies a minority sample generation approach to create new minority samples. The logistic regression, support vector machine (SVM) classification, and neural network (NN) classification use an imbalanced dataset. They were used as benchmarks with a single prediction model that used a balanced dataset corrected by the minority samples generation approach. Instead of using prediction-oriented tests and the overall accuracy, the true positive rate (TPR), the true negative rate (TNR), G-mean, and F-score are used to measure the performance of default prediction models for imbalanced dataset. In this paper, we describe an empirical experiment that used a sampling of 14 default and 315 non-default listed real estate companies in China and report that most results using single prediction models with a balanced dataset generated better results than an imbalanced dataset.

One-step hydrothermal synthesis of Ag decorated TiO₂ nanoparticles for dye-sensitized solar cell application

Dong, Yong Xiang,Wang, Xuan Liang,Jin, En Mei,Jeong, Sang Mun,Jin, Bo,Lee, See Hoon Elsevier 2019 RENEWABLE ENERGY Vol.135 No.-

<P><B>Abstract</B></P> <P>Over the past few years, many efforts have been made to develop efficient visible light-activated photovoltaic materials. In this study, the Ag-TiO<SUB>2</SUB> nanoparticles were synthesized by using the hydrothermal method. Ag-TiO<SUB>2</SUB> nanoparticles showed significantly higher visible light absorption and better photovoltaic activity than anatase TiO<SUB>2</SUB>. TiO<SUB>2</SUB> nanoparticles were decorated with different concentrations of Ag to improve their photovoltaic properties. All the as-prepared TiO<SUB>2</SUB> and Ag-TiO<SUB>2</SUB> nanoparticles showed a pure anatase crystalline structure. In addition, the Ag-doped nanoparticles showed broader absorption edges (which shifted to higher wavelengths) than the undoped nanoparticles. The solar conversion efficiency (<I>η</I>) of 0.1M Ag-decorated (Ag<SUB>0.1</SUB>-TiO<SUB>2</SUB>) nanoparticle-based dye-sensitized solar cell (DSSC) was 6.44%, which is ∼22% higher than that of the TiO<SUB>2</SUB> nanoparticle-based DSSC (<I>η</I> of 5.05%).</P> <P><B>Highlights</B></P> <P> <UL> <LI> A hydrothermal method has been used to synthesize Ag-doped TiO<SUB>2</SUB> (Ag-TiO<SUB>2</SUB>) nanoparticles. </LI> <LI> Ag-TiO<SUB>2</SUB> nanoparticles showed high visible light absorption in the visible spectral region. </LI> <LI> Ag-TiO<SUB>2</SUB> nanoparticles showed high photocurrent density (<I>J</I> <SUB> <I>sc</I> </SUB>) and solar conversion efficiency (<I>η</I>). </LI> <LI> Ag doping increased the solar conversion efficiency by 22% than anatase TiO<SUB>2</SUB>. </LI> </UL> </P>

Molecular-Scale Electronics: From Concept to Function

Xiang, Dong,Wang, Xiaolong,Jia, Chuancheng,Lee, Takhee,Guo, Xuefeng American Chemical Society 2016 Chemical reviews Vol.116 No.7

<P>Creating functional electrical circuits using individual or ensemble molecules, often termed as 'molecular-scale electronics', not only meets the increasing technical demands of the miniaturization of traditional Si-based electronic devices, but also provides an ideal window of exploring the intrinsic properties of materials at the molecular level. This Review covers the major advances with the most general applicability and emphasizes new insights into the development of efficient platform methodologies for building reliable molecular electronic devices with desired functionalities through the combination of programmed bottom-up self-assembly and sophisticated top-down device fabrication. First, we summarize a number of different approaches of forming molecular-scale junctions and discuss various experimental techniques for examining these nanoscale circuits in details. We then give a full introduction of characterization techniques and theoretical simulations for molecular electronics. Third, we highlight the major contributions and new concepts of integrating molecular functionalities into electrical circuits. Finally, we provide a critical discussion of limitations and main challenges that still exist for the development of molecular electronics. These analyses should be valuable for deeply understanding charge transport through molecular junctions, the device fabrication process, and the roadmap for future practical molecular electronics.</P>

Mechanically Controllable Break Junctions for Molecular Electronics

Xiang, Dong,Jeong, Hyunhak,Lee, Takhee,Mayer, Dirk WILEY‐VCH Verlag 2013 ADVANCED MATERIALS Vol.25 No.35

<P><B>Abstract</B></P><P>A mechanically controllable break junction (MCBJ) represents a fundamental technique for the investigation of molecular electronic junctions, especially for the study of the electronic properties of single molecules. With unique advantages, the MCBJ technique has provided substantial insight into charge transport processes in molecules. In this review, the techniques for sample fabrication, operation and the various applications of MCBJs are introduced and the history, challenges and future of MCBJs are discussed.</P>

Synthesis, characterization, and antioxidant activity in vitro of selenium‑Euryale ferox Salisb. polysaccharide

Dong Fang,Zheng Hu-Zhe,Jeong Woo-Sik,Chung Shin-Kyo,Qu Zhong-Yuan,Zou Xiang,Liu Chen,Xiang Qiong,Feng Feng 한국응용생명화학회 2021 Applied Biological Chemistry (Appl Biol Chem) Vol.64 No.S

In order to obtain and explore selenide composed of selenium and polysaccharide, three parameters were selected to optimize the synthesis process of selenium-Euryale ferox Salisb. polysaccharide (Se-ESPS) by Box-Behnken design. Furthermore, ESPS-B1 separated from ESPS was selenitized to Se-ESPS-B1 by the optimal synthesis process, then the characterization, and antioxidant activity in vitro of Se-ESPS-B1 were explored. The result manifested that the Se content of Se-ESPS was (2.915 ± 0.03) mg/g according to the optimal synthesis process of Se-ESPS (reaction time at 5 h, reaction temperature at 81 ℃, weight ratio of Na2SeO3 to ESPS at 0.9 g/g). A series of detection results indicated that the characterizations of Se-ESPS-B1 were apparently distinguished from that of ESPS-B1. Moreover, the antioxidant experiments in vitro demonstrated that Se-ESPS-B1 could exert antioxidant activity by scavenging DPPH, ABTS,·OH, and increasing reduction ability. In conclusion, the synthesis process is an effective approach to harvest seleniumpolysaccharide, and Se-ESPS-B1 may be utilized as a potential antioxidant or selenium nutritional supplement.