Bead Necklace-Shaped Single Walled Carbon Nanotube-Polypyrrole Nanocomposites for Ammonia Gas Sensor

Wen Xuan Du,변준호,강성민,Masaki Takada,김진열 한국고분자학회 2021 Macromolecular Research Vol.29 No.6

The nanocomposite of bead necklace-like structure in which single stands of single-walled carbon nanotube (SWCNT) are impregnated in several polypyrrole (PPy)/phenylalanine (PA), PPy@PA, nanoparticles, with an average bead diameter of 80 nm and SWCNT length of 5 μm, as a sensing material for detecting ammonia gas, was synthesized by simple emulsion polymerization. The synthesized nanocomposite showed an electrical conductivity more than 5 times higher than that of PPy alone with a selective reactivity to ammonia gas. In addition, it exhibited a high sensitivity of less than 100 ppb at room temperature and was not significantly affected by the sensitivity even under the humidity conditions of 0 ~70% RH (relative humidity).

Associations of Single Nucleotide Polymorphisms in miR-146a, miR-196a, miR-149 and miR-499 with Colorectal Cancer Susceptibility

Du, Wei,Ma, Xue-Lei,Zhao, Chong,Liu, Tao,Du, Yu-Liang,Kong, Wei-Qi,Wei, Ben-Ling,Yu, Jia-Yun,Li, Yan-Yan,Huang, Jing-Wen,Li, Zi-Kang,Liu, Lei Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.2

Background: MicroRNAs (miRNAs) are an abundant class of endogenous small non-coding RNAs of 20-25 nucleotides in length that function as negative gene regulators. MiRNAs play roles in most biological processes, as well as diverse human diseases including cancer. Recently, many studies investigated the association between SNPs in miR-146a rs2910164, miR-196a2 rs11614913, miR-149 rs229283, miR-499 rs3746444 and colorectal cancer (CRC), which results have been inconclusive. Methodology/Principal Findings: PubMed, EMBASE, CNKI databases were searched with the last search updated on November 5, 2013. For miR-196a2 rs11614913, a significantly decreased risk of CRC development was observed under three genetic models (dominant model: OR = 0.848, 95%CI: 0.735-0.979, P = 0.025; recessive model: OR = 0.838, 95%CI: 0.721-0.974, P = 0.021; homozygous model: OR = 0.754, 95%CI: 0.627-0.907, P = 0.003). In the subgroup analyses, miR-$196a2^*T$ variant was associated with a significantly decreased susceptibility of CRC (allele model: OR = 0.839, 95%CI: 0.749-0.940, P = 0.000; dominant model: OR = 0.770, 95%CI: 0.653-0.980, P = 0.002; recessive model: OR = 0.802, 95%CI: 0.685-0.939, P = 0.006; homozygous model: OR = 0.695, 95%CI: 0.570-0.847, P = 0.000). As for miR-149 rs2292832, the two genetic models (recessive model: OR = 1.199, 95% CI 1.028-1.398, P = 0.021; heterozygous model: OR = 1.226, 95% CI 1.039-1.447, P = 0.013) demonstrated increased susceptibility to CRC. On subgroup analysis, significantly increased susceptibility of CRC was found in the genetic models (recessive model: OR = 1.180, 95% CI 1.008-1.382, P = 0.040; heterozygous model: OR = 1.202, 95% CI 1.013-1.425, P = 0.013) in the Asian group. Conclusions: These findings supported that the miR-196a2 rs11614913 and miR-149 rs2292832 polymorphisms may contribute to susceptibility to CRC.

Distributed Optimization Algorithms on Structurally Balanced Signed Networks

Wen Du,Yusheng Wei,Mingjun Du 제어로봇시스템학회 2021 제어로봇시스템학회 국제학술대회 논문집 Vol.2021 No.10

In this paper, we consider the distributed optimization problem under structurally balanced signed graph. First, we convert the original distributed optimization problem into a conditional minimum problem under the condition that the graph is structurally balanced. Our goal is to find the saddle points of augmented Lagrange function. Inspired by the Lagrange multiplier method, we present our algorithms for both undirected graph and digraph, and show that our algorithms asymptotically converge to the global minimizer. Particularly, our algorithms for digraph can not only handle the weight balanced case but the weight unbalanced case. We show that the unsigned graph is a special case of our signed graph cases. Finally, theoretical results are illustrated by numerical simulations.

Head-on Collision Between Two Envelope Solitary Waves in a Granular Medium

Wen-Qing Du,Jian-An Sun,Juan-Fang Han,Wen-Shan Duan,Yang-Yang Yang,Xin Jiang 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.75 No.11

We investigated the head-on collision between two envelope solitary waves. Head-on collisions between two envelope solitary waves are first discussed in one-dimension (1D) granular chains. The interesting result is that no phase shift or phase delay detected after the head-on collision between two envelope solitary waves. The maximum amplitude during the head-on collision between two envelope solitary waves is also found to be less than the sum of the amplitudes of the two envelope solitary waves, but is larger than the amplitude of the either of the envelope solitary waves.

Event-triggering Signed-average Consensus Algorithms under Directed Signed Networks

Wen Du,Yusheng Wei,Shengli Fu 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.9

In this paper, we consider a signed-average consensus problem under signed networks in which the interactions between agents depicted by edges with positive and negative weights. In order to decrease communication and computation burden, two dynamic event-triggering procotols have been proposed under the signed network that is depicted by the signed digraph. We prove that signed-average consensus is reached exponentially when the signed digraph is structurally balanced and strongly connected; state stability is reached when the signed digraph is structurally unbalanced and strongly connected; and Zeno behavior is excluded. Besides, when the underlying topology is structurally balanced (structurally unbalanced, respectively), we show that static event-triggering laws, which also achieve signed-average consensus (state stability, respectively), are special cases of the dynamic eventtriggering laws. We also conclude that when all agents cooperate with each other, which implies that the underlying signed digraph collapses into an unsigned digraph, our algorithms still work. Finally, numerical examples are given to verify our theoretical results.

現代漢語"V+P+NP"格式硏究綜述

두문하 ( Wen Xia Du ),임소영 ( So Young Yim ) 중국학연구회 2009 中國學硏究 Vol.- No.49

Cervical Cancer Mortality Trends in China, 1991-2013, and Predictions for the Future

Du, Pei-Ling,Wu, Ku-Sheng,Fang, Jia-Ying,Zeng, Yang,Xu, Zhen-Xi,Tang, Wen-Rui,Xu, Xiao-Ling,Lin, Kun Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.15

Background: To analyze cervical cancer mortality trends in China from 1991-2013 and forecast the mortality distribution in future five years (2014-2018), and provide clues for prevention and treatment. Materials and Methods: Mortality data for cervical cancer in China from 1991 to 2013 were used to describe the epidemiological characteristics and distribution, including the trend of the standardized mortality rate, urban-rural differences, and age variation. Trend-surface analysis was used to analyze the geographical distribution of mortality. Curve estimation, time series, gray modeling, and joinpoint regression were performed to predict and forecast mortality trends. Results: In recent years, the mortality rate of cervical cancer has increased, and there is also a steady increase in the incidence from 2003 to 2013 in China. Mortality rates in rural areas are higher than in urban areas. The mortality dramatically increases in the 40+ yr age group, reaching a peak in the >85 yr age group. In addition, geographical analysis showed that the cervical cancer mortality increased from the southwest to west-central and from the southeast to northeast of the country. Conclusions: The incidence rate and the mortality rate are increasing from 1991 to 2013, and the predictions show this will continue in the future. Thus, implementation of prevention and management programs for cervical cancer are necessary in China, especially for rural areas, young women in urban areas, and high risk regions (the west-central).

Fuzzy Control with Pole Assignment and Variance Constraints for Continuous-time Perturbed Takagi-Sugeno Fuzzy Models: Application to Ship Steering Systems

Wen-Jer Chang,Yan-Horng Lin,Jialu Du,Chih-Ming Chang 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.10

The stability analysis and controller design of stochastic systems have become much more important because the stochastic behaviors usually exist in practical nonlinear systems. In this paper, a robust fuzzy controller design approach is proposed with multiple constraints, including state variance constraints, output variance constraints, and pole placement constraints. At first, nonlinear systems are expressed as the Takagi-Sugeno fuzzy model, and the parallel distributed compensation method is applied to design the robust fuzzy controllers. Next, considering the stability analysis and the performance constraints of perturbed Takagi-Sugeno fuzzy models, Lyapunov conditions are developed based on covariance control theory, pole placement theory and robust control theory. By constructing the stability conditions with multiple constraints, the proposed fuzzy control problem can be effectively transferred into the linear matrix inequality problem. It can be solved by the convex optimal programming algorithm. At last, a nonlinear ship steering system is selected to verify the effectiveness and applicability of the proposed robust fuzzy controller design method.

Enhancement of the Polar Coercive Force for Annealed Co/Ir(111) Ultrathin Films

Wen-Yuan Chan,Du-Cheng Tsai,Wei-Hsiang Chen,Cheng-Hsun-Tony Chang,Jyh-Shen Tsay 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.12

The alloy formation and the magnetic properties of Co/Ir(111) ultrathin films have been investigated. As the temperature is increased above 400 K, interdiffusion of Co and the Ir substrate occurs. Due to a compositional change in the surface layers, the polar coercive force is greatly enhanced. At temperatures above 600 K, magnetic hysteresis appears only in the polar configuration. Thisshows that the easy axis of the magnetization of Co/Ir(111) may be stabilized in the direction ofthe surface normal by thermal-annealing treatments. From systematic investigations of Co/Ir(111)ultrathin films thinner than 4 monolayers, a magnetic phase diagram has been established. Accordingto the compositional changes and related magnetic properties, the phase diagram can beseparated into three regions. In region I at temperatures below 400 K, Co films are ferromagnetic. In region II where atomic interdiffusion occurs in the surface layers, an enhanced polar coerciveforce is observed. The phase transition from phase I to II is related to the interdiffusion betweenthe Co overlayer and the iridium substrate. In region III for low coverage or at high temperatures,a nonferromagnetic behavior is observed. The phase transition from phase II to III is mainly dueto the reduced atomic percent of cobalt in the Co-Ir alloy and to the lowered Curie temperaturecaused by a reduction in the thickness of the magnetic layers.

Improved Sufficient LMI Conditions for the Robust Stability of Timedelayed Neutral-type Lur’e Systems

Wen-Yong Duan,Baozhu Du,Yan Li,Cuifeng Shen,Xuelai Zhu,Xiaofan Li,Jian Chen 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.5

In this paper, we focus on the problem of the absolute and robustly absolute stability for the neutraltype Lur’e system with time-varying delay. By combining the piecewise analysis theory with extended doubleintegral and Wirtinger-based inequalities technology, some new delay-dependent stability criteria for the absolute and robustly absolute stability are proposed via Lyapunov-Krasovskii functional (LKF) approach. The stability conditions can be expressed as convex linear matrix inequality (LMI) framework, which can be solved by using standard LMI convex optimization solvers. The criteria proposed in this paper are less conservative than some previous ones. Finally, some numerical examples are presented to show the effectiveness of the proposed approach.