PRESENT SITUATION OF WATER RESOURCES IN YIYUAN COUNTY AND COUNTERMEASURES FOR SUSTAINABLE DEVELOPMENT

HONGXIA TANG,ZHIFANG ZHOU 한국수자원학회 2005 한국수자원학회 학술대회 Vol.2005 No.1

One-step synthesis of Pt-Pd catalyst nanoparticles supported on few-layer graphene for methanol oxidation

Hongxia Wang,Leimei Sheng,Xinluo Zhaoa,Kang An,Zhongmin Ou,Yanghao Fang 한국물리학회 2018 Current Applied Physics Vol.18 No.8

In this study, Pt-Pd nanoparticles (NPs) supported on few-layer graphene (FLG) have been firstly prepared by one-step arc discharge evaporation of carbon electrodes containing both Pt and Pd elements. The few-layer graphene and Pt-Pd nanoparticles were achieved simultaneously through the evaporation process. After a hightemperature hydrogen treatment, the Pt-Pd/graphene was applied in the study of methanol oxidation in direct methanol fuel cell. The total weight of electrocatalyst keeps 2 wt% of the electrode. The sample with a mass ratio of Pt:Pd=3:1 (H-Pt3Pd1/G) exhibits better electrocatalytic activity (198 mA mg-1 pt) and better tolerance to carbon monoxide(CO) poisoning (If/Ib=1.26). It is noteworthy that the value of If/Ib can reach to 1.55 for the sample with the mass ratio of Pt:Pd=2:1 (H-Pt2Pd1/G),which implies its excellent ability of CO tolerance. The introduction of Pd element may open a new strategy to improve the CO tolerance by arc discharge evaporation.

NDFT-based Image Steganographic Scheme with Discrimination of Tampers

( Hongxia Wang ),( Mingquan Fan ) 한국인터넷정보학회 2011 KSII Transactions on Internet and Information Syst Vol.5 No.12

A new and secure image steganographic scheme based on nonuniform discrete Fourier transform (NDFT) is proposed in this paper. First, the chaotic system is introduced to select embedding points randomly in NDFT domain suitable range, and NDFT is implemented on every non-overlapping block of eight consecutive pixels. Second, the secret messages are scrambled by chaotic systems, and embedded into frequency coefficients by quantization method. The stego-image is obtained by inverse NDFT (INDFT). Besides, in order to discriminate tampers, the low frequency wavelet coefficients of 7 most significant bits (MSBs) of the stego-image are converted into the binary sequence after nonuniform scalar quantization. Then the obtained binary sequence is scrambled by the chaotic systems, and embedded into the least significant bit (LSB) of the stego-image. Finally, the watermarked stego-image can be obtained by a new improved LSB steganographic method. The embedded secret messages can be extracted from the watermarked stego-image without the original cover image. Experimental results show the validity of the proposed scheme, and dual statistics attacks are also conducted to indicate the security.

Geometrically Invariant Image Watermarking Using Connected Objects and Gravity Centers

( Hongxia Wang ),( Bangxu Yin ),( Linna Zhou ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.11

The design of geometrically invariant watermarking is one of the most challenging work in digital image watermarking research area. To achieve the robustness to geometrical attacks, the inherent characteristic of an image is usually used. In this paper, a geometrically invariant image watermarking scheme using connected objects and gravity center is proposed. First, the gray-scale image is converted into the binary one, and the connected objects according to the connectedness of binary image are obtained, then the coordinates of these connected objects are mapped to the gray-scale image, and the gravity centers of those bigger objects are chosen as the feature points for watermark embedding. After that, the line between each gravity center and the center of the whole image is rotated an angle to form a sector, and finally the same version of watermark is embedded into these sectors. Because the image connectedness is topologically invariant to geometrical attacks such as scaling and rotation, and the gravity center of the connected object as feature points is very stable, the watermark synchronization is realized successfully under the geometrical distortion. The proposed scheme can extract the watermark information without using the original image or template. The simulation results show the proposed scheme has a good invisibility for watermarking application, and stronger robustness than previous feature-based watermarking schemes against geometrical attacks such as rotation, scaling and cropping, and can also resist common image processing operations including JPEG compression, adding noise, median filtering, and histogram equalization, etc.

A fatigue and low-energy shock-based approach to predict fatigue life

Hongxia Chen,Yunxia Chen,Yi Yang 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.10

A product that is characterized by fatigue-induced failure always suffers from complex fatigue loads, and the damage caused by fatigueloads accumulates with time. The existence of shocks not only directly increases the risk of failure but also affects the magnitude ofdamage caused by fatigue loads. This study analyzes the reliability of a product when fatigue loads and shocks are both involved. Thefeatures of fatigue damage and shock damage are investigated, and the coupling relationship between them is discussed. With assumptionsof high cycle fatigue and low-energy shocks, the effect of shocks on fatigue damage is expressed as the degradation of the ultimatestrength of the product. An overall reliability model with fatigue and shock failures is developed. Two conditions are considered for thereliability model: shocks with fixed period and shocks with a homogeneous Poisson process. Three important cumulative damage theoriesare adopted. An engineering case of actuator cylinder is provided to demonstrate the proposed approach.

FUNCTIONALIZED MULTIWALLED CARBON NANOTUBES BY GRAFTING HYPERBRANCHED POLYSILOXANE

HONGXIA YAN,YUAN JIA,LEI MA,YANLI WANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.3

Multi-walled carbon nanotubes (MWCNTs) are grafted with hyperbranched polysiloxane(HBPSi) by an e±cient hydrosilylation method. In this hydrosilylation process, hydroxylatedMWCNTs (HO-MWCNTs) are ¯rst functionalized by triethoxyvinylsilane to introduce carbon –carbon double bonds (C ¼ C) on the surface of MWCNTs. The C ¼ C is then reacted with themonomer of methylbis(dimethylvinylsiloxy)silane in the presence of the platinum – carbon cata-lyst, thus HBPSi is ultimately grafted on the surface of MWCNTs. Fourier transform infraredspectrometry (FTIR), Transmission electron microscope (TEM) and X-ray photoelectron spec-troscopy (XPS) are employed to characterize the changes in MWCNTs surface morphology,chemistry and physical conditions at di®erent processing stages. The content of HBPSi on thesurface of MWCNTs was also measured by the thermogravimetric analysis (TGA). The resultsindicate that the HBPSi successfully grafted on the surface of MWCNTs, and the dispersion ofMWCNTs in organic solvent is also improved after functionalization.

Why do Sovereign Wealth Funds Invest in Asia?

Hongxia Zhang,Heeho Kim 한국무역학회 2021 Journal of Korea trade Vol.25 No.1

Purpose – This paper aims to examine the determinants of SWFs’ investment in Asian countries and to identify consistent investment patterns of SWFs in specific target firms from Asia, particularly China and South Korea. Design/methodology – This study extends the Tobin’s Q model to examine the relationship between SWF investments in target firms and their returns with other firm-level control variables. We collect consistent data on SWF investments and the matched firm-level data on target firms, which of observation is 1,512 firms (333 in South Korea and 1,179 in China) targeted by 20 SWF sources during 1997–2017. The panel random effect model is used to estimate the extended Tobin’s Q model. The robustness of the estimations is tested by the simultaneous equation models and the panel GEE model. Findings – The evidence shows that sovereign wealth funds are more inclined to invest in the financial sector with a monopoly position and in large firms with higher growth opportunity and superior cash asset ratios in China. In contrast to their investments in China, sovereign wealth funds in South Korea prefer to invest in strategic sectors, such as energy and information technology, and in large firms with high performance and low leverage. Sovereign wealth funds’ investments tend to significantly improve the target firm’s performance measured by sales growth and returns in both Korea and China. Originality/value – The existing literature focuses on examining the determination of SWFs investment in the developed countries, such as Europe and the United States. Our paper contributes to the literature in three ways; first, we analyzes case studies of SWF investments in Asian markets, which are less developed and riskier. Second, we examine whether the determination of SWF investment in Asian target firms depends on the different time periods, on types of sources of SWFs, and on acquiring countries. Third, our research uses vast sample data on target firms in longer time periods (1997-2017) than other previous studies on the SWFs for Asian markets.

NEIGHBORHOOD CONDITION AND FRACTIONAL f-FACTORS IN GRAPHS

Hongxia Liu,Guizhen Liu 한국전산응용수학회 2009 Journal of applied mathematics & informatics Vol.27 No.5

Let G be a graph with vertex set V (G) and let f be a nonnegative integer-valued function defined on V (G). A spanning subgraph F of G is called a fractional f-factor if dhG(x) = f(x) for all x ∈ V (G), where dhG(x) = ∑e2Ex h(e) is the fractional degree of x ∈ V (F) with Ex = {e : e = xy ∈ E(G)}. In this paper it is proved that if δ(G) ≥ <수식>, n > <수식> and |NG(x1)∪ NG(x2) ∪ ·· · ∪ NG(xk)|≥ <수식> for any independent subset {x1, x2, ..., xk} of V (G), then G has a fractional f-factor . Where k≥ 2 be a positive integer not larger than the independence number of G, a and b are integers such that 1≤ a≤ f(x) ≤b for every x ∈ V (G). Furthermore, we show that the result is best possible in some sense. Let G be a graph with vertex set V (G) and let f be a nonnegative integer-valued function defined on V (G). A spanning subgraph F of G is called a fractional f-factor if dhG(x) = f(x) for all x ∈ V (G), where dhG(x) = ∑e2Ex h(e) is the fractional degree of x ∈ V (F) with Ex = {e : e = xy ∈ E(G)}. In this paper it is proved that if δ(G) ≥ <수식>, n > <수식> and |NG(x1)∪ NG(x2) ∪ ·· · ∪ NG(xk)|≥ <수식> for any independent subset {x1, x2, ..., xk} of V (G), then G has a fractional f-factor . Where k≥ 2 be a positive integer not larger than the independence number of G, a and b are integers such that 1≤ a≤ f(x) ≤b for every x ∈ V (G). Furthermore, we show that the result is best possible in some sense.

A three-dimensional in vitro culture model for primary neonatal rat ventricular myocytes

Hongxia Zheng,Shanshan Liu,Wei-ming Tian,Hong-ji Yan,Yao Zhang,Yu Li 한국물리학회 2012 Current Applied Physics Vol.12 No.3

To overcome bad prognosis of patients with heart failure and the lack of organ donors, cardiac tissue engineering has developed as a biomimetic approach to repair, replace, and regenerate the damaged cardiac tissue. During the past decade years, researchers are devoted to find different natural and/or synthetic materials that can build appropriate physical structures to contain and organize implanted cells. In this study, we present a new method for primary neonatal rat cardiomyocytes culture in vitro using alginate/collagen/chitosan hydrogel. To investigate the feasibility of this material as scaffold for cardiac myocytes, neonatal rat ventricular myocytes were isolated and encapsulated in alginate-based beads cross-linked with calcium ion. The growth of cells was evaluated by staining with a-Sarcomeric actin (a-SCA) and Troponin T type 2 (TNNT2), and the viability of cardiomyocytes was studied in vitro by assessing the expression levels of several cardiac ion channels, including CACNL1A1, Connexin 43 and SCN5A. The results showed a significant increase in cardiac myocytes number, and the expression levels of CACNL1A1, Connexin 43 (Cx43) were up-regulated significantly except SCN5A, as compared with twodimensional cultures. Moreover, extracellular matrix produced by the seeded cells themselves was observed by staining with fibronectin. Taken together, these findings indicate that this alginate/collagen/chitosan hydrogel bead is suitable for supporting the growth and retaining the morphologic and electrophysiologic characteristics of primary cultured rat cardiac muscle cells.

Approaching Cicero’s Contact and Communication Zones: Stereotypes, Belittling, and Inverted Roles in Pro Cluentio

Hongxia Zhang 중앙대학교 중앙사학연구소 2020 중앙사론 Vol.0 No.51

본고는 하나의 중요한 사례인 『크루엔티우스를 위한 변론』에 나타난 키케로의 수사적 의사소통 전략에 초점을 맞춘다. 서론에서 “접촉지대”와 “고정관념”의 의미, 그리고 사회학자 Erving Goffman의 상호작용 모델을 분석의 틀로 간략하게 정의하여 짧게 소개한 뒤에, 본문을 두 개의 주요 부분으로 나눠 비교하는 방식으로 진행한다. 로마 사회의 고상한 남성과 어머니라는 이미지의 전형을 키케로가 변호하는 피고인 대 오피아니쿠스 Oppianicus the Elder와 사시아 Sassia의 적대자들로 구성된 반대 이미지와 비교함으로써 키케로가 적용한 전략을 보여준다. 로마의 남성과 로마의 어머니에 반대하는 자들에 대한 키케로의 묘사는 다른 무엇보다도 고정관념, 과소평가, 그리고 역할뒤집기의 충돌에 의해 세밀하게 전개된다. 전략을 짜는 것에 대한 상세한 검토를 통해, 키케로의 설득 방식을 상하 의사소통방식의 일방적 행위가 아닌, 이미 존재하는 청중의 경험과 기대라는 틀 속에서 그가 쌓아올린 이미지들을 세심한 계획 하에 고정시킨 것으로 이해하려 했다. 이러한 구도를 정확하게 인지한 상태에서 키케로는 크루엔티우스의 결백함을 증명하기 위해 목표를 정하고 틀을 구축하여 최종적으로 판사들을 설득시켰다. This article focuses on the rhetorical communication strategy of Cicero in one important course case, Pro Cluentio. After a short introduction where I briefly define the meaning of “contact zone”, “stereotype”, and the interaction model of the sociologist Erving Goffman as framework of my analysis, I proceed in two main sections, and in a comparative way. By contrasting the typical image of being a decent Roman man and Roman mother in Roman society with the anti-images constructed of the antagonists of Cicero’s defendant, Oppianicus the Elder and Sassia, I shall show the case strategy applied by our orator. Cicero’s portrayal of an anti-Roman man and an anti-Roman mother is carefully conducting by clashing stereotypes, belittling, and inverting roles, among others. Through a detailed examination of the framing strategy, I attempt to understand Cicero’s way of persuasion not as a one-directional act of top-down-communication but as a carefully designed anchoring of his constructed images in the already existing frames of experience and expectation of the audience. Exactly knowing these frames, Cicero targeted, framed, and eventually convinced the judges of the innocence of Cluentius.