College Students' self-positioning and the cell-phone consumption

Shanhua Yang 한국방송학회 2004 한국방송학회 세미나 및 보고서 Vol.- No.-

In recent years it has been popular to see the use of cell phones among college students in China. Based on series of interviews with college students in Beijing, this paper tries to study the self-positioning of college students via understanding their consumption pattern in cell phone usage. The self-positioning here involves an understanding of their self-identification and the influence of the socio-ecological context surrounding them. Most students see themselves as a group who basically has to rely on their families for financial support. Consequently, their cell-phone consumption turns on a restrained and rational look. On the other hand, the proportion of people who can be college students remains relatively low these days. College students are expected to gain higher positions in society, and they do not need to prove their success by luxuries. This contrasts sharply with the consumption pattern found in other social groupings. The third aspect of their identification is that certain criteria in communication and sociability - such as independence, selectiveness, and taste - also influence their consumption practice. As for the socio-ecological context, most of them live on campus. They need not only to pay attention to their timetables, but also to avoid bothering others. Secondly, different kinds of communication instruments are accessible. In between the choices of instruments is a result of students' articulation of the socio-ecological context they are situated in. Finally, their selection of phone models and usage patterns are influenced by each other, especially by certain groups they belong to, and interpersonal relations are strengthened or reconstructed in such a process. To conclude, if we want to depict the cell phone usage and its social implication for college students in China, we should take the unique self-positioning of the students into account and set this articulation against the campus life in China.

Simple fabrication of single- and multi-layer polymer nanotubes by spin-casting method within anodized aluminum oxide (AAO) templates

Jin, Shanhua,Lee, Yuwon,Jeon, Seung-Min,Sohn, Byeong-Hyeok,Chae, Weon-Sik,Lee, Jin-Kyu The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.44

<P>Polymer nanotubes (PNTs) were fabricated by a simple spin casting of the polymer solution into nanochannels of anodic aluminum oxide (AAO) membranes. The thickness of the polymer nanotubes could be reproducibly controlled by changing the concentration of the polymer solutions. Furthermore, multiple spin casting of different polymer solutions could produce multi-layer PNTs (MPNTs), whose formation was confirmed by a selective staining technique in transmission electron microscope (TEM) experiments. Luminescent molecules such as blue-emitting Ir(<SMALL>III</SMALL>) complex and orange-emitting rhodamine B derivative could be uniformly incorporated into each polymer layer simply by mixing them into each polymer solution. These dye-incorporated MPNTs could be easily fabricated by the same spin casting method. Their optical properties were determined by UV-Vis spectroscopy, photoluminescence, and fluorescence microscopy. The morphology of the nanotubes was characterized using a field emission-scanning electron microscope (FE-SEM) and TEM. These results showed that the MPNTs could be reproducibly fabricated throughout the length of the nanochannels of the AAO templates.</P> <P>Graphic Abstract</P><P>Various single-layer and multi-layer polymer nanotubes were successfully fabricated by a simple spin-casting method using AAO templates. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm34726a'> </P>

HGM을 이용한 화포천 습지의 기능평가

윤선화(Yin Shanhua),김덕길(Kim Duck Gil),김형수(Kim Hung Soo),곽재원(Kwak Jae Won) 대한토목학회 2010 대한토목학회논문집 B Vol.30 No.1B

습지는 종 다양성이 높고 영양물질이 풍부하며 생산성이 높은 생태계로서 수문학적으로나 생태학적으로 여러 가지 기능을 수행하고 있다. 본 연구는 습지 기능을 평가하는데 이용되는 다양한 평가 방법중 하나인 HGM (Hydrogeomorphic)을 적용하여 화포습지에 대한 기능평가를 실시하였다. HGM방법은 하나의 기준습지를 선정한 후 대상습지와의 비교를 통해 습지의 기능을 지수화하여 평가하는 방법이다. 본 연구에서는 람사르 협약에 등록된 우포늪을 기준습지로 선정하여 화포천 습지의 기능을 평가한 결과 대부분의 기능이 0.6점 이상으로 우포늪과 비교하여 비교적 긍정적인 기능지수의 값을 보여주었다. 이는 화포천 습지가 수문학적, 생지화학적, 식물서식처, 동물서식처 기능을 수행하고 있고 보전 및 관리를 한다면 보다 더 효과적으로 기능을 수행할 수 있을 것으로 판단된다. A wetland is an ecosystem which has high species diversity, rich nutritional substances and high productivity. In this study we used the HGM(Hydrogeomorphic) approach among various evaluation models for the assessment of the Hwapo riverine wetland function. HGM is a method which estimates the functional index of a study wetland by comparing it with a reference wetland. In this study the Woopo wetland which is registered in the Ramsar Convention was selected as a reference wetland to assess the functional index of the Hwapo wetland. As the results, we obtained the functional index values over 0.6 for most indices of the Hwapo riverine wetland. Therefore we found that the Hwapo riverine wetland shows relatively high functional index values comparing with the Woopo wetland and it has valuable hydrological, biochemical, plant habitat, and animal habitat functions.

Influence of thermal annealing on bonding structure and dielectric properties of fluorinated amorphous carbon film

Zhaoyuan Ning,Shanhua Cheng,Shendong Yang 한국물리학회 2002 Current Applied Physics Vol.2 No.6

Keywords: The bond structure and dielectric properties of fluorinated carbon films after thermal annealing in N2 ambience were studied. The results show that dielectric constant and dielectric loss increased, and optical gap decreased with increasing annealing temperature. The composition and bonding structure of the films were obtained by FTIR and XPS analysis. The data indicate that fluorine-to carbon ratio decreased and C@C group increased in the films after the films were annealed. It suggests that the structural and dielectric property changes correlate with the release of fluorine and increase of cross-linking during the annealing. 2002 Elsevier Science B.V. All rights reserved.

Study on the flexural behavior of corroded built-up cold-formed thin-walled steel beams

Zongxing Zhang,Shanhua Xu,Han Li,Rou Li,Biao Nie 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.37 No.3

Eight cold-formed thin-walled steel beams were performed to investigate the effect of corrosion damage on the flexural behavior of steel beams. The relationships between failure modes or load-displacement curves and corrosion degree of steel beams were investigated. A series of parametric analysis with more than forty finite element models were also performed with different corrosion degrees, types and locations. The results showed that the reduction of cross-section thickness as well as corrosion pits on the surface would lead to a decline in the stiffness and flexural capacity of steel beams, and gradually intensified with the corrosion degree. The yield load, ultimate load and critical buckling load of the corroded specimen IV-B46-4 decreased by 22.2%, 26% and 45%, respectively. The failure modes of steel beams changed from strength failure to stability failure or brittle fracture with the corrosion degree increasing. In addition, thickness damage and corrosion pits at different locations caused the degradation of flexural capacity, the worst of which was the thickness damage of compression zone. Finally, the method for calculating flexural capacity of corroded cold-formed thin-walled steel beams was also proposed based on experimental investigation and numerical analysis results.

Time-Dependent Reliability Analysis of Corroded Steel Beam

Biao Nie,Shanhua Xu,Youde Wang 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.1

The time-dependent reliability of corroded steel beam was investigated. Nine groups of specimenswere subjected to accelerate corrosion by the outdoor periodic spray test and monotonic tensile test. The surface profile of corroded steel plates and the 3D data of corrosion depth were measured by the three-dimensional non-contact surface topography instrument (PS50 3D). The probability distribution of corrosion depth and nominal yield strength of corroded steel plates were studied. Finally, a probabilistic limit state equation for corroded steel beams was established and the time-dependent failure probability and reliability index of corroded steel beams was calculated by Monte Carlo simulation method (MCS). The results of study show that the corrosion depth on steel plate surface and nominal yield strength of corroded steel plate conformed to the normal distribution. With the increase of corrosion time, the average, the standard deviation of the corrosion depth and relative yield strength increased while the mean of relative yield strength, nominal yield strength, nominal ultimate strength, the elongation decreased. The reliability index decreased rapidly with corrosion time, which shows that the reliability of steel structures under the aggressive environmental should be caused attention.

Experimental and numerical studies on the behaviour of corroded cold-formed steel columns

Nie Biao,Xu Shanhua,Zhang Haijiang,Zhang Zongxing 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.35 No.5

Experimental investigation and finite element analysis of corroded cold-formed steel (CFS) columns are presented. 11 tensile coupon specimens and 6 stub columns of corroded CFS that had a channel section of C160x60x20 were subjected to monotonic tensile tests and axial compression tests, respectively. The degradation laws of the mechanical properties of the tensile coupon specimens and stub columns were analysed. An appropriate finite element model for the corroded CFS columns was proposed and the influence of local corrosion on the stability performance of the columns was studied by finite element analysis. Finally, the axial capacity of the experimental results was compared with the predictions obtained from the existing design specifications. The results indicated that with an increasing average thickness loss ratio, the ultimate strength, elastic modulus and yield strength decreased for the tensile coupon specimens. Local buckling deformation was not noticeable until the load reached about 90% of the ultimate load for the non-corroded columns, while local buckling deformation was observed when the load was only 40% of the ultimate load for the corroded columns. The maximum reduction of the ultimate load and critical buckling load was 57% and 81.7%, respectively, compared to those values for the non-corroded columns. The ultimate load of the columns with web thickness reduced by 2 mm was 53% lower than that of the non-corroded columns, which indicates that web corrosion most significantly affects the bearing capacity of the columns with localized corrosion. The results predicted using the design specifications of MOHURD were more accurate than those predicted using the design specifications of AISI.

Oxidative stress and calcium dysregulation by palmitate in type 2 diabetes

Luong Dai Ly,Shanhua Xu,최성경,하채명,THOUDAMTHEMIS,차승규,Andreas Wiederkehr,Claes B. Wollheim,이인규,박규상 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-

Free fatty acids (FFAs) are important substrates for mitochondrial oxidative metabolism and ATP synthesis but also cause serious stress to various tissues, contributing to the development of metabolic diseases. CD36 is a major mediator of cellular FFA uptake. Inside the cell, saturated FFAs are able to induce the production of cytosolic and mitochondrial reactive oxygen species (ROS), which can be prevented by co-exposure to unsaturated FFAs. There are close connections between oxidative stress and organellar Ca2+ homeostasis. Highly oxidative conditions induced by palmitate trigger aberrant endoplasmic reticulum (ER) Ca2+ release and thereby deplete ER Ca2+ stores. The resulting ER Ca2+ deficiency impairs chaperones of the protein folding machinery, leading to the accumulation of misfolded proteins. This ER stress may further aggravate oxidative stress by augmenting ER ROS production. Secondary to ER Ca2+ release, cytosolic and mitochondrial matrix Ca2+ concentrations can also be altered. In addition, plasmalemmal ion channels operated by ER Ca2+ depletion mediate persistent Ca2+ influx, further impairing cytosolic and mitochondrial Ca2+ homeostasis. Mitochondrial Ca2+ overload causes superoxide production and functional impairment, culminating in apoptosis. This vicious cycle of lipotoxicity occurs in multiple tissues, resulting in β-cell failure and insulin resistance in target tissues, and further aggravates diabetic complications.

Transforming Growth Factor β1-induced Apoptosis in Podocytes via the Extracellular Signal-regulated Kinase-Mammalian Target of Rapamycin Complex 1-NADPH Oxidase 4 Axis

Das, Ranjan,Xu, Shanhua,Nguyen, Tuyet Thi,Quan, Xianglan,Choi, Seong-Kyung,Kim, Soo-Jin,Lee, Eun Young,Cha, Seung-Kuy,Park, Kyu-Sang American Society for Biochemistry and Molecular Bi 2015 The Journal of biological chemistry Vol.290 No.52

<P>TGF-β is a pleiotropic cytokine that accumulates during kidney injuries, resulting in various renal diseases. We have reported previously that TGF-β1 induces the selective up-regulation of mitochondrial Nox4, playing critical roles in podocyte apoptosis. Here we investigated the regulatory mechanism of Nox4 up-regulation by mTORC1 activation on TGF-β1-induced apoptosis in immortalized podocytes. TGF-β1 treatment markedly increased the phosphorylation of mammalian target of rapamycin (mTOR) and its downstream targets p70S6K and 4EBP1. Blocking TGF-β receptor I with SB431542 completely blunted the phosphorylation of mTOR, p70S6K, and 4EBP1. Transient adenoviral overexpression of mTOR-WT and constitutively active mTORΔ augmented TGF-β1-treated Nox4 expression, reactive oxygen species (ROS) generation, and apoptosis, whereas mTOR kinase-dead suppressed the above changes. In addition, knockdown of mTOR mimicked the effect of mTOR-KD. Inhibition of mTORC1 by low-dose rapamycin or knockdown of p70S6K protected podocytes through attenuation of Nox4 expression and subsequent oxidative stress-induced apoptosis by TGF-β1. Pharmacological inhibition of the MEK-ERK cascade, but not the PI3K-Akt-TSC2 pathway, abolished TGF-β1-induced mTOR activation. Inhibition of either ERK1/2 or mTORC1 did not reduce the TGF-β1-stimulated increase in Nox4 mRNA level but significantly inhibited total Nox4 expression, ROS generation, and apoptosis induced by TGF-β1. Moreover, double knockdown of Smad2 and 3 or only Smad4 completely suppressed TGF-β1-induced ERK1/2-mTORactivation. Our data suggest that TGF-β1 increases translation of Nox4 through the Smad-ERK1/2-mTORC1 axis, which is independent of transcriptional regulation. Activation of this pathway plays a crucial role in ROS generation and mitochondrial dysfunction, leading to podocyte apoptosis. Therefore, inhibition of the ERK1/2-mTORC1 pathway could be a potential therapeutic and preventive target in proteinuric and chronic kidney diseases.</P>

Random Field Model of Corroded Steel Plate Surface in Neutral Salt Spray Environment

Kong Deliang,Nie Biao,Xu Shanhua 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.7

The random field model of corrosion depth on steel plate surface in neutral salt spray environment was investigated. 10 groups of specimens were subjected to accelerate corrosion by the neutral salt spray test, and the surface profile of corroded steel plates and the 3D data of corrosion depth were measured by three-dimensional non-contact surface topography instrument. The probability characteristics of corrosion depth were studied and the relationship between the average and the standard deviation of corrosion depth and the mass loss rate were analyzed. The corrosion depth were tested for ergodicity and stationarity and the autocorrelation function model of random field model of corrosiondepth was proposed. The results of the study show that the corrosion depth on steel plate surface in neutral salt spray environment conformed to the normal distribution. With the increase of mass loss rate, the average and the standard deviation of the corrosion depth increased. The corrosion depth has ergodicity and stationarity. The random field model of cosine trigonometric function can accurately characterize the distribution of corrosion depth, which prepared the preliminary preparation for the finite element analysis of the corroded steel structure.