A fractal model for predicting thermal contact conductance considering elasto-plastic deformation and base thermal resistances

JinHua Zhang,Yili Liu,Ke Yan,Bin Fang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.1

A prediction model of thermal contact conductance is developed. Engineering rough surfaces are characterized by three-dimensional fractal Weierstrass-Mandelbrot fractal function. Three deformation modes, including fully plastic deformation, elasto-plastic deformation and elastic deformation, are considered to analyze the contact mechanism. Fractal surface and three deformation modes are incorporated into the calculation of thermal contact conductance. A comprehensive thermal contact conductance computation model considering both base thermal resistance and constricted thermal resistance is established. The results show that thermal contact conductance increases with the increase of normal contact pressure; the relative contribution of constricted resistance component to base resistance component tends to increase with the increase of normal contact pressure; fractal dimension and fractal roughness both have significant influences on thermal contact conductance.

A novel model for high-speed angular contact ball bearing by considering variable contact angles

JinHua Zhang,Bin Fang,Ke Yan,Jun Hong 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.2

In this study, on the basis of the various contact angles and the hybrid theory, a new mathematic model without the raceway control hypothesis is proposed for the analysis of ball bearing under the combined axial, radial and moment loads. Instead of the orthogonal decomposition method, the triangular geometric theorem and vector diagram method have been used in the force analysis of local ball to improve the computation efficiency of bearing analysis. For validation purpose, the comparative analysis of the ball-raceway contact angles and loads of ball bearing under different operation conditions obtained by the proposed model and the Jones’ model with different raceway control hypotheses has been conducted. The results show that the proposed model has a higher applicability and rationality compared to the Jones’ model, and a proper moment load can be used to improve the load distribution and service performance of ball bearing subjected to the radial load.

Cell-Penetrating Peptide-Modified PLGA Nanoparticles for Enhanced Nose-to-Brain Macromolecular Delivery

Lu Yan,Huiyuan Wang,Yifan Jiang,Jinhua Liu,Zhao Wang,Yongxin Yang,Shengwu Huang,Yongzhuo Huang 한국고분자학회 2013 Macromolecular Research Vol.21 No.4

Macromolecular drugs become an essential part in neuroprotective treatment. However, the nature of ineffective delivery crossing the blood brain barrier (BBB) renders those macromolecules undruggable for clinical practice. Recently, brain target via intranasal delivery have provided a promising solution to circumventing the BBB. Despite the direct route from nose to brain (i.e. olfactory pathway), there still are big challenges for large compounds like proteins to overcome the multiple delivery barriers such as nasal mucosa penetration, intracellular transport along the olfactory neuron, and diffusion across the heterogeneous brain compartments. Herein presented is an intranasal strategy mediated by cell-penetrating peptide modified poly(lactic-co-glycolic acid) (PLGA) nanoparticles for the delivery of insulin to the brain, a potent therapeutic against Alzheimer’s disease. The results revealed that the cell-penetrating peptide can potentially deliver insulin into brain via the nasal route, showing a total brain delivery efficiency of 6%. It could serve as a potential treatment for neurodegenerative diseases.

Novel Flower-Like CuO/N-rGO as Enhanced Electrocatalyst for Oxygen Reduction Reaction

Lijuan Zhang,Jinhua Lu,Jianfeng Wei,Yan Wang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.10

Flower-like copper oxide (CuO)/nitrogen-doped reduced graphene oxide (N-rGO) was synthesized through a one-pot microwave hydrothermal method by using polyvinylpyrrolidone (PVP) as surfactant. In the process, in situ formation of nanomaterial CuO, reduction of graphene oxide and doping of nitrogen species occurred simultaneously in urea solution. The structural and surface properties of the material were investigated by field emission scanning electron microscopy (FESEM) and transmission electron microscopies (TEM), the energy dispersive spectroscopic (EDS) and powder X-ray diffraction (XRD). This showed the flower-like CuO with an interconnected architecture was successfully uniformed and grown on the surface of N-rGO. Moreover, the surfactant PVP and urea were found to be the key factors to control the morphology of the CuO nanostructure. Electrochemical investigations indicated that the CuO/N-rGO composite exhibited a significantly enhanced ORR activity in comparison to pure CuO and N-rGO in an alkaline solution. The enhancement in ORR activity of CuO/N-rGO composite can be attributed to the synergistic effects of good electron transport from N-rGO as well as abundance of exposed catalytic sites and meso/macroporosity from CuO nanostructures.

웹기반 연구윤리교육의 유효성에 대한 실증적 연구

곽진선 ( Jinsun Kwak ),엄금화 ( Jinhua Yan ),한인수 ( Insoo Han ) 한국컴퓨터교육학회 2016 컴퓨터교육학회 논문지 Vol.19 No.1

본 연구는 국가연구개발과제를 수행하는 연구책임자를 대상으로 웹기반 연구윤리 교육의 유효성을 실험연구를 통해 실증적으로 분석하고자 하는 목적을 지니고 있다. 연구책임자를 연구분야별로 분류하여 연구윤리교육 콘텐츠를 개발하고 웹상에서 교육을 실시한 후에 교육만족도, 교육이해도, 도덕판단력 등의 교육 유효성을 측정하였다. 연구 분석결과 교육 사후의 교육만족도와 연구윤리에 대한 교육이해도는 높아지는 것으로 나타났다. 반면 연구윤리교육 후 도덕판단력에는 큰 변화가 없음을 확인하였다. 이는 단기적인 연구윤리교육이 교육판단력을 높여주지는 못한다는 선행연구들의 결과와 부합하는 것이다. 끝으로 연구윤리교육의 유효성을 높이기 위해서는 연구자에 대한 장기적인 웹기반 연구윤리교육이 필요하며, 쌍방향 의사소통이 가능한 학습방식의 보완이 필요하다는 점을 시사해주고 있다. This study empirically investigates the effect of web-based research ethics education to principal investigator who conduct national research project. The web-based research ethics education program was devised and operate for each research field. After education educational satisfaction, understanding and moral judgement were investigated. The research results revealed that education was improving educational satisfaction and but also understanding whereas moral judgement was not. These findings imply that moral judgement was not enhancing though short-term research ethics education as preceding research. Moreover, this paper speaks to a supplemented program with methods of ethics education which needs more interactive communication within long-term education for enhancing effectiveness of instruction.

감정표현규범, 감정노동, 감정소진 간의 관계에서 직무자원의 조절된 매개효과 분석

이윤형(Lee, Yunhyung),엄금화(Yan, Jinhua),한인수(Han, Insoo) 한국인적자원개발학회 2016 인적자원개발연구 Vol.19 No.4

Lactate exacerbates lung damage induced by nanomicroplastic through the gut microbiota–HIF1a/PTBP1 pathway

Xuan Lihui,Xu Zheng,Luo Jinhua,Yin Wang,Yan Yuhui,Qu Can,Xie Zuozhong,Skonieczna Magdalena,Zhou Ping-Kun,Huang Ruixue 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

Exposure to nanomicroplastics (nano-MPs) can induce lung damage. The gut microbiota is a critical modulator of the gut–lung axis. However, the mechanisms underlying these interactions have not been elucidated. This study explored the role of lactate, a key metabolite of the microbiota, in the development of lung damage induced by nano-MPs (LDMP). After 28 days of exposure to nano-MPs (50–100 nm), mice mainly exhibited damage to the lungs and intestinal mucosa and dysbiosis of the gut microbiota. Lactate accumulation was observed in the lungs, intestines and serum and was strongly associated with the imbalance in lactic acid bacteria in the gut. Furthermore, no lactate accumulation was observed in germ-free mice, while the depletion of the gut microbiota using a cocktail of antibiotics produced similar results, suggesting that lactate accumulation in the lungs may have been due to changes in the gut microbiota components. Mechanistically, elevated lactate triggers activation of the HIF1a/PTBP1 pathway, exacerbating nano-MP-induced lung damage through modulation of the epithelial–mesenchymal transition (EMT). Conversely, mice with conditional knockout of Ptbp1 in the lungs (Ptbp1flfl) and PTBP1-knockout (PTBP1-KO) human bronchial epithelial (HBE) cells showed reversal of the effects of lactate through modulation of the HIF1a/PTBP1 signaling pathway. These findings indicate that lactate is a potential target for preventing and treating LDMP.

The effect of environmental innovation behavior on economic and environmental performance of 182 Chinese firms

Long, Xingle,Chen, Yaqiong,Du, Jianguo,Oh, Keunyeob,Han, Insoo,Yan, Jinhua Elsevier 2017 JOURNAL OF CLEANER PRODUCTION Vol.166 No.-

<P><B>Abstract</B></P> <P>This paper investigated the role of environmental innovation behavior in the economic and environmental performance of 182 Chinese firms. We established an extended theory of planned behavior (TPB) model and proposed seven hypotheses by combining TPB and environmental innovation theory. Through structure equation model, we found that attitude toward environment behavior, subjective environmental norm, perceived environment behavioral control positively impact environmental innovation intention. Environmental innovation behavior had a 0.232 larger effect on environmental performance than on economic performance. Production processes have a 0.028 greater positive influence on environmental performance than on economic performance. Enhancing environmental innovation promotes sustainable development. It is important to strengthen cleaner production processes to reduce environmental pollution. It is a significant obligation to conduct environment-related education or training for personnel within firms.</P>

Association between Metabolic Syndrome and Microvascular Complications in Chinese Adults with Type 1 Diabetes Mellitus

Qianwen Huang,Daizhi Yang,Hongrong Deng,Hua Liang,Xueying Zheng,Jinhua Yan,Wen Xu,Xiangwen Liu,Bin Yao,Sihui Luo,Jianping Weng 대한당뇨병학회 2022 Diabetes and Metabolism Journal Vol.46 No.1

Background: Both type 1 diabetes mellitus (T1DM) and metabolic syndrome (MetS) are associated with an elevated risk of morbidity and mortality yet with increasing heterogeneity. This study primarily aimed to evaluate the prevalence of MetS among adult patients with T1DM in China and investigate its associated risk factors, and relationship with microvascular complications.Methods: We included adult patients who had been enrolled in the Guangdong T1DM Translational Medicine Study conducted from June 2010 to June 2015. MetS was defined according to the updated National Cholesterol Education Program criterion. Logistic regression models were used to estimate the odds ratio (OR) for the association between MetS and the risk of diabetic kidney disease (DKD) and diabetic retinopathy (DR).Results: Among the 569 eligible patients enrolled, the prevalence of MetS was 15.1%. While female gender, longer diabetes duration, higher body mass index, and glycosylated hemoglobin A1c (HbA1c) were risk factors associated with MetS (OR, 2.86, 1.04, 1.14, and 1.23, respectively), received nutrition therapy education was a protective factor (OR, 0.46). After adjustment for gender, age, diabetes duration, HbA1c, socioeconomic and lifestyle variables, MetS status was associated with an increased risk of DKD and DR (OR, 2.14 and 3.72, respectively; both P<0.05).Conclusion: Although the prevalence of MetS in adult patients with T1DM in China was relatively low, patients with MetS were more likely to have DKD and DR. A comprehensive management including lifestyle modification might reduce their risk of microvascular complications in adults with T1DM.

The effect of environmental innovation behavior on economic and environmental performance of 182 Chinese firms

LONG Xingle,CHEN Yaqiong,DU Jianguo,OH Keunyeob,HAN Insoo,YAN Jinhua 한국무역학회 2017 한국무역학회 국제학술대회 Vol.2017 No.11