The Investigation on Thermal Aging Characteristics of Oil-Paper Insulation in Bushing

Liao, Rui-jin,Hu, En-de,Yang, Li-jun,Xu, Zuo-ming The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.3

Bushing is the key link to connect outer and inner insulating systems and also the essential electric accessory in electric power system, especially in the high voltage engineering (AC 1000kV, DC 800kV). This paper presented the experimental research of thermal aging characteristic of oil-paper insulation used in bushing. A thermally accelerated aging experiment at 90℃ was performed. The bushing models containing five layers of paper were sealed into the aging vessels and further aged for 250 days. Then several important parameters associated with the aging were observed and evaluated. The results showed that the degree of polymerization (DP) of papers gradually decreased. The DP values of outermost layer and middle layer fit well into the second-order kinematic model and first-order kinematic model, respectively. Less deterioration speed of the inter-layer paper than outer layer was confirmed by the variation of DP. Hydrolysis was considered as the main cause to this phenomenon. In addition, the logarithm of the furfural concentrations in insulation oil was found to have good linear relationship with DP of papers. Interestingly, when the aging time is about 250 days and DP is 419, the aging process reaches an inflection point at which the DP approaches the leveling off degree of polymerization (LODP) value. Both tanδ and acid number of oils increased, while surface and volume resistivity of papers decreased. The obtained results demonstrated that thermal aging and moisture absorbed in papers brought great influence to the degradation of insulating paper, leading to rapid decrease of DP and increase of the tanδ. Thus, the bushing should be avoided from damp and real-time monitoring to the variation of tanδ and DP values of paper is an effective way to evaluate the insulation status of bushing.

The Investigation on Thermal Aging Characteristics of Oil-Paper Insulation in Bushing

Rui-jin Liao,En-de Hu,Li-jun Yang,Zuo-ming Xu 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.3

Bushing is the key link to connect outer and inner insulating systems and also the essential electric accessory in electric power system, especially in the high voltage engineering (AC 1000kV, DC 800kV). This paper presented the experimental research of thermal aging characteristic of oilpaper insulation used in bushing. A thermally accelerated aging experiment at 90℃ was performed. The bushing models containing five layers of paper were sealed into the aging vessels and further aged for 250 days. Then several important parameters associated with the aging were observed and evaluated. The results showed that the degree of polymerization (DP) of papers gradually decreased. The DP values of outermost layer and middle layer fit well into the second-order kinematic model and first-order kinematic model, respectively. Less deterioration speed of the inter-layer paper than outer layer was confirmed by the variation of DP. Hydrolysis was considered as the main cause to this phenomenon. In addition, the logarithm of the furfural concentrations in insulation oil was found to have good linear relationship with DP of papers. Interestingly, when the aging time is about 250 days and DP is 419, the aging process reaches an inflection point at which the DP approaches the leveling off degree of polymerization (LODP) value. Both tanδ and acid number of oils increased, while surface and volume resistivity of papers decreased. The obtained results demonstrated that thermal aging and moisture absorbed in papers brought great influence to the degradation of insulating paper, leading to rapid decrease of DP and increase of the tanδ . Thus, the bushing should be avoided from damp and real-time monitoring to the variation of tanδ and DP values of paper is an effective way to evaluate the insulation status of bushing.

Augmenter of Liver Regeneration Alleviates Renal Hypoxia-Reoxygenation Injury by Regulating Mitochondrial Dynamics in Renal Tubular Epithelial Cells

Long, Rui-ting,Peng, Jun-bo,Huang, Li-li,Jiang, Gui-ping,Liao, Yue-juan,Sun, Hang,Hu, Yu-dong,Liao, Xiao-hui Korean Society for Molecular and Cellular Biology 2019 Molecules and cells Vol.42 No.12

Mitochondria are highly dynamic organelles that constantly undergo fission and fusion processes that closely related to their function. Disruption of mitochondrial dynamics has been demonstrated in acute kidney injury (AKI), which could eventually result in cell injury and death. Previously, we reported that augmenter of liver regeneration (ALR) alleviates renal tubular epithelial cell injury. Here, we gained further insights into whether the renoprotective roles of ALR are associated with mitochondrial dynamics. Changes in mitochondrial dynamics were examined in experimental models of renal ischemia-reperfusion (IR). In a model of hypoxia-reoxygenation (HR) injury in vitro, dynamin-related protein 1 (Drp1) and mitochondrial fission process protein 1 (MTFP1), two key proteins of mitochondrial fission, were downregulated in the Lv-ALR + HR group. ALR overexpression additionally had an impact on phosphorylation of Drp1 Ser637 during AKI. The inner membrane fusion protein, Optic Atrophy 1 (OPA1), was significantly increased whereas levels of outer membrane fusion proteins Mitofusin-1 and -2 (Mfn1, Mfn2) were not affected in the Lv-ALR + HR group, compared with the control group. Furthermore, the mTOR/4E-BP1 signaling pathway was highly activated in the Lv-ALR + HR group. ALR overexpression led to suppression of HR-induced apoptosis. Our collective findings indicate that ALR gene transfection alleviates mitochondrial injury, possibly through inhibiting fission and promoting fusion of the mitochondrial inner membrane, both of which contribute to reduction of HK-2 cell apoptosis. Additionally, fission processes are potentially mediated by promoting tubular cell survival through activating the mTOR/4E-BP1 signaling pathway.

Augmenter of Liver Regeneration Alleviates Renal Hypoxia-Reoxygenation Injury by Regulating Mitochondrial Dynamics in Renal Tubular Epithelial Cells

Xiao-hui Liao,Rui-ting Long,Jun-bo Peng,Li-li Huang,Gui-ping Jiang,Yue-juan Liao,Hang Sun,Yu-dong Hu 한국분자세포생물학회 2019 Molecules and cells Vol.42 No.12

Mitochondria are highly dynamic organelles that constantly undergo fission and fusion processes that closely related to their function. Disruption of mitochondrial dynamics has been demonstrated in acute kidney injury (AKI), which could eventually result in cell injury and death. Previously, we reported that augmenter of liver regeneration (ALR) alleviates renal tubular epithelial cell injury. Here, we gained further insights into whether the renoprotective roles of ALR are associated with mitochondrial dynamics. Changes in mitochondrial dynamics were examined in experimental models of renal ischemia-reperfusion (IR). In a model of hypoxia-reoxygenation (HR) injury in vitro, dynamin-related protein 1 (Drp1) and mitochondrial fission process protein 1 (MTFP1), two key proteins of mitochondrial fission, were downregulated in the Lv-ALR + HR group. ALR overexpression additionally had an impact on phosphorylation of Drp1 Ser637 during AKI. The inner membrane fusion protein, Optic Atrophy 1 (OPA1), was significantly increased whereas levels of outer membrane fusion proteins Mitofusin-1 and -2 (Mfn1, Mfn2) were not affected in the Lv-ALR + HR group, compared with the control group. Furthermore, the mTOR/4E-BP1 signaling pathway was highly activated in the Lv-ALR + HR group. ALR overexpression led to suppression of HR-induced apoptosis. Our collective findings indicate that ALR gene transfection alleviates mitochondrial injury, possibly through inhibiting fission and promoting fusion of the mitochondrial inner membrane, both of which contribute to reduction of HK-2 cell apoptosis. Additionally, fission processes are potentially mediated by promoting tubular cell survival through activating the mTOR/4E-BP1 signaling pathway.

Modified nonlinear force density method for form-finding of membrane SAR antenna

Rui Xu,DongXu Li,Wang Liu,JianPing Jiang,YiHuan Liao,Jie Wang 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.54 No.6

Form-finding for cable-membrane structures is a delicate operation. During the last decades, the force density method (FDM) was considered to be an efficient method to address the problem. Many researchers were devoted to improving this method and proposed many methods such as natural force density method (NFDM), improved nonlinear force density method (INFDM), et al. In this paper, a modified nonlinear force density method (MNFDM) is proposed. In this method, the stresses of membrane elements were transformed to the force-densities of cable nets by an equivalent relationship, and then they can be used as initial conditions. By comparing with the forming finding results by using the FDM, NFDM, INFDM and MNFDM, it had demonstrated that the MNFDM presented in this paper is the most efficient and precise.

An automatic detection method for lung nodules based on multi-scale enhancement filters and 3D shape features

( Rui Hao ),( Yan Qiang ),( Xiaolei Liao ),( Xiaofei Yan ),( Guohua Ji ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.1

In the computer-aided detection (CAD) system of pulmonary nodules, a high false positive rate is common because the density and the computed tomography (CT) values of the vessel and the nodule in the CT images are similar, which affects the detection accuracy of pulmonary nodules. In this paper, a method of automatic detection of pulmonary nodules based on multi-scale enhancement filters and 3D shape features is proposed. The method uses an iterative threshold and a region growing algorithm to segment lung parenchyma. Two types of multi-scale enhancement filters are constructed to enhance the images of nodules and blood vessels in 3D lung images, and most of the blood vessel images in the nodular images are removed to obtain a suspected nodule image. An 18 neighborhood region growing algorithm is then used to extract the lung nodules. A new pulmonary nodules feature descriptor is proposed, and the features of the suspected nodules are extracted. A support vector machine (SVM) classifier is used to classify the pulmonary nodules. The experimental results show that our method can effectively detect pulmonary nodules and reduce false positive rates, and the feature descriptor proposed in this paper is valid which can be used to distinguish between nodules and blood vessels.

Microwave hydrothermal synthesis and temperature sensing behavior of Lu2Ti2O7:Yb3þ/Er3þ nanophosphors

Jinsheng Liao,Qi Wang,Lifang Lan,Jiangfei Guo,Liling Nie,Suijun Liu,He-Rui Wen 한국물리학회 2017 Current Applied Physics Vol.17 No.3

Lu2Ti2O7:Yb3þ/Er3þ (LTO:Yb3þ/Er3þ) nanophosphors codoped with Yb3þ (8e20 at%) and Er3þ ions (0.5 e4 at%) were synthesized by a microwave hydrothermal process. Under the 980 nm excitation, the sample gives a set of upconversion light: very strong red emissions near 661 nm (4F9/2 / 4I15/2), weak green around 523 nm and 545 nm (2H11/2/4I15/2 and 4S3/2/4I15/2, respectively). The optimum doping concentrations of Er3þ and Yb3þ for the highest emission intensity were determined by photoluminescence (PL) analyses. Concentration dependent studies revealed that the optimal composition was realized for the 12 at% Yb3þ and 2.0 at% Er3þ-doping concentration with a strong emission. A possible UC mechanism for LTO:Yb3þ/Er3þ is discussed via the change of the pump power. The temperature dependence of the fluorescence intensity ratios (FIR) for the two green UC emission bands peaked at 523 and 545 nm was studied in the range of 298e573 K under excitation by a 980 nm diode laser and the maximum sensitivity was approximately 0.00313 K『1 at 536 K. This indicates that LTO:Yb3þ/Er3þ nanophosphors are potential candidates for optical temperature sensors with high sensitivity.

A Fast Detection and Recognition Algorithm for Pedestrian at Night Based on Entropy Weight Fast Support Vector Machine

Liang Rui,Wei Honglei,Zhu Qingxin,Liao Shujiao,Deng Hongyao 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.5

In allusion to such problems as real-time requirement dissatisfaction and significant recognition difference caused by dimension difference existing in the imaging and recognition algorithm for pedestrian in dark scene, a fast head detection and recognition method for pedestrian at night based on fast support vector machine (FC-SVM) algorithm optimization and entropy weight is established in this paper according to relevant principle of statistics. Based on entropy weight, this method aims at improving the extraction process based on histogram gradient features in order to establish threebranch SVM for the deep recognition of pedestrian at night; meanwhile, FC-SVM algorithm is combined to optimize the recognition calculation overhead in order to ensure the real-time property of the recognition algorithm. Furthermore, the falsely detected pedestrians are evaluated on the basis of the head detection mode so as to improve pedestrian imaging matching accuracy. The simulation result shows that this method can not only effectively recognize FIR target of pedestrian at night, but also effectively adapt to such different application environments as urban and suburban areas on the basis of ensuring the real-time requirement for pedestrian recognition, thus presenting good practicability.

Photoluminescence properties of NaGd(WO_4)_2:Eu^3+ nanocrystalline prepared by hydrothermal method

Jinsheng Liao,Hangying You,Bao Qiu,He-Rui Wen,Ruijin Hong,Weixiong You,Zhipeng Xie 한국물리학회 2011 Current Applied Physics Vol.11 No.3

NaGd(WO_4)_2:Eu^3+ (hereafter NGW:Eu) red-phosphors were synthesized via a facile hydrothermal method at different pH value. X-ray power diffraction (XRD), transmission electron microscope (TEM),energy dispersive X-ray spectra (EDS), photoluminescence excitation and emission spectra and decay curve were used to characterize the NGW:Eu phosphors. It was found that the pH value has a crucial effect on synthesis of the scheelite structure NGW:Eu. The intense red emission is obtained by exciting into the 5^L_6 state with 395 nm, which corresponds to the popular emission line from near-UV LED chips. The values of Ω2,4 experimental intensity parameters (14.9 × 10^-20 and 5.6 × 10^-20 cm^2) are determined. The high emission quantum efficiency and suitable color coordination of the NGW:Eu phosphor suggest the material could be a promising red phosphor for generating white light in phosphor-converted white light emitting diodes (WLEDs).

Distinctive Judicial-Tailored Causation References of Construction Accidents

Jiaming Wang,Rui Cheng,Heap-Yih Chong,Pin-Chao Liao 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.8

Accident liability allocation is significant for social justice and industry safety. The allocation of liability between individuals and organizations depends on the judgment of their negligence in accidents. However, current judicial practice does not show a clear distinction between different accident types when allocating liabilities, and there is a lack of scientific evidence to guide the legal decision-making process in liability allocation. Unfortunately, current accident causation research does not sufficiently meet the requirements as scientific evidence to support the realization of more strategic and targeted liability allocation. This study introduces the qualitative comparative analysis (QCA) method into the field of accident analysis using crisp-set QCA (csQCA) to explore the causal distinctions between fall and non-fall accidents based on the human factor analysis and classification system (HFACS). The results show that organizational influence and unsafe acts distinctively signify fall and non-fall accidents, and that the precondition of unsafe acts is their junction. Theoretically, this study 1) furnishes a QCA tool that allows academic research with uncertainty to be used in the body of evidence that meets the requirements of law, thereby extending the application scope of accident research to the legal practice of liability allocation; and 2) provides meaningful references for the judgment of negligence and accident liability for judicial practice.