Nano Silica/Polyamide 박막의 제조 및 특성 연구

Xiaokun Ma,이남희,오효진,이대걸,윤영웅,황종선,김선재 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.10

Zero‑current‑switching full‑bridge DC/DC converter with reduced conduction losses for renewable energy MVDC collection systems

Xiaokun He,Renjie Hu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.3

When compared to the conventional AC collection system, the DC collection system for renewable energy sources presents lots of advantages. High power high-voltage DC/DC converters are essential equipment for medium voltage DC (MVDC) grid. A novel zero-current-switching full-bridge DC/DC converter is proposed in this paper. In particular, a blocking capacitor is introduced to rapidly decay the circulating current to zero. Hence, both the switching loss and conduction loss can be reduced. A scaled-down 120 V/1.2 kV, 2 kW prototype was built to validate the effectiveness of the proposed converter.

An experimental study on the flexural performance of laminated glass

Xiaokun Huang,Gang Liu,Qiang Liu,Stephen J. Bennison 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.2

This paper reported an experimental study on creep behaviors of PVB and Ionoplast laminated glass (LG) under load duration of 30 days. The tests were carried out in room temperature (23°C). The study revealed that after sustaining loads for 30 days, the mid-span deflection of PVB LG increased by almost 102% compared with its short term deflection, while that of Ionoplast LG approximately increased by 14%; composite effects between two glass plies in PVB LG gradually reduced with time, but did not fully vanish at the 30th day; two glass plies in Ionoplast LG on the other hand was able to withstand loads as an effective composite section during the entire loading period; the creep behaviors of both LG were not finished yet at the 30th day. In addition to this, also studied was the varying of the bending stresses of PVB and Ionoplast LG under load duration of 2 hours. The tests were carried out in ambient temperatures of 30°C, 50°C and 80°C respectively. It was found that under a given load, although the bending stresses of both LG increased with increasing temperature, for PVB LG the increasing rate of the bending stress decreased with increasing temperature, while for Ionoplast LG the increasing rate of the bending stress increased with increasing temperature.

The flexural performance of laminated glass beams under elevated temperature

Xiaokun Huang,Gang Liu,Qiang Liu,Stephen J. Bennison 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.52 No.3

A series of experimental work is carried out with the aim to understand the flexural performance of laminated glass (LG) beams using polyvinyl butyral (PVB) and Ionoplast interlayers subjected to short term duration loads in the circumstance of elevated temperature. The study is based on a total of 42 laboratory tests conducted in ambient temperature ranging from 25°C to 80°C. The load duration is kept within 20 seconds. Through the tests, load-stress and load-deflection curves of the LG are established; appropriate analytical models for the LG are indentified; the effective thicknesses as well as the shear transfer coefficients of the LG are semi-empirically determined. The test results show that within the studied temperature range the bending stresses and deflections at mid-span of the LG develop linearly with respect to the applied loads. From 25°C to 80°C the flexural behavior of the PVB LG is found constantly between that of monolithic glass and layered glass having the same nominal thickness; the flexural behavior of the Ionoplast LG is equivalent to monolithic glass of the same nominal thickness until the temperature elevates up to 50°C. The test results reveal that in calculating the effective thicknesses of the PVB and Ionoplast LG, neglecting the shear capacities of the interlayers is uneconomic even when the ambient temperature is as high as 80°C. In the particular case of this study, the shear transfer coefficient of the PVB interlayer is found in a range from 0.62 to 0.14 while that of the Ionoplast interlayer is found in a range from 1.00 to 0.56 when the ambient temperature varies from 25°C to 80°C.

ER membrane protein complex subunit 6 (EMC6) is a novel tumor suppressor in gastric cancer

( Xiaokun Wang ),( Yan Xia ),( Chentong Xu ),( Xin Lin ),( Peng Xue ),( Shijie Zhu ),( Yun Bai ),( Yingyu Chen ) 생화학분자생물학회(구 한국생화학분자생물학회) 2017 BMB Reports Vol.50 No.8

The endoplasmic reticulum (ER) membrane protein complex subunit 6 (EMC6) is a novel human autophagy-related molecule. Here, using tissue microarray and immunohistochemistry, we report that EMC6 protein is lost or reduced in glandular cells of patients with gastric adenocarcinoma, compared to normal stomach mucosa. Overexpression of EMC6 in gastric cancer cells inhibited cell growth, migration, invasion, and induced apoptosis and cell cycle arrest at S-phase. Further investigation suggested that EMC6 overexpression in BGC823 human adenocarcinoma gastric cancer cells reduced tumorigenicity in a xenograft model, demonstrating that EMC6 has the characteristics of a tumor suppressor. This is the first study to show that EMC6 induces cell death in gastric cancer cells. The molecular mechanism of how EMC6 functions as a tumor suppressor needs to be further explored. [BMB Reports 2017; 50(8): 411-416]

Accuracy analysis for machine tool spindles considering full parallel connections and form errors based on skin model shapes

Xiaokun Hu,Qiangqiang Zhao,Yitao Yang,Shaoke Wan,Yanhui Sun,Jun Hong 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.5

The rotation accuracy of a machine tool spindle is essential for ensuring the machining precision. Due to the existence of manufacturing and assembly errors, the rotation accuracy of the spindle will be inevitably impacted and degraded. Therefore, to reduce the influence of the errors and improve the work performance, this paper focuses on accuracy analysis for the spindle and a novel optimization-oriented skin model shape method to tackle this highly complex problem. First, a structural analysis of the spindle is carried out to elaborate the intractable full parallel collections in the assembly. Then, based on the iterative closest point method, the deviation propagation of the spindle considering complex full parallel collections is transformed into an optimization problem, in which the skin model shapes and small displacement torsor are utilized to represent the form and pose errors of the part, respectively. By solving the optimization problem, assembly accuracy analysis for the spindle in terms of full parallel connections and form errors is accordingly achieved. On this basis, the tolerance analysis model of the spindle is also comprehensively established by employing the corresponding error simulation. Finally, measurement experiments are conducted to validate the effectiveness of the proposed method. The experiments show the predicted rotation runout and tolerance magnitude are close to the testing results, therefore indicating the proposed method can provide effective accuracy analysis for spindles.

Preparation and Characterization of Silica/Polyamide-imide Nanocomposite Thin Films

Ma, Xiaokun,Lee, Nam-Hee,Oh, Hyo-Jin,Hwang, Jong-Sun,Kim, Sun-Jae Springer 2010 NANOSCALE RESEARCH LETTERS Vol.5 No.11

<P>The functional silica/polyamide-imide composite films were prepared via simple ultrasonic blending, after the silica nanoparticles were modified by cationic surfactant—cetyltrimethyl ammonium bromide (CTAB). The composite films were characterized by scanning electron microscope (SEM), thermo gravimetric analysis (TGA) and thermomechanical analysis (TMA). CTAB-modified silica nanoparticles were well dispersed in the polyamide-imide matrix, and the amount of silica nanoparticles to PAI was investigated to be from 2 to 10 wt%. Especially, the coefficients of thermal expansion (CET) continuously decreased with the amount of silica particles increasing. The high thermal stability and low coefficient of thermal expansion showed that the nanocomposite films can be widely used in the enamel wire industry.</P>

Simultaneous Detection of Dual Nucleic Acids Using a SERS-Based Lateral Flow Assay Biosensor

Wang, Xiaokun,Choi, Namhyun,Cheng, Ziyi,Ko, Juhui,Chen, Lingxin,Choo, Jaebum American Chemical Society 2017 ANALYTICAL CHEMISTRY - Vol.89 No.2

<P>A new class of surface-enhanced Raman scattering (SERS)-based lateral flow assay (LFA) biosensor has been developed for the simultaneous detection of dual DNA markers. The LFA strip in this sensor was composed of two test lines and one control line. SERS nano tags labeled with detection DNA probes were used for quantitative evaluation of dual DNA markers with high sensitivity. Target DNA, associated with Kaposis sarcoma-associated herpesvirus (KSHV) and bacillary angiomatosis (BA), were tested to validate the detection capability of this SERS-based LFA strip. Characteristic peak intensities of SERS nano tags on two test lines were used for quantitative evaluations of KSHV and BA. The limits of detection for KSHV and BA, determined from our SERS-based LFA sensing platform, were estimated to be 0.043 and 0.074 pM, respectively. These values indicate approximately 10000 times higher sensitivity than previously reported values using the aggregation-based colorimetric method. We believe that this is the first report of simultaneous detection of two different DNA mixtures using a SERS-based LFA platform. This novel detection technique is also a promising multiplex DNA sensing platform for early disease diagnosis.</P>

An experimental study on the flexural performance of laminated glass

Huang, Xiaokun,Liu, Gang,Liu, Qiang,Bennison, Stephen J. Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.2

This paper reported an experimental study on creep behaviors of PVB and Ionoplast laminated glass (LG) under load duration of 30 days. The tests were carried out in room temperature ($23^{\circ}C$). The study revealed that after sustaining loads for 30 days, the mid-span deflection of PVB LG increased by almost 102% compared with its short term deflection, while that of Ionoplast LG approximately increased by 14%; composite effects between two glass plies in PVB LG gradually reduced with time, but did not fully vanish at the 30th day; two glass plies in Ionoplast LG on the other hand was able to withstand loads as an effective composite section during the entire loading period; the creep behaviors of both LG were not finished yet at the 30th day. In addition to this, also studied was the varying of the bending stresses of PVB and Ionoplast LG under load duration of 2 hours. The tests were carried out in ambient temperatures of $30^{\circ}C$, $50^{\circ}C$ and $80^{\circ}C$ respectively. It was found that under a given load, although the bending stresses of both LG increased with increasing temperature, for PVB LG the increasing rate of the bending stress decreased with increasing temperature, while for Ionoplast LG the increasing rate of the bending stress increased with increasing temperature.

The flexural performance of laminated glass beams under elevated temperature

Huang, Xiaokun,Liu, Gang,Liu, Qiang,Bennison, Stephen J. Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.52 No.3

A series of experimental work is carried out with the aim to understand the flexural performance of laminated glass (LG) beams using polyvinyl butyral (PVB) and Ionoplast interlayers subjected to short term duration loads in the circumstance of elevated temperature. The study is based on a total of 42 laboratory tests conducted in ambient temperature ranging from $25^{\circ}C$ to $80^{\circ}C$. The load duration is kept within 20 seconds. Through the tests, load-stress and load-deflection curves of the LG are established; appropriate analytical models for the LG are indentified; the effective thicknesses as well as the shear transfer coefficients of the LG are semi-empirically determined. The test results show that within the studied temperature range the bending stresses and deflections at mid-span of the LG develop linearly with respect to the applied loads. From $25^{\circ}C$ to $80^{\circ}C$ the flexural behavior of the PVB LG is found constantly between that of monolithic glass and layered glass having the same nominal thickness; the flexural behavior of the Ionoplast LG is equivalent to monolithic glass of the same nominal thickness until the temperature elevates up to $50^{\circ}C$. The test results reveal that in calculating the effective thicknesses of the PVB and Ionoplast LG, neglecting the shear capacities of the interlayers is uneconomic even when the ambient temperature is as high as $80^{\circ}C$. In the particular case of this study, the shear transfer coefficient of the PVB interlayer is found in a range from 0.62 to 0.14 while that of the Ionoplast interlayer is found in a range from 1.00 to 0.56 when the ambient temperature varies from $25^{\circ}C$ to $80^{\circ}C$.