Synthesis and Application of Cationic Waterborne Polyurethane as Fixing Agent for Cotton Fabric

Zhiwei Xu,Xiangdong Zhou 한국고분자학회 2021 폴리머 Vol.45 No.1

The traditional reactive dyeing of cotton has the disadvantage of poor fastness. In order to improve the fastness, a novel environment-friendly cationic waterborne polyurethane (CWPU) was successfully synthesized via step-by-step polymerization. The CWPU was prepared from isophorone diisocyanate (IPDI), polypropylene glycol (PPG-1000), methyl ethyl ketone oxime and hydrophilic monomer (EGDEA). The chemical structure of CWPU was characterized by Fourier transform infrared spectroscopy. Effects of n (IPDI/PPG-1000), EGDEA dosage, and the neutralizational degree on the properties of the waterborne polyurethane emulsion and the fastness of the treated dyed cotton fabrics were investigated. Particle size and zeta potential were tested to evaluate the emulsion stability. Scanning electron microscope showed that CWPU had been successfully finished on the fabric. Compared with the untreated cotton fabric, the dry and wet rubbing fastness of the treated cotton fabric dyed with reactive dyes increase 0~0.5 and 0.5~1 level, respectively, and the wash fastness increases 0.5~1 level.

N형 폴리 저항 기반의 시간영역 CMOS 스마트 온도센서

허지위(Zhiwei Xu),변상진(Sangjin Byun) 대한전자공학회 2019 대한전자공학회 학술대회 Vol.2019 No.11

Numerical Analysis of a Novel Prefabricated Concrete Beam with Double-Grouted Couplers under Static Loading

Zhiwei Lu,Bin Wu,Guoshan Xu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.8

This paper provides a nonlinear finite element (FE) investigation of a novel prefabricated beam with double-grouted coupler splices to complement the experimental work and promote its application. FE model considering the surface-to-surface contact behaviour between the prefabricated concrete and grouting mortar is constructed and validated using test data. The validated model is subsequently utilised to conduct a parametric analysis of the most influential factors comprising the diameter and eccentricity of linking rebar and connecting length. Results indicate that the fewer the grouted couplers and the shorter the coupler length, the smaller the effect on the damage pattern and stress distribution of the beam. As the tensile linking rebar diameter increases by 2 mm and 4 mm, the ultimate stress of the linking rebar decreases by 33.4% and 44.0%, respectively, and the maximal crack width in the linking region drops by 85.9% and 97.7%, respectively. Increasing the tension linking rebar diameter significantly reduces the unfavourable influence of linking rebar eccentricity on the linking zone crack width. A decrease in the filler length helps lessen the crack width in the connecting region. Based on the present study, several recommendations for practical engineering use of the developed beam are also presented.

A 5.6 kW 11.7 kW per kg Four-Phase Interleaved Buck Converter for the Unmanned Aerial Vehicle

Cheng Xu-Feng,Peng Zhenzhen,Yang Yulong,Liang Zhimin,Wu Chaofeng,Shao Zhiwei,Wang Dianlong 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.2

This paper proposed a 5.6 kW 11.7 kW/kg four-phase interleaved buck converter (FPIBC) for the unmanned aerial vehicle (UAV) low-voltage power system. The UAV mainly concerns the lightweight strategy and the power density of the DC-DC converter. We proposed a comprehensive lightweight strategy with the characteristics of reduced inductor current ripples, small size of fi lter inductors and capacitors, and high output power. The output current ripples are reduced by using interleaved modulation strategy and integrated CLC fi lters cascaded to the input side and output side respectively. In addition, the aluminum based printed circuit board (PCB) is used with SMD power transistors to obtain better heat dissipation capability without fans. With abovementioned methods, the designed DC-DC converter has a power of 5.6 kW @ 0.48 kg, the powerto-weight ratio is improved to be 11.7 kW/kg, and the power density is 3 W/cm 3 . The effi ciency of this DC-DC converter is up to 95.8%.

SKP2 Contributes to AKT Activation by Ubiquitination Degradation of PHLPP1, Impedes Autophagy, and Facilitates the Survival of Thyroid Carcinoma

Chongwen Xu,Yuan Shao,Wanli Ren,Hao Dai,Fangli Yang,Xiang Li,Shaoqiang Zhang,Junsong Liu,Xiaobao Yao,Qian Zhao,Xin Sun,Zhiwei Zheng 한국분자세포생물학회 2023 Molecules and cells Vol.46 No.6

Papillary thyroid carcinoma (PTC) is the most common subtype of thyroid carcinoma. Despite a good prognosis, approximately a quarter of PTC patients are likely to relapse. Previous reports suggest an association between S-phase kinase-associated protein 2 (SKP2) and the prognosis of thyroid cancer. SKP1 is related to apoptosis of PTC cells; however, its role in PTC remains largely elusive. This study aimed to understand the expression and molecular mechanism of SKP2 in PTC. SKP2 expression was upregulated in PTC tissues and closely associated with clinical diagnosis. In vitro and in vivo knockdown of SKP2 expression in PTC cells suppressed cell growth and proliferation and induced apoptosis. SKP2 depletion promoted cell autophagy under glucose deprivation. SKP2 interacted with PH domain leucine-rich repeat protein phosphatase-1 (PHLPP1), triggering its degradation by ubiquitination. Furthermore, SKP2 activates the AKT-related pathways via PHLPP1, which leads to the cytoplasmic translocation of SKP2, indicating a reciprocal regulation between SKP2 and AKT. In conclusion, the upregulation of SKP2 leads to PTC proliferation and survival, and the regulatory network among SKP2, PHLPP1, and AKT provides novel insight into the molecular basis of SKP2 in tumor progression.

Error modeling and accuracy optimization of rotating ultrasonic vibration assisted EDM machine tool

Minggang Xu,Zhiwei Wu,Feng Gao,Linlin Liu,Enyu Song 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.7

Rotating ultrasonic vibration assisted EDM is a composite machining method that uses EDM to etch a metal surface and adds rotating and ultrasonic vibration. It has high efficiency and a wide range of workpiece materials. Aiming at the structural characteristics of rotary ultrasonic vibration assisted EDM machine tool, the errors caused by the main moving parts of the machine tool were analyzed. The structure relationship is described by multi-body system theory, and the geometric error model is deduced by homogeneous coordinate transformation method. The aim was to improve the overall accuracy, reduce the cost, trace the error source, and get the corresponding relationship between the basic geometric errors and the precision parameters of the related parts. Under the requirement of ensuring the overall accuracy, an optimization function was established that minimizes the cost and relaxes all accuracy parameters to the greatest extent. Finally, MATLAB and its genetic algorithm toolbox was used for analysis. Verification shows that this model can properly reduce the cost on the premise of ensuring the accuracy.

Realization of GPS Information Real-time Marking System

Yan Zhiwei,Du Junping,Xu Feng 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

Multimedia tourism intelligent navigation system requires that the third party identifies and displays the location of GPS information receiver. A comprehensive method is presented to realize a GPS information real time marking system by the use of GPS, GPRS and GIS technology. Information is received through the GPS module, GPRS network as a transmission channel, MAPXTREME control as graphics platform. This paper describes the structure of this system and how to realize its functions.

Applying Basic-Elements and the Extension Theory to Alert-centric Event Correlation for Unified Network Security Management

Hui Xu,Chunzhi Wang,Hongwei Chen,Zhiwei Ye 보안공학연구지원센터 2013 International Journal of Security and Its Applicat Vol.7 No.3

Boosting the oxygen evolution reaction activity of a perovskite through introducing multi-element synergy and building an ordered structure

Sun, Hainan,Xu, Xiaomin,Hu, Zhiwei,Tjeng, Liu Hao,Zhao, Jie,Zhang, Qin,Lin, Hong-Ji,Chen, Chien-Te,Chan, Ting-Shan,Zhou, Wei,Shao, Zongping The Royal Society of Chemistry 2019 Journal of Materials Chemistry A Vol.7 No.16

<P>If different active sites in a catalyst have optimal binding to different reaction intermediates and short reaction paths among them, they may work cooperatively to enhance the oxygen evolution reaction (OER) activity. Based on this design principle, in this study, we start with a B-site ordered double perovskite Sr2FeMoO6−δ with poor OER activity as the host material to fulfill the requirement of a short pathway, and then, replace Mo with Ni and Fe with Co to optimize the synergistic interplay of the multi-active sites. Replacing Mo with Ni indeed dramatically enhances the OER activity and structural/operating stability. Further improvement in OER performance is realized by partial substitution of Fe with Co, leading to the development of a material with the nominal composition of Sr2Fe0.8Co0.2Mo0.65Ni0.35O6−δ, which outperforms the noble metal oxide IrO2 and is better than most of the electrocatalysts developed based on a single descriptor, such as Ba0.5Sr0.5Co0.8Fe0.2O3−δ (eg occupancy close to unity), PrBaCo2O5+δ (O 2p-band center relative to the Fermi level), and La0.5Sr0.5CoO3−δ (charge-transfer energy) in many aspects. As a universal method, combined structural and compositional tuning to create a cooperative effect among different active sites for intermediate adsorption and reaction in an ordered structure may provide a new way for the design of superior electrocatalysts for various applications.</P>

Ternary Phase Diagram-Facilitated Rapid Screening of Double Perovskites As Electrocatalysts for the Oxygen Evolution Reaction

Sun, Hainan,Hu, Zhiwei,Xu, Xiaomin,He, Juan,Dai, Jie,Lin, Hong-Ji,Chan, Ting-Shan,Chen, Chien-Te,Tjeng, Liu Hao,Zhou, Wei,Shao, Zongping American Chemical Society 2019 Chemistry of materials Vol.31 No.15

<P>The development of cost-effective, non-noble metal electrocatalysts for the oxygen evolution reaction (OER) is of paramount importance for sustainable technologies. Efficient screening strategies for electrocatalysts can greatly increase the commercialization speed of these advanced technologies. Here, ternary phase diagrams with large-scale tuning and designated-scale tuning strategies are applied for the first time to provide a new method for screening perovskite oxide-based electrocatalysts for OERs. Specifically, the family of double perovskites (Sr<SUB>2</SUB>Fe<SUB>1.5-<I>x</I>-<I>y</I></SUB>Co<SUB><I>x</I></SUB>Ni<SUB><I>y</I></SUB>Mo<SUB>0.5</SUB>O<SUB>6−δ</SUB>, 0 ≤ <I>x</I>, <I>y</I> ≤ 1.5) was utilized to understand the role of transition metals in perovskite oxides. Ternary phase diagrams can facilitate a rapid screening process, provide a straightforward relationship between phase structures and catalytic activities, and help to confirm the effects of various combinations of transition metals on the OER activity. The Fe-Co system (Sr<SUB>2</SUB>Fe<SUB>1.5-<I>x</I></SUB>Co<SUB><I>x</I></SUB>Mo<SUB>0.5</SUB>O<SUB>6−δ</SUB>) improves the catalytic activities, as demonstrated by the reduced Tafel slope and enhanced stability, while the Fe-Ni system (Sr<SUB>2</SUB>Fe<SUB>1.5-<I>y</I></SUB>Ni<SUB><I>y</I></SUB>Mo<SUB>0.5</SUB>O<SUB>6−δ</SUB>) improves the surface kinetic properties of the OER, as demonstrated by its reduced overpotential. Significantly, the Co, Ni, and Fe ternary phase systems can serve as the synergistic coactive sites (Sr<SUB>2</SUB>Fe<SUB>1.5-<I>x</I>-<I>y</I></SUB>Co<SUB><I>x</I></SUB>Ni<SUB><I>y</I></SUB>Mo<SUB>0.5</SUB>O<SUB>6−δ</SUB>) to catalyze the OER, resulting in an improved overall OER performance. This systematic study not only demonstrates a new strategy to allow the rapid screening of double perovskite OER catalysts based on large-scale tuning and designated-scale tuning strategies but, more importantly, also provides an insightful understanding of the use of multitransition metal-based double perovskites for catalysis of the OER.</P> [FIG OMISSION]</BR>