Process and property characterization of La-Al-B-O/Al2O3 glass ceramic composites

Wen-Cheng J. Wei,Chih-Lung Chen,S.F. Wang 한양대학교 세라믹연구소 2006 Journal of Ceramic Processing Research Vol.7 No.1

A LAB glass with a composition of 10 mol% La2O3 + 10 mol% Al2O3 + 80% B2O3 made into a composite with 30-50% Al2O3 filler was prepared and investigated. Processing optimization and several engineering properties used for microwave substrates are reported, including densification, interaction with Ag electrodes, dielectric properties as a function of frequency, acid dissolution and microstructure. The glass ceramic composite, i.e. L30A, without lead and alkali, can be densified by two-step sintering to a density better than 99% with minimal glass residue. The densified composite does not react with Ag up to 950 oC in 1 h, and does not dissolve in an acid solution (pH=3.5) in 2 h. The dielectric constant and loss are in the range of 5.6-5.9 and 1.4 × 10−3-5.5 × 10−3, respectively. The coefficient of thermal expansion (CTE) and thermal conductivity of the composite are reported.

A Multi-Inlet Microfluidic Nozzle Head with Shape Memory Alloy-Based Switching for Biomaterial Printing with Precise Flow Control

Karthick Mani,Wei-Chen Lin,Chun-Fang Wang,Bivas Panigrahi,Yong-Jin Wu,Cheng-Lung Wu,Chia-Yuan Chen 한국바이오칩학회 2020 BioChip Journal Vol.14 No.4

3D bioprinting is one of the rapidly evolving fields of tissue engineering where microengineering meets cells biology within an unprecedented precision to construct tissue structures of various forms with complexity. However, enabling simultaneous printing of heterogeneous biomaterial along with scaffold components through the currently available printers is still considered as a major challenge due to the lack of instrumentation. Flow control is one of the major issues associated with the process. In this aspect, a microfluidic nozzle head equipped with two shape-memory alloy (SMA) actuators was proposed and integrated with a commercially available 3D printer to assist the biomaterial printing in a more systematic manner. The SMA actuator restrains the amount of flows for fabricating the desired scaffold components. Experimental results illustrated that the use of SMA actuator ensued a rapid and precise flow control of biomaterial and can further facilitate to maintain the width of any printed structures. As a proof of concept for the profound biomedical applications with the present manufacturing configuration, a 3D printed hydrogel platform was fabricated with demonstrated characters for later cell seeding after the printing further opens a new chapter in terms of biomaterial printing.

The Study of Taiwan‘s New Immigrant Children‘s Mathematics Achievement

Wen Tsung Lai,Lung Wei Cheng,Chiu Chu Lu 한국수학교육학회 2013 수학교육연구 Vol.17 No.1

Introduction: According the 2011 Taiwanes Government Statistics, the lower secondary shool enrollment number of the new-immigrant-children is about 200,000. As known, most of the new immigrants are from the Southeast Asian countries, such as Vietnam, China, Indonesia, Thailand, the Philippines and Cambodia. In order to satisfy the increasing needs and demands on education of the children of new immigrant (CNI,henceforth), Taiwanese government not only develops, but also puts the after-school learning assistance policy into pracice from 2006. Therefore, the main purpose of this study is to explore the mathematics achievement of the CNI after the implementation of the after school learning assistance policy (AsLA plicy, henceforth). Purposes: Firstly, to compare the mathematics achievenment of the CNI by coutries. Secondly, to compare the mathematics performance among the CNI, the children from high-risk family (CHRF, henceforth)and the children of general families. Samples:The 2,452 samples, selccted from two junior high schools located in central Taiwan, include 157 CNI, 522 CHRF. Methosd:The main method used in this study is interval fuzzy number(IFN, henceforth) in order to compare the mathematics achievement of the children after the implementation of the AsLA policy from different type of families. Results: To reach the two purposes of this study. We can find the effectiveness of mathematics performance from three group‘s children of new immigrants, high-risk, general family. Therefore, the results provide one of the ways to review the new immigrant‘s education policy of after-school learning assistance in Taiwan.

The Study of Taiwan`s New Immigrant Children`s Mathematics Achievement

( Wen Tsung Lai ),( Lung Wei Cheng ),( Chiu Chu Lu ) 한국수학교육학회 2013 수학교육 학술지 Vol.2013 No.1

Introduction: According the 2011 Taiwanese Government Statistics, the lower secondary school enrollment number of the new-immigrant-children is about 200,000. As known, most of the new immigrants are from the Southeast Asian countries, such as Vietnam, China, Indonesia, Thailand, the Philippines and Cambodia. In order to satisfy the increasing needs and demands on education of the children of new immigrant (CNI, henceforth), Taiwanese government not only develops, but also puts the after-school learning assistance policy into practice from 2006. Therefore, the main purpose of this study is to explore the mathematics achievement of the CNI after the implementation of the afterschool learning assistance policy (AsLA policy, henceforth). Purposes: Firstly, to compare the mathematics achievement of the CNI by countries. Secondly, to compare the mathematics performance among the CNI, the children from high-risk family (CHRF, henceforth) and the children of general families. Samples: The 2,452 samples, selected from two junior high schools located in central Taiwan, include 157 CNI, 522 CHRF. Methods: The main method used in this study is interval fuzzy number (IFN, henceforth) in order to compare the mathematics achievement of the children after the implementation of the AsLA policy from different type of families. Results: To reach the two purposes of this study .We can find the effectiveness of mathematics performance from three group`s children of new immigrants, high-risk, general family. Therefore, the results provide one of the ways to review the new immigrant`s education policy of after-school learning assistance in Taiwan.

Material Saving and Product Quality Improvement with the Visualization of Hot Runner Design in Injection Molding

Tzu-Chau Chen,Chao-Tsai Huang,Yan-Chen Chiu,Wei-Da Wang,Cheng-Li Hsu,Chen-Yang Lin,Lung-Wen Kao 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.

Runner system plays a very important role in injection molding process. A quality runner design is helpful in improving product qualities and saving material. However, traditional cold runner systems have certain inherent issues. Moreover, poor product cosmetics are commonly seen with the use of traditional cold runners. As a result, hot runner technology has been widely applied. On the other hand, It has been one of the green molding solutions for material/energy saving and clean environments. But the mechanism behind the hot runner system is too complicated to be fully understood. There exist some critical issues currently. As a result, the simulation technolgy is highly needed to examine hot runner designs before the real manufacturing. Through simulation analyses, designers and manufafctuers are able to catch the potential issues on their hot runner systems and revise their designs. Hot runner simulation technology helps with the investigations into the behavior in hot runner system. In this paper, a true 3D numerical method is proposed and applied to investigate the temperature behavior in a real hot runner system for PC material. The experiment is conducted and the simulating result is compared with that from the experiment for the validation purpose.

Dissipative Particle Dynamics Simulation on the Formation Process of CeO₂ Nanoparticles in Alcohol Aqueous Solutions

Zhang, Qi,Zhong, Jing,Yang, Bao-Zhu,Huang, Wei-Qiu,Chen, Ruo-Yu,Liao, Jun-Min,Gu, Chi-Ruei,Chen, Cheng-Lung Korean Chemical Society 2012 대한화학회지 Vol.56 No.4

Dissipative particle dynamics (DPD) was carried out to study the nucleation and crystal growth process of $CeO_2$ nanoparticles in different alcohol aqueous solutions. The results showed that the nucleation and crystal growth process of $CeO_2$ can be classified into three stages: nuclei growth, crystal stabilization and crystal aggregation except the initial induction stage, which could be reproduced by collecting simulation results after different simulation time. Properly selecting the sizes of $CeO_2$ and water bead was crucial in the simulation system. The influence of alcohol type and content in solutions, and precipitation temperature on the particle dimension were investigated in detail and compared with the experimental results. The consistency between simulation results and experimental data verify that the simulation can reproduce the macroscopic particle aggregation process. The effect of solvent on the nucleation and crystal growth of $CeO_2$ nanoparticles are different at three stages and can not be simply described by Derjaguin-Landau-Verwey-Overbeek (DLVO) theory or nucleation thermodynamics theory. Our work demonstrated that DPD methods can be applied to study nanoparticle forming process.