New Method of Solving the Proper Rational Function and Application to Electrical Control System

Chen Chung-Cheng,Chen Yen-Ting 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.4

The paper is dedicated to develop a new method of addressing the linear nonhomogeneous time-invariant diff erential equation with same diff erential numbers for inputs and outputs. The Laplace transformed output of the electrical state-space equation is a rational function with the same degrees of the numerator and the denominator, and then the bored processes involving the long division of both complicated polynomials, the expanded multiplication of all polynomial factors, the diff erentiation of complicated polynomials and the complex derivations of all partial fraction parameters are inevitable for existing traditional methods. However, by applying the proposed method in this paper, we can explicitly express the general form of the desired output solution and directly solve the desired problem with shorter time than those traditional approaches. To give the signifi cant applications of the new proposed method, we apply it to address the famous electrical circuit based on our recent researches of Chen’s electrical unifying approach.

Effects of Neodymium and Calcium on the Thermal Stability of AZ71 Magnesium Alloys

Cheng‑Feng Yue,Shi‑Jei Huang,Jhewn‑Kuang Chen,Hsien‑Tsung Li,Kam‑Shau Chan 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.2

The effects of an addition of 0–2 wt% Nd on thermal stability of 0–3 wt% Ca-containing modified AZ71 magnesium alloyswas investigated. The ignition temperature was found to increase from that of AZ71, 574, to 825 °C with the addition of0.5 wt% Ca and 1 wt% Nd. The ignition temperature was further increased to 1114 °C when 3 wt% Ca was added. The CaandNd-added AZ71 was isothermally maintained at a temperature of 500 °C in air for 12 h. The MgO–CaO–Nd2O3 formedon the surface to improve the thermal stability of the AZ71–xCa–yNd alloys. While both the tensile strength and ductilitydecreased with the Ca concentration in the alloy, an addition of 1 wt% Nd was found able to alleviate the degradation effectsof Ca on the tensile strength and ductility at 170 °C. Both solid solution formation and precipitation strengthening contributedto the increase in toughness. AZ71 containing 0.5–2 wt% Ca and 1 wt% Nd provides the optimum combination of ignitionresistance and mechanical properties.

Dislocation Density-Based Constitutive Model and Processing Map for T2 Copper During Isothermal and Time-Variant Deformation

Gang Chen,Yu Jin,Jing Wang,Cheng Zhang,Qiang Chen,Hongming Zhang,Xingjian Zhao,Zhiyong Li,Changhai Xie,Zhiming Du 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.9

Isothermal compression tests were carried out to study the hot deformation behavior of T2 copper under various conditions. The deformation parameters, such as temperature and strain rate, have strong influence on flow stress and microstructureevolution of the alloy. A unified dislocation density-based model considering dynamic recovery and recrystallization wasestablished. And material parameters of the developed model were optimized by genetic algorithm. Comparisons betweenthe experimental and model data demonstrates that the developed model can precisely describe the flow behavior at quitewide range of deformation conditions. Meanwhile, the designed iterative procedure allows the model to be applied in timevariantdeformation conditions. Processing map and microstructure examination were constructed to optimize the processingwindow of the studied alloy. According to the processing maps, flow instability mainly appeared at low temperatures of500–650 °C and strain rates higher than 0.1 s−1. The optimum deformation parameters of T2 copper was concluded as thetemperature range of 700–800 °C and the strain rate of 0.1–1 s−1.

고속액체크로마토그래피에 의한 나프록센 광학이성질체의 분리 및 품질관리

정수진,진전성,이은주,이은실,강종성 忠南大學校 生命科學硏究院 醫藥品開發硏究所 2006 藥學論文集 Vol.21 No.-

Enantiomeric separation of naproxen is necessary in drug evaluation processes as the pharmacological activity of naproxen resides mainly in the (S)-enantiomer, The enantioseparation of naproxen was carried out with three different stationary phases. The methods were validated with the terms of linearity, intraday and interday precision, accuracy, selectivity and recovery. Among the selected stationary phases, ChiroSil DMB column with hexane : t-butylmethylether : acetic acid (60:40:0.1, v/v/v) as mobile phase showed the best enantioseparation of the naproxen in the commercial preparations. The wavelength for detection was 270 nm and flow rate was 2.0 mL/min. The contents of (S)-naproxen in the commercial preparations were 92.7 - 98.3%, indicating that all tested preparations were satisfactory to current regulation. However, the contents of (R)-naproxen as impurity in the commercial preparations were varied from 0.08% to 1.08%.

녹음 구어 제시가 중도정신지체 성인여성의 목욕 능력 개선에 미치는 효과

鄭如意,陳明聰,陳政見 대구대학교 특수교육재활과학연구소 2006 再活科學硏究 Vol.24 No.2

1. This study aimed to explore the effect of recorded auditory prompts on helping an adult with profound mental retardation to take bath independently. 「A-B-C-A-C」design, a kind of single-subject experiment was adopted. Three phases, baseline phase, intervention phase(B): auditory prompt, and intervention phase(C): recorded auditory prompt were included. A female with profound mental retardation participated in the experiment. It took over seven months to finishing the intervention. The results of the experiment indicated that auditory prompts, whether human auditory prompt or recorded prompt, could help the client to take bath more independently. The families of the client also regarded recorded auditory prompt was a feasible solution. Based on the result, there were some suggestions for the further research. 본 연구의 목적은 녹음 구어 제시를 이용해서 극 중도 지능장애 성인 여성 스스로 목욕 동작을 완성 할 수 있도록 도와주는 효과에 대한 연구입니다. 본 연구에 사용하는 연구법은 ⌜A-B-A-C-A-C⌟역 설계이다. 기선기의(A)개입一(B)인공구어제시 개입二(C)녹음 구어 제시로 나누어졌다. 실험기간은 모두 7개월 반이었다. 연구결과는 피 실험자가 스스로 목욕할 때와 비교했을 때 인공구어 제시와 녹음구어 제시는 모두 피 실험자가 목욕 동작을 완성 하는 데에 효과가 있는 것으로 나타났다. 이 외에도 녹음 구어 제시는 피 실험자 가족들도 받아들일 수 있다. 본 연구 결과에 근거해서 연구자들은 미래 응용과 연구에 대한 건의도 제출하였다.

Radiative decay of theψ(2S)into two pseudoscalar mesons

Bai, J. Z.,Ban, Y.,Bian, J. G.,Blum, I.,Chen, A. D.,Chen, G. P.,Chen, H. F.,Chen, H. S.,Chen, J.,Chen, J. C.,Chen, X. D.,Chen, Y.,Chen, Y. B.,Cheng, B. S.,Choi, J. B.,Cui, X. Z.,Ding, H. L.,Dong, L. Y American Physical Society 2003 Physical review. D, Particles and fields Vol.67 No.3

Pure Ultraviolet Emission from ZnO Quantum Dots-Based/GaN Heterojunction Diodes by MgO Interlayer

Cheng Chen,Renli Liang,Jingwen Chen,Jun Zhang,Shuai Wang,Chong Zhao,Wei Zhang,Jiangnan Dai,Changqing Chen 대한금속·재료학회 2017 ELECTRONIC MATERIALS LETTERS Vol.13 No.4

We demonstrate the fabrication and characterization of ZnO/GaNbasedheterojunction light-emitting diodes (LEDs) by using air-stableand solution-processable ZnO quantum dots (QDs) with a thin MgOinterlayer acting as an electron blocking layer (EBL). The ZnO QDs/MgO/p-GaN heterojunction can only display electroluminescence(EL) characteristic in reverse bias regime. Under sufficient reversebias, a fairly pure ultraviolet EL emission located at 370 nm derivingfrom near band edge of ZnO with a full width at half maximum(FWHM) of 8.3 nm had been obtained, while the deep-level emissionhad been almost totally suppressed. The EL origination andcorresponding carrier transport mechanisms were investigatedqualitatively in terms of photoluminescence (PL) results and energyband diagram.

The Nature of Acid-Catalyzed Acetalization Reaction of 1,2-Propylene Glycol and Acetaldehyde

( Chen Cheng ),( Hui Chen ),( Xia Li ),( Jian Li Hu ),( Bao Chen Liang ) 한국화학공학회 2015 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.53 No.4

We investigated catalytic activity of ion-exchange resins in acetalization of 1,2-propylene glycol with acetaldehyde. The impacts of reaction variables, such as temperature, reaction time, catalyst loading and feedstock composition, on the conversion of 1,2-propylene glycol were measured. The life of the catalyst was also studied. Furthermore, the reaction kinetics of 1,2-propylene glycol acetalization was studied. It was found that reaction rate followed the firstorder kinetics to acetaldehyde and 1,2-propylene glycol, respectively. Therefore, overall acetalization reaction should follow the second-order reaction kinetics, expressed as r=kC pile{nA#A} C pile{nB#B} =19.74 {-6650} over {T} C pile{1#A} C pile{1#B}.

Early Childhood Administrators’ Admission Decision Making Process in Including Children with Special Needs in Singapore

Chen-Chen Cheng 환태평양유아교육연구학회 2014 Asia-Pacific journal of research in early childhoo Vol.8 No.1

In Singapore, many parents find it difficult to locate early childhood services for their children with special needs. As Singapore does not have laws protecting the right to education for children with special needs, early childhood center administrators (managers and principals) make admission decisions at their own discretion on a case-by-case basis. This qualitative interview study examines the individual, varied patterns of early childhood center administrators’ admission decision making process in relation to children with special needs in Singapore. The results revealed an on-going, dynamic decision making process jointly participated in by both administrators and parents. The researcher investigated and documented the steps and efforts these administrators took to make the inclusion of children with special needs possible in regular early childhood education settings. The implications of this unique Singapore inclusion model are focused on the moral and professional aspects of inclusion and administrators’ sense of ownership in inclusion without the presence of the law.

Eye on the Future: Diverse Family Language Policy in Three Singaporean Malay Homes with Preschool Children

Chen-Chen Cheng 환태평양유아교육연구학회 2020 Asia-Pacific journal of research in early childhoo Vol.14 No.1

Singapore’s bilingual education policy mandates children study English and a mother-tongue in school. To understand the language shift from Malay to English in Malay homes from the perspective of family language policy, this paper reports on the diverse language ideologies and practices of three Singaporean Malay mothers of preschool children. The in-depth interviews were conducted in 2013- 2014 and transcribed verbatim by a bilingual English-Malay transcriptionist. Although the mothers were of similar ethnic, religious, and socioeconomic backgrounds, their home language practices were distinctly different. Their language practices reflected the beliefs, values, and feelings they ascribed to Malay, English, and Mandarin, languages their preschool-age children were exposed to as well as their ideas about language development and bilingualism in Singapore. While subscribing to some state bilingual education policy assumptions, mothers actively formed different family language policies to resist the state bilingual policy, shield their children from academic pressure, and carve out a unique Malay identity. Major forces such as Malay as a minority, language and social mobility, and English ownership, in addition to state bilingual policy and education system, were discussed in connection to mothers’ family language policy.