A Switching Capacitor Control in Single-Stage AC-DC Reconfigurable RGB-LED Driver

Pang-Jung Liu,Ho-Hua Yu,Zhi-Yuan Hong 전력전자학회 2023 ICPE(ISPE)논문집 Vol.2023 No.-

A single-stage ac-dc LED driver operating in discontinuous conduction mode is presented to realize ac-dc rectification with high power factor and current regulation of red, green, blue (RGB) LEDs in this paper. The features of single-stage architecture reduce component cost and lower circuit size. A switching capacitor control is employed to hop the output voltage instantly for precisely adjusting LED currents. The voltage difference between the green/blue and red LEDs is automatically reflected on a hopping capacitor while the fast hopping scheme can rapidly regulate the output voltage level. The experimental results demonstrate the fast hopping scheme of the ac-dc LED driver and the capability in current regulation.

A SUPERLINEAR VU SPACE-DECOMPOSITION ALGORITHM FOR SEMI-INFINITE CONSTRAINED PROGRAMMING

Pang Li-Ping,Ming Huang,Yuan Lu,Zun-Quan Xia 한국전산응용수학회 2012 Journal of applied mathematics & informatics Vol.30 No.5

In this paper, semi-infinite constrained programming, a class of constrained nonsmooth optimization problems, are transformed into unconstrained nonsmooth convex programs under the help of exact penalty function. The unconstrained objective function which owns the primal-dual gradient structure has connection with VU-space decomposition. Then a VU-space decomposition method can be applied for solving this unconstrained programs. Finally, the superlinear convergence algorithm is proved under certain assumption.

How to evaluate the adequacy of staging for nodal-negative epithelial ovarian cancer? Use of nodal staging score

Yuan Xu,Haoran Li,Xiaoxia Tong,Yangyang Pang,Xiaojuan Tong,Luhong Li,Lei Cheng 대한부인종양학회 2019 Journal of Gynecologic Oncology Vol.30 No.2

Objective: No guideline has been provided to assess the minimal number of lymph nodes (LNs) that should be dissected for accurate staging in patients with epithelial ovarian cancer (EOC). The aim of the study was to develop a nodal staging score (NSS) as an index to assess whether a pathologic (p)N0 EOC patient is indeed free of a nodal disease. Methods: A total of 16,361 EOC patients staged I–III between 2004 and 2013 were identified from the Surveillance, Epidemiology and End Result database. With a β-binomial model, NSS was calculated to assess the probability of true-negative findings of LN status. Results: With an increased number of LNs examined, the probability of missing a nodal disease decreased and varied among different pT stages. Given 1 LN examined, an NSS of 93.76% calculated could ensure a high adequacy of nodal-negative classification for pT1N0 EOC patients. For pT2N0 patients, 5 LNs examined could guarantee an NSS of 90% for adequate staging. Likewise, 11 and 29 LNs examined in pT3N0 patients could maintain NSS at the level of 80% and 90%, respectively. Our study suggested the optimal number of LNs that could be examined and stratified by the pT stages for EOC patients based on this statistical model derived from large pathologic data of clinical surgery patients. Conclusion: NSS, as an auxiliary tool, not only could assist the International Federation of Gynecology and Obstetrics staging more precisely, but also would provide a statistical basis for postoperative evaluation for further clinical decision-making.

DC-DC Converter with Self-Regulated Output Voltage Control Scheme for Multiple-String Dimmable LED Driver Control

Pang-Jung Liu,Yu-Chi Hsu,Ting-Yu Wei,Zhi-Yuan Hong 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

This paper presents a dc-dc converter with selfregulated output voltage (SROV) and phase shift PWM (PSPWM) control methods for multiple LED strings. The LED driver is composed of a boost converter and dimmable current balancing regulators (CBRs). Compared with traditional linear current regulator, the CBR is adopted to reduce power consumption. To keep a designed constant voltage on the CBRs, the output voltage of the boost converter is dynamically adjusted with the SROV control method. It results in high efficiency and current balance of the CBRs and prevents output voltage oscillation. The PSPWM control is employed to mitigate the output current variation supplied by the boot converter, leading to smaller output transient ripple when the PWM dimming signals are changed. The CBRs and control circuits were fabricated with a 0.35-μm standard CMOS technology. The experimental results demonstrate the theoretical analysis of the proposed LED driver.

Structure and Properties of Konjac Glucomannan/Galactoglucomannan Nanofiber Membrane

Yi Yuan,Xin Hong,Ruojun Mu,Jingni Gong,Lin Wang,Rongxun Huang,Jiayu Wu,Yongsheng Ni,Xianhui Wu,Jie Pang 한국고분자학회 2017 Macromolecular Research Vol.25 No.10

Konjac glucomannan (KGM)/galactoglucomannan (GGM) nanofiber membranes were obtained through electrospinning technology. Rheological properties of KGM/GGM solutions were observed by using a rotary rheometer. The apparent morphological, characteristic group and thermal stability of nanofiber membranes were studied through scanning electron microscopy (SEM), Fourier transform infrared spectoscopy (FTIR) and differential scanning calorimeter (DSC) respectively. The physical and mechanical properties were also evaluated. Results revealed that the addition of GGM did not significantly affect the rheological properties of electrospinning solution. Increase in the amount of GGM in the nanofiber membrane resulted in gradual smoothening, uniformity and decrease in the number of nodes. KGM interacts with GGM through hydrogen-bond. Addition of GGM markedly enhanced the thermal stability, physical and mechanical properties of the nanofiber membrane. The study showed that the KGM/GGM nanofiber membrane have good potential for use in developing membrane based materials.

Preparation of activated carbon from waste cation exchange resin and its application in wastewater treatment

Yang Chane-Yuan,Kao Chao-Lang,Hung Pang-Yu 한국탄소학회 2022 Carbon Letters Vol.32 No.2

Recently, the circular economy aiming at elimination of waste and the continual use of resources has attracted a lot of attentions. In the circular system, the resource recovery uses the recycled wastes as the raw material to manufacture new valuable products. This work focuses on a low-cost process, in which an activated carbon (AC) adsorbent was prepared from waste cation exchange resin by calcination and HNO3 activation hydrothermal method. Surface structure and chemistry of AC were characterized by SEM, XRD, FTIR and Boehm titration. It was found that the acid treatment could increase the number of pores and the content of oxygen-containing functional groups on AC surface. In the adsorption experiment, Methylene blue (MB) was used to assess the adsorption capacity of AC. Experimental results showed that the highest efficiency of MB removal was achieved by AC with modification of 4M HNO3, showing the acidification effect on the adsorption capacity of AC. Adsorption isotherms of Langmuir and Freundlich were employed to fit the experimental data. It was shown that MB adsorption on AC is more consistent with Langmuir model that assumes a homogeneous adsorption. In the adsorption kinetic analysis, the adsorption was found to follow the pseudo-second-order model, indicating that adsorption of MB on acidified AC is dominated by chemical adsorption. The study revealed that the waste ion-exchange resin is a proper precursor of carbon adsorbent for MB dye. This low-cost method would specifically reduce the environmental cost of waste disposal.

A SUPERLINEAR $\mathcal{VU}$ SPACE-DECOMPOSITION ALGORITHM FOR SEMI-INFINITE CONSTRAINED PROGRAMMING

Huang, Ming,Pang, Li-Ping,Lu, Yuan,Xia, Zun-Quan The Korean Society for Computational and Applied M 2012 Journal of applied mathematics & informatics Vol.30 No.5

In this paper, semi-infinite constrained programming, a class of constrained nonsmooth optimization problems, are transformed into unconstrained nonsmooth convex programs under the help of exact penalty function. The unconstrained objective function which owns the primal-dual gradient structure has connection with $\mathcal{VU}$-space decomposition. Then a $\mathcal{VU}$-space decomposition method can be applied for solving this unconstrained programs. Finally, the superlinear convergence algorithm is proved under certain assumption.

Free vibration analysis of uniform and stepped functionally graded circular cylindrical shells

Haichao Li,Fuzhen Pang,Yuan Du,Cong Gao 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.33 No.2

A semi analytical method is employed to analyze free vibration characteristics of uniform and stepped functionally graded circular cylindrical shells under complex boundary conditions. The analytical model is established based on multi-segment partitioning strategy and first-order shear deformation theory. The displacement functions are handled by unified Jacobi polynomials and Fourier series. In order to obtain continuous conditions and satisfy complex boundary conditions, the penalty method about spring technique is adopted. The solutions about free vibration behavior of functionally graded circular cylindrical shells were obtained by approach of Rayleigh-Ritz. To confirm the dependability and validity of present approach, numerical verifications and convergence studies are conducted on functionally graded cylindrical shells under various influencing factors such as boundaries, spring parameters <i>et al</i>. The present method apparently has rapid convergence ability and excellent stability, and the results of the paper are closely agreed with those obtained by FEM and published literatures.

Load Interval Prediction of the Power System based on Type-2 Fuzzy Theory

He Tao,Liang Zhidong,Pang Jihong,Ye Xianquan,Yuan Jinxin 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.2

According to the power load has strong randomness and difficult to forecast, the introduction of the two types of fuzzy logic in order to improve the prediction accuracy. The interval type two non-single valued two type Mamdani fuzzy model for power load time series forecasting, and reverse the spread of a similarity of a singular value decomposition iterative blending algorithm to simplify the redundant rules in the model of fuzzy sets and redundant fuzzy rules, in order to eliminate the adverse effects. For ordinary type-2 fuzzy sets, uncertainty of the trace and once the membership function is the most important factor, therefore in the calculation formula for construction of two kinds of measure when considering these two factors; analysis of the ordinary type-2 fuzzy inclusion degree properties; discussed two kinds of conversion between the new measure of the relationship, revealing its internal relations; finally through an example to verify the performance of the new measure ordinary type-2, and the fuzzy similarity and Yang Shih clustering method combining cluster analysis used in Gauss plain type-2 fuzzy sets, obtained the reasonable clustering results, verify the rationality of the new measure and effectiveness.

Tunable magnetic properties of double perovskite La₂Fe_2-xCo_xO₆

Wang, Weihua,Feng, Wuwei,Yuan, Jiangyan,Pang, Ning,Zhao, Xiaoxue,Li, Meiyun,Bao, Zhidi,Zhu, Kun,Odkhuu, Dorj Elsevier 2018 PHYSICA B-CONDENSED MATTER - Vol.540 No.-

<P><B>Abstract</B></P> <P>Double perovskite La<SUB>2</SUB>Fe<SUB>2-x</SUB>Co<SUB>x</SUB>O<SUB>6</SUB> was prepared and studied. Orthorhombic and trigonal structures were obtained depend on the molar ratio of Fe to Co. Fe-rich sample demonstrate ferrimagnetic properties; with increasing content of Co, trigonal structure is favored and the net magnetic moment of sample decrease gradually to zero. Our experimental results were further supported by first-principle theoretical calculations and demonstrate that La<SUB>2</SUB>Fe<SUB>2-x</SUB>Co<SUB>x</SUB>O<SUB>6</SUB> is a new high <I>T</I> <SUB> <I>c</I> </SUB> ferromagnetic semiconductor with tunable magnetic properties and is thus a promising material for spintronics devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Phase-pure double perovskite La2Fe2-xCoxO6 was prepared. </LI> <LI> Orthorhombic and trigonal structures were obtained depending on the ratio of Fe to Co. </LI> <LI> La2Fe2-xCoxO6 is a new high Tc ferromagnetic semiconductor with tunable magnetic properties. </LI> <LI> Theoretical ab initio calculations further support our experimental results. </LI> </UL> </P>