Effect of rapid thermal oxidation on structure and photoelectronic properties of silicon oxide in monocrystalline silicon solar cells

Chung Ping Liu,Ming Wei Chang,Chuan Lung Chuang 한국물리학회 2014 Current Applied Physics Vol.14 No.5

This paper concerns the topic of surface passivation properties of rapid thermal oxidation on p-type monocrystalline silicon wafer for use in screen-printed silicon solar cells. It shows that inline thermal oxidation is a very promising alternative to the use of conventional batch type quartz tube furnaces for the surface passivation of industrial phosphorus-diffused emitters. Five minutes was the most favorable holding time for the rapid thermal oxidation growth of the solar cell sample, in which the average carrier lifetime was increased 19.4 ms. The Fourier transform infrared spectrum of the rapid thermal oxidation sample, whose structure was Al/Al-BSF/p-type Si/n-type SiP/SiO2/SiNx/Ag solar cell with an active area of 15.6 cm2, contained an absorption peak at 1085 cm1, which was associated with the SieO bonds in silicon oxide. The lowest average reflectance of this sample is 0.87%. Furthermore, for this sample, its average of internal quantum efficiency and conversion efficiency are respectively increased by 8% and 0.23%, compared with the sample without rapid thermal oxidation processing.

Influence of the Ratio of Surfactant Additives on the Anisotropic Etching Process Used to Make Small Pyramids for Use in Solar Cells

Chung Ping Liu,Ming Wei Chang,Chuan Lung Chuang 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.9

This paper focuses on surfactant additives (SA) that are used in alkaline etching of p-typemonocrystalline silicon wafers for use in screen-printed silicon solar cells. An Al/p-type Si/ntypeSiP/SiNx/Ag solar cell with an active area of 15.6 cm2 was fabricated. The highest measuredefficiency of the solar cells was 19.24%, which proves that the SA method is highly efficient for fabricatingmonocrystalline silicon solar cells. The results show that 0.4 L of SA is the most favorablevolume for alkaline etching of solar-cell samples. Samples etched at this volume exhibit the lowestaverage reflectance of 0.596%, an average internal quantum efficiency (IQE) gain of 5.6% and anefficiency gain of 0.84%, thus showing the SA method to be an efficient anisotropic etching process. In addition, the cell with the highest efficiency had an increase of 4.57% in power, an increase of3.1% in the short-circuit current, and an increase of 1.43% in the open-circuit voltage. In summary,microstructural, reflectance, IQE, and I − V measurements revealed that the best cell was formedusing an optimal SA volume of 0.4 L.

Isolation of a Natural Antioxidant, Dehydrozingerone from Zingiber officinale and Synthesis of Its Analogues for Recognition of Effective Antioxidant and Antityrosinase Agents

Ping-Chung Kuo,Amooru G. Damu,Ching-Yuh Cherng,Jye-Fu Jeng,Che-Ming Teng,E-Jian Lee,Tian-Shung Wu 대한약학회 2005 Archives of Pharmacal Research Vol.28 No.5

In the present study, the antioxidative and inhibitory activity of Zingiber officinale Rosc. rhizomes- derived materials (on mushroom tyrosinase) were evaluated. The bioactive components of Z. officinale rhizomes were characterized by spectroscopic analysis as zingerone and dehydrozingerone, which exhibited potent antioxidant and tyrosinase inhibition activities. A series of substituted dehydrozingerones [(E)-4-phenyl-3-buten-2-ones] were prepared in admirable yields by the reaction of appropriate benzaldehydes with acetone and the products were evaluated in terms of variation in the dehydrozingerone structure. The synthetic analogues were examined for their antioxidant and antityrosinase activities to probe the most potent analogue. Compound 26 inhibited Fe2+-induced lipid peroxidation in rat brain homogenate with an IC50 = 6.3±0.4 µM. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical quencher assay, compounds 2, 7, 17, 26, 28, and 29 showed radical scavenging activity equal to or higher than those of the standard antioxidants, like α-tocopherol and ascorbic acid. Compound 27 displayed superior inhibition of tyrosinase activity relative to other examined analogues. Compounds 2, 17, and 26 exhibited non-competitive inhibition against oxidation of 3,4- dihydroxyphenylalanine (L-DOPA). From the present study, it was observed that both number and position of hydroxyl groups on aromatic ring and a double bond between C-3 and C-4 played a critical role in exerting the antioxidant and antityrosinase activity.

Research on Traditional Chinese Medicine harmonising two approaches

Chung, Leung Ping,Wai, Lau Tai,Sang, Woo Kam Kyung Hee Oriental Medicine Research Center 2008 Oriental pharmacy and experimental medicine Vol.8 No.1

While full recognition of the practical value of Traditional Chinese Medicine is being endorsed, the current stand on the research methodology of this field should be worked out. Since modern medicine has already developed a logical system of research methodology basing on the principles of deduction, any research on any system of medicine need to take reference to what is most popularly used and commonly recommended. The best way to approach research on Chinese Medicine, therefore, would be one that would take full reference to the methodology being used in modern medicine, while at the same time respecting the traditional approach. This would enable traditional medicine to be elevated to the level of general modern recognition. Nevertheless, innate problems in traditional medicine are making its research difficult. The problems lie in difficulties to achieve uniform herb supply, principles of randomization and placebo arrangements, uncertain chemical structures and toxicology etc. A practical approach centered on carefully planned evidence-based clinical trials, with parallel studies on biological activities and herb authentication is being recommended.

Chemical Constituents from Lobelia chinensis and Their Anti-virus and Anti-inflammatory Bioactivities

Ping-Chung Kuo,Yann-Lii Leu,Tsong-Long Hwang,Ying-Ting Lin,Yuh-Chi Kuo 대한약학회 2011 Archives of Pharmacal Research Vol.34 No.5

In total, forty six compounds, including the novel compound lobechine (1), were characterized from the methanol extracts of Lobelia chinensis. The chemical structures of known metabolites were identified by comparing their spectroscopic and physical data with compounds reported in the literature. The structure of lobechine (1) was comprehensively established with the aid of 1D and 2D NMR spectroscopic analyses. In addition, selected isolates were screened for their inhibition of HSV-1 replication, superoxide anion generation, and elastase release. Among the tested compounds, scoparone (10) exhibited significant inhibition of superoxide anion generation with IC_50 of 6.14 ± 1.97 μM and lobechine (1) exhibited moderate inhibition of elastase release with IC_50 of 25.01 ± 6.95 μM, respectively.

Formation of CuInGaSe2 Thin Film Photovoltaic Absorber by Using Rapid Thermal Sintering of Binary Nanoparticle Precursors

Chung Ping Liu,Ming Wei Chang,Chuan Lung Chuang 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.11

It was known that properties of copper-indium-gallium-diselenide (CIGS) thin films were evidentlyaffected by precursor nanoparticle-ink and sintering technology. The nanoparticles were fabricatedby using a rotary ball-milling (RBM) technique. After RBM, the particle size of the agglomeratedCIGS powder was smaller than 100 nm. The nanoparticle ink was printed onto a Mo/soda limeglass substrate and baked at a low temperature to remove solvents and to form a dry precursor. Crystallographic, morphological, and stoichiometric properties of films were then obtained by usingthe precursor CIGS samples sintered at various heating rates in a non-vacuum environment withoutselenization. Analytical results revealed that the 2-theta data of the sample sintered at a heatingrate of 15 C/s were the closest to the data on the JCPDS card for Cu(Ga0.3In0.7)Se2.0 because theirangles were 26.8, 44.5, and 52.7, respectively. In addition, analytical results indicated that theCIGS absorption layer prepared at a heating rate of 15 C/s had a chalcopyrite structure and favorablecompositions. For this sample, the mole ratio of Cu:In:Ga:Se was equal to 0.98:0.81:0.28:1.93,and related ratios of Ga/(In+Ga) and Cu/(In+Ga) were 0.26 and 0.90, respectively.

Can herbal extracts be used as skin penetrating agent

Chung, Leung Ping,Xin, Zhao,Tak, Law Wai,David, Lau Tai Wai Kyung Hee Oriental Medicine Research Center 2007 Oriental pharmacy and experimental medicine Vol.7 No.3

Swollen and painful extremities have been treated with herbal baths in attempts to alleviate the symptoms. A popular herbal bath used in China, contains a component called 'bone-penetrating herb' which is believed to facilitate the penetration of herbal substances across the skin to the swollen site, so swollen site, so that pain and swelling will be improved. A search from the Chinese pharmacopedia revealed that 22 different herbs have been traditionally used as 'bone-penetrating herb'. Five of these herbs were available in market and were chosen for experimental studies. Standard diffusion experiments were done to identify the most effective herb among the five, in the penetration facilitation. Glechoma longituba at a concentration of 20% was found to give the best results in the facilitation of Bromophenol blue diffusion across artificial and biological membranes. When compared with one commonly used diffusion facilitator, viz. azone, azone was found to be more effective than glechoma longituba. The encouraging observations support future studies on the basic science behind the use of herbal components as topical agents to treat pain and swelling.

Rehabilitation training in artificially heated environment

Ping-Chung Leung 한국운동재활학회 2017 JER Vol.13 No.5

State-Dependent Call Admission Control in Hierarchical Wireless Multiservice Networks

Chung Shun-Ping,Lee Jin-Chang The Korea Institute of Information and Commucation 2006 Journal of communications and networks Vol.8 No.1

State-dependent call admission control (SDCAC) is proposed to make efficient use of scarce wireless resource in a hierarchical wireless network with heterogeneous traffic. With SDCAC, new calls are accepted according to an acceptance probability taking account of not only cell dwell time but also call holding time and system state (i.e., occupied bandwidth). An analytical method is developed to calculate performance measures of interest, e.g., new call blocking probability, forced termination probability, over. all weighted blocking probability. Numerical results with not only stationary but nonstationary traffic loads are presented to show the robustness of SDCAC. It is shown that SDCAC performs much better than the other considered schemes under nonstationary traffic load.

Research on Traditional Chinese Medicine harmonising two approaches

Leung Ping Chung,Lau Tai Wai,Woo Kam Sang 경희대학교 융합한의과학연구소 2008 Oriental Pharmacy and Experimental Medicine Vol.8 No.1

While full recognition of the practical value of Traditional Chinese Medicine is being endorsed, the current stand on the research methodology of this field should be worked out. Since modern medicine has already developed a logical system of research methodology basing on the principles of deduction, any research on any system of medicine need to take reference to what is most popularly used and commonly recommended. The best way to approach research on Chinese Medicine, therefore, would be one that would take full reference to the methodology being used in modern medicine, while at the same time respecting the traditional approach. This would enable traditional medicine to be elevated to the level of general modern recognition. Nevertheless, innate problems in traditional medicine are making its research difficult. The problems lie in difficulties to achieve uniform herb supply, principles of randomization and placebo arrangements, uncertain chemical structures and toxicology etc. A practical approach centered on carefully planned evidence-based clinical trials, with parallel studies on biological activities and herb authentication is being recommended. While full recognition of the practical value of Traditional Chinese Medicine is being endorsed, the current stand on the research methodology of this field should be worked out. Since modern medicine has already developed a logical system of research methodology basing on the principles of deduction, any research on any system of medicine need to take reference to what is most popularly used and commonly recommended. The best way to approach research on Chinese Medicine, therefore, would be one that would take full reference to the methodology being used in modern medicine, while at the same time respecting the traditional approach. This would enable traditional medicine to be elevated to the level of general modern recognition. Nevertheless, innate problems in traditional medicine are making its research difficult. The problems lie in difficulties to achieve uniform herb supply, principles of randomization and placebo arrangements, uncertain chemical structures and toxicology etc. A practical approach centered on carefully planned evidence-based clinical trials, with parallel studies on biological activities and herb authentication is being recommended.