Performance optimization of flexible a-Si:H solar cells with nanotextured plasmonic substrate by tuning the thickness of oxide spacer layer

Xiao, Huapeng,Wang, Jun,Huang, Hongtao,Lu, Linfeng,Lin, Qingfeng,Fan, Zhiyong,Chen, Xiaoyuan,Jeong, Chaehwan,Zhu, Xufei,Li, Dongdong Elsevier 2015 Nano energy Vol.11 No.-

<P><B>Abstract</B></P> <P>Plasmonic thin film solar cells deposited on periodically textured photonic crystal substrates have been extensively studied since the substantially enhanced light absorption. The reduction of parasitic absorption losses in the metal and spacer layers becomes one of the key issues to achieve high efficiency solar cells. Herein, plasmonic amorphous silicon (a-Si:H) flexible thin film solar cells with different thickness of oxide spacer layers are systematically investigated. An increase of the spacer layer thickness leads to an evolution in surface morphology of AZO and final devices. More intriguingly, the increase of spacer layer thickness reduces the absorption in Ag layer while induces more absorption in spacer layer. The highest light absorption in silicon layer is observed as applying 100nm spacer layer, which is further verified by electrical measurements. Our observations demonstrate a versatile and convenient route towards rational design of light harvesting nanostructure for high performance plasmonic solar cells based on a broad range of materials.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Amorphous silicon thin film solar cells are constructed on patterned substrates. </LI> <LI> The devices properties are studied as a function of spacer layer thickness. </LI> <LI> An increase of spacer layer thickness reduces the absorption loss of Ag layer. </LI> <LI> The device with 100nm spacer layer confines more incident light in silicon layer. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Shear-strain induced structural relaxation of Cu Σ3 [110](112) symmetric tilt grain boundary: The role of foreign atoms and temperature

Li Yang,Xue Hongtao,Zhou Xin,Tang Fuling,Li Xiuyan,Ren Junqiang,Lu Xuefeng 한국물리학회 2021 Current Applied Physics Vol.28 No.-

Grain boundaries (GBs) relaxation is a promising and effective strategy to improving GB stability or stabilizing nanocrystalline metals. However, previous studies mainly focused on nanocrystalline pure metals and GB behaviors therein, without considering the role of foreign atoms such as impurity or alloying atoms in GB relaxation. In this work, the shear-strain induced structural relaxation of pure Cu Σ3 [110](112) symmetric tilt GBs (STGBs), and the effects of foreign elements (Fe and Ni) and temperature on the GB relaxation were investigated in detail by molecular dynamics method. The results show that shear strain can trigger the structural relaxation of pure, Fe- and Ni-containing Cu GBs by the emission of Shockley partial dislocations from Cu GBs. Both Fe and Ni have impediment effects on the shear-strain induced GB relaxation, though the content of Fe or Ni atom (0.00165 at.%) is quite low in the GB model. The temperature cannot trigger GB relaxation independently within the considered temperature range, but play a positive role in the shear-strain induced structural relaxations of pure, Fe- and Ni-containing Cu Σ3 [110](112) STGBs. Our work might gain new insights into the mechanically induced GB relaxation in nanocrystalline copper and could be beneficial for improving the stability of Cu GBs.

Development of Rectangle-Pulse Marx Generator Based on PFN

Hongtao Li,Hong-Je Ryoo,Jong-Soo Kim,Geun-Hie Rim,Young-Bae Kim,Jianjun Deng IEEE 2009 IEEE transactions on plasma science Vol.37 No.1

<P>In this paper, two designs of the rectangle-pulse Marx generator based on pulse-forming network (PFN) for pulse-power application are reported. The PFN is composed of inductors and capacitors. Proposed schemes consist of several identical PFNs that are connected according to Marx generator scheme. PFN Marx generators can output rectangle pulse several hundreds of nanoseconds in duration and several tens of nanoseconds in rising time. The effect of component parameter to the waveform is studied. Prototypes made of four PFNs have been tested. One of the prototypes is designed according to classical Marx mode, while another is designed as an <I>L</I>-<I>C</I> Marx generator in which only one command switch and one isolating switch is needed. In a 500-ns duration, 65-ns rising-time rectangle pulse has been achieved on the matching load.</P>

Dynamic positioning error analysis and modeling of CNC machine tool guideway system

Li Li,Hongtao Yang,Yu Zhang,Qun Ma 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.5

The dynamic characteristics of the XY worktable are thoroughly analyzed in this study to accurately compensate the measurement errors of on-machine measurement systems caused by the dynamic and static characteristics under multiple factors. The dynamic positioning error model of the XY worktable motion components is established, and the theoretical model of the dynamic positioning error of the XY worktable is derived. The actual parameters of the experimental platform for the correlation error of CNC machine tools are substituted into the model for theoretical calculation and analysis. Results show that the motion speed of the worktable, the weight of the measured workpiece, the installation position of the workpiece, and the friction force are the main factors causing the dynamic positioning error. Dynamic positioning error analysis and verification experiments were conducted to verify the validity of the proposed theoretical model. Experimental results show that a regular change occurs between the dynamic positioning error and the movement speed of the XY worktable, and the actual measurement results are basically consistent with the theoretical calculation results. The research results can lay a good foundation for establishing the measurement error prediction and compensation model of on-machine measurement systems of CNC machine tools and improving its measurement accuracy.

Acute and repeated dose 26-week oral toxicity study of 20(S)-ginsenoside Rg3 in Kunming mice and Sprague-Dawley rats

Li, Chunmei,Wang, Zhezhe,Li, Guisheng,Wang, Zhenhua,Yang, Jianrong,Li, Yanshen,Wang, Hongtao,Jin, Haizhu,Qiao, Junhua,Wang, Hongbo,Tian, Jingwei,Lee, Albert W.,Gao, Yonglin The Korean Society of Ginseng 2020 Journal of Ginseng Research Vol.44 No.2

Background: 20(S)-ginsenoside-Rg3 (C₄₂H₇₂O₁₃), a natural triterpenoid saponin, is extracted from red ginseng. The increasing use of 20(S)-ginsenoside Rg3 has raised product safety concerns. Methods: In acute toxicity, 20(S)-ginsenoside Rg3 was singly and orally administrated to Kunming mice and Sprague-Dawley (SD) rats at the maximum doses of 1600 mg/kg and 800 mg/kg, respectively. In the 26-week toxicity study, we used repeated oral administration of 20(S)-ginsenoside Rg3 in SD rats over 26 weeks at doses of 0, 20, 60, or 180 mg/kg. Moreover, a 4-week recovery period was scheduled to observe the persistence, delayed occurrence, and reversibility of toxic effects. Results: The result of acute toxicity shows that oral administration of 20(S)-ginsenoside Rg3 to mice and rats did not induce mortality or toxicity up to 1600 and 800 mg/kg, respectively. During a 26-week administration period and a 4-week withdrawal period (recovery period), there were no significant differences in clinical signs, body weight, food consumption, urinalysis parameters, biochemical and hematological values, or histopathological findings. Conclusion: The mean oral lethal dose (LD₅₀) of 20(S)-ginsenoside Rg3, in acute toxicity, is above 1600 mg/kg and 800 mg/kg in mice and rats, respectively. In a repeated-dose 26-week oral toxicity study, the no-observed-adverse-effect level for female and male SD rats was 180 mg/kg.

Acute and repeated dose 26-week oral toxicity study of 20(S)-ginsenoside Rg3 in Kunming mice and Sprague – Dawley rats

Chunmei Li,ZhezheWang,Guisheng Li,ZhenhuaWang,Jianrong Yang,Yanshen Li,Hongtao Wang,Haizhu Jin,Junhua Qiao,Hongbo Wang,Jingwei Tian,Albert W. Lee,Yonglin Gao 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.2

Background: 20(S)-ginsenoside-Rg3 (C42H72O13), a natural triterpenoid saponin, is extracted from redginseng. The increasing use of 20(S)-ginsenoside Rg3 has raised product safety concerns. Methods: In acute toxicity, 20(S)-ginsenoside Rg3 was singly and orally administrated to Kunming miceand SpragueeDawley (SD) rats at the maximum doses of 1600 mg/kg and 800 mg/kg, respectively. In the26-week toxicity study, we used repeated oral administration of 20(S)-ginsenoside Rg3 in SD rats over 26weeks at doses of 0, 20, 60, or 180 mg/kg. Moreover, a 4-week recovery period was scheduled to observethe persistence, delayed occurrence, and reversibility of toxic effects. Results: The result of acute toxicity shows that oral administration of 20(S)-ginsenoside Rg3 to mice andrats did not induce mortality or toxicity up to 1600 and 800 mg/kg, respectively. During a 26-weekadministration period and a 4-week withdrawal period (recovery period), there were no significantdifferences in clinical signs, body weight, food consumption, urinalysis parameters, biochemical andhematological values, or histopathological findings. Conclusion: The mean oral lethal dose (LD50) of 20(S)-ginsenoside Rg3, in acute toxicity, is above 1600mg/kg and 800 mg/kg in mice and rats, respectively. In a repeated-dose 26-week oral toxicity study, theno-observed-adverse-effect level for female and male SD rats was 180 mg/kg.

Design and Practice of Teacher Training Supported by a Web 2.0 Community

Shuang Li,Li Chen,Hongtao Sun APEC국제교육협력원 2010 Asia-Pacific Cybereducation Journal Vol.6 No.2

Web 2.0 communities are providing new opportunities for teachers’ professional development by supporting more flexible sharing, communicating, and collaborating among teachers at a distance. Meanwhile, literature concerning teachers’ professional development increasingly places value on communities of practice and web-based learning communities. This paper presents a case study on the design of teacher training supported by a Web 2.0 community. The training program discussed in the paper is characterized by employing peer-coaching to facilitate teachers’ learning in a Web 2.0 community, and is a part of a project funded by the Ford Foundation. The paper gives a brief introduction to the training program, and reports some important findings and reflections on design and practice for in-service teacher training. It includes the theoretical framework design, a training model as well as activity design, and the implementation and evaluation of the training program and useful experiences. Initially, taking account school teachers’ needs at the K12 level for curriculum reform and quality education, theory, knowledge and practice competences for learner-centered instruction were examined by using peer-coaching methods supported by online communities. The suggested training program was delivered in two Chinese districts in August 2009: Tianhe district of Guangzhou, and Wuhou district of Chengdu. More than 120 participants, including subject teachers, school principals and local teaching researchers, took part in the f2f training, online activities and the further practice activities. Even still on-going, the comprehensive investigation and evaluation of the training program explains that the initial results and observations collected during the process of training are very positive. With cause for optimism as to the prospect of achieving the training program’s goals, the study has demonstrated that a task-driven approach and peer-coaching supported by a web 2.0 community are effective methods for in-service teacher training, and that peer-coaching can be greatly extended by out-of-school activities.

Novel In Situ Synthesized Fe@C Magnetic Nanocapsules Used as Adsorbent for Removal of Organic Dyes and Its Recycling

Ranran Li,Jieyi Yu,Asif Shah,Xinglong Dong,Xiaona Li,Hongtao Yu,Xie Quan,Youngguan Jung 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.2

Core/shell type carbon-coated Fe nanocapsules (Fe@C NCs) were in situ synthesized by DC arcdischarge plasma method in methane atmosphere. Such Fe nanocapsules have saturation magnetization of 29.32 emu/g and specific surface area of 85.86 m2/g. The carbon shell of Fe@C NCs was functionalized with oxygen-containing groups (such as –OH or –COOH) by using H2O2. The adsorption of organic dye, e.g., methylene blue (MB) was systematically investigated in different conditions, such as contact time, pH values and temperature. The maximum adsorption capacity (46.5 mg/g) was calculated by fitting the adsorption isotherms with Langmuir model, coincident with the experimental result of 44.5 mg/g. Kinetics data supported pseudo-second order model, and the thermodynamic process of adsorption was revealed as endothermic and spontaneous physisorption. The MB-absorbed Fe@C NCs can be entirely separated from the contaminative solution by a magnetic field and then successfully cycled for regeneration. After repetitive cycles of the adsorption/desorption experiments for five times, the removal efficiency can be maintained over 90%.

The hydrogen storage nanomaterial MgH2 improves irradiation-induced male fertility impairment by suppressing oxidative stress

Jing Ma,Suhe Dong,Hongtao Lu,Zhongmin Chen,Huijie Yu,Xuejun Sun,Renjun Peng,Wei Li,Sinian Wang,Qisheng Jiang,Fengsheng Li,Li Ma 한국생체재료학회 2022 생체재료학회지 Vol.26 No.2

Objective: This study aimed to reveal the protective effect of hydrogen storage nanomaterial MgH2 on radiationinduced male fertility impairment. Methods: The characterization of MgH2 were analyzed by scanning electron microscopy (SEM) and particle size analyzer. The safety of MgH2 were evaluated in vivo and in vitro. The radioprotective effect of MgH2 on the reproductive system were analyzed in mice, including sperm quality, genetic effect, spermatogenesis, and hormone secretion. ESR, flow cytometry and western blotting assay were used to reveal the underlying mechanisms. Results: MgH2 had an irregular spherical morphology and a particle size of approximately 463.2 nm, and the content of Mg reached 71.46%. MgH2 was safe and nontoxic in mice and cells. After irradiation, MgH2 treatment significantly protected testicular structure, increased sperm density, improved sperm motility, reduced deformity rates, and reduced the genetic toxicity. Particularly, the sperm motility were consistent with those in MH mice and human semen samples. Furthermore, MgH2 treatment could maintain hormone secretion and testicular spermatogenesis, especially the generation of Sertoli cells, spermatogonia and round sperm cells. In vitro, MgH2 eliminated the [·OH], suppressed the irradiation-induced increase in ROS production, and effectively alleviated the increase in MDA contents. Moreover, MgH2 significantly ameliorated apoptosis in testes and cells and reversed the G2/M phase cell cycle arrest induced by irradiation. In addition, MgH2 inhibited the activation of radiation-induced inflammation and pyroptosis. Conclusion: MgH2 improved irradiation-induced male fertility impairment by eliminating hydroxyl free radicals.

Effect of Co doping on the resistance switching behavior of Zn<SUB>1-x</SUB>O:Co<SUB>x</SUB> Films

Hongtao Xu,Zhao Xiahou,Ying Li,Yemin Hu,Min Zhong,Chunli Liu 한국자기학회 2015 한국자기학회 학술연구발표회 논문개요집 Vol.2015 No.5