ZnO@Ni–Co–S Core–Shell Nanorods-Decorated Carbon Fibers as Advanced Electrodes for High-Performance Supercapacitors

Yanwei Sui,Man Zhang,Haihua Hu,Yuanming Zhang,Jiqiu Qi,Fuxiang Wei,Qingkun Meng,Yezeng He,Yaojian Ren,Zhi Sun 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.12

The interconnected three-dimensional Ni–Co–S nanosheets were successfully deposited on ZnO nanorods by a one-step potentiostatic electrodeposition. The Ni–Co–S nanosheets provide a large electrode/electrolyte interfacial area which has adequate electroactive sites for redox reactions. Electrochemical characterization of the ZnO@Ni–Co–S core–shell nanorods presents high specifc capacitance (1302.5 F/g and 1085 F/g at a current density of 1 A/g and 20 A/g), excellent rate capabilities (83.3% retention at 20 A/g) and great cycling stability (65% retention after 5000 cycles at a current density of 30 A/g). The outstanding electrochemical performance of the as-prepared electrode material also can be ascribed to these reasons that the special structure improved electrical conductivity and allowed the fast diffusion of electrolyte ions.

Error-immune Algorithm for Absolute Testing of Rotationally Asymmetric Surface Deviation

Yanwei Zhang,Dongqi Su,Le Li,Yongxin Sui,Huaijiang Yang 한국광학회 2014 Current Optics and Photonics Vol.18 No.4

Based on Zernike polynomial fitting, we propose an algorithm believed to be new for interferometric measurements of rotationally asymmetric surface deviation of optics. This method tests and calculates each angular surface by choosing specified rotation angles with lowest error. The entire figure can be obtained by superimposing these sub-surfaces. Simulation and experiment studies for verifying the proposed algorithm are presented. The results show that the accuracy of the proposed method is higher than single-rotation algorithm and almost comparable to the rotation-averaging algorithm with fewer rotation measurements. The new algorithm can achieve a balance between the efficiency and accuracy.

Effect of different short-term high ambient temperature on chicken meat quality and ultra–structure

Minghao Zhang,Lixian Zhu,Yimin Zhang,Yanwei Mao,Mingyue Zhang,Pengcheng Dong,Lebao Niu,Xin Luo,Rongrong Liang 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.5

Objective: This study investigated the effect of different acute heat stress (HS) levels on chicken meat quality and ultra-structure. Methods: Chickens were randomly divided into 7 groups to receive different HS treatments: i) 36°C for 1 h, ii) 36°C for 2 h, iii) 38°C for 1 h, iv) 38°C for 2 h, v) 40°C for 1 h, vi) 40°C for 2 h, and vii) un-stressed control group (25°C). Blood cortisol level, breasts initial temperature, color, pH, water holding capacity (WHC), protein solubility and ultra-structure were analyzed. Results: HS temperatures had significant effects on breast meat temperature, lightness (L*), redness (a*), cooking loss and protein solubility (p<0.05). The HS at 36°C increased L*24 h value (p<0.01) and increased the cooking loss (p<0.05), but decreased a*24 h value (p<0.05). However, as the temperature increased to 38°C and 40°C, all the values of L*24 h, cooking loss and protein denaturation level decreased, and the differences disappeared compared to control group (p> 0.05). Only the ultimate pH24 h at 40°C decreased compared to the control group (p<0.01). The pH in 36°C group declined greater than other heat-stressed group in the first hour postmortem, which contributed breast muscle protein degeneration combining with high body temperature, and these variations reflected on poor meat quality parameters. The muscle fiber integrity level in group 40°C was much better than those in 36°C with the denatured position mainly focused on the interval of muscle fibers which probably contributes WHC and light reflection. Conclusion: HS at higher temperature (above 38°C) before slaughter did not always lead to more pale and lower WHC breast meat. Breast meat quality parameters had a regression trend as HS temperature raised from 36°C. The interval of muscle fibers at 24 h postmortem and greater pH decline rate with high body temperature in early postmortem period could be a reasonable explanation for the variation of meat quality parameters.

Anthocyanins in Tree Peony (Paeonia suffruticosa) and Their Relationship with Flower Color

Yanzhao Zhang,Yan Zhang,Xujia Duan,Xin Liu,Shuiqing Yuan,Jianming Han,Yanwei Cheng 한국원예학회 2020 원예과학기술지 Vol.38 No.6

Flower color is an important trait of tree peony (Paeonia suffruticosa), an economically important species. The accurate classification of flower color and understanding of the mechanism involved in creating variations in flower color provide the basis of tree peony breeding and genetic research. This study used the International Commission of Illumination Color System, known as CIELAB or CIE L<SUP>*</SUP>a<SUP>*</SUP>b<SUP>*</SUP>, to measure the flower color of 150 cultivars of the Zhongyuan cultivar group of tree peony. Hierarchical cluster analysis and visual observations were used to divide this cultivar group into five major color lines: white, pink, red, purple, and fuchsia. The brightness (L<SUP>*</SUP>) of the flower color gradually decreased with an increase in anthocyanin content. The redness (a<SUP>*</SUP>) of the flower color was significantly negatively correlated with total anthocyanin (TA) content in the fuchsia line but was positively correlated with TA in the remaining four color lines. Six types of anthocyanins, including Cy3G, Cy3G5G, Pn3G, Pn3G5G, Pg3G, and Pg3G5G, were mainly found in the Zhongyuan cultivar group by liquid chromatography except in the white line. Stepwise regression analysis showed that Pg3G5G had a significant positive correlation with redness of flower color. Cy3G5G and Pn3G5G had a significant positive correlation with redness in pink, red, and purple color lines. However, Pn3G was negatively correlated with redness in the fuchsia line. This study lays the foundation for further development of new breeds and flower colors in tree peony and for genetic research related to flower color.

Low-voltage blue light emission from n-ZnO/p-GaN heterojunction formed by RF magnetron sputtering method

Yanwei Shen,Xiang Chen,Xiaoqin Yan,Fang Yi,Zhiming Bai,Xin Zheng,Pei Lin,Yue Zhang 한국물리학회 2014 Current Applied Physics Vol.14 No.3

High quality n-ZnO/p-GaN heterojunction was fabricated by growing highly crystalline ZnO epitaxial films on commercial p-type GaN substrates via radio frequency (RF) magnetron sputtering. Low-voltage blue light emitting diode with a turn-on voltage of w2.5 V from the n-ZnO/p-GaN heterojunction was demonstrated. The diode gives a bright blue light emission located at w460 nm and a low threshold voltage of 2.7 V for emission. Based on the results of the photoluminescence (PL) and electroluminescence (EL) spectra, the origins of the EL emissions were studied in the light of energy band diagrams of ZnOeGaN heterojunction, and may attribute to the radiative recombination of the holes in p-GaN and the electrons injected from n-ZnO, which almost happened on the side of p-GaN layer. These results may have important implications for developing short wavelength optoelectronic devices.

Models of Pseudomonas Growth Kinetics and Shelf Life in Chilled Longissimus dorsi Muscles of Beef

Zhang, Yimin,Mao, Yanwei,Li, Ke,Dong, Pengcheng,Liang, Rongrong,Luo, Xin Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.5

The aim of this study was to confirm Pseudomonas spp. as the specific spoilage organism (SSO) of chilled beef during aerobic storage and to establish a model to predict the shelf life of beef. Naturally contaminated beef was stored at $4^{\circ}C$, and the spoilage limit of Pseudomonas organisms was determined by measuring several quality indicators during storage, including the number of Pseudomonas organisms, total number of bacteria, total volatile basic nitrogen (TVBN) values, L value color scale scores and sensory evaluation scores. The beef was then stored at 0, 4, 7, 10, 15 or $20^{\circ}C$ for varying amounts of time, and the number of Pseudomonas organisms were counted, allowing a corresponding growth model to be established. The results showed that the presence of Pseudomonas spp. was significantly correlated to each quality characteristic (p<0.01), demonstrating that Pseudomonas spp. are the SSO of chilled beef and that the spoilage limit was $10^{8.20}$ cfu/g. The Baranyi and Roberts equation can predict the growth of Pseudomonas spp. in beef, and the $R^2$ value of each model was greater than 0.95. The square root model was used as follows, and the absolute values of the residuals were less than ${0.05:\;{\mu_{max}}^{1/2}$ = 0.15604 [T+(-0.08472)] (p<0.01), $R^2$ = 0.98, $\lambda^{-1/2}$ = 0.0649+0.0242T (p<0.01, $R^2$ = 0.94). The model presented here describes the impact of different temperatures on the growth of Pseudomonas spp., thereby establishing a model for the prediction of the shelf life of beef stored between 0 to $20^{\circ}C$.

Underdetermined Blind Source Separation from Time-delayed Mixtures Based on Prior Information Exploitation

Zhang, Liangjun,Yang, Jie,Guo, Zhiqiang,Zhou, Yanwei The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.5

Recently, many researches have been done to solve the challenging problem of Blind Source Separation (BSS) problems in the underdetermined cases, and the “Two-step” method is widely used, which estimates the mixing matrix first and then extracts the sources. To estimate the mixing matrix, conventional algorithms such as Single-Source-Points (SSPs) detection only exploits the sparsity of original signals. This paper proposes a new underdetermined mixing matrix estimation method for time-delayed mixtures based on the receiver prior exploitation. The prior information is extracted from the specific structure of the complex-valued mixing matrix, which is used to derive a special criterion to determine the SSPs. Moreover, after selecting the SSPs, Agglomerative Hierarchical Clustering (AHC) is used to automaticly cluster, suppress, and estimate all the elements of mixing matrix. Finally, a convex-model based subspace method is applied for signal separation. Simulation results show that the proposed algorithm can estimate the mixing matrix and extract the original source signals with higher accuracy especially in low SNR environments, and does not need the number of sources before hand, which is more reliable in the real non-cooperative environment.

Effects of Carbonization Temperature on Nature of Nanostructured Electrode Materials Derived from Fe-MOF for Supercapacitors

Yanwei Sui,Dongling Zhang,Yongpeng Han,Zhi Sun,Jiqiu Qi,Fuxiang Wei,Yezeng He,Qingkun Meng 대한금속·재료학회 2018 ELECTRONIC MATERIALS LETTERS Vol.14 No.5

This work successfully demonstrates various temperature carbonization of iron based metal organic framework to deriveelectrode materials for supercapacitors. Furthermore, impacts of calcined temperatures on the nature of as-prepared productsare reported, and samples obtained at 300, 400, 500, 600 and 700 °C were investigated respectively. The products revealsexcellent electrochemical performance. Carbonized at 600 °C, the composite materials display the highest specific capacitanceof 972 F/g at a current density of 1 A/g. Carbonized at 500 °C, the capacitance retention of materials reach up to 93%. The high specific capacitance and excellent cyclic stability of the developed materials would exhibit nice prospect for thepractical utilization of electrode materials.

Bio-protective potential of lactic acid bacteria: Effect of Lactobacillus sakei and Lactobacillus curvatus on changes of the microbial community in vacuum-packaged chilled beef

Zhang, Yimin,Zhu, Lixian,Dong, Pengcheng,Liang, Rongrong,Mao, Yanwei,Qiu, Shubing,Luo, Xin Asian Australasian Association of Animal Productio 2018 Animal Bioscience Vol.31 No.4

Objective: This study was to determine the bacterial diversity and monitor the community dynamic changes during storage of vacuum-packaged sliced raw beef as affected by Lactobacillus sakei and Lactobacillus curvatus. Methods: L. sakei and L. curvatus were separately incubated in vacuumed-packaged raw beef as bio-protective cultures to inhibit the naturally contaminating microbial load. Dynamic changes of the microbial diversity of inoculated or non-inoculated (control) samples were monitored at $4^{\circ}C$ for 0 to 38 days, using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Results: The DGGE profiles of DNA directly extracted from non-inoculated control samples highlighted the order of appearance of spoilage bacteria during storage, showing that Enterbacteriaceae and Pseudomonas fragi emerged early, then Brochothrix thermosphacta shared the dominant position, and finally, Pseudomonas putida showed up became predominant. Compared with control, the inoculation of either L. sakei or L. curvatus significantly lowered the complexity of microbial diversity and inhibited the growth of spoilage bacteria (p<0.05). Interestingly, we also found that the dominant position of L. curvatus was replaced by indigenous L. sakei after 13 d for L. curvatus-inoculated samples. Plate counts on selective agars further showed that inoculation with L. sakei or L. curvatus obviously reduced the viable counts of Enterbacteraceae, Pseudomonas spp. and B. thermosphacta during later storage (p<0.05), with L. sakei exerting greater inhibitory effect. Inoculation with both bio-protective cultures also significantly decreased the total volatile basic nitrogen values of stored samples (p<0.05). Conclusion: Taken together, the results proved the benefits of inoculation with lactic acid bacteria especially L. sakei as a potential way to inhibit growth of spoilage-related bacteria and improve the shelf life of vacuum-packaged raw beef.

Controllable Zn0.76Co0.24S Nanoflower Arrays Grown on Carbon Fiber Papers for High-Performance Supercapacitors

Man Zhang,Yanwei Sui,Xiaofang Yuan,Jiqiu Qi,Fuxiang Wei,Qingkun Meng,Yezeng He,Yaojian Ren,Zhi Sun,Jinlong Liu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.3

A nanoflower structure of Zn0.76Co0.24S directly grown on carbon fiber papers (CFP) was successfully designed by a mild two-step hydrothermal method. Benefiting from their fascinating structural features, Zn0.76Co0.24S/CFP electrode exhibits a maximum specific capacitance of 300 F g -1 at current density of 1 A g -1 and 84% capacitance retention after 5,000 cycles at current density of 5 Ag -1. Subsequently, Zn0.76Co0.24S/CFP//AC all-solid-state asymmetric supercapacitor (ASC) device is assembled and able to illuminate the red LEDs. ASC devices deliver a maximum energy density of 9.59 Wh kg -1 at a power density of 750 W kg -1. Therefore, this impressive result demonstrates that the nanoflower Zn0.76Co0.24S have promising applications in the development of high-performance supercapacitors.