The Characterization of ZrO2 Films with Di??erent Substrate Bias Voltages

Zhao Sha,Xu Kewei 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.46 No.1

ZrO2 thin ¯lms were deposited by r.f. reactive magnetron sputtering. The e??ect of substrate negative bias voltages on phase structure and optical properties of ZrO2 thin ¯lms was investigated by X-ray di??raction, transmission-electron microscopy, electron spectroscopy for chemical analysis (ESCA), atomic-force microscopy and spectrophotometry. The results show that higher crystallinity of tetragonal-(101) ZrO2 ¯lms deposited on glass is produced at high substrate bias voltages and smaller grains can be obtained. SiO2 will be introduced near the interface when high bias voltages are applied on silicon. Under biased sputter deposition, the morphology of ZrO2 ¯lms is ameliorated and the surface roughness decreases with an increase of bias voltage. The transmittance increases with the increase of bias voltages, while the transmittance of ZrO2 ¯lms under biased sputtering is slightly lower than for those deposited with no bias voltages. The maximum refractive index (at ¸ = 500 nm) can reach 2.1607, that matches the corresponding value of bulk ZrO2

Morphological Characterization of Cu-W Thin Films Based on Wavelet Transform and its Application for Nanoindentation Hardness Scattering Evaluation

Yuan Wang,Kewei Xu,Yuanhua Chen 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.46 No.1

A strategy based on wavelet transform to describe surface morphology of thin ¯lms is presented in the present paper. The discrete wavelet transform method was used to investigate the evolution of surface morphology of Cu-W thin ¯lms with deposition time on silicon wafers. The results indicate that the surface morphology of thin ¯lms is unstable until the sputtering time exceeds 600 seconds. The surface morphology variation of dierent thin ¯lms can be distinguished primarily by high frequency signals. A scattering of the nanoindentation hardness values, which results from roughness of the surface of thin ¯lms, can be characterized by the roughness de¯ned by surface texture based on wavelet transform.

First-principles Study on the Relaxed Structures and Electronic Properties of Cu [110] Nanowires

Yue Sun,Jian-Min Zhang,Kewei Xu 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.7

Under the generalized gradient approximation (GGA), first-principles calculations are employed to study the structural stability of Cu nanowires (NWs) along the [110] direction by using the projector-augmented wave potential based on the density functional theory. We present different geometrical structures of Cu [110] NWs with the first three diameters, formed by stacking of atomic polygons with rectangular or hexagonal cross sections perpendicular to the wire axis. For all six-sized Cu NWs, the relaxed structures still have C₂ symmetry and show a "round corner" phenomenon. The calculated binding energies and electronic band structures show the hexagonal wire is not only more stable but also more metallic than the corresponding rectangular one. Therefore the [110] oriented Cu NWs is energetically more favorable in hexagonal cross sections perpendicular to the wire axis in agreement with the experimental result. The vanishing of the neighbor atoms outside the NWs after being cleaved from bulk crystal causes the “skin effect” phenomenon. In fact, the conclusions drawn here are applicable to not only the NWs but also the other surface cases, such as nanobelts, nanotubes, nanocables, clusters, thin films, and so on.

Production of Transgenic Pigs with an Introduced Missense Mutation of the Bone Morphogenetic Protein Receptor Type IB Gene Related to Prolificacy

Zhao, Xueyan,Yang, Qiang,Zhao, Kewei,Jiang, Chao,Ren, Dongren,Xu, Pan,He, Xiaofang,Liao, Rongrong,Jiang, Kai,Ma, Junwu,Xiao, Shijun,Ren, Jun,Xing, Yuyun Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.7

In the last few decades, transgenic animal technology has witnessed an increasingly wide application in animal breeding. Reproductive traits are economically important to the pig industry. It has been shown that the bone morphogenetic protein receptor type IB (BMPR1B) A746G polymorphism is responsible for the fertility in sheep. However, this causal mutation exits exclusively in sheep and goat. In this study, we attempted to create transgenic pigs by introducing this mutation with the aim to improve reproductive traits in pigs. We successfully constructed a vector containing porcine BMPR1B coding sequence (CDS) with the mutant G allele of A746G mutation. In total, we obtained 24 cloned male piglets using handmade cloning (HMC) technique, and 12 individuals survived till maturation. A set of polymerase chain reactions indicated that 11 of 12 matured boars were transgene-positive individuals, and that the transgenic vector was most likely disrupted during cloning. Of 11 positive pigs, one (No. 11) lost a part of the terminator region but had the intact promoter and the CDS regions. cDNA sequencing showed that the introduced allele (746G) was expressed in multiple tissues of transgene-positive offspring of No.11. Western blot analysis revealed that BMPR1B protein expression in multiple tissues of transgene-positive $F_1$ piglets was 0.5 to 2-fold higher than that in the transgene-negative siblings. The No. 11 boar showed normal litter size performance as normal pigs from the same breed. Transgene-positive $F_1$ boars produced by No. 11 had higher semen volume, sperm concentration and total sperm per ejaculate than the negative siblings, although the differences did not reached statistical significance. Transgene-positive $F_1$ sows had similar litter size performance to the negative siblings, and more data are needed to adequately assess the litter size performance. In conclusion, we obtained 24 cloned transgenic pigs with the modified porcine BMPR1B CDS using HMC. cDNA sequencing and western blot indicated that the exogenous BMPR1B CDS was successfully expressed in host pigs. The transgenic pigs showed normal litter size performance. However, no significant differences in litter size were found between transgene-positive and negative sows. Our study provides new insight into producing cloned transgenic livestock related to reproductive traits.

In-silico annotation of the chemical composition of Tibetan tea and its mechanism on antioxidant and lipid-lowering in mice

Wang Ning,Li Linman,Zhang Puyu,Mehmood Muhammad Aamer,Lan Chaohua,Gan Tian,Li Zaixin,Zhang Zhi,Xu Kewei,Mo Shan,Xia Gang,Wu Tao,Zhu Hui 한국영양학회 2023 Nutrition Research and Practice Vol.17 No.4

BACKGROUND/OBJECTIVES: Tibetan tea is a kind of dark tea, due to the inherent complexity of natural products, the chemical composition and beneficial effects of Tibetan tea are not fully understood. The objective of this study was to unravel the composition of Tibetan tea using knowledge-guided multilayer network (KGMN) techniques and explore its potential antioxidant and hypolipidemic mechanisms in mice. MATERIALS/METHODS: The C57BL/6J mice were continuously gavaged with Tibetan tea extract (T group), green tea extract (G group) and ddH2O (H group) for 15 days. The activity of total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) in mice was detected. Transcriptome sequencing technology was used to investigate the molecular mechanisms underlying the antioxidant and lipid-lowering effects of Tibetan tea in mice. Furthermore, the expression levels of liver antioxidant and lipid metabolism related genes in various groups were detected by the real-time quantitative polymerase chain reaction (qPCR) method. RESULTS: The results showed that a total of 42 flavonoids are provisionally annotated in Tibetan tea using KGMN strategies. Tibetan tea significantly reduced body weight gain and increased T-AOC and SOD activities in mice compared with the H group. Based on the results of transcriptome and qPCR, it was confirmed that Tibetan tea could play a key role in antioxidant and lipid lowering by regulating oxidative stress and lipid metabolism related pathways such as insulin resistance, P53 signaling pathway, insulin signaling pathway, fatty acid elongation and fatty acid metabolism. CONCLUSIONS: This study was the first to use computational tools to deeply explore the composition of Tibetan tea and revealed its potential antioxidant and hypolipidemic mechanisms, and it provides new insights into the composition and bioactivity of Tibetan tea.