Three-point Bending Behavior and Energy Absorption Capacity of Composite Tube Reinforced by Gradient Braided Structure in Radial Direction

Zhenyu Wu,Yong Shen,Zhongxiang Pan,Xudong Hu 한국섬유공학회 2019 Fibers and polymers Vol.20 No.7

This study aims to investigate the radial gradient structural effect on energy absorption and failure behavior ofbraided composite tubes. Two-layer tubular braided fabrics were fabricated using over-braiding technology with three typesof radial gradient configurations in terms of uninform, descending and ascending pattern. The structure of surface layertouching with indenter roll was found to have a significant role on the bending behavior and failure mode. The compositetube possessing the small angle surface layer tends to fail in top-surface mode characterized by compression damage incontact area between indenter roll and tube. With the increasing of the braiding angle in surface layer, the bottom-surfacefailure mode characterized by penetrating crack in circumferential direction was observed, which accompanies abruptlyloading drop and loss of energy absorption capacity. In addition, the tube in descending gradient pattern contributes to higherflexural modulus and peak load due to high fiber volume fraction, while keeps top-surface failure mode because of loadspreading ability provided by surface layer with small braiding angle. The results show that a proper selection of stackingsequence and braiding angle in multi-layer braided tube is capable of effectively enhancing the energy absorption of tubalstructures under bending load.

Risk Measurement and Investment Myopia in Hedge Fund Management

Zhenyu Wu,Xun Li 한국증권학회 2009 Asia-Pacific Journal of Financial Studies Vol.38 No.1

Lo (2001) surveys the literature on risk management for hedge funds, and recommends a dynamic and transparent risk measurement for the evolutionary hedge fund industry by citing Albert Einstein’s comments. This study is to explore the feasibility and advantages of adopting a dynamic absolute-deviation risk measurement in hedge fund management. It does not only provide an optimal asset allocation strategy both analytically and nu-merically in a dynamic mean-absolute deviation (DMAD) setting for hedge fund managers, but also contributes to mitigation of potential investment myopia problems in their risk-taking behaviors. It sheds light on risk management and investor-fund manager agency conflicts in the hedge fund industry and adds to the literature on portfolio selection and optimal asset allocation.

Hair follicle development and related gene and protein expression of skins in Rex rabbits during the first 8 weeks of life

Zhenyu Wu,Liangzhan Sun,Gongyan Liu,Hongli Liu,Hanzhong Liu,Zhiju Yu,Shuang Xu,Fuchang Li,Yingbe Qin 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.4

Objective: We aimed to observe hair follicle (HF) development in the dorsal skin and elucidate the expression patterns of genes and proteins related to skin and HF development in Rex rabbits from birth to 8 weeks of age. Methods: Whole-skin samples were obtained from the backs of Rex rabbits at 0, 2, 4, 6, and 8 weeks of age, the morphological development of primary and secondary HFs was observed, and the gene transcript levels of insulin-like growth factor-I (IGF-I), epidermal growth factor (EGF), bone morphogenetic protein 2 (BMP2), transforming growth factor β-1, 2, and 3 (TGFβ-1, TGFβ-2, and TGFβ-3) were examined using quantitative real-time polymerase chain reaction (PCR). Additionally, Wnt family member 10b (Wnt10b) and β-Catenin gene and protein expression were examined by quantitative real-time PCR and western blot, respectively. Results: The results showed significant changes in the differentiation of primary and secondary HFs in Rex rabbits during their first 8 weeks of life. The IGF-I, EGF, TGFβ-2, and TGFβ-3 transcript levels in the rabbits were significantly lower at 2 weeks of age than at birth and gradually increased thereafter, while the BMP2 and TGFβ-1 transcript levels at 2 weeks of age were significantly higher than those at birth and gradually decreased thereafter. β-Catenin gene expression was also significantly affected by age, while the Wnt10b transcript level was not. However, the Wnt10b and β-catenin protein expression levels were the lowest at 2 and 4 weeks of age. Conclusion: Our data showed that a series of changes in HFs in dorsal skin occurred during the first 8 weeks. Many genes, such as IGF-I, EGF, BMP2, TGFβ-1, TGFβ-2, TGFβ-3, and β-Catenin, participated in this process, and the related proteins Wnt10b and β-Catenin in skin were also affected by age.

Array Organization and Data Management Exploration in Racetrack Memory

Zhenyu Sun,Xiuyuan Bi,Wenqing Wu,Sungjoo Yoo,Hai Helen Li IEEE 2016 IEEE Transactions on Computers Vol. No.

<P>As the descendant of spin-transfer random access memory (STT-RAM), racetrack memory technology saves data in magnetic domains along nanoscopic wires. Such a unique structure can achieve unprecedentedly high storage density meanwhile inheriting the promising features of STT-RAM, such as fast access speed, non-volatility, zero standby power, hardness to soft errors, and compatibility with CMOS technology. Moreover, the recent success in planar racetrack nanowire promised its fabrication feasibility and continuous scalability. In this paper, we investigate the design and optimization of racetrack memory as last-level cache by embracing design considerations across multiple abstraction layers, including the cell design, the array structure, the architecture organization, and the data management. The cross-layer optimization makes racetrack memory based last-level cache achieve 6.4 x reduction in area, 25 percent enhancement in system performance, and 62 percent saving in energy consumption, compared to STT-RAM cache design. Its benefit over SRAM technology is even more significant.</P>

Accelerated Partial Breast Irradiation with Intensity-Modulated Radiotherapy Is Feasible for Chinese Breast Cancer Patients

Zhenyu He,San-Gang Wu,Juan Zhou,Fengyan Li,Jiayan Sun,Qin Lin,Huanxin Lin,Xunxing Guan 한국유방암학회 2014 Journal of breast cancer Vol.17 No.3

Purpose: Several accelerated partial breast irradiation (APBI)techniques are being investigated in patients with early-stagebreast cancer. The present study evaluated the feasibility, earlytoxicity, initial efficacy, and cosmetic outcomes of acceleratedpartial breast intensity-modulated radiotherapy (IMRT) for Chinesefemale patients with early-stage breast cancer after breastconservingsurgery. Methods: A total of 38 patients met the inclusioncriteria and an accelerated partial breast intensity-modulatedradiotherapy (APBI-IMRT) plan was designed for each patient. The prescription dose was 34 Gy in 10 fractions, 3.4 Gy per fraction,twice a day, in intervals of more than 6 hours. Results: Of the38 patients, six patients did not meet the planning criteria. Theremaining 32 patients received APBI-IMRT with a mean targetvolume conformity index of 0.67 and a dose homogeneity indexof 1.06. The median follow-up time was 53 months and no localrecurrence or distant metastasis was detected. The most commonacute toxicities observed within 3 months after radiotherapywere erythema, breast edema, pigmentation, and pain in the irradiatedlocation, among which 43.8%, 12.5%, 31.3%, and28.1% were grade 1 toxicities, respectively. The most commonlate toxicities occurring after 3 months until the end of the followupperiod were breast edema, pigmentation, pain in the irradiatedlocation, and subcutaneous fibrosis, among which 6.2%,28.1%, 21.9%, and 37.5% were grade 1 toxicities, respectively. Thirty-one patients (96.8%) had fine or excellent cosmetic outcomes,and only one patient had a poor cosmetic outcome. Conclusion: It is feasible for Chinese females to receive APBIIMRTafter breast conserving surgery. The radiotherapeutic toxicityis acceptable, and both the initial efficacy and cosmeticoutcomes are good.

Antioxidant and Antigenotoxic Activities of Ethanol Extracts from Rhus chinensis Mill Leaves

Zhenyu Qiu,Mingli Tang,Guanjun Deng,Hao Yang,Xuan Zhang,Shengwei Huang,Lifang Wu 한국식품과학회 2014 Food Science and Biotechnology Vol.23 No.4

Ethanol extracts were obtained from Rhuschinensis Mill (RCM) leaves and used for antioxidant andantigenotoxic activity assays. IC50 values in DPPH assayswere 15.96, 18.83, 20.43, 27.93, 37.43, 46.21, and 141.84μg/mL for TPP, IPE, LLE, Vc, CE, BHT, and Trolox. Similar results were obtained using ABTS and FRAPassays. In vivo testing showed strong antioxidant activitiesthat were positively correlated with polyphenol contents. Leaf tissue contained abundant polyphenols, and more than10 phenolic compounds were detected in extracts. Quantitative results showed that quercetin-3-rhamnoside(26.4±0.76 mg/g of extract) was the most abundantingredient, followed by hyperoside (15.2±0.42 mg/g ofextract), quercetin (1.5±0.07mg/g of extract), and kaempferol(0.48±0.05 mg/g of extract). This study increases theknowledge for possible uses of forest by-products as asubstitute for gallnuts.

Experimental Measurement and Monte Carlo Simulation the Correction Factor for the Medium-Energy X-ray Free-air Ionization Chamber

Yu Jili,Wu Jinjie,Liao Zhenyu,Zhou Zhenjie 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.10

A key comparison has been made between the air-kerma standards of the National Institute of Metrology (NIM), China, and other Asia Pacific Metrology Programme (APMP) members in the medium-energy X-ray. This paper reviews the primary standard Free-air ionization chamber correc- tion factor experimental method and Monte Carlo simulation method in the NIM. The experimental method and the Monte Carlo simulation method are adopted to obtain the correction factor for the medium-energy X-ray primary standard free-air ionization chamber at 100 kV, 135 kV, 180 kV, 250 kV four CCRI reference qualities. The correction factor has already been submitted to the APMP as key comparison data and the results are in good agreement with those obtained in pre- vious studies. This study shows that the experimental method and the EGSnrc simulation method are usually used in the measurement of the correction factor. In particular, the application of the simulation methods is more common.

A facile and efficient gas phase process for purifying single-walled carbon nanotubes

Haiqin Rong,Zhenyu Liu,Qilin Wu,이영희 한국물리학회 2010 Current Applied Physics Vol.10 No.4

Reproducible, low loss and high-yield purification process for single-walled carbon nanotubes (SWNTs)was developed by coupling of oxidation in wet air and treatment with gas phase nitric acid. Oxidation in wet air can burn out the carbonaceous particles and gas phase nitric acid treatment can etch away the catalytic metals. The as-synthesized SWNTs and the purified SWNTs were characterized by field emission scanning electron microscopy, high resolution transmission electron microscopy, Raman spectrophotometer and thermal gravimetric analysis. It was shown that such a facile and controllable gas phase process for purifying SWNTs can lead to the minimal losses and minimal destruction of SWNTs,thus highly purified SWNTs without amorphous carbon and with very low metal content were obtained.

Micro-XCT Characterization and Numerical Analysis of Bending Damage Mechanism in Carbon Fiber Plain, Twill and Winding Composite Tubes

Zhongxiang Pan,Heng Ma,Zhenyu Wu,Xiaohong Zhou 한국섬유공학회 2020 Fibers and polymers Vol.21 No.4

Transverse bending damage morphologies of carbon fiber composite tubes with different ply structures wereinvestigated by the micro-XCT characterization. Structural effects of the plain, twill and winding on the damage mechanismwere analyzed. The experimental results present fiber-resin cracking, interlayer delamination and fiber tows breakage withstructural deformation from the peak load to final catastrophic failure. Woven fabric plies in the plain and twill compositetubes cannot be effectively slipped because of their tight interlaced structures, which makes the load propagate along the warpand weft fiber tows, resulting in more fiber tows breakage under bending-induced stretching. There is no interlaced effect onthe failure mechanism for the winding tubes, resulting in a fact that the bending load can only be transferred from the fiberresinor the layer-to-layer interface, with more interlaminar slippage and obvious springback behaviors under in-plane shear. For investigating the interlaced effect on failure mechanism, plain and winding models under transverse bending wereestablished using continuous shell elements, and different constitutive description were used to simulate interlayer failure andintra-layer failure behaviors. By comparing the numerical results with the experimental ones, the influence of the fabricstructure on the failure behavior of the tube were analyzed.

Projector Calibration Method using Orthogonal Gray Code Combined with Trapezoid Phase Shift Code

Yu Xiaoyang,Meng Xiaoliang,Wu Haibin,Zang Tianjian,Xiao Zhenyu 보안공학연구지원센터 2014 International Journal of Multimedia and Ubiquitous Vol.9 No.10