^(64)Zn and ^(67)Zn (n,α) Reactions in the MeV Neutron Energy Region

Guohui Zhang,Jiaguo Zhang,Hao Wu,Jiaming Liu,Jinxiang Chen,Yuri Gledenov,Milana Sedysheva,Gonchigdorj Khuukhenkhuu,Pavel Szalanski 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23

Nuclear reactions of ^(64)Zn(n,α)^(61)Ni and ^(67)Zn(n,α)^(64)Ni are important because they are gas pro-duction reactions and zinc is a reactor constituent element with a signicant fraction. But the cross section data of these reactions are scanty because the residual nuclei ^(61)Ni and ^(64)Ni are stable and the commonly used activation method is not feasible. In the present work, differential cross sections and angleintegrated cross sections were measured for the ^(64)Zn(n,α)^(61)Ni reaction at neutron energies of 2.5, 4.0, 5.0, 5.5, and 6.0 MeV and cross sections of the ^(67)Zn(n,α)^(64)Ni reaction were measured at 4.0, 5.0, and 6.0 MeV. A twin gridded ionization chamber was employed as alpha particle detector. Experiments were performed at the 4.5 MV Van de Graaff accelerator of Peking University. Monoenergetic neutrons of 2.5 MeV were produced through the T(p, n)^3He reaction with a solid Ti-T target, and those of other energies were produced through the D(d, n)^3He reaction with a deuterium gas target. Absolute neutron fluxes were determined through the ^(238)U(n, f) reaction and a BF^3 long counter was used as the neutron flux monitor. Present results are compared with other measurements and evaluations.

Numerical Prediction of Unsteady Turbulent Flow and Pressure Fluctuation in an Axial-flow Pump by LES

Guohui Cong,Fujun Wang,Ling Zhang 한국전산유체공학회 2006 한국전산유체공학회 학술대회논문집 Vol.2006 No.5

Multifunctional hydrogels: advanced therapeutic tools for osteochondral regeneration

Wenqian Zhang,Kangkang Zha,Weixian Hu,Yuan Xiong,Samuel Knoedler,Doha Obed,Adriana C. Panayi,Ze Lin,Faqi Cao,Bobin Mi,Guohui Liu 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Various joint pathologies such as osteochondritis dissecans, osteonecrosis, rheumatic disease, and trauma, may result in severe damage of articular cartilage and other joint structures, ranging from focal defects to osteoarthritis (OA). The osteochondral unit is one of the critical actors in this pathophysiological process. New approaches and applications in tissue engineering and regenerative medicine continue to drive the development of OA treatment. Hydrogel scaffolds, a component of tissue engineering, play an indispensable role in osteochondral regeneration. In this review, tissue engineering strategies regarding osteochondral regeneration were highlighted and summarized. The application of hydrogels for osteochondral regeneration within the last five years was evaluated with an emphasis on functionalized physical and chemical properties of hydrogel scaffolds, functionalized delivery hydrogel scaffolds as well as functionalized intelligent response hydrogel scaffolds. Lastly, to serve as guidance for future efforts in the creation of bioinspired hydrogel scaffolds, a succinct summary and new views for specific mechanisms, applications, and existing limitations of the newly designed functionalized hydrogel scaffolds were offered.

Highly Yellow-Emitting Photoluminescent Carbon Dots Derived from Dendrimer Toward Fluorescent Nanocomposites and White LEDs

Yan Zhang,Guohui Yuan,Youyuan Huang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.7

Photoluminescent carbon dots (CDs) are synthesized and derived from carboxyl-modified PAMAM dendrimer precursor by a one-pot solvothermal method. The obtained CDs exhibit highly bright Yellow-emitting fluorescence with quantum yield of 62.6%. In practice, using their excellent photoluminescence and good compatibility, the CDs are processed with polymers for various fluorescent nanocomposites (such as film, microfiber and bulk hydrogel) and applied as light conversion materials for white LEDs.

A flow rate on-line monitoring method for piezoelectric pump based on self-sensing circuit

Hong Jiang,Guohui Wu,Lipeng He,Yuecheng Wang,Dianbin Hu,Zheng Zhang,Guangming Cheng 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.5

This paper presents a new flow rate monitoring method for a piezoelectric micropump based on a self-sensing circuit. Utilizing the voltage generated by the secondary direct piezoelectric effect as the sensing voltage, a soft sensor of the piezoelectric actuator can be implemented onto the piezoelectric micropump. A bridge-type circuit is proposed as the selfsensing circuit, the piezoelectric micropump is fabricated with a circular piezoelectric actuator, the characteristics of the self-sensing voltage and the flow rate are experimentally investigated under different excitation voltages and frequencies. The results show that the method can accurately determine optimal frequency of the micropump (100 Hz, 280 Hz), and for a fixed frequency of 100 Hz and a voltage range of 50-180 V, the correlation between the self-sensing voltage and the flow rate is 0.9732. As a result, the method demonstrated in this paper allows precise monitoring of the flow rate of the piezoelectric micropump without using external sensors.

Human Localization based on Distributed Laser Range Finders

Peng Duan,Guohui Tian,Wei Zhang 보안공학연구지원센터 2014 International Journal of Hybrid Information Techno Vol.7 No.3

Crystallization Morphology Transition of Poly(3-hydroxybutyrate) Films Depending on Nucleation Temperature under Temperature Gradient

Qing Chen,Guohui Zhang,Kaixuan Wang,Chao Wang,Guangzhu Ding,Jieping Liu 한국고분자학회 2017 Macromolecular Research Vol.25 No.4

The growth of spherulites is an intricate process and the final morphology is dependent on many process conditions. The spherulitic morphologies of poly(3-hydroxybutyrate) (PHB) crystallized from melt film are observed under various crystallization temperature gradient (the non-isothermal crystallization) in this work. Characterization reveals that the crystal morphologies (banded or nonbanded spherulites) of PHB film are determined significantly by nucleation temperature (not growth temperature). Interestingly, banded spherulites, nucleated between 60-135 oC, are able to grow completely above growth temperature 135 oC or below 60 oC yet and non-banded shperulites nucleated at above 135 oC can also develop steadily till below growth temperature 135 oC under temperature gradient condition. Therefore, the conclusion drawn from the temperature gradient or non-isothermal process is novel and different from the result of isothermal crystallization (morphology mainly depending on the growth temperature). In addition, the growth and evolution kinetics of banded and non-banded spherulites are both investigated for some polymer thin films under the temperature gradient in detail.

Investigation of (n,α) Reaction for Rare-earth Elements in the MeV Neutron Energy Region

Y. Gledenov,M. Sedysheva,Guohui Zhang,Jiaguo Zhang,Hao Wu,Jiaming Liu,Jinxiang Chen,P. Koehler,G. Khuukhenkhuu,P. Szalanski 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23

Cross sections and forward/backward ratios in the laboratory reference system were measured for ^(143)Nd(n,α)^(140)Ce at 4.0, 5.0, and 6.0 MeV, ^(147)Sm(n,α)^(144)Nd at 5.0 and 6.0 MeV, and ^(149)Sm(n,α)^(146)Nd at 6.0 MeV. A twin gridded ionization chamber and large-area back-to-back ^(143)Nd^2O^3 and ^(147,149)Sm^2O^3 samples were employed. Experiments were performed at the 4.5 MV Van de Graaff of Peking University, China. Fast neutrons were produced through the D(d, n)^3He reaction by using a deuterium gas target. A small ^(238)U fission chamber was employed for absolute neutron flux determination and a BF_3 long counter was used as neutron flux monitor. Present experimental data are compared with previous measurements, evaluations, and model calculations.

The protective effect of procyanidinson tert-butyl hydroperoxide induced human hepatocyte HL7702 cell injury

Yanru Li,Hua Zhang,Guohui Lu 한국통합생물학회 2015 Animal cells and systems Vol.19 No.6

The present study aims to investigate the mechanism of the protective action of Procyanidins (PC) against tertiary butyl hydroperoxide (TBHP)-induced cytotoxicity and cell death in human hepatocyte-derived cell line HL7702 cells. Incubation of HL7702 cells with PC prevented TBHP-induced loss in cell viability and reduction in GSH/GSSG ratio and activities of antioxidant enzymes have also been found to be prevented by PC.Western blot was used to evaluate the levels of cytochrome c, Bcl-2, Bax, Sirt3 and IDH2. The results showed that PC effectively protect TBHP-treated HL7702 cells from death, and increase superoxide dismutase activity and significantly decrease malondialdehyde production. PC increased the ratio of GSH/GSSG and NADPH/NADP+, and reduced the release of cytochrome c from mitochondria and decreased the Bax expression, and also increased the expression of Bcl-2, IDH2 and Sirt3. PC prevented TBHP-induced oxidative stress injury in HL7702 cells and functioning via Sirt3-dependent mitochondria pathways.

Identification of genes involved in inbreeding depression of reproduction in Langshan chickens

Xue Qian,Li Guohui,Cao Yuxia,Yin Jianmei,Zhu Yunfen,Zhang Huiyong,Zhou Chenghao,Shen Haiyu,Dou Xinhong,Su Yijun,Wang Kehua,Zou Jianmin,Han Wei 아세아·태평양축산학회 2021 Animal Bioscience Vol.34 No.6

Objective: Inbreeding depression of reproduction is a major concern in the conservation of native chicken genetic resources. Here, based on the successful development of strongly inbred (Sinb) and weakly inbred (Winb) Langshan chickens, we aimed to evaluate inbreeding effects on reproductive traits and identify candidate genes involved in inbreeding depression of reproduction in Langshan chickens. Methods: A two-sample t-test was performed to estimate the differences in phenotypic values of reproductive traits between Sinb and Winb chicken groups. Three healthy chickens with reproductive trait values around the group mean values were selected from each of the groups. Differences in ovarian and hypothalamus transcriptomes between the two groups of chickens were analyzed by RNA sequencing (RNA-Seq). Results: The Sinb chicken group showed an obvious inbreeding depression in reproduction, especially for traits of age at the first egg and egg number at 300 days (p<0.01). Furthermore, 68 and 618 differentially expressed genes (DEGs) were obtained in the hypothalamus and ovary between the two chicken groups, respectively. In the hypothalamus, DEGs were mainly enriched in the pathways related to vitamin metabolism, signal transduction and development of the reproductive system, such as the riboflavin metabolism, Wnt signaling pathway, extracellular matrix-receptor interaction and focal adhesion pathways, including stimulated by retinoic acid 6, serpin family F member 1, secreted frizzled related protein 2, Wnt family member 6, and frizzled class receptor 4 genes. In the ovary, DEGs were significantly enriched in pathways associated with basic metabolism, including amino acid metabolism, oxidative phosphorylation, and glycosaminoglycan degradation. A series of key DEGs involved in folate biosynthesis (gamma-glutamyl hydrolase, guanosine triphosphate cyclohydrolase 1), oocyte meiosis and ovarian function (cytoplasmic polyadenylation element binding protein 1, structural maintenance of chromosomes 1B, and speedy/RINGO cell cycle regulator family member A), spermatogenesis and male fertility (prostaglandin D2 synthase 21 kDa), Mov10 RISC complex RNA helicase like 1, and deuterosome assembly protein 1) were identified, and these may play important roles in inbreeding depression in reproduction. Conclusion: The results improve our understanding of the regulatory mechanisms underlying inbreeding depression in chicken reproduction and provide a theoretical basis for the conservation of species resources. Objective: Inbreeding depression of reproduction is a major concern in the conservation of native chicken genetic resources. Here, based on the successful development of strongly inbred (Sinb) and weakly inbred (Winb) Langshan chickens, we aimed to evaluate inbreeding effects on reproductive traits and identify candidate genes involved in inbreeding depression of reproduction in Langshan chickens.Methods: A two-sample t-test was performed to estimate the differences in phenotypic values of reproductive traits between Sinb and Winb chicken groups. Three healthy chickens with reproductive trait values around the group mean values were selected from each of the groups. Differences in ovarian and hypothalamus transcriptomes between the two groups of chickens were analyzed by RNA sequencing (RNA-Seq).Results: The Sinb chicken group showed an obvious inbreeding depression in reproduction, especially for traits of age at the first egg and egg number at 300 days (p<0.01). Furthermore, 68 and 618 differentially expressed genes (DEGs) were obtained in the hypothalamus and ovary between the two chicken groups, respectively. In the hypothalamus, DEGs were mainly enriched in the pathways related to vitamin metabolism, signal transduction and development of the reproductive system, such as the riboflavin metabolism, Wnt signaling pathway, extracellular matrix-receptor interaction and focal adhesion pathways, including stimulated by retinoic acid 6, serpin family F member 1, secreted frizzled related protein 2, Wnt family member 6, and frizzled class receptor 4 genes. In the ovary, DEGs were significantly enriched in pathways associated with basic metabolism, including amino acid metabolism, oxidative phosphorylation, and glycosaminoglycan degradation. A series of key DEGs involved in folate biosynthesis (gamma-glutamyl hydrolase, guanosine triphosphate cyclohydrolase 1), oocyte meiosis and ovarian function (cytoplasmic polyadenylation element binding protein 1, structural maintenance of chromosomes 1B, and speedy/RINGO cell cycle regulator family member A), spermatogenesis and male fertility (prostaglandin D2 synthase 21 kDa), Mov10 RISC complex RNA helicase like 1, and deuterosome assembly protein 1) were identified, and these may play important roles in inbreeding depression in reproduction.Conclusion: The results improve our understanding of the regulatory mechanisms underlying inbreeding depression in chicken reproduction and provide a theoretical basis for the conservation of species resources.