Comparative study on the high frequency performances of the easy-plane FeNi@SiO2 powder soft magnetic composite

Wang Guowu,Zhang Junming,Zheng Zuying,Qiao Liang,Wang Tao,Li Fashen 한국물리학회 2022 Current Applied Physics Vol.41 No.-

In this work, an easy-plane FeNi@SiO2 powder soft magnetic composite (SMC) was imitated and fabricated and its high frequency magnetic properties were comparatively investigated with a non-easy-plane composite. Due to the planar distribution of easy magnetization axes, the easy-plane composite exhibits a constant permeability of 38 up to 100 MHz. Moreover, the easy-plane SMC exhibits a lower core loss at higher frequencies. Loss separated results show that the hysteresis loss plays a dominant loss component in the composite, rather than dominant excess loss in the non-easy-plane powder composite. These results indicate that, compared with non-easy-plane powder composite, the easy-plane powder composites exhibit comprehensive advantages of higher permeability, wider effective operating frequencies and lower loss, which suggest that the use of easy-plane ferromagnetic powder is a promising and efficient measure to develop a new generation of soft magnetic composites for higher frequency application.

Mesenchymal Stem Cells Modified with Stromal Cell-Derived Factor 1б Improve Cardiac Remodeling via Paracrine Activation of Hepatocyte Growth Factor in a Rat Model of Myocardial Infarction

Junming Tang,Jianing Wang,Linyun Guo,Xia Kong,Jianye Yang,Fei Zheng,Lei Zhang,Yongzhang Huang 한국분자세포생물학회 2010 Molecules and cells Vol.29 No.1

Mesenchymal stem cells (MSCs) are a promising source for cell-based treatment of myocardial infarction (MI), but existing strategies are restricted by low cell survival and engraftment. We examined whether SDF-1 transfection improve MSC viability and paracrine action in infarcted hearts. We found SDF-1-modified MSCs effectively ex-pressed SDF-1 for at least 21days after exposure to hy-poxia. The apoptosis of Ad-SDF-1-MSCs was 42% of that seen in Ad-EGFP-MSCs and 53% of untreated MSCs. In the infarcted hearts, the number of DAPI-labeling cells in the Ad-SDF-1-MSC group was 5-fold that in the Ad-EGFP-MSC group. Importantly, expression of antifibrotic factor, HGF, was detected in cultured MSCs, and HGF expression lev-els were higher in Ad-SDF-MSC-treated hearts, compared with Ad-EGFP-MSC or control hearts. Compared with the control group, Ad-SDF-MSC transplantation significantly decreased the expression of collagens I and III and matrix metalloproteinase 2 and 9, but heart function was im-proved in d-SDF-MSC-treated animals. In conclusion, SDF-1–modified MSCs enhanced the tolerance of engrafted MSCs to hypoxic injury in vitro and improved their viability in infarcted hearts, thus helping preserve the contractile function and attenuate left ventricle (LV) remodeling, and this may be at least partly mediated by enhanced paracrine signaling from MSCs via antifibrotic factors such as HGF.

An Isolated Bidirectional Modular Multilevel DC/DC Converter for Power Electronic Transformer Applications

Wang, Zhaohui,Zhang, Junming,Sheng, Kuang The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

With high penetration of renewable energies, power electronic transformers (PETs) will be one of the most important infrastructures in the future power delivery and management system. In this study, an isolated bidirectional modular multilevel DC/DC converter is proposed for PET applications. A modular multilevel structure is adopted as switching valves to sustain medium voltages to achieve modular design and high reliability. Only one high-frequency transformer is used in the proposed converter, which significantly simplifies the circuit and galvanic insulation design. A dual-phase-shift modulation strategy is proposed to regulate the output power and achieve a simple voltage balancing control. A down-scaled (2 kW/20 kHz) prototype is constructed to demonstrate the proposed converter and verify the control strategy. The experimental results comply with the theoretical analysis well, with the highest power efficiency reaching 97.6%.

Modular Multilevel Power Electronic Transformer

Zhaohui Wang,Junming Zhang,Kuang Sheng 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

In this paper, a modular multilevel power electronic transformer structure for power distribution system is discussed. The proposed structure consists of two completely decoupled power stages. Modular multilevel converter is adopted as the front-end ac-dc stage to convert the medium ac voltage to medium dc voltage, or vice versa. Galvanic isolation and voltage conversion are realized by the cascaded dc-dc stage. Only one high frequency transformer is used in the dc-dc converter, which dramatically simplifies the circuit and galvanic isolation design. A dual phase shift control method is proposed to regulate the output and balance the submodule voltage in the dc-dc stage. To verify the effectiveness of the proposed converter and control method, a down-scaled prototype is constructed. The experimental results comply with the theoretical analysis very well.

Parameter Calibration of a Discrete Element Model for Three-Compartment Separation and Fragmentation of Castor Capsules During Harvesting

Hou Junming,Ren Zhaotan,Liu Deyu,Ma Zhi,Liu Xu,Wang Wei 한국농업기계학회 2023 바이오시스템공학 Vol.48 No.2

Purpose In order to analyze the damage of castor capsule during mechanical harvesting, it is necessary to establish a suitable model and obtain the parameters of discrete element model. Therefore, the study establishes a three-compartment separation and crushing discrete element model of castor; the contact parameters and bonding parameters of the model are calibrated. The TongBi No. 16 castor variety in harvest period was taken as the research object. The sizes of whole castor capsule and single part were measured; then, the moisture content of castor in harvest period was measured. Methods In order to obtain the inherent parameters of the capsule, the elastic modulus was measured by TMS pro professional food physical property analyzer. In order to realize the three-compartment separation and fragmentation of castor, a discrete element model combining the aggregation and bonding model was established. The contact parameters are calibrated by stacking angle and formed by lifting method. The contour curve of accumulation angle is obtained with MATLAB software. The results show that the stacking angle of physical test is 26.216°. Through Plackett–Burman test, the contact parameters that have a greater impact on the stacking angle are the static friction coefficient between castors and the dynamic friction coefficient between castors. After the steepest climbing test, the value range is selected. Finally, through response surface optimization, the optimal static and dynamic friction coefficients between castors are determined to be 0.41 and 0.05, respectively. Results In order to obtain accurate bonding parameters, it is carried out through compression test. In order to reduce the damage to single compartment in the process of compression, spherical compression head is used. The results show that the maximum destructive force is 52.65 N. In conducting the simulation tests, the Box-Behnken response surface design is applied to derive the optimal bonding parameters, the normal stiffness per unit area is 9.47× 107 N/m3, shear stiffness per unit area is 4.59× 107 N/m3, normal strength is 7.92× 103 Pa, and shear strength is 1.13× 104 Pa. Finally, the stacking angle test and cone compression test are carried out by the final calibrated parameters. The relative errors between the simulation and the actual test are 1.82% and 4.10%, respectively, which indicate that the calibration results are reliable. Conclusion This study can provide the support of discrete element simulation parameters for analyzing the mechanism of castor capsule damage during mechanized harvest.

An Isolated Bidirectional Modular Multilevel DC/DC Converter for Power Electronic Transformer Applications

Zhaohui Wang,Junming Zhang,Kuang Sheng 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

With high penetration of renewable energies, power electronic transformers (PETs) will be one of the most important infrastructures in the future power delivery and management system. In this study, an isolated bidirectional modular multilevel DC/DC converter is proposed for PET applications. A modular multilevel structure is adopted as switching valves to sustain medium voltages to achieve modular design and high reliability. Only one high-frequency transformer is used in the proposed converter, which significantly simplifies the circuit and galvanic insulation design. A dual-phase-shift modulation strategy is proposed to regulate the output power and achieve a simple voltage balancing control. A down-scaled (2 kW/20 kHz) prototype is constructed to demonstrate the proposed converter and verify the control strategy. The experimental results comply with the theoretical analysis well, with the highest power efficiency reaching 97.6%.

A novel class of pyranocoumarin anti-androgen receptor signaling compounds.

Guo, Junming,Jiang, Cheng,Wang, Zhe,Lee, Hyo-Jeong,Hu, Hongbo,Malewicz, Barbara,Lee, Hyo-Jung,Lee, Jae-Ho,Baek, Nam-In,Jeong, Jin-Hyun,Kim, Dae-Keun,Kang, Kyung-Sun,Kim, Sung-Hoon,Lu, Junxuan American Association for Cancer Research 2007 Molecular Cancer Therapeutics Vol.6 No.3

<P>Androgen and the androgen receptor (AR)-mediated signaling are crucial for prostate cancer development. Novel agents that can inhibit AR signaling in ligand-dependent and ligand-independent manners are desirable for the chemoprevention of prostate carcinogenesis and for the treatment of advanced prostate cancer. We have shown recently that the pyranocoumarin compound decursin from the herb Angelica gigas possesses potent anti-AR activities distinct from the anti-androgen bicalutamide. Here, we compared the anti-AR activities and the cell cycle arrest and apoptotic effects of decursin and two natural analogues in the androgen-dependent LNCaP human prostate cancer cell culture model to identify structure-activity relationships and mechanisms. Decursin and its isomer decursinol angelate decreased prostate-specific antigen expression with IC(50) of approximately 1 mumol/L. Both inhibited the androgen-stimulated AR nuclear translocation and transactivation, decreased AR protein abundance through proteasomal degradation, and induced G(0/1) arrest and morphologic differentiation. They also induced caspase-mediated apoptosis and reactive oxygen species at higher concentrations. Furthermore, they lacked the agonist activity of bicalutamide in the absence of androgen and were more potent than bicalutamide for suppressing androgen-stimulated cell growth. Decursinol, which does not contain a side chain, lacked the reactive oxygen species induction and apoptotic activities and exerted paradoxically an inhibitory and a stimulatory effect on AR signaling and cell growth. In conclusion, decursin and decursinol angelate are members of a novel class of nonsteroidal compounds that exert a long-lasting inhibition of both ligand-dependent and ligand-independent AR signaling. The side chain is critical for sustaining the anti-AR activities and the growth arrest and apoptotic effects.</P>

Mesenchymal Stem Cells Modified with Stromal Cell-Derived Factor 1${\alpha}$ Improve Cardiac Remodeling via Paracrine Activation of Hepatocyte Growth Factor in a Rat Model of Myocardial Infarction

Tang, Junming,Wang, Jianing,Guo, Linyun,Kong, Xia,Yang, Jianye,Zheng, Fei,Zhang, Lei,Huang, Yongzhang Korean Society for Molecular and Cellular Biology 2010 Molecules and cells Vol.29 No.1

Mesenchymal stem cells (MSCs) are a promising source for cell-based treatment of myocardial infarction (MI), but existing strategies are restricted by low cell survival and engraftment. We examined whether SDF-1 transfection improve MSC viability and paracrine action in infarcted hearts. We found SDF-1-modified MSCs effectively expressed SDF-1 for at least 21days after exposure to hypoxia. The apoptosis of Ad-SDF-1-MSCs was 42% of that seen in Ad-EGFP-MSCs and 53% of untreated MSCs. In the infarcted hearts, the number of DAPI-labeling cells in the Ad-SDF-1-MSC group was 5-fold that in the Ad-EGFP-MSC group. Importantly, expression of antifibrotic factor, HGF, was detected in cultured MSCs, and HGF expression levels were higher in Ad-SDF-MSC-treated hearts, compared with Ad-EGFP-MSC or control hearts. Compared with the control group, Ad-SDF-MSC transplantation significantly decreased the expression of collagens I and III and matrix metalloproteinase 2 and 9, but heart function was improved in d-SDF-MSC-treated animals. In conclusion, SDF-1-modified MSCs enhanced the tolerance of engrafted MSCs to hypoxic injury in vitro and improved their viability in infarcted hearts, thus helping preserve the contractile function and attenuate left ventricle (LV) remodeling, and this may be at least partly mediated by enhanced paracrine signaling from MSCs via antifibrotic factors such as HGF.

A potential red-emitting phosphor with high color-purity for near-UV light emitting diodes

Zhengliang Wang,Yaling Zhang,Li Xiong,Xiaofan Li,Junming Guo,Menglian Gong 한국물리학회 2012 Current Applied Physics Vol.12 No.4

New red tungstates phosphors, Na5La1-xLnx(WO4)4 (Ln = Eu, Sm) and Na5Eu1-xSmx(WO4)4, were prepared by solid-state reaction technique. And their structure and photo-luminescent properties were investigated. The introduction of Sm3+ broadened the excitation band around 400 nm of the phosphors,and strengthened the red emission. And the possible energy transfer process from Sm3þ to Eu3+ is discussed. The single red LED was fabricated by combining InGaN chip with Na5Eu0.94Sm0.06(WO4)4 as red phosphor, intense red light can be observed by naked eyes. Then the phosphor Na5Eu0.94Sm0.06(WO4)4 may be a good candidate for red component of near-UV InGaN-based W-LEDs,because of efficient red-emitting with broadened absorption around 400 nm and appropriate CIE chromaticity coordinates (x = 0.65, y = 0.34).

Spatial mechanical behaviors of long-span V-shape rigid frame composite arch bridges

Hongye Gou,Qianhui Pu,Junming Wang,Zeyu Chen,Shiqiang Qin 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.1

The Xiaolan channel super large bridge is unique in style and with greatest span in the world with a total length of 7686.57 m. The main bridge with spans arranged as 100m+220m+100m is a combined structure composed of prestressed concrete V-shape rigid frame and concrete-filled steel tubular flexible arch. First of all, the author compiles APDL command flow program by using the unit birth-death technique and establishes simulation calculation model in the whole construction process. The creep characteristics of concrete are also taken into account. The force ratio of the suspender, arch and beam is discussed. The authors conduct studies on the three-plate webs’s rule of shear stress distribution, the box girder’s longitudinal bending normal stress on every construction stage, meanwhile the distribution law of longitudinal bending normal stress and transverse bending normal stress of completed bridge’s box girder. Results show that, as a new combined bridge, it is featured by: Girder and arch resist forces together; Moment effects of the structure are mainly presented as compressed arch and tensioned girder; The bridge type brings the girder and arch on resisting forces into full play; Great in vertical stiffness and slender in appearance.