철근콘크리트의 부식 및 방식에 관한 최신기술

( Yuanlong Du,Zhiming Shi ) 한국재료부식학회 1995 국제학술회의 논문집 Vol.- No.-

Magnetic Resonance Imaging of the Peripheral Nerves and Fascicles of the Knee Using Double Echo Steady State Sequence at 7 Tesla

Chen Pinzhen,Zhen Zhiming,Li Jing,Yang Taotao,Hou Wenjing,Zeng Meng,Du Mingshan,Zhou Suyi,Chen Wei,Hsu Yicheng,Wang Bo,Liu Zhi,Wu Yi,Chen Jiafei,Chen Wei 대한영상의학회 2025 Korean Journal of Radiology Vol.26 No.6

Objective: To evaluate the applicability of the double echo steady state (DESS) sequence at 7 tesla (7T) for high-resolution imaging of the peripheral nerves and fascicles of the knee. Materials and Methods: We prospectively included 32 healthy participants (mean age 39 ± 14 years, 20 females). The patients underwent 7T magnetic resonance imaging (MRI) of the knee using proton density turbo spin-echo fat suppression (PD-TSE FS), three-dimensional DESS (3D-DESS), and higher in-plane resolution DESS (DESSHR) sequences. The signal-to-noise ratios (SNRs) of the peroneal nerve (PN) and tibial nerve (TN) and contrast-to-noise ratios (CNRs) between the nerves and adjacent fat, vessels, and muscles were quantitatively measured by two readers and averaged. Five radiologists qualitatively assessed the overall image quality, pulsatile flow artifacts, and visualization of the PN and its branches, the TN, and the saphenous nerve (SN) using a five-point Likert-type scale, with the results averaged. The results of the three image sequences were compared. Results: The SNR for the TNs in the DESSHR sequence were lower than those in the PD-TSE FS (P < 0.001) and 3D-DESS (P = 0.024) sequences, whereas the SNR for the PNs did not differ significantly across the three sequences. The DESSHR sequence exhibited superior TN- or PN-to-fat and PN-to-muscle CNR values when compared with the PD-TSE FS and 3D-DESS sequences (P ≤ 0.016). The TN- and PN-to-vessel CNR values in the DESSHR and PD-TSE FS sequences were higher than those in the 3D-DESS sequence (P ≤ 0.001). Qualitative assessments revealed fewer pulsatile artifacts in 3D-DESS than in DESSHR and PD-TSE FS (P < 0.001), with DESSHR exhibiting fewer artifacts than PD-TSE FS (P = 0.035). DESSHR excelled in visualizing the common PN, TN, and SN when compared with other sequences (P < 0.001), whereas 3D-DESS provided superior visualization of PN branches when compared with other sequences (P ≤ 0.042). Conclusion: The DESS sequence at 7T MRI enhances visualization of peripheral nerves and fascicular structures around the knee.

Enhanced Mechanical Properties and Thermal Conductivity for GNPs/Al2024 Composites with In Situ SiC Nanorods

Lili Chen,Yushi Qi,Yanhan Fei,Zhiming Du 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10

In order to significantly enhance the performance of graphene in metal matrix composites, in situ SiC nanorods were successfullyfabricated to enhance graphene nanoplatelets (GNPs)-reinforced Al2024 composite, which was prepared by powdersemi-solid processing and friction stir processing. The SiC–GNPs dispersed in the Al matrix uniformly, SiC nanorodswere randomly grown on GNPs sheets in any direction, bridging GNPs as well as GNPs and the Al matrix. Meanwhile, theinterfacial bonding was effective. The hybrid reinforcement of SiC and GNPs endowed composites with superior mechanicalproperties and thermal conductivity. The in situ SiC nanorods transfer phonons and reduce phonon scattering effect inthe through-plane direction of GNPs, which conducive to heat transmission. The composite exhibits improved mechanicalproperties, maximum tensile strength and hardness of 589 MPa and 193 HV are obtained, with 1.0 wt% GNPs addition,respectively. The thermal conductivity of composite increases with the content of SiC–GNPs. When the content of SiC–GNPsreaches 1.5 wt%, the composite has significantly enhanced thermal conductivity (224 W m−1 K−1), which is 115% timeshigher than that of Al2024. Moreover, the effects of SiC–GNPs on the properties were discussed.

Effect of pulse electrodeposition parameters on electrocatalytic the activity of methanol oxidation and morphology of Pt/C catalyst for direct methanol fuel cells

Ye, Feng,Xu, Chao,Liu, Guicheng,Yuan, Mengdi,Wang, Zhiming,Du, Xiaoze,Lee, Joong Kee Pergamon 2018 Energy Conversion and Management Vol. No.

<P><B>Abstract</B></P> <P>The electrodeposition technique for preparing direct methanol fuel cell electrodes has been developed to increase the Pt utilization and lower the Pt loading. The performance of the Pt/C electrode for methanol oxidation reaction (MOR) was optimized by adjusting the electrodeposition parameters such as applied electrical signal types, ratios of t<SUB>on</SUB>/t<SUB>off</SUB>, deposition temperatures, and electrolyte concentrations, systematically. Furthermore, the effects of two kinds of additives, i.e. polyethylene glycol (PEG) and sodium dodecyl sulfonate (SDS), on the catalytic performance and morphology of Pt catalyst were investigated for MOR by SEM, XRD, cyclic voltammetry and linear sweep voltammetry. The results show that the optimal Pt catalyst has been prepared by the square wave current method with t<SUB>on</SUB>/t<SUB>off</SUB> of 1 s/5 s at 30 °C in a 1.0 mmol L<SUP>−1</SUP> H<SUB>2</SUB>PtCl<SUB>6</SUB> solution with a 10<SUP>−4</SUP> mmol L<SUP>−1</SUP> PEG additive. Moreover, the effect of the additive type and amount on the formation mechanism of the Pt crystallite morphology has also been discussed. From the results, introducing additives into the deposition solution in the pulse electrodeposition process is useful for designing and fabricating electrocatalytic electrodes for direct methanol fuel cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Signals include square wave current and potential, cyclic voltammetry and constant current pulse. </LI> <LI> Effects of four applied electrical signal types on Pt catalytic performance are compared. </LI> <LI> Parameters for Pt electrodeposition in constant current pulse mode are optimized systematically. </LI> <LI> Effect mechanism of additive on growth of Pt catalyst is studied in pulse electrodeposition. </LI> <LI> Optimal condition is t<SUB>on</SUB>/t<SUB>off</SUB> of 1 s/5 s, 30 °C, 1 mmol L<SUP>−1</SUP> H<SUB>2</SUB>PtCl<SUB>6</SUB> solution with 10<SUP>−4</SUP> mmol L<SUP>−1</SUP> PEG. </LI> </UL> </P>

Investigation on evolution characteristic of dynamic pore and reactive transport of leaching solute in uranium-bearing sandstone during in-situ alkaline leaching mining: An in-situ LF-NMR leaching experiment

Zhang Tong,Yang Xin,Yuan Liang,Su Xuebin,Du Zhiming,Yang Yihan,Tang Ming,Zhang Chuanfei,Qiao Peng,Li Bingzhang 한국원자력학회 2025 Nuclear Engineering and Technology Vol.57 No.12

In-situ uranium leaching involves complex physicochemical interactions critically influencing reservoir permeability and leaching efficiency. This study investigated microstructural changes in uranium-bearing sandstone during alkaline leaching mining through integrated column leaching experiments, real-time multi-pore geometry structure and leaching solution morphology was motored using online low-field nuclear magnetic resonance (LFNMR), and uranium-bearing sandstone component and leaching agent was analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray fluorescence (XRF). The uranium-bearing sandstone predominantly comprises micropores (T2 < 2.5 ms), mesopores (2.5 ms < T2 < 100 ms), and macropores (T2 > 100 ms), with the pore system mainly composed of quartz, clinochlore, kaoline, and orthoclase. The results demonstrate that permeability reduction of 48.6 % (from 0.976 to 0.502 mD), with total pore porosity increase of 2.44 % was primarily driven by a substantial micropore reduction of 5.98 %. A significant micropore clogging was induced by precipitation of secondary minerals (CaSO4, Mg(OH)2, and silica colloids) during late-stage leaching (156–363 PV). An innovative empirical relation model for microporosity and permeability was established, and enhanced the prediction accuracy of permeability evolution. These insights reveal that micropore dynamically influence permeability evolution and uranium recovery efficiency, which benefits the technology optimization in alkaline leaching mining.

Identification and Characterization of EDT1 Conferring Drought Tolerance in Rice

Tao Wu,Mingxing Zhang,Hongjia Zhang,Kai Huang,Mojun Chen,Chen Chen,Xue Yang,Zhao Li,Haoyuan Chen,Zhiming Ma,Xunming Zhang,Wenzhu Jiang,Xinglin Du 한국식물학회 2019 Journal of Plant Biology Vol.62 No.1

Basic Leucine Zipper (bZIP) transcription factors(TFs) play important roles in many processes, especially inabiotic stress response in plants. In this study, we characterizeda new gene EHANCED DROUGHT TOLERANCE 1 (EDT1),member of group E of bZIP transcription factor family inrice. The EDT1 protein contains one bZIP domain, oneputative nuclear localization signal (NLS) and six conservedphosphorylation sites. The expression of EDT1 is suppressedby several abiotic stresses, such as cold, droutht, and salt. Corresponding with expression patterns, several stress-associatedcis-acting elements were found in the EDT1 promoter. Theresults of subcellular localization and transactivation abilityanalyses indicated that EDT1 was localized in the nucleusand functioned as a nuclear protein, with its transactivationactivity primarily located in N-terminal. Transgenic riceoverexpressing EDT1 showed drought tolerance that hasbeen significantly improved. Real-time PCR analysis revealedthat some stress-related genes, such as OsbZIP12, SNAC1,OsLEA3, OsbZIP16, OsbZIP10 and OsABI2 were up-regulatedin EDT1 overexpression lines. These results indicate thatEDT1 plays a positive role in drought tolerance and providesvaluable targets for breeding drought-tolerant rice cultivars.

Dislocation Density-Based Constitutive Model and Processing Map for T2 Copper During Isothermal and Time-Variant Deformation

Gang Chen,Yu Jin,Jing Wang,Cheng Zhang,Qiang Chen,Hongming Zhang,Xingjian Zhao,Zhiyong Li,Changhai Xie,Zhiming Du 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.9

Isothermal compression tests were carried out to study the hot deformation behavior of T2 copper under various conditions. The deformation parameters, such as temperature and strain rate, have strong influence on flow stress and microstructureevolution of the alloy. A unified dislocation density-based model considering dynamic recovery and recrystallization wasestablished. And material parameters of the developed model were optimized by genetic algorithm. Comparisons betweenthe experimental and model data demonstrates that the developed model can precisely describe the flow behavior at quitewide range of deformation conditions. Meanwhile, the designed iterative procedure allows the model to be applied in timevariantdeformation conditions. Processing map and microstructure examination were constructed to optimize the processingwindow of the studied alloy. According to the processing maps, flow instability mainly appeared at low temperatures of500–650 °C and strain rates higher than 0.1 s−1. The optimum deformation parameters of T2 copper was concluded as thetemperature range of 700–800 °C and the strain rate of 0.1–1 s−1.