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Analytical investigations of in situ stress inversion from borehole breakout geometries

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2375-2387页

作者： Zizhuo Xiang Taehyun Moon joung Oh Guangyao Si Ismet Canbulat School of minerals and Energy Resources Engineering University of New South WalesSydneyNSW2052Australia HNTB Corporation 3505th Ave.58th FloorNew YorkNY10118USA

This study aims to investigate the feasibility of deriving in situ horizontal stresses from the breakout width and depth using the analytical ***-three breakout data with different borehole sizes were collected and three failure criteria were *** on the Kirsch equations,relatively accurate major horizontal stress(sH)estimations from known minor horizontal stress(sh)were achieved with percentage errors ranging from 0.33%to 44.08%using the breakout *** Mogi-Coulomb failure criterion(average error:13.1%)outperformed modified Wiebols-Cook(average error:19.09%)and modified Lade(average error:18.09%)failure ***,none of the tested constitutive models could yield reasonable sh predictions from known sH using the same approach due to the analytical expression of the redistributed stress and the nature of the constitutive *** consideration of this issue,the horizontal stress ratio(sH/sh)is suggested as an alternative input,which could estimate both sH and sh with the same level of ***,the estimation accuracies for both large-scale and laboratory-scale breakouts are comparable,suggesting the applicability of this approach across different breakout *** breakout depth,conformal mapping and complex variable method were used to calculate the stress concentration around the breakout tip,allowing the expression of redistributed stresses using binomials composed of sH and ***,analysis of the breakout depth stabilisation mechanism indicates that additional parameters are required to utilise normalised breakout depth for stress estimation compared to breakout *** parameters are challenging to obtain,especially under field conditions,meaning utilising normalised breakout depth analytically in practical applications faces significant challenges and remains infeasible at this ***,the normalised breakout depth should still be considered a critical input for any empirical and statistical stres

关键词： Borehole failure In situ stress estimation In situ horizontal stress ratio Conformal mapping Complex variable method Breakout stabilisation

Ag-GST/HfO_(x)-based unidirectional threshold switching selector with low leakage current and threshold voltage distribution for high-density cross-point arrays

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Rare Metals 2024年第1期43卷 280-288页

作者： Kyoung-joung Yoo Dae-Yun Kang Nahyun Kim Ho-Jin Lee Ta-Hyeong Kim Taeho Kim Tae Geun Kim School of Electrical Engineering Korea UniversitySeoul 02841Republic of Korea

The use of electrochemical-metallization-based volatile threshold switching selectors in cross-point arrays has been widely explored owing to their high on-off ratios and simple ***,these devices are unsuitable for cross-point architectures because of the difficulty in controlling the random filament formation that results in large fluctuations in the threshold voltage during *** this study,we investigated the unidirectional threshold transition characteristics associated with an Ag/GST/HfO_(x)/Pt-based bilayer selector and demonstrated the occurrence of a low leakage current(ming currents of the device could be significantly *** the crossbar array configuration,we performed equivalent circuit analysis of a one-selector oneresistor(1S1R) devices and estimated the optimal array size to demonstrate the applicability of the proposed *** maximum acceptable crossbar array size of the 1S1R device with the Ag/GST/HfO_(x)/Pt/Ti/NiO_(x)/Pt structure was 5.29×10^(14)(N^(2),N=2.3×10^(7)).

关键词： Selector device Tunneling barrier Threshold switching Sputtering 1S1R Cross-point array

Applying heteroatom co-doped carbon nanotube for manifesting high performance in the electrochemical reduction of aqueous nitrogen oxide by gold nanoparticles

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Nano Research 2024年第3期17卷 1151-1164页

作者： Jane Chung Haibo Yin Rong Wang Yunlong Wang Junyang Zhang Yue Peng joung Woo Han Seongyun Ryu Junhua Li State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China EHS Research Center Samsung Electronics Co.Ltd.Gyeonggi-do 18448Republic of Korea

Electrochemical NO-to-NH_(3) under ambient conditions could be a viable alternative having advantages in terms of energy consumption and exhaust gas recycling of NO,replacing a traditional ammonia synthesis method of the Haber–Bosch *** synthesizing boron(B-)and nitrogen(N-)co-doped carbon nanotube(CNT)based gold(Au)catalysts,B-dopants elevate the conductivity of carbon nanotube by sp2 hybridization on graphene and implant B–N domains within the graphene layer,and result in facilitating the embedding amount of Au accompanied by high dispersibility with low particle *** density functional theory(DFT)calculations elucidate that the electron cloud transmitted from B-dopant to the active site of Au induces the Lewis acidic site,and the O-distal pathway occurs following a spontaneous *** of the electron-deficient B-doping area accompanied by N-defects and B–O edges retains the major valence state of Au as Au^(δ+),and suppresses hydrogen evolution reaction(HER)by repulsing the hindrance of H*.This record exhibits the highest faradaic efficiency(FE)of 94.7%,and NH_(3) yield rate of 1877.4μg·h^(-1)·mg_(cat)^(-1),which is the optimal yield over energy consumption in the field of the ambient reduction of aqueous NO.

关键词： boron heteroatom nitrogen defect gold nanoparticles valence states of gold electrochemical NO-to-NH3

Gastrointestinal stromal tumor solitary distant recurrence in the left brachialis muscle

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World Journal of Gastroenterology 2015年第20期21卷 6404-6408页

作者： Su-Sin Jin Hyeong-Seok Jeong Hyun-Jin Noh Woo-Hyung Choi Seung-Hwa Choi Kang-Yeon Won Dong-Pil Kim Ji-Chan Park mi-kyong joung Jeong-Goo Kim Hae-joung Sul Seung-Woo Lee Division of Gastroenterology Department of Internal MedicineDaejeon St.Mary’s HospitalThe Catholic University of Korea Department of Internal Medicine Anyang Sam Hospital Department of General Surgery Daejeon St.Mary’s HospitalThe Catholic University of Korea Department of Pathology Daejeon St.Mary’s HospitalThe Catholic University of Korea

Gastrointestinal stromal tumors(GISTs) are mesenchymal tumors of the gastrointestinal tract that are most commonly found in the stomach. Although GISTs can spread to the liver and peritoneum, metastasis to the skeletal muscle is very rare and only four cases have previously been reported. These cases involved concurrent skeletal metastases of primary GISTs or liver metastases. Here, we report the first case of a distant recurrence in the brachialis muscle after complete remission of an extra-luminal gastric GIST following a wedge resection of the stomach, omental excision, and adjuvant imatinib therapy for one year. Ten months after therapy completion, the patient presented with swelling and tenderness in the left arm. Magnetic resonance imaging revealed a large mass in the brachialis muscle, which showed positivity for c-kit and CD34 upon pathologic examination. This is the first reported case of a solitary distant recurrence of a GIST in the muscle after complete remission had been achieved.

关键词： Brachialis muscle Distant recurrence Gastrointestinal stromal tumor Skeletal metastasis Tyrosine kinase inhibitor

Value of glucose transport protein 1 expression in detecting lymph node metastasis in patients with colorectal cancer

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World Journal of Clinical Cases 2024年第5期12卷 931-941页

作者： Hongsik Kim Song-Yi Choi Tae-Young Heo Kyeong-Rok Kim Jisun Lee min Young Yoo Taek-Gu Lee joung-Ho Han Department of Internal Medicine Chungbuk National University HospitalCheongju 28644South Korea Department of Pathology Chungnam National University College of MedicineDaejeon 35015South Korea Information and Statistics Chungbuk National UniversityCheongju 28644South Korea Department of Radiology College of MedicineChungbuk National UniversityChungbuk National University HospitalCheongju-si 28644South Korea Department of Nuclear Medicine School of MedicineInha UniversityIncheon 22332South Korea Department of Surgery Chungbuk National UniversityCollege of MedicineCheongju-si 28644South Korea Department of Internal Medicen Chungbuk National UniversityCollege of medicineCheongju-si 28644South Korea

BACKGROUND There are limited data on the use of glucose transport protein 1(GLUT-1)expre-ssion as a biomarker for predicting lymph node metastasis in patients with colorectal ***-1 and GLUT-3,hexokinase(HK)-II,and hypoxia-induced factor(HIF)-1 expressions may be useful biomarkers for detecting primary tumors and lymph node metastasis when combined with fluorodeoxyglucose(FDG)uptake on positron emission tomography/computed tomography(PET/CT).AIM To evaluate GLUT-1,GLUT-3,HK-II,and HIF-1 expressions as biomarkers for detecting primary tumors and lymph node metastasis with 18F-FDG-PET/*** This retrospective study included 169 patients with colorectal cancer who underwent colectomy and preoperative 18F-FDG-PET/CT at Chungbuk National University Hospital between January 2009 and May *** tissue cores from the central and peripheral areas of the tumors were obtained and were examined by a dedicated pathologist,and the expressions of GLUT-1,GLUT-3,HK-II,and HIF-1 were determined using immunohisto-chemical *** analyzed the correlations among their expressions,various clinicopathological factors,and the maximum standardized uptake value(SUVmax)of PET/*** GLUT-1 was found at the center or periphery of the tumors in 109(64.5%)of the 169 ***-1 positivity was significantly correlated with the SUVmax of the primary tumor and lymph nodes,regardless of the biopsy site(tumor center,P<0.001 and P=0.012;tumor periphery,P=0.030 and P=0.010,respectively).GLUT-1 positivity and negativity were associated with higher and lower sensitivities of PET/CT,respectively,for the detection of lymph node metastasis,regardless of the biopsy ***3,HK-II,and HIF-1 expressions were not significantly correlated with the SUVmax of the primary tumor and lymph *** GLUT-1 expression was significantly correlated with the SUVmax of 18F-FDG-PET/CT for primary tumors and lymph *** should consider GLUT-1 expression in preoperative endoscop

关键词： 18F-FDG-PET-CT Biomarker Colorectal neoplasms Glucose transporter type 1 Lymph node

Assessments of the effects of various fracture surface morphology on single fracture flow: A review

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International Journal of mining Science and Technology 2023年第1期33卷 1-29页

作者： min Gao Chengguo Zhang joung Oh School of minerals and Energy Resources Engineering University of New South WalesSydney NSW 2052Australia

Natural rock joint permeability deviates from the classic fluid flow governing equations due to the inher-ent fracture surface roughness(i.e.,contact points,spatial correlation,matching,varying aperture,iso-lated voids,infilling material,tortuosity and channellings)and engineering disturbance such as *** improve the accuracy of fracture permeability evaluation,many efforts have been made in analytical,experimental,and numerical *** study reviews the modified mathematical gov-erning equations of fluid flow and classifies them based on different influencing factors,such as friction factor,aperture,tortuosity,inertia,and various in situ stress *** experimental and simulation techniques for the coupled normal-and shear-stress flow problems were assessed,and their advantages and disadvantages were also ***,different surface roughness descriptions and their impacts on mechanical and hydraulic behaviours were discussed,followed by the potential research directions for fracture flow problems.

关键词： Surface roughness Single fracture Nonlinear flow Coupled hydromechanical(HM)behaviours

A novel elastoplastic model for Yunnan sandstone under poly-axial loading

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International Journal of mining Science and Technology 2023年第7期33卷 801-814页

作者： Xu Li Guangyao Si joung Oh Ismet Canbulat Rui Kong Jian Zhang School of minerals and Energy Resources Engineering University of New South WalesSydney NSW 2052Australia Key Laboratory of ministry of Education on Safe mining of Deep Metal mines Northeastern UniversityShenyang 110819China School of Safety Science and Engineering Henan Polytechnic UniversityJiaozuo 454003China

The lack of understanding of plastic hardening(softening)laws,especially under anisotropic stress conditions,results in inappropriate geotechnical *** of the yielding envelopes do not consider the effect of intermediate principal stress and the influence of Lode's *** addition,the application of plastic flow rules regarding yielding surfaces compromises the softening of rock internal friction as well as the influence of Lode's angle on the plastic ***,the ductility to brittleness transition in the intermediate principal stress direction still requires a theoretical *** this study,based on poly-axial testing results of Yunnan sandstone,we adopted a failure criterion with the intermediate principal stress proposed by Menétrey and *** proposed new failure envelope was applied to capture the plastic evolution of rock samples.A plastic hardening-softening model is constructed,based on the framework of the plastic *** softening envelope is modified to better present the stress drop and considers the deterioration of rock internal friction in the post-peak stage of poly-axial *** differential of plastic potential according to the principal stresses is also modified,considering the rotation of Lode's angle in the poly-axial loading *** model results were compared with laboratory testing results,which showed great consistency across 9 different loading tests(5 under triaxial stress and 4 under poly-axial stress with 22 stress-strain curves in total).The induced brittleness by the intermediate principal stress is also well captured by the proposed model.

关键词： Elastoplastic model Rock mechanics Poly-axial stress state True-triaxial

Modular Multilevel Converter with Wireless Magnetic Power Decoupling for Three-phase MV Adjustable-speed Drives

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CSEE Journal of Power and Energy Systems 2022年第5期8卷 1497-1507页

作者： Mohamed Atef Tawfik Mohammad Sameer Irfan Ashraf Ahmed joung-Hu Park Department of Electrical Engineering Soongsil UniversitySeoul 156-743South Korea

In this paper,we propose a modular multilevel converter(MMC)with a wireless magnetic power decoupling approach suitable for medium-voltage high-power variable-speed machine *** proposed power decoupling approach is independent of the operating frequency,which solves the issue of wide fluctuations of low-frequency voltage ripple components in submodule(SM)capacitors,especially at low-speed operations without using any ripple power *** wireless magnetic elements reduces the amount of high-voltage insulation between the transformer windings,resulting in a significant reduction in the overall size of the *** basic idea of our proposed approach is to magnetically couple the instantaneous three-phase ripple power of each of the three adjacent-arm *** proposed MMC is free from low-frequency capacitors,resulting in enhanced system reliability,volume,and *** operation principles of the proposed MMC are explained,and a control design is *** performance of the proposed scheme was verified via simulation and experimental tests.

关键词： Modular multilevel converter power decoupling submodule capacitor voltage ripple variable-speed drives wireless high-frequency transformer

Quantitative analysis of mechanical properties associated with aging treatment and microstructure in Mg-Al-Zn alloys through machine learning

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Journal of Materials Science & Technology 2022年第12期107卷 52-63页

作者： joung Sik Suh Byeong-Chan Suh Sang Eun Lee Jun Ho Bae Byoung Gi Moon Advanced Metals Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea

The present study proposes a methodology for predicting the mechanical properties of AZ61 and AZ91alloys associated with microstructure,texture and aging parameters and estimating predictor *** this,we investigate quantitative correlations between microstructure,texture and mechanical properties of aged AZ61 and AZ91 rods through machine *** regression analysis focuses on the precipitation behavior of Mg17Al12as the main second phase of Mg-Al-Zn alloys with respect to aging *** simplify data generation,only SEM images were used to quantify the features of discontinuous and continuous *** overcome the lack of data and make the most of the measured data,we devised a method to extend the existing dataset by a factor of 9 using the mean and standard deviation of the measured *** neural networks predicted tensile and compressive yield strengths and resultant yield asymmetry with a high accuracy of over 98%using 11 predictors for a total of *** tree learning quantitatively assessed the importance of predictors in determining the mechanical properties of aged AZ61 and AZ91 rods.

关键词： Magnesium alloy Aging treatment microstructure Mechanical properties Machine learning