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Shear mechanical properties and frictional sliding responses of rough joint surfaces under dynamic normal displacement conditions

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Journal of Central South University 2024年第7期31卷 2393-2410页

作者： ZHU Qiang YIN Qian TAO Zhi-gang HE Man-chao ZHENG Bo-wen JING Hong-wen ren shu-lin ZHANG Qiang MENG Bo BAI Dong-feng WU Sai-sai WU Jiang-yu State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering Xuzhou 221116China State Key Laboratory for Geomechanics&Deep Underground Engineering China University of Mining and Technology(Beijing)Beijing 100083China Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China CCCC First Highway Survey and Design Research Institute Co. Ltd.Xi’an 710075China

A comprehensive understanding of the dynamic frictional characteristics in rock joints under high normal load and strong confinement is essential for ensuring the safety of deep engineering construction and mitigating geological *** study conducted shear experiments on rough rock joints under displacement-controlled dynamic normal loads,investigating the shear behaviors of joints across varying initial normal loads,normal loading frequencies,and normal loading *** results showed that the peak/valley shear force values increased with initial normal loads and normal loading frequencies but showed an initial increase followed by a decrease with normal loading *** normal loading can either increase or decrease shear strength,while this study demonstrates that higher frequencies lead to enhanced *** initial normal loading and normal loading frequency result in a gradual decrease in joint roughness coefficient(JRC)values of joint surfaces after *** correlations existed between frictional energy dissipation and peak shear forces,while post-shear joint surface roughness exhibited a negative correlation with peak shear forces through linear regression *** study contributes to a better understanding of the sliding responses and shear mechanical characteristics of rock joints under dynamic disturbances.

关键词： dynamic normal displacement shear strength variations phase lag phenomenon stick-slip

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Host susceptibility to persistent hepatitis B virus infection

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World Journal of Gastroenterology 2006年第30期12卷 4788-4793页

作者： Ying-Li He Ying-ren Zhao shu-lin Zhang shu-Mei lin Department of Infectious Diseases the First Hospital of Xi'an Jiaotong University Xi'an 710061 Shaanxi Province China

Genetic epidemiology researches such as twin studies, family-clustering of hepatitis B virus （HBV） infection studies and ethnic difference studies have provided the evidence that host genetic factors play an important role in determining the outcome of HBV infection. The opening questions include which human genes are important in infection and how to find them. Though a number of studies have sought genetic associations between HBV infection/persistence and gene polymorphisms, the candidate gene-based approach is clearly inadequate to fully explain the genetic basis of the disease. With the advent of new genetic markers and automated genotyping, genetic mapping can be conducted extremely rapid. This approach has been successful in some infectious diseases. linkage analysis can find host genes susceptible to HBV and is of great clinical importance.

关键词： Hepatitis B virus Susceptibility Association study linkage study

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Geomechanics model test and numerical simulation of 2G-NPR bolt support effect in an active fault tunnel

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Journal of Mountain Science 2022年第9期19卷 2729-2741页

作者： ren shu-lin HE Man-chao lin Wei-jun ZHANG Teng-wu TAO Zhi-gang State Key Laboratory for Geomechanics&Deep Underground Engineering Beijing 100083China School of Mechanics and Civil Engineering China University of Mining&Technology Beijing 100083China 3 Department of Civil and Environmental EngineeringUniversity of AlbertaEdmonton T6G 1H9Canada

Active faults are a common adverse geological phenomenon that can occur during tunnel excavation and has a very negative impact on the construction and operation of the *** this paper,the grade IV rock surrounding the cross-fault tunnel with poor geological conditions has been chosen for the *** support capacity of 2^(nd) Generation-Negative Poisson’s Ratio(2G-NPR)bolt in an active fault tunnel has been carried out on the basis of relevant results obtained from the geomechanical model test and numerical investigations of failure model for existing unsupported fault *** investigation shows that surrounding rock of the tunnel is prone to shear deformation and crack formation along the fault,as a result,the rock mass on the upper part of the fault slips as a ***,small-scale deformation and loss of blocks are observed around the tunnel;however,the 2G-NPR bolt support is found to be helpful in keeping the overall tunnel intact without any damage and *** to the blocking effect of fault,the stress of the surrounding rock on the upper and lower parts of the fault is significantly different,and the stress at the left shoulder of the tunnel is greater than that at the right *** asymmetrical arrangement of 2G-NPR bolts can effectively control the asymmetric deformation and instability of the surrounding *** present numerical scheme is in good agreement with the model test results,and can reasonably reflect the stress and displacement characteristics of the surrounding rock of the *** comparison to unsupported and ordinary PR(Poisson’s Ratio)bolt support,2G-NPR bolt can effectively limit the fault slip and control the stability of the surrounding rock of the fault *** research findings may serve as a guideline for the use of 2G-NPR bolts in fault tunnel support engineering.

关键词： Tunnel engineering Fault 2G-NPR bolt Geomechanics model test Numerical simulation

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Model test on support scheme for carbonaceous slate tunnel in high geostress zone at high depth

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Journal of Mountain Science 2021年第3期18卷 764-778页

作者： TAO Zhi-gang ren shu-lin LI Gan XU Hao-tian LUO Sen-lin HE Man-chao State Key Laboratory for Geomechanics&Deep Underground Engineering China University of Mining and TechnologyBeijing 100083China School of Mechanics and Civil Engineering China University of Mining and TechnologyBeijing 100083China State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing 100084China

The Muzhailing extra-long highway tunnel and corresponding inclined shafts in Lanzhou,Gansu Province,China passes through structurally complex carbonaceous slate that is under high ground ***-designed and effective support is of high importance for achieving safe and efficient tunnel *** No.2 inclined shaft of Muzhailing Tunnel was taken as the engineering background prototype,for which,a similar model test was conducted to evaluate the effect of highly pretightened constant resistance(NPR,Negative Poisson’s Ratio)anchor cable support provision to the geologically complex carbonaceous slate at different *** schemes were proposed during testing:one scheme was without support and the second was with asymmetric support from highly pre-tightened constant resistance anchor *** speckle displacement analysis system and micro-groundstress sensors were employed to measure the deformation and shear stress distribution of the *** results demonstrated that through the second support scheme,the deformation of the surrounding rock could be effectively ameliorated,while this support scheme was applied on the project site of the No.2 inclined shaft,to explore the rationality of the scheme through field engineering ***-site monitoring indicated that the deformation of the surrounding rock was within the reasonable design range and the problem of severe tunnel deformation was effectively *** research methods and related conclusions can be used as a reference for the treatment of large deformation problems in deep-buried soft rock tunnels.

关键词： Tunnel engineering Support design Carbonaceous slate Similar simulation NPR anchor cable

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Effects of Altered Intra-abdominal Pressure on the Upper Airway Collapsibility in a Porcine Model

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Chinese Medical Journal 2015年第23期128卷 3204-3210页

作者： shu-lin ren Yan-Ru Li Ji-Xiang Wu Jing-Ying Ye Rachel Jen Department of General Surgery Beijing Tongren Hospital Capital Medical University Beijing 100730 China Department of Otolaryngology Head and Neck Surgery Beijing Tongren Hospital Capital Medical University Beijing 100730 China Department of Otolaryngology Head and Neck Surgery Beijing Tsinghua Changgung Hospital Tsinghua University Beijing 102218 China Department of Medicine Respiratory Division University of British Columbia Vancouver BC Canada

Background： Obstructive sleep apnea is strongly associated with obesity, particularly abdominal obesity common in centrally obese males. Previous studies have demonstrated that intra-abdominal pressure （IAP） is increased in morbid obesity, and tracheal traction forces may influence pharyngeal airway collapsibility. This study aimed to investigate that whether IAP plays a role in the mechanism of upper airway （UA） collapsibility via IAP-related caudal tracheal traction. Methods： An abdominal wall lifting （AWL） system and graded CO2 pneumoperitoneum pressure was applied to four supine, anesthetized Guizhou miniature pigs and its effects on tracheal displacement （TD） and airflow dynamics of UA were studied. Individual run data in 3 min obtained before and after AWL and obtained before and after graded pneumoperitoneum pressure were analyzed. Differences between baseline and AWL/graded pneumoperitoneum pressure data of each pig were examined using a Student＇s t-test or analysis of variance. Results： Application of AWL resulted in decreased IAP and significant caudal TD. The average displacement amplitude was 0.44 mm （P 〈 0.001 ）. There were three subjects showed increased tidal volume （TV）（P 〈 0.01 ） and peak inspiratory airflow （P 〈 0.01 ）; however, the change of flow limitation inspiratory UA resistance （Rua） was not significant. Experimental increased lAP by pneumoperitoneum resulted in significant cranial TD. The average displacement amplitude was 1.07 mm （P 〈 0.001） when lAP was 25 cmH2O compared to baseline. There were three subjects showed reduced Rua while the TV increased （P 〈 0.01 ）. There was one subject had decreased TV and elevated Rua （P 〈 0.001）. Conclusions： Decreased IAP significantly increased caudal TD, and elevated lAP significantly increased cranial TD. However, the mechanism of UA collapsibility appears primarily mediated by changes in lung volume rather than tracheal traction effect. TV plays an independent role in the mechanism of UA collapsibil

关键词： Abdominal Obesity Intra-abdominal Pressure Lung Volume Obstructive Sleep Apnea Trachea Traction

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Negative Poisson's ratio and peripheral strain of an NPR anchor cable

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Journal of Mountain Science 2022年第8期19卷 2435-2448页

作者： TAO Zhi-gang XU Hao-tian ren shu-lin GUO Long-ji QIN Ke ZHU Yi-fei State Key Laboratory for Geomechanics&Deep Underground Engineering Beijing 100083China School of Mechanics and Civil Engineering China University of Mining&TechnologyBeijing 100083China

Materials with a negative Poisson’s ratio effect perform significantly better than traditional materials for rock mass impact resistance,shear resistance,and energy *** on these advantages,a negative Poisson’s ratio anchor cable(NPR anchor cable)with high elongation and constant resistance was developed and successfully applied in the field of mine disaster ***,theoretical and experimental research on the negative Poisson’s ratio effect and peripheral strain characteristics of NPR anchor cables is currently *** study used several theories and methods,such as static tensile,peripheral strain measurement,and static negative Poisson’s ratio measurement,to investigate the radial deformation law of an NPR anchor cable and the negative Poisson’s ratio *** results elucidated constant resistance changes in an NPR anchor cable during operation,the motion of the constant resistance body in the constant resistance sleeve,and the deformation law of the constant resistance *** Poisson’s ratio characteristics of the NPR anchor cable and its superior energy absorption characteristics were verified and it provided a theoretical and experimental basis for energy absorption mechanisms of an NPR anchor cable.

关键词： NPR anchor cable Static tensile test Negative Poisson’s ratio Energy absorption

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Stability analysis of open-pit gold mine slopes and optimization of mining scheme in Inner Mongolia,China

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Journal of Mountain Science 2020年第12期17卷 2997-3011页

作者： ren shu-lin TAO Zhi-gang HE Man-chao PANG Shi-hui LI Meng-nan XU Hao-tian State Key Laboratory for Geomechanics&Deep Underground Engineering Beijing 100083China School of Mechanics and Civil Engineering China University of Mining&TechnologyBeijing 100083China

The geological structure of the Changshanhao open-pit mine in Urad Middle Banner,Inner Mongolia,China is extremely complicated,and slope instability has frequently occurred in various forms,such as wedge sliding,bedding sliding,and toppling *** order to study the failure mechanisms of these slopes,the geological structure and mechanical rock properties were investigated based on field investigations and laboratory *** models for the present mining area and final mining area of the original scheme were established to analyze slope *** results showed that the unique geomorphological characteristics of the mining area were generated by geological tectonism,and the north side of the stope is an anti-dip layered rock slope and the south side is a dip layered rock *** failure is the consequence of endogenic and exogenic integration,including physical and mechanical properties of the rock mass,geological structures such as faults and joints,and human-caused factors such as blasting and excavation *** the original excavation scheme was redesigned mainly by optimizing the slope angle and decreasing the final mining depth to maintain slope ***,the Monte Carlo method was used to analyze the reliability of the slope angle optimization *** open-pit mine excavation plan that meets the stability requirements was obtained eventually.

关键词： Open pit mine Slope stability Numerical simulation Excavation scheme

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Ki-67 Change in Anthracyline-containing Neoadjuvant Chemotherapy Response in Breast Cancer

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Current Medical Science 2024年第1期44卷 156-167页

作者： Zi-guo YANG Le-hao ren Feng WANG Pi-lin WANG Wen-yan WANG shu-ye lin Department of General Surgery Beijing Tiantan HospitalCapital Medical UniversityBeijing 100070China Department of Critical Care Medicine Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430022China Cancer Research Center Beijing Chest HospitalCapital Medical University/Beijing Tuberculosis and Thoracic Tumor Research InstituteBeijing 101149China

Objective Anthracycline-containing regimens are irreplaceable in neoadjuvant chemotherapy(NAC)for breast cancer(BC)at ***,30% of early breast cancer(EBC)patients are resistant to anthracycline-containing chemotherapy,leading to poor prognosis and higher ***-67 is associated with the prognosis and response to therapy,and it changes after *** A total of 105 BC patients who received anthracycline-containing NAC were ***,the optimal model of Ki-67 was selected,and its predictive efficacy was ***(IHC)was used to determine the estrogen receptor(ER),progesterone receptor(PR),and human epidermal growth factor receptor 2(HER-2)status and Ki-67 *** in situ hybridization(FISH)was used to verify the HER-2 when the IHC score was 2+.Results The post-NAC Ki67 level after treatment with anthracycline drugs was lower than pre-NAC Ki-67(19.6%±23.3%vs.45.6%±23.1%,Pline higher pathological complete response(pCR)rate(17.2%vs.0.0%,P=0.068),and a higher overall response rate(ORR)(73.6%vs.27.8%,P<0.001),when compared to patients without the Ki-67 *** ΔKi-67 and ΔKi-67%were valuable markers for the prediction of both the pCR rate and *** area under the curve(AUC)for ΔKi-67 on pCR and ORR was 0.809(0.698-0.921)and 0.755(0.655-0.855),respectively,while the AUC for ΔKi-67% on pCR and ORR was 0.857(0.742-0.972)and 0.720(0.618-0.822),*** logistic regression model 1 revealed thatΔKi-67 was an independent predictor for both pCR[odds ratio(OR)=61.030,95% confidence interval(CI)=4.709-790.965;P=0.002]and ORR(OR=10.001,95%CI:3.044-32.858;P<0.001).Multivariate logistic regression model 2 revealed thatΔKi-67%was also an independent predictor for both pCR(OR=408.922,95%CI=8.908-18771.224;P=0.002)and ORR(OR=5.419,95%CI=1.842-15.943;P=0.002).Conclusions The present study results suggest thatΔKi67 andΔKi67%are candidate predictor

关键词： breast cancer change in Ki-67 neoadjuvant chemotherapy anthracycline,response

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A novel route to enhance high-temperature mechanical property and thermal shock resistance of low-carbon Mgo-C bricks by introducing ZrSiO_(4)

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Journal of Iron and Steel Research International 2024年第6期31卷 1436-1448页

作者： Chun-hui Sun ling-ling Zhu Hao Yan Wei Zhao Jing-xuan Liu lin ren Xian-tang Zhao Xiao-song Tong shu-wen Yu Beijing Lirr High-Temperature Materials Co. Ltd.Beijing 102211China School of Materials Science and Engineering Henan Province Industrial Technology Research Institute of Resources and MaterialsZhengzhou UniversityZhengzhou 450001HenanChina School of Chemistry and Chemical Engineering Suzhou UniversitySuzhou 234000AnhuiChina

Conventional MgO-C bricks(graphite content>14 wt.%)produce a great deal of greenhouse gas emission,while low-carbon MgO-C bricks have serious thermal shock resistance during high-temperature *** enhance the high-temperature mechanical property and thermal shock resistance of low-carbon MgO-C bricks,a novel route of introducing ZrSiO_(4) powder into low-carbon MgO-C bricks was reported in such refractories with 2 wt.% flaky *** results indicate that the low-carbon MgO-C brick with 0.5 wt.%ZrSiO_(4) addition has the maximum hot modulus of rupture at 1400℃ and the corresponding specimen fired in the carbon embedded atmosphere has the maximum residual strength ratio(98.6%)after three thermal shock *** is found that some needle-like AlON and plate-like Al_(2)O_(3)-ZrO_(2) composites were in situ formed in the matrices after the low-carbon MgO-C bricks were coked at 1400℃,which can enhance the high-temperature mechanical property and thermal shock resistance due to the effect of fiber toughening and particle ***,CO_(2) emission of the newly developed low-carbon MgO-C bricks is reduced by 58.3% per ton steel after using them as the working lining of a 90 t vacuum oxygen decarburization ladle.

关键词： Low-carbon MgO-C brick ZrsiO_(4) Synergistic toughening effect High-temperature mechanical property Thermal shock resistance Vacuum oxygen decarburization ladle

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Evolution of inclusions in vacuum induction melting of superalloys containing 70%return material

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Journal of Iron and Steel Research International 2024年第3期31卷 719-728页

作者： Jin-guo Gao shu-lei Yang shu-feng Yang Jing-she Li Wei Liu Meng-jing Zhao An-ren Wang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Metallurgical and Building Materials Business Department China International Engineering Consulting CorporationBeijing 100048China

The variation law of inclusions type and size in the vacuum induction melting process and ingot of Ni-based superalloy containing 70%return material was studied by industrial test sampling,and the mechanism of inclusions formation was analyzed with thermodynamic *** results show that there are mainly two types of composite inclusions in the vacuum induction melting of Ni-based superalloys,which are nitride-and oxide-based composite inclusions,like Al_(2)O_(3)-SiO_(2)-Cr_(2)O_(3),TiN-(Mo,Nb)C,*** type and proportion of inclusions from the center to the edge of the vacuum induction ingot did not change *** number density of inclusions from the center to the edge of the ingot varied less,and the size of inclusions became smaller from the center to the *** addition,thermodynamic calculations show that oxides(M_(2)O_(3))are present in the liquid phase and mainly contain Al,Ti,Cr,Fe and O *** nitride consists mainly of Ti and N and contains small amounts of Cr,C,Nb,and Mo *** is consistent with the results of industrial *** the temperature decreases,the precipitation phases such as M_(2)O_(3),MN,γ,MC,δ,γ'andμphases are gradually precipitated,where oxides and nitrides are present in the liquid *** contents of O and N elements are the main influencing factors for the inclusions content and precipitation temperature;when the nitrogen content is reduced to below 0.0015%,it can make MN precipitate below the liquid-phase line.

关键词： Ni-based superalloy Vacuum induction melting Return material Inclusion Thermodynamic

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