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A mathematical diffusion model of carbon isotopic reversals inside ultra-tight Longmaxi shale matrixes

Petroleum Science 2022年第5期19卷 2014-2026页

作者： Bao-Jian Shen zhi-liang He Cheng Tao Jin-Cai Shen Zong-Quan Hu zhi-ming li Yuan-Hao Cao Wei Chen State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development SINOPECBeijing100083China Wuxi Petroleum Geology Institute SINOPEC Petroleum Exploration and Production Research InstituteWuxiJiangsu 214126China China Petroleum&Chemical Corporation Beijing100728China Chongqing Fuling Shale Gas Exploration and Development Co. Ltd.SINOPECChongqing408014China Petroleum Exploration and Production Research Institute SINOPECBeijing100083China School of Energy Soochow UniversitySuzhouJiangsu 215006China

Developing mathematical models for high Knudsen number(Kn)flow for isotopic gas fractionation in tight sedimentary rocks is still challenging.In this study,carbon isotopic reversals(δ^(13)C_(1)>δ^(13)C_(2))were found for four Longmaxi shale samples based on gas degassing experiments.Gas in shale with higher gas content exhibits larger reversal.Then,a mathematical model was developed to simulate the carbon isotopic reversals of methane and ethane.This model is based on these hypotheses:(i)diffusion flow is dominating during gas transport process;(ii)diffusion coefficients are nonlinear depending on concentration gradient.Our model not only shows a good agreement with isotopic reversals,but also well predicts gas production rates by selecting appropriate exponents m and m^(*) of gas pressure gradient,where m is for ^(12)C and m^(*)is for ^(13)C.Moreover,the(m−m^(*))value has a positive correlation with fractionation level.(m1−m1^(*))of methane are much higher than that of ethane.Finally,the predicted carbon isotopic reversal magnitude(δ^(13)C_(1)−δ^(13)C_(2))exhibits a positive relationship with total gas content since gas in shale with higher gas content experiences a more extensive high Kn number diffusion flow.As a result,our model demonstrates an impressive agreement with the experimental carbon isotopic reversal data.

关键词： Diffusion Isotopic fractionation Carbon isotopic reversal Modeling

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Hot Deformation and Corrosion Resistance of High-Strength Low-Alloy Steel

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Acta Metallurgica Sinica(English Letters) 2019年第4期32卷 495-505页

作者： Wilasinee Kingkam Cheng-zhi Zhao Hong li He-Xin Zhang zhi-ming li College of Materials Science and Chemical Engineering Harbin Engineering University Key Laboratory of Superlight Materials and Surface Technology Ministry of EducationHarbin Engineering University College of Power and Energy Engineering Harbin Engineering University

The hot deformation characteristics and the corrosion behavior of a high-strength low-alloy(HSLA) steel were investigated at deformation temperatures ranging from 800 to 1100 ℃ and strain rates ranging from 0.1 to 10 s-1 using an MMS-200 thermal simulation testing machine. Based on the flow curves from the experiment, the effects of temperature and strain rate on the dynamic recrystallization behavior were analyzed. The flow stress decreased with increasing deformation temperature and decreasing strain rate. With the assistance of the process parameters, constitutive equations were used to obtain the activation energy and hot working equation. The hot deformation activation energy of HSLA steel in this work was 351.87 kJ/mol. The work hardening rate was used to determine the critical stress(strain) or the peak stress(strain). The dependence of these characteristic values on the Zener-Hollomon parameter was found. A dynamic recrystallization kinetics model of the tested HSLA steel was constructed, and the validity of the model was confirmed by the experimental results. Observation of the microstructures indicated that the grain size increased with increasing deformation temperature,which led to a lowered corrosion resistance of the specimens.

关键词： Dynamic recrystallization Potentiodynamic polarization Hot deformation Flow stress High-strength low-alloy steel

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Real-time in vivo distal margin selection using confocal laser endomicroscopy in transanal total mesorectal excision for rectal cancer

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World Journal of Gastrointestinal Surgery 2022年第12期14卷 1375-1386页

作者： Jie Tan Hong-li Ji Yao-Wen Hu zhi-ming li Bao-Xiong Zhuang Hai-Jun Deng Ya-Nan Wang Ji-XiangZheng Wei Jiang Jun Yan Department of General Surgery Nanfang HospitalGuangzhou 510515Guangdong ProvinceChina Department of General Surgery Southern Medical UniversityGuangzhou 510515Guangdong ProvinceChina Guangdong Provincial Key Laboratory of Precision Medicine for Gastrointestinal Tumor Nanfang HospitalGuangzhou 510515Guangdong ProvinceChina

BACKGROUND Transanal total mesorectal excision(TaTME)allows patients with ultralow rectal cancer to be treated with sphincter-saving surgery.However,accurate delineation of the distal resection margin(DRM),which is essential to achieve R0 resection for low rectal cancer in TaTME,is technically demanding.AIM To assess the feasibility of optical biopsy using probe-based confocal laser endomicroscopy(pCLE)to select the DRM during TaTME for low rectal cancer.METHODS A total of 43 consecutive patients who were diagnosed with low rectal cancer and scheduled for TaTME were prospectively enrolled from January 2019 to January 2021.pCLE was used to determine the distal edge of the tumor as well as the DRM during surgery.The final pathological report was used as the gold standard.The diagnostic accuracy of pCLE examination was calculated.RESULTS A total of 86 pCLE videos of 43 patients were included in the analyses.The sensitivity,specificity and accuracy of real-time pCLE examination were 90.00%[95%confidence interval(CI):76.34%-97.21%],86.96%(95%CI:73.74%-95.06%)and 88.37%(95%CI:79.65%-94.28%),respectively.The accuracy of blinded pCLE reinterpretation was 86.05%(95%CI:76.89%-92.58%).Furthermore,our results show satisfactory interobserver agreement(κ=0.767,standard error=0.069)for the detection of cancer tissue by pCLE.There were no positive DRMs(≤1 mm)in this study.The median DRM was 7 mm[interquartile range(IQR)=5-10 mm].The median Wexner score was 5(IQR=3-6)at 6 mo after stoma closure.CONCLUSION Real-time in vivo pCLE examination is feasible and safe for selecting the DRM during TaTME for low rectal cancer(clinical trial registration number:NCT04016948).

关键词： Transanal total mesorectal excision Probe-based confocal laser endomicroscopy Optical biopsy Distal resection margin Low rectal cancer

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Clinical characteristics of the patients with Hodgkin's lymphoma involving extranodal sites

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Chinese Journal of Cancer 2012年第7期31卷 342-347页

作者： zhi-ming li Ying-Jie Zhu Yi Xia Jia-Jia Huang Wen-Qi Jiang State Key Laboratory of Oncology in South China GuangzhouGuangdong 510060P.R.China Department of Medical Oncology Sun Yat-sen University Cancer CenterGuangzhouGuangdong 510060P.R.China

Differences between Hodgkin's lymphoma (HL) patients in China and Western countries are known to exist, but data on Chinese patients with HL are limited. It is not clear whether there are clinical and histological differences in patients with HL involving different extranodal sites. This is the first study to analyze Chinese patients with HL involving different extranodal sites. We selected 22 HL patients with extranodal involvement from more than 250 previously untreated HL patients. Most patients were young males, and 20 of the 22 patients had stage IV disease. The major pathologic types were nodular sclerosis classical HL (NSCHL) and mixed cellularity classical HL(MCCHL). At diagnosis, the most commonly involved extranodal sites were the liver and lung, followed by the bones. There was no significant association between the international prognostic score(IPS) and survival in patients with different extranodal sites. Our data showed the overall survival (OS) and disease-free survival (DFS) rates of low-risk group (IPS = 0-2) were relatively higher than those of high-risk group (IPS ≥ 3), but the IPS did not show predictive power for survival. Although HL with extranodal involvement is rare, it should be considered as a unique form of HL.

关键词：临床特点淋巴瘤患者部位金 IPS 西方国家数据显示

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Hydrocarbon generation from lacustrine shales with retained oil during thermal maturation

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Petroleum Science 2020年第6期17卷 1478-1490页

作者： Xin-He Shao Xiong-Qi Pang Mao-Wen li zhi-ming li Yi Zhao State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing 102249China College of Geosciences China University of PetroleumBeijing 102249China State Key Laboratory of Shale Oil and Shale Gas Resources and Eff ective Development SINOPEC Petroleum Exploration and Production Research InstituteBeijing 100083China SINOPEC Key Laboratory of Petroleum Accumulation Mechanisms Wuxi Institute of Petroleum GeologyWuxi 214126JiangsuChina

Thermal maturation in the shale oil/gas system is inherently complex due to the competitive interplays between hydrocarbon generation and retention processes.To study hydrocarbon generation characteristics from shales within different stages of thermal maturation under the influence of retained oil,we performed Micro-Scale Sealed Vessels(MSSV)pyrolysis on a set of artificially matured lacustrine shale s amples from the Shahejie Formation in the Dongpu Depression in Bohai B ay Basin,China.Experimental results show that hydrocarbon yields of shale samples with or without retained oil at various thermal maturities follow different evolution paths.Heavy components(C15+)in samples crack at high temperatures and generally follow a sequence,where they first transform into C6-14 then to C2-5 and C1.Methane accounts for most of the gaseous products at high temperatures in all samples,with different origins.The cracking of C2-5 is the main methane-generating process in samples with retained oil,whereas the source of methane in samples without retained oil is kerogen.In the studied shales,retained oils at early-mature stage retard the transformation of liquid to gaseous hydrocarbon and prompt the cracking of C2-5 to C1 to some extent.TSR reaction related to gypsum in the studied samples is the primary reason that can explain the loss of hydrocarbon yields,especially at high temperatures.In addition,transformation of volatile hydrocarbons to gas and coke also accounts for the loss of generated hydrocarbon,as a secondary factor.

关键词： MSSV pyrolysis Hydrocarbon generation Lacustrine shales Thermal maturation Retained oil

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Characterization of Zn-doped GaN grown by metal–organic vapor phase epitaxy

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Rare Metals 2020年第11期39卷 1328-1332页

作者： Cui-Ting Wu Yue Zhou Qiao-Yun Sun Lu-Qiu Huang Ai-Lan li zhi-ming li Information Department Beijing City UniversityBeijing100083China State Key Laboratory of Luminescence and Applications Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of ScienceChangchun130033China State Key Laboratory of Applied Optics Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun130033China

The point defects and photoluminescence(PL)spectra of gallium nitride(GaN)epilayers with Mg,Zn,and unintentional doping were investigated in this study.The concentration of point defects(Ga vacancy and its related complexes)in the Zn-doped GaN is consistent with that in the Mg-doped GaN,but lower than that in undoped GaN.It is suggested that Zn(Mg)atoms occupy Ga sites and suppress the formation of Ga vacancies.Comparing the blue luminescence(BL)band intensity of GaN:Zn with that of GaN:Mg,a factor of 10 strong PL intensity demonstrates that a moderate incorporation of Zn to GaN is likely to improve the structural quality of GaN.Detailed studies on 2.93 eV BL band for GaN:Zn reveal that the Zn related BL band behaves as a donor-acceptor pairs character.For the acceptor level,isolated Zn_(Ga)with the activation energy of 0.386 eV above the valence band is obtained from temperature-dependent PL measurements,whereas the deep donor defect responsible for the 2.93 eV band is deduced to be 164 meV below the conduction band.An O_(N)-H complex model is suggested to explain the deep donor origin.

关键词： GaN Metal–organic chemical vapor deposition Zn-doped Photoluminescence Donor–acceptor pairs

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Effect of Cr on microstructure and oxidation behavior of TiAl-based alloy with high Nb

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China Foundry 2018年第1期15卷 17-22页

作者： Zhu-Hang Jiang Cheng-zhi Zhao Jiao-Jiao Yu He-Xin Zhang zhi-ming li Key Laboratory of Superlight Materials and Surface Technology College of Materials Science and Chemical Engineering Harbin Engineering University College of Power and Energy Engineering Harbin Engineering University

Three novel multi-microalloying TiAl-based alloys containing high Nb were designed and fabricated Thermogravimetric method was applied to investigate the influence of Cr on the oxidation behavior of high Nb TiAl alloy at 1,073 K for 200 h in laboratory air. The 2 at.% and 4 at.% Cr were added into the alloy,(respectivel named 2 Cr and 4 Cr compared to the Cr-free ternary alloy, 0 Cr alloy). The alloys' microstructure and compositio as well as the composition distribution of the oxidation scale were analyzed by means of Scanning Electro Microscopy(SEM), Energy Dispersive Spectroscopy(EDS), and X-Ray Diffractometry(XRD). The results show that the addition of Cr decreases the grain size of the Nb-TiAl alloy and leads to a transformation from a full lamellar structure to a nearly fully lamellar structure. When oxidized at 1,073 K for 200 h, the oxidized mass gai of the alloy increases with an increase in Cr addition amount in the first 100 h and decreases in the last 100 h With the increase of Cr content, the oxidation surface turns compact but uneven in morphology, which may affec the oxidation resistance of the alloy by increasing the peeling off risk of the oxidation layer at friction conditions.

关键词： TiAl-based alloys microstructure oxidation Cr addition

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Effect of coiling and annealing temperatures on yield point behavior of low-carbon steel

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Journal of Iron and Steel Research(International) 2020年第3期27卷 325-333页

作者： zhi-ming li Xiang li Lei Yang Zheng-yan Shen Bi-lei Wang Shun-li Zhao Gao-fei liang Chang-jiang Song State Key Laboratory of Advanced Special Steel School of Materials Science and EngineeringShanghai UniversityShanghai 200072China Technology Center of Baoshan Iron&Steel Co. Ltd.Shanghai 201900China

Low-carbon steel is widely used for household appliance and automotive panel steel because of its excellent plasticity.Unfortunately,yield point phenomena easily appear in the low-carbon steel produced by a continuous annealing process and cause degradation to the surface quality during processing.The effect of the coiling temperature(600-750℃)and annealing temperature(740-820℃)on the yield point behavior is studied.Tensile tests show that coiling temperature has a greater effect on yield point elongation(YPE)and aging index(AI)than the annealing temperature.Microstructure observations show that coiling temperature at 750℃would make the micron-sized carbides appearing at the grain boundary disappear and a number of dispersed nanoscale carbides precipitate in grain interior,corresponding to the highest solid solution carbon content in the matrix of 750℃coiled sample.The experimental results suggest that AI rather than YPE has a positive relationship with the solid solution carbon content of the low-carbon steel.And YPE has a positive relationship with the upper/lower yield strength.

关键词： Low-carbon steel Carbide Yield point elongation Coiling temperature Annealing temperature

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Determination of Trace Mercury by Catalytic Solid Substrate-room Temperature Phosphorimetry

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Chinese Chemical Letters 2006年第12期17卷 1582-1584页

作者： Jia ming liU Yun Xiong WU Shao Xian liN Fei ming li Xiu Mei SHI Zhong Bin SHI Guo Hui ZHU zhi ming li Xiao Mei HUANG Department of Chemistry and Environmental Science Zhangzhou Normal College Zhangzhou 363000 Department of Food and Chemical Engineering Zhangzhou Institute of Technology Zhangzhou 363000

A new highly sensitive method （detection limit： 4.1 ag spofx, sample volume： 0.4 gL spot^·l） for the determination of trace Hg2^2＋ by catalytic solid substrate-room temperature phosphorimetry has been establishe... 详细信息

关键词： Hg^2＋ α-naphthylamine sulfanilic acid catalytic solid substrate-room temperature phosphorimetry.

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Numerical simulation and experimental validation of moisture-heat coupling for saturated frozen soils

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Research in Cold and Arid Regions 2017年第3期9卷 250-257页

作者： zhi ming li Jian Chen Kai Sun Bin Zhang Key Lab of Structures Dynamic Behavior and Control (Harbin Institute of Technology) Ministry of Education School of Civil Engineering Harbin Institute of Technology Heilongjiang Water Conservancy Science Research Institute

In seasonally frozen regions,freezing-and-thawing action is the main cause responsible for the destruction of canals,which is closely linked to the temperature gradient and water transport.To investigate the behaviour of soils under freezing-and-thawing actions,many numerical models have been established that consider the important coupling of moisture transport and temperature evolution;but they contain excessive parameters,some of which are rather difficult to determine.Based on the well-known Harlan's theory,a simple moisture-heat coupling model was recently proposed to quantify the coupled moisture-heat transport performance of soils in terms of the central temperature and porosity.The mathematical module of COMSOL Multiphysics was further employed to solve the governing equations numerically.To validate our model,a thorough experimental scheme was carried out in our lab.The measured temperature distribution was found to be consistent with the predicted results.

关键词： saturated frozen soil moisture-heat coupling freezing-and-thawing action canal

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