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On the Uniqueness of Ghost-Free Special Gravity

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Communications in Theoretical Physics 2017年第9期67卷 329-334页

作者： Dong Bai Yu-hang xing Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100190 China School of Physical Sciences University of Chinese Academy of Sciences No. 19A Yuquan Road Beijing 100049 China

Special gravity refers to interacting theories of massless gravitons in Minkowski space-time which are invariant under the abelian gauge invariance hab → hab ＋ δ（axb） only. In this article we determine the most general form of special gravity free of Ostrogradski ghosts, meaning its equation of motion is of at most second order. Together with the recent works, this result could be helpful in formulating proofs of General Relativity as the unique physical theory of self-interacting massless gravitons. We also study how to construct gauge invariant couplings to matter fields.

关键词： abelian gauge invariance massless graviton matter couplings

Impact of cooling rate on mechanical properties and failure mechanism of sandstone under thermal-mechanical coupling effect

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International Journal of Coal Science & Technology 2023年第2期10卷 97-116页

作者： Pingye Guo Peng Zhang Mohua Bu hang xing Manchao He State Key Laboratory for Geo-Mechanics and Deep Underground Engineering Beijing 100083China School of Mechanics and Civil Engineering China University of Mining and TechnologyBeijing 100083China

High geo-temperature is one of the inevitable geological disasters in deep engineering such as resource extraction,space development,and energy *** of the key issues is to understand the mechanical properties and failure mechanism of high-temperature rock disturbed by low-temperature airflow after ***,.the experimental and numerical investigation were carried out to study the impact of cooling rate on mechanical properties and failure mechanism of high temperature ***,uniaxial compression experiments of high temperature sandstone at different real-time cooling rates were carried out to study the mechanical properties and failure *** experimental results indicate that the cooling rate has a significant effect on the mechanical properties and failure modes of *** peak strain,peak stress,and elastic modulus decrease with an increase in cooling rate,and the fragmentation degree after failure increases ***,the equivalent numerical model of heterogeneous sandstone was established using particle flow code(PFC)to reveal the failure *** results indicate that the sandstone is dominated by intragrain failure in the cooling stage,the number of microcracks is exponentially related to the cooling rate,and the higher the cooling rate,the more cracks are concentrated in the exterior *** axial loading,the tensile stress is mostly distributed along the radial direction,and the damage in the cooling stage is mostly due to the fracture of the radial *** addition,axial loading,temperature gradient and thermal stress mismatch between adjacent minerals are the main reasons for the damage of sandstone in the cooling ***,the excessive temperature gradient in the exterior region of the sandstone is the main reason for the damage concentration in this region.

关键词： High geo-temperature Thermo-mechanical coupling effect Cooling rate Sandstone PFC

Studies of Solvent Effects on Structure and Low Frequency Vibrational Spectra of 2,4-Dinitrotoluene

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Chemical Research in Chinese Universities 2009年第3期25卷 373-376页

作者： WANG Lin JIN Ming-xing LIU hang DING Da-jun Institute of Atomic and Molecular Physics Jilin University Changchun 130012 P. R. China

Solvent effects on 2,4-dinitrotoluene（2,4-DNT） molecule in different solvents（toluene, ethanol, and water） were studied via DFT PCM method at B3LYP/6-311＋G（d,p） level. The influences of these solvents on the molecular structure, vibrational spectra, charge distribution, and dipole moment were studied as well. The results show that PCM computations are successful in describing the vibrational spectra of 2,4-DNT molecules in these solutions and the solvent effects on the low frequency vibrational spectra are weak.

关键词： Density functional theory Solvent effect Polarizable continuum model 2,4-Dinitrotoluene

APPLICATION OF A MODIFIED QUICK SCHEME TO DEPTH-AVERAGED k-ε TURBULENCE MODEL BASED ON UNSTRUCTURED GRIDS

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Journal of Hydrodynamics 2008年第4期20卷 514-523页

作者： HUA Zu-lin xing Ling-hang GU Li Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering College of Environmental Science and Engineering Hohai University Nanjing 210098 China

The modified QUICK scheme on unstructured grid was used to improve the advection flux approximation, and the depth-averaged κ-ε turbulence model with the scheme based on FVM by SIMPLE series algorithm was established and applied to spur-dike flow computation. In this model, the over-relaxed approach was adopted to estimate the diffusion flux in view of its advantages in reducing errors and sustaining numerical stability usually encountered in non-orthogonal meshes. Two spur-dike cases with different defection angles （90°and 135°） were analyzed to validate the model. Computed results show that the predicted velocities and recirculation lengths are in good agreement with the observed data. Moreover, the computations on structured and unstructured grids were compared in terms of the approximately equivalent grid numbers. It can be concluded that the precision with unstructured grids is higher than that with structured grids in spite that the CPU time required is slightly more with unstructured grids Thus, it is significant to apply the method to numerical simulation of practical hydraulic engineering.

关键词： unstructured grid modified QUICK FVM κ-ε turbulence model spur-dike

Longitudinal dispersion coefficients of pollutants in compound channels with vegetated floodplains

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Journal of Hydrodynamics 2019年第4期31卷 740-749页

作者： Li Gu Xin-xin Zhao Ling-hang xing Zi-nan Jiao Zu-lin Hua Xiao-dong Liu Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education College of Environment Hohai University Nanjing 210098 China National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety Hohai University Nanjing 210098 China Nanjing Guohuan Science and Technology Co. Ltd. Nanjing 210001 China Changjiang River Scientific Research Institute Wuhan 430010 China

The characteristics of the longitudinal dispersion of pollutants in compound channels remain unclear. This study examines the relationships among the vegetation density, the width of the floodplain, the water depth ratio, the cross-sectional mean velocity, and the longitudinal dispersion coefficient of a symmetrical compound channel with a rigid non-submerged vegetated floodplain. The longitudinal dispersion coefficient is found to increase significantly with the presence of vegetation on floodplains, and is positively correlated with the plant density. When the density of the vegetation on the floodplains exceeds a certain value, the dispersion coefficient no longer changes with the vegetation density. The longitudinal dispersion coefficient is found to increase with the increase of the width of the floodplain. Moreover, the combined effects of the mean velocity and the water depth ratio have a positive correlation with the dispersion coefficient. The effects of the vegetation on the longitudinal dispersion coefficient in the channels with various cross-sections are also compared. The compound channels with a vegetated floodplain are found to differ significantly from the channels with a rectangular cross-section.

关键词： Compound channel longitudinal dispersion coefficient relationship vegetated floodplain

Effect of slope gradient on the subsurface water flow velocity of sand layer profile

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Journal of Mountain Science 2020年第3期17卷 641-652页

作者： HAN Zhen CHEN Xiao-yan HUANG Yu-han LUO Bang-lin xing hang HUANG Yong-chao College of Resources and Environment/Key Laboratory of Eco-environment in Three Gorges Region(Ministry of Education) Southwest UniversityChongqing 400716China College of Water Resource and Civil Engineering China Agricultural UniversityBeijing 100083China Chongqing Surveying and Design Institute of Water Resources Electric Power and Architecture Chongqing 401120China

Subsurface water flow velocity influences the hydrodynamic characteristics of soil seepage and the interaction between subsurface water flow and surface runoff during soil erosion and sediment transport.A visualized method and equipment was adopted in this study to observe the subsurface water *** sand was used as the test material of subsurface water flow and fluorescent dye was used as the indicator for tracing subsurface water *** was supplied at the same flow discharge to the three parts at the bottom of the test flume,and the subsurface water flow were determined with four slope gradients(4°,8°,10°,and 12°).The results showed that the seepage velocity gradually increased with increasing slope *** pore water velocity at different depths of sand layer profile increased with increasing slope gradient,whereas the thickness of the flow front gradually *** the same slope gradient,the pore water velocity in the lower layer was the largest,whereas the thickness of the flow front was the *** analysis of the relationship between seepage velocity and pore water velocity at different depths of sand layer profile showed that the maximum relative difference between the measured pore water velocity and the computational pore water velocity at different depths of sand profile in the experiment was 4.38%.Thus,the test method for measuring the subsurface water flow velocity of sand layer profile adopted in this study was effective and *** development of this experiment and the exploration of research methods would lay a good test foundation for future studies on the variation law of subsurface water flow velocity and the determination of flow velocity in purple soils,thus contributing to the improvement of the hydrodynamic mechanism of purple soils.

关键词： Subsurface water flow Pore water velocity Seepage velocity Slope gradient Sand layer

Study of Migration and Safety Assessment of Manganese(Mn)from Food Contact Stainless-Steel Products in China

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Biomedical and Environmental Sciences 2022年第4期35卷 361-365页

作者： Zhang Hong xing hang LIU Zai Mei LI Qian Yun CHEN Shao Hong ZHU Lei China National Center for Food Safety Risk Assessment Beijing 100022China Ningbo Customs Technology Center Ningbo 315192ZhejiangChina

Metal alloys,especially stainless-steel,are widely used in the preparation,production and storage of food,because of their corrosion resistance and barrier *** food contact(FC)stainlesssteel articles are designed for repeated,long-term use,and the migration of heavy metals is regarded as the main safety risk when they make contact with ***(Mn)is an important alloying element in stainless-steel,and its potential to migrate has caused considerable consumer concern.

关键词： properties. steel migrate

Methyl-CpG-Binding protein 2 duplication syndrome in a Chinese patient:A case report and review of the literature

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World Journal of Clinical Cases 2023年第27期11卷 6505-6514页

作者： Xu-hang xing Russel Takam Xiu-Ying Bao Nour Abdallah Ba-alwi Hong Ji Department of Pediatrics The First Part of The First Affiliated Hospital of Dalian Medical UniversityDalian 116011Liaoning ProvinceChina

BACKGROUND Chromosomal Xq28 region duplication encompassing methyl-CpG-binding protein 2(MECP2)results in an identifiable phenotype and global developmental delay known as MECP2 duplication syndrome(MDS).This syndrome has a wide range of clinical manifestations,including abnormalities in appearance,neurodevelopment,and gastrointestinal motility;recurrent infections;and ***,we report a case of confirmed MDS at our *** SUMMARY A 12-year-old Chinese boy presented with intellectual disability(poor intellectual[reasoning,judgment,abstract thinking,and learning]and adaptive[lack of communication and absent social skills,apraxia,and ataxia]functioning)and *** had no history of recurrent infections,seizures,or bowel dysfunction,which is different from that in reported *** comparative genomic hybridization confirmed MECP2 duplication in the patient and his mother who is a *** duplication size was the same in the patient and his *** prophylactic antibiotic or anti-seizure therapy was offered to the patient or his mother before or after the *** MDS is rare and has various clinical *** suspicion is critical in patients presenting with developmental delays.

关键词： Methyl-CpG-binding protein 2 Neurodevelopmental Delay Xq28 duplication Array comparative genomic hybridization Case report

Comparison of prognosis and postoperative morbidities between standard pancreaticoduodenectomy and the TRIANGLE technique for resectable pancreatic ductal adenocarcinoma

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World Journal of Gastrointestinal Surgery 2024年第3期16卷 689-699页

作者： He-xing hang Zheng-Hua Cai Yi-Fei Yang Xu Fu Yu-Dong Qiu Hao Cheng Division of Pancreatic Surgery Department of General SurgeryNanjing Drum Tower HospitalThe Affiliated Hospital of Medical SchoolNanjing UniversityNanjing 210008Jiangsu ProvinceChina

BACKGROUND Radical surgery combined with systemic chemotherapy offers the possibility of long-term survival or even cure for patients with pancreatic ductal adenocar-cinoma(PDAC),although tumor recurrence,especially locally,still inhibits the treatment *** TRIANGLE technique was introduced as an extended dissection procedure to improve the R0 resection rate of borderline resectable or locally advanced ***,there was a lack of studies concerning postoperative complications and long-term outcomes of this procedure on patients with resectable *** Patients with resectable PDAC eligible for PD from our hospital between June 2018 and December 2021 were enrolled in this retrospective cohort *** the patients were divided into PDstandard and PDTRIANGLE groups according to the surgical *** characteristics,surgical data,and postoperative morbidities were *** of the patients were followed up,and the date and location of tumor recurrence,and death were *** Kaplan-Meier method and log-rank test were used for the survival *** There were 93 patients included in the study and 37 underwent the TRIANGLE *** of operation was longer in the PDTRIANGLE group compared with the PDstandard group[440(410-480)min vs 320(265-427)min](P=0.001).Intraoperative blood loss[700(500-1200)mL vs 500(300-800)mL](P=0.009)and blood transfusion[975(0-1250)mL vs 400(0-800)mL](P=0.009)were higher in the PDTRIANGLE *** was a higher incidence of surgical site infection(43.2%vs 12.5%)(P=0.001)and postoperative diarrhea(54.1%vs 12.5%)(P=0.001)in the PDTRIANGLE *** rates of R0 resection and local recurrence,overall survival,and disease-free survival did not differ significantly between the two *** The TRIANGLE technique is safe,with acceptable postoperative morbidities compared with standardized PD,but it does not improve prognosis for patients with resectable PDAC.

关键词： Pancreatic ductal adenocarcinoma TRIANGLE technique Pancreaticoduodenectomy Prognosis Postoperative morbidities