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Characterization of vortex structures with self-excited oscillations based on Liutex-Omega vortex identification method

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Journal of Hydrodynamics 2023年第1期35卷 95-111页

作者： dong-dong wang Zhao-hui wang Yi-wei Fan Xiao Sun Quan-jie Gao Key Laboratory of Metallurgical Equipment and Control Technology of Ministry of Education Wuhan University of Science and TechnologyWuhan430081China Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering Wuhan University of Science and TechnologyWuhan430081China

The self-excited oscillation effect produces a continuous periodic pulsation without an external excitation *** is widely used in fluid heat and mass transfer,cavitation and resistance reduction,and other related *** self-excited oscillation effect is significantly influenced by the vortex structure created by the jet passing through the specially designed *** flow field in a self-excited oscillation cavity is simulated in this paper using the large eddy simulation(LES)*** Liutex-Omega([Math Processing Error])method is used to analyze the vortex structure’s evolution inside the cavity and is contrasted with the Q-criterion,the λ_(2)-criterion,and the Omega(Ω)*** studies indicate that the[Math Processing Error]method is less sensitive to threshold selection compared with other methods,while it is more capable of identifying weak *** change in cavity vortex structure can be devided into the four stages of vortex ring priming,growth and development,wall touch separation,and *** turbulent energy generated by shear effect can promote the growth and development of the vortex ring structure and has an important influence on the formation of the vortex ring *** vortex strength reveals the interaction mechanism between the shear effect and vortex *** vortex core area illustrates that the small-scale vortices are mainly distributed inside the collision walls of the cavity and the downstream flow *** Liutex-omega method has unique advantages in analyzing the cavity flow field and revealing the mechanism of self-excited oscillations.

关键词： Vortex identification Liutex-Omega([Math Processing Error]) self-excited oscillation large eddy simulation(LES)

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Molecular Dynamics Study of Star Polymer Melts under Start-up Shear

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Chinese Journal of Polymer Science 2022年第7期40卷 807-816页

作者： dong-dong wang Kai-Feng Yu Xiao-Lei Xu Wen-Sheng Xu Key Laboratory of Automobile Materials Ministry of Education and College of Materials Science and EngineeringJilin UniversityChangchun130025China State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China

It has been established that star polymers with a large number of arms display both the conventional chain relaxation and a slower interchain relaxation due to the formation of hard cores,which is called the local structural ***,we demonstrate that this unique relaxation property of multi-arm stars leads to unusual rheological *** study the response of star polymer melts with various arm numbers to start-up shear flow via nonequilibrium molecular dynamics *** simulation results indicate that the stress-strain response of multi-arm star polymer melts differs from that of star polymers with a small number of arms in both quantitative and qualitative *** the multi-arm star polymer melts exhibit an overshoot peak in the stress-strain curve both at relatively small and sufficiently large shear rates,two overshoot peaks appear when the flow strength is comparable to the relaxation time of the star *** double stress overshoot is absent in linear polymers and star polymers with a small number of arms and is evidently related to the presence of the local structural relaxation in star polymers with a large number of *** present a detailed analysis of the conformational and dynamical properties of star polymer melts under start-up shear to gain a molecular understanding of their stress response.

关键词： Simulation Star polymer Start-up shear

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Intensive peatland wildfires during the Aptian-Albian oceanic anoxic event 1b:Evidence from borehole SK-2 in the Songliao Basin,NE China

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Journal of Palaeogeography 2022年第3期11卷 448-467页

作者： Zhi-Hui Zhang Da-Wei Lü Tian-Tian wang dong-Zhao An Hai-Yan Liu dong-dong wang Cheng-Shan wang Shandong Provincial Key Laboratory of Depositional Mineralization and Sedimentary Minerals College of Earth Sciences and EngineeringShandong University of Science and TechnologyQingdao 266590Shandong ProvinceChina Institute of Earth Sciences China University of GeosciencesBeijing 100083China School of Earth Sciences and Resources China University of GeosciencesBeijing 100083China Chinese Academy of Geological Sciences Beijing 100037China

The Cretaceous has been considered a“high-fire”world accompanied by widespread by-products of combustion in the rock *** mid-Cretaceous oceanic anoxic event 1b(OAE1b)is marked by one of the major perturbations in the global carbon cycle characterized by deposition of organic-rich sediments in both marine and terrestrial ***,our understanding is still limited on changes in wildfire activity during OAE1b ***,we carried out a comprehensive analysis,including organic carbon isotope(δ^(13)C_(org)),total organic carbon(TOC),coal petrology,trace elements,and pyrolytic polycyclic aromatic hydrocarbons(pyroPAHs),of coal seams of the middle Aptian to early Albian Shahezi Formation from borehole SK-2 in Songliao Basin,Northeast *** negativeδ^(13)C_(org) excursions in the Shahezi Formation can be corresponded with the 113/Jacob and Kilian sub-events of ***,the intensive peatland wildfires have been identified during the sub-event periods of OAE1b based on the co-occurrence of high abundance of charcoal and pyroPAHs at that *** addition,Sr/Ba,Sr/Cu and Sr/Rb ratios demonstrate that enhanced peatland wildfires were controlled by dryer climate conditions owing to episodic northward migration of arid zones in East Asia related with rising global temperature during the sub-events of *** climate-driven extensive wildfire activity in the mid-latitude terrestrial ecosystems can be a contributing factor for OAE1b through the increased flux of nutrients fuelling primary producers in the lake and marine environments and leading to more speculative anoxia to allow the deposition of organic-rich *** results provide essential understanding of the importance of wildfires in driving mechanism of oceanic anoxic events(OAEs)in Earth's history.

关键词： Lower Cretaceous OAEs Peatland Wildfire Coals

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The genetic environmental transformation mechanism of coal and oil shale deposits in eastern China’s continental fault basins and the developmental characteristics of the area’s symbiotic assemblages——taking Huangxian Basin as an example

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Petroleum Science 2019年第3期16卷 469-491页

作者： dong-dong wang Zeng-Xue Li Hai-Yan Liu Da-Wei Lyu Guo-Qi dong College of Earth Science and Engineering Shandong University of Science and Technology Qingdao 266590Shandong China School of Geosciences China University of Petroleum (East China) Qingdao 266580 ShandongChina

Coal and oil shale are two common sedimentary energy sources which are often symbiotically developed in M esozoic- Cenozoic continental fault basins. However, the mechanisms and characteristics of the symbiotic development are not yet clearly known. In this research study, the typical continental fault basins of eastern China were chosen as examples for the purpose of conducting an examination of the coal and oil shale symbiotic assemblage types, genetic environmental differences, and transformation mechanisms, as well as the development and occurrence characteristics o f different assemblage types. Through a large number of investigations, systematic experimental testing, and sequence stratigraphy studies, the following conclusions were obtained:(1) There were five types of coal and oil shale symbiotic assemblages observed in the continental fault basins,(2) The development of coal and oil shale deposits requires a warm and humid climate, stable structure, abundant organic matter supply, a certain water depth, and a lower terrestrial source debris supply. The observed differences were that the water depth conditions were diversified in the study area, as well as the sources, types, and content of the organic matter.(3) The rapid transformations of the coal and oil shale genetic environments were mainly controlled by the tectonic settings and climatic conditions, which were determined to control the changes in the water depths, salinity,redox conditions, and lake productivity of the genetic environments. Also, in the symbiotic assemblages, genetic environment changes had induced the development of oil shale deposits, which gradually evolved into coal genetic environments.(4) In the isochronous sequence stratigraphic framework of the coal and oil shale symbiotic assemblages, the lake expansion system tracts (EST) were determined to be the most beneficial to the growth o f all the types of assemblages and were characterized by more assemblage development phases and sm

关键词： Coal and oil shale symbiotic assemblages Genetic environments Conversion mechanism Sequence stratigraphic framework Occurrence characteristics Continental fault basin

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Characteristics and evolution of inertinite abundance and atmospheric pO_(2) during China's coal-forming periods

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Journal of Palaeogeography 2021年第2期10卷 259-283页

作者： dong-dong wang Lu-Sheng Yin Long-Yi Shao Da-Wei Lyu Hai-Yan Liu Shuai wang Guo-Qi dong College of Earth Science and Engineering Shandong University of Science and TechnologyQingdao 266590Shandong ProvinceChina College of Geoscience and Surveying Engineering China University of Mining and Technology(Beijing)Beijing 100083China

Coal, especially the inertinite in it, is highly sensitive to climate changes, showing an obvious response to paleoclimate conditions, in particular, to paleo-oxygen concentration(pO_2 ). In this study, the inertinite abundance data of typical coal-forming periods in China were systematically collected and analyzed. Its characteristics and control factors were studied, and its evolution was established. Based on inertinite abundance data, pO_2 evolution curves of various coal-forming periods in China were established, which fluctuated between 15% and 30% during the entire Phanerozoic. The inertinite abundance in coal deposits during Paleozoic in China was basically consistent with that of other areas of the world, while it was quite different globally from the Mesozoic to the Cenozoic. The results show that the inertinite abundance in coal deposits is controlled by pO_2 and other factors including climatic zones, plant differentiation, sedimentary environments, and tectonic activities. The inertinite abundance in coal deposits in China during the Jurassic was high, suggesting dry paleoclimate of inland China.

关键词： Inertinite abundance pO_2 Paleoclimate Sedimentary environment Coal-forming period Comparative analysis China

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Effect of neoadjuvant chemoradiotherapy on prognosis and surgery for esophageal carcinoma

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World Journal of Gastroenterology 2009年第39期15卷 4962-4968页

作者： Jin Lv Xiu-Feng Cao Bin Zhu Lv Ji Lei Tao dong-dong wang Oncology Center Department of Surgery Affiliated Nanjing First Hospital of Nanjing Medical University and Oncology Center of Nanjing Medical University Nanjing 210006 Jiangsu Province China

AIM:To investigate the role of neoadjuvant chemoradiotherapy in prognosis and surgery for esophageal carcinoma by a ***:PubMed and manual searches were done to identify all published randomized controlled trials(RCTs) that compared neoadjuvant chemoradiotherapy plus surgery(CRTS) with surgery alone(S) for esophageal *** to the test of heterogeneity,a fi xed-effect model or a random effect model was used and the odds ratio(OR) was the principal measure of ***:Fourteen RCTs that included 1737 patients were selected with quality assessment ranging from A to C(Cochrane Reviewers' Handbook 4.2.2).OR(95% CI,P value),expressed as CRTS vs S(values>1 favor CRTS arm),was 1.19(0.94-1.48,P=0.28) for 1-year survival,1.33(1.07-1.65,P=0.69) for 2-year survival,1.76(1.42-2.19,P=0.11) for 3-year survival,1.41(1.06-1.87,P=0.11) for 4-year survival,1.64(1.28-2.12,P=0.40) for 5-year survival,0.82(0.39-1.73,P<0.0001) for rate of resection,1.53(1.33-2.84,P=0.007) for rate of complete resection,1.78(1.14-2.78,P=0.79) for operative mortality,1.12(0.89-2.48,P=0.503) for all treatment mortality,1.33(0.94-1.88,P=0.04) for the rate of adverse treatment,1.38(1.23-1.63,P=0.0002) for local-regional cancer recurrence,1.28(0.85-1.58,P=0.60) for distant cancer recurrence,and 1.27(0.86-1.65,P=0.19) for all cancer recurrence.A complete pathological response to chemoradiotherapy occurred in 10%-45.5% of *** 5-year survival benefi t was most pronounced when chemotherapy and radiotherapy were given concurrently(OR:1.45,95% CI:1.26-1.79,P=0.015) instead of sequentially(OR:0.85,95% CI:0.64-1.35,P=0.26).CONCLUSION:Compared with surgery alone,neoadjuvant chemoradiotherapy can improve the long-term survival and reduce local-regional cancer *** administration of neoadjuvant chemoradiotherapy was superior to sequential chemoradiotherapy.

关键词： Esophageal neoplasms/surgery Esophageal neoplasms/radiotherapy Antineoplastic agents Postoperative complications Prospective studies Randomized controlled trial Meta-analysis

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Impurity-induced bound states as a signature of pairing symmetry in multiband superconducting CeCu2Si2

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Frontiers of physics 2019年第1期14卷 99-104页

作者： dong-dong wang Bin Liu Min Liu Yi-Feng Yang Shi-Ping Feng Department of Physics Beijing Jiaotong University Beijing 100044 China Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China Collaborative Innovation Center of Quantum Matter Beijing 100190 China Department of Physics Beijing Normal University Beijing 100875 China

The notion of multiband superconductivity with dominant two-gap features has been recently applied to the unconventional superconductor CeCu2Si2 for challenging the previously accepted concept of nodal d-wave pairing. In the proposed study, the realistic multiband Fermi surface topology of CeCu2Si2 was obtained through first-principles calculations, and analysis was conducted with an effective two-band hybridization model including detailed band structure. Within the T-matrix approximation, the obtained calculation results show that different pairing candidates, including fully gapped s-wave, loop-nodal s-wave, and d-wave pairings, could yield qualitatively distinct features characterized by impurity-induced bound states. These features can be verified through high-resolution scanning tunneling microscopy or spectroscopy and provide corroborative justification that would be beneficial for the ongoing research regarding the superconducting gap symmetry of CeCu2Si2 at ambient pressure.

关键词： heavy-fermion superconductivity pairing symmetry impurity effect local density of states

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Thermodynamic study on the interaction between anti-tumor drug tegafur and human serum albumin

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Chinese Chemical Letters 2007年第7期18卷 891-894页

作者： Lin Wei Li dong dong wang De Zhi Sun Min Liu You Ying Di Hua Chao Yan College of Chemistry and Chemical Engineering Liaocheng University Liaocheng 252059 China

The changes of thermodynamic properties of the system on interaction between tegafur and human serum albumin （HSA） and the changes of secondary structure units of HSA in the system at 298.15 K have been investigated by the Nano-Watt-Scale isothermal titration calorimetry （ITC）, the Langmuirs binding model and the circular dichroism （CD） spectrometry.

关键词： Tegafur Human serum albumin Isothermal titration calorimetry Circular dichroism

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A new phenanthraquinone from the roots of Peucedanum praeruptorum

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Chinese Chemical Letters 2010年第7期21卷 816-817页

作者： Cun Zhang Li Li Yong Qing Xiao Wen Li Xiao Jie Yin Guo Fang Tian dong dong Chen Yun wang Institute of Chinese Materia Madica China Academy of Traditional Chinese MedicineBeijing 100700China

A new compound,9,10-dihydrophenanthrinic acid,9,10-dione-3,4-methylenedioxy-8-methoxy（1） was isolated from the roots of Peucedanum praeruptorum Dunn on the basis of spectral evidences.

关键词： Peucedanum praeruptorum 9 10-Phenanthraquinone 9 10-Dihydrophenanthrinic acid 9 10-Dione-3 4-methylenedioxy-8-methoxy

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Discovery of Highly Oxidized Abietane Diterpenoids from the Roots of Euphorbia fischeriana with Anti-tumor Activities

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Chinese Journal of Chemistry 2021年第11期39卷 2973-2982页

作者： Jiang-Chun Wei Yu-Ning Gao dong-dong wang Xiao-Yu Zhang San-Peng Fan Te-Ri-Gen Bao Xiao-Xu Gao Gao-Sheng Hu An-Hua wang Jing-Ming Jia School of Traditional Chinese Materia Medica Shenyang Pharmaceutical UniversityShenyangLiaoning110016 China

Four previously undescribed ent-abietane diterpenoids(1—4),along with eleven known analogues(5—15),were isolated from the roots of wild Euphorbia *** gross structures were determined via extensive spectroscopic data,and the absolute configurations were elucidated by means of single-crystal X-ray diffraction analysis,Rh2(OCOCF3)4-induced CD spectrum and ECD *** cervical carcinoma inhibition activities counteract HeLa cells were screened by MTT assay,and the structure-activity relationships were further *** results demonstrated that 2(IC50 value at 3.75μmol/L)was more potent than *** underlying mechanism study revealed that 2 could distinctly induce apoptosis accompanied by increasing reactive oxygen species(ROS)production,Ca^(2+)influx and decreasing mitochondrial membrane ***,signal pathways including MAPKs/AKT might play a significant role in 2-induced cervical cancer cells death.

关键词： Euphorbia fischeriana Diterpenoids Structure elucidation Biological activity Anti-tumor

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