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Experimental study on wax deposition of highly paraffinic oil in intermittent gas-oil flow in pipelines

Petroleum Science 2024年第3期21卷 2080-2088页

作者： Chuan-Shuo Wang Qian-Li Ma Xiao-Fang Lv Jie Zhang Yang Liu shi-dong Zhou Jiangsu Key Laboratory of Oil and Gas Storage and Transportation Technology Changzhou UniversityChangzhou213164JiangsuPR China Hade Oil and Gas Development Department Tarim Oilfield BranchKorla841000XinjiangPR China

Oil-gas two phase wax deposition is a fairly common and open-ended question in flow assurance of multiphase transportation *** paper investigated the two main aspects of oil-gas two phase wax deposition layer:apparent thickness and crystal structure characteristics.A typical highly paraffinic oil in Bohai Sea,China,was used as the experimental material to investigate the wax deposition thickness in oil-gas two phase under the influence of different oil temperatures,superficial gas/liquid phase velocities and gas-oil ratios by using multiphase flow loop experimental *** as in the classical theory of wax molecular diffusion,it showed that wax deposition thickness of oil-gas two phase increased with increasing oil *** of the impact of different superficial phase velocities found that the actual liquid flow heat transfer and shear stripping was the gas phase dominant mechanisms determining wax deposit *** addition,the crystal structure of the wax deposition layer was characterized with the help of small-angle X-ray scattering(SAXS)for different circumferential positions,flow rates and gas-oil *** bottom deposition layer had a complex crystal structure and high hardness,which were subject to change over flow rate ***,the SAXS results provided evidence that the indirect effect of the actual liquid velocity modified by the gas phase was the main *** study of the effect of gas phase on the wax deposition of oil-gas two phase will help shed light onto the mechanism by which this important process *** findings address a very urgent need in the field of wax deposition of highly paraffinic oil to understand the flow security of oilgas two phase that occurs easily in multiphase field pipelines.

关键词： Oil-gas two phase Highly paraffinic oil Wax deposition SAXS

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Development of lithium-free P2-type high-sodium content cathode materials with enhanced cycle and air stability for sodium-ion batteries

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Rare Metals 2024年第1期43卷 113-123页

作者： Jin-Lv Tian Lin-Rong Wu hai-Jun Zhao Shou-dong Xu Liang Chen Ding Zhang Xiao-Chuan Duan College of Chemical Engineering and Technology Taiyuan University of TechnologyTaiyuan 030024China College of Chemistry Taiyuan University of TechnologyTaiyuan 030024China School of Chemical Engineering and Pharmacy Wuhan Institute of TechnologyWuhan 430205China

The effect of partial substitution of Mg for Ni on a high-sodium and lithium-free layered P2-type Na_(45/54)Mg_(6)/_(54)Ni_(12/54)Mn_(34/54)O_(2) cathode with high initial Coulombic efficiency and excellent cyclic stability has been investigated in this *** on the crystal structural analysis,the Mg doping can retain the P2 structure up to 4.3 V,thus restraining the detrimental phase transformation of P2-02during the Na-ion intercalation/deintercalation ***,the obtained Mg-doped P2-type cathode exhibits a reversible specific capacity of 109 mAh·g^(-1) at 0.1C between 2.0 and 4.3 V and a retention rate of 81.5% after 200cycles at *** addition,the full cell consisting of Mg-doped P2-type cathode and hard carbon anode shows a capacity retention rate of 85.6% after 100 *** study provides new insight into the development of durable cathode materials for sodium-ion batteries.

关键词： Sodium-ion batteries Cathode material High sodium content Air stability

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Enzymatic self-assembly/disassembly turns “ON”/“OFF” the mimetic hydrolytic activity of histidine nanofibers

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Science China Chemistry 2024年第2期67卷 517-522页

作者： Xianbao Sun Manli Wang Xiaoyang Liu Wenjun Zhan Guangqiong Xu Qiaochu Jiang hai-dong Xu Fuqiang Wang Gaolin Liang State Key Laboratory of Digital Medical Engineering School of Biological Science and Medical EngineeringSoutheast UniversityNanjing210096China Analysis Center Nanjing Medical UniversityNanjing210029China

Mimetic enzymes are devised as alternates or supplements of natural enzymes in broad fields but regulating their activities in a switchable manner remains ***,we proposed an enzymatic self-assembly/disassembly strategy to address this issue.A peptide molecule Nap FFEYIH(YH) was rationally designed which,after self-assembling into nanofibers,lined up the histidine moieties to form active hydrolysis centers for mimicking hydrolase *** dephosphorylation of Nap FFEYp IH(Yp H) by alkaline phosphatase to yield YH also turned “ON” the hydrolase *** turn,phosphorylation of YH by phosphokinase epidermal growth factor receptor to yield Yp H disassembled the nanofibers and thus turned the activity “OFF”.As such,the “ON”/“OFF” of the mimetic hydrolase activities could be regulated under physiological conditions through ALP/EGFR-mediated self-assembly/disassembly of histidine *** work provides a feasible strategy for the on-demand fabrication of artificial enzymes with controllable and superior activities.

关键词： disassembly hydrolytic activity mimetic enzyme phosphorylation self-assembly

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Lateral root elongation in maize is related to auxin synthesis and transportation mediated by N metabolism under a mixed NO_(3)^(–) and NH_(4)^(+) supply

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Journal of Integrative Agriculture 2024年第3期23卷 1048-1060页

作者： Peng Wang Lan Yang Xichao Sun Wenjun shi Rui dong Yuanhua Wu Guohua Mi Key Laboratory of Tobacco Biology and Processing of Ministry of Agriculture and Rural Affairs Tobacco Research InstituteChineseAcademy of Agricultural SciencesQingdao 266101China Department of Plant Nutrition College of Resources and Environmental SciencesChina Agricultural UniversityBeijing 100193China College of Resources Hunan Agricultural UniversityChangsha 410128China Agro-Environmental Protection Institute Ministry of Agriculture and Rural AffairsTianjin 300191China

A mixed nitrate (NO_(3)^(–)) and ammonium (NH_(4)^(+)) supply can promote root growth in maize (Zea mays),however,the changes in root morphology and the related physiological mechanism under different N forms are still ***,maize seedlings were grown hydroponically with three N supplied in three different forms (NO_(3)^(–)only,75/25 NO_(3)^(–)/NH_(4)^(+)and NH_(4)^(+)only).Compared with sole NO_(3)^(–)or NH_(4)^(+),the mixed N supply increased the total root length of maize but did not affect the number of axial *** main reason was the increased total lateral root length,while the average lateral root (LR) length in each axle was only slightly *** addition,the average LR density of 2nd whorl crown root under mixed N was also *** with sole nitrate,mixed N could improve the N metabolism of roots (such as the N influx rate,nitrate reductase (NR) and glutamine synthase (GS)enzyme activities and total amino content of the roots).Experiments with exogenously added NR and GS inhibitors suggested that the increase in the average LR length under mixed N was related to the process of N assimilation,and whether the NR mediated NO synthesis participates in this process needs further ***,an investigation of the changes in root-shoot ratio and carbon (C) concentration showed that C transportation from shoots to roots may not be the key factor in mediating lateral root elongation,and the changes in the sugar concentration in roots further proved this ***,the synthesis and transportation of auxin in axial roots may play a key role in lateral root elongation,in which the expression of ZmPIN1B and ZmPIN9 may be involved in this *** study preliminarily clarified the changes in root morphology and explored the possible physiological mechanism under a mixed N supply in maize,which may provide some theoretical basis for the cultivation of crop varieties with high N efficiency.

关键词： maize NO_(3)^(–)/NH_(4)^(+)ratio lateral root elongation N assimilation indole-3-acetic acid

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Internal electric field modulation by copper vacancy concentration of cuprous sulfide nanosheets for enhanced selective CO_(2) photoreduction

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Journal of Energy Chemistry 2024年第4期91卷 324-330页

作者： Xian shi Weidong Dai Xiaoqian Li Yang Bai Qin Ren Yao Lei Xing'an dong School of Chemistry and Environmental Engineering Sichuan University of Science&EngineeringZigong 643000SichuanChina State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation School of Oil&Natural Gas EngineeringSouthwest Petroleum UniversityChengdu 610500SichuanChina Chongqing Key Laboratory of Photo-Electric Functional Materials College of Physics and Electronic EngineeringChongqing Normal UniversityChongqing 401331SichuanChina Research Center for Environmental and Energy Catalysis Institute of Fundamental and Frontier SciencesUniversity of Electronic Science and Technology of ChinaChengdu 611731SichuanChina

Although the internal electric field(IEF)of photocatalysts is acknowledged as a potent driving force for photocharge separation,modulating the IEF intensity to achieve enhanced photocatalytic performances remains a ***,cuprous sulfide nanosheets with different Cu vacancy concentration were employed to study IEF modulation and corresponding direct charge *** the samples,Cu_(1.8)S nanosheets possessed intensified IEF intensity compared with those of Cu_(2)S and Cu_(1.95)S nanosheets,suggesting that an enhanced IEF intensity could be achieved by introducing more Cu *** intensified IEF of Cu_(1.8)S nanosheets induced numerous photogenerated electrons to migrate to its surface,and the dissociative electrons were then captured by Cu vacancies,resulting in efficient charge separation *** addition,the Cu vacancies on Cu_(1.8)S nanosheets accumulated electrons as active sites to lower the energy barrier of rate-determining step of CO_(2)photoreduction,leading to the selective conversion of CO_(2)to ***,the manipulation of IEF intensity through Cu vacancy concentration regulation of cuprous sulfide photocatalysts for efficient charge separation has been discussed,providing a scientific strategy to rationally improve photocata lytic performances for solar energy conversion.

关键词： Internal electric field intensity Cuprous sulfide photocatalysts Cu vacancies Charge separation Selective CO_(2) photoreduction

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Industrial Policy,Product Switching,and Export Performance

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China & World Economy 2024年第1期32卷 167-196页

作者： Jiemiao dong Zhuangxiong Yu Xunpeng shi Yang Yang School of Economics and Trade Guangdong University of Foreign StudiesChina Institute of Industrial Economics Jinan UniversityChina Australia-China Relations Institute University of Technology SydneyAustrialia International School of Business&Finance Sun Yat-sen UniversityChina

Industrial policy can promote economic growth and industrial upgrading by encouraging enterprises to adopt product *** utilizing comprehensive industrial policies and customs trade databases from 2000 to 2015,this paper found that firms with product ranges within policy-supported areas were more active in product *** all the enterprises that adopted the product switching,those with nonmain products in policy-supported areas were more inclined to adjust their main *** tended to transform nonmain product to main product as opposed to introducing new main product in order to effectively leverage their export experience and established ***,for enterprises whose main product was within the policy-supported areas,their tendency to switch products significantly *** analysis suggested that policy support,by alleviating industry distress and mitigating excessive market competition,encouraged firms to switch products to areas with policy ***,we estimated trade performance after product switching from the perspective of product unit price and export product *** found that for firms whose main product was in policy-supported areas,such switching was more likely to result in“low price,high quality”exports,whereas for firms with nonmain products in supported areas,such switching was more likely to lead to“high price,low quality”exports,which indicates that firms switching to policy-supported areas need to continuously develop their core competencies and operate effectively to improve their production performance.

关键词： export performance high-quality development industrial policy product switching

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Risk evaluation for the task transfer of an aircraft maintenance program based on a multielement connection number

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Frontiers of Engineering Management 2024年第1期11卷 16-31页

作者： Tao LIU Zhibo shi Huifen dong Jie BAI Yu YAN College of Electronics Information and Automation Civil Aviation University of ChinaTianjin 300300China College of Airworthiness Civil Aviation University of ChinaTianjin 300300China

This paper proposes a framework for evaluating the efficacy and suitability of maintenance programs with a focus on quantitative risk assessment in the domain of aircraft maintenance task transfer. The analysis is anchored in the principles of Maintenance Steering Group-3 (MSG-3) logic decision paradigms. The paper advances a holistic risk assessment index architecture tailored for the task transfer of maintenance programs. Utilizing the analytic network process (ANP), the study quantifies the weight interrelationships among diverse variables, incorporating expert-elicited subjective weighting. A multielement connection number-based evaluative model is employed to characterize decision-specific data, thereby facilitating the quantification of task transfer-associated risk through the appraisal of set-pair potentials. Moreover, the paper conducts a temporal risk trend analysis founded on partial connection numbers of varying orders. This analytical construct serves to streamline the process of risk assessment pertinent to maintenance program task transfer. The empirical component of this research, exemplified through a case study of the Boeing 737NG aircraft maintenance program, corroborates the methodological robustness and pragmatic applicability of the proposed framework in the quantification and analysis of mission transfer risk.

关键词： risk evaluation maintenance steering group analytic network process task transfer maintenance program

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The diagnostic value of tenascin-C in acute aortic syndrome

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Journal of Geriatric Cardiology 2024年第3期21卷 359-368页

作者： Ming MA Wei CHEN hai-Long CAO Jun PAN Qing ZHOU Xin-Long TANG dong-Jin WANG Department of Thoracic and Cardiovascular Surgery Nanjing Drum Tower Hospital Clinical College of Nanjing Medical UniversityNanjingChina Department of Thoracic and Cardiovascular Surgery Nanjing Drum Tower HospitalAffiliated Hospital of Medical SchoolNanjing UniversityNanjingChina Department of Thoracic surgery Kunshan Hospital of Traditional Chinese MedicineJiangsuChina

OBJECTIVES Misdiagnosis of acute aortic syndrome(AAS)significantly increases ***-C(TN-C)is an extracellular matrix glycoprotein related to cardiovascular *** elevation of TN-C in AAS and whether it can discriminate suddenonset of acute chest pain in Chinese remains *** We measured the plasma concentration of TN-C by ELISA in a cohort of 376 patients with chest or back *** to discriminate AAS from acute coronary syndrome(ACS)were compared and *** From October 2016 to September 2021,376 undiagnosed patients with chest or back pain were enrolled.166 of them were finally diagnosed as AAS,100 were ACS and 110 without cardiovascular diseases(NCV).TN-C was significantly elevated in AAS at 18.18 ng/mL(IQR:13.10–27.68)compared with 7.51 ng/mL(IQR:5.67–11.38)in ACS(P<0.001)and 3.68 ng/mL(IQR:2.50–5.29)in NCV(P<0.001).There was no significant difference in TN-C level among the subtypes of *** the 166 AAS patients,the peaked level of TN-C was at acute stage(P=0.012),then a slight of decrease was observed at subacute *** area under receiver operating characteristic curve for AAS patients versus NCV was 0.979(95%CI:0.964-0.994)for *** a cutoff level of 11.474 ng/mL,TN-C has a sensitivity of 76.0%,specificity of 85.5%,accuracy of 82.0%,positive predictive value(PPV)of 76.0%,negative predictive value(NPV)of 85.5%.Diagnostic performance of TN-C was superior to D-dimer and *** The concentration of serum TN-C in AAS patients was significantly higher than that in ACS patients and ***-C could be a new biomarker to distinguish AAS patients in the early stage after symptoms onset from other pain diseases.

关键词： acute cardiovascular elevated

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Natural product-induced oxidative stress-synergistic anti-tumor effects of chemotherapeutic agents

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Traditional Medicine Research 2024年第3期9卷 10-23页

作者： Shu-Fan Wang shi-Qi dong Quan dong Wen-Xin Lin Mei dong Duo Liu Department of Pharmacy Harbin Medical University Cancer HospitalHarbin 150086China

Reactive oxygen species are closely related to tumor *** recent years,reactive oxygen species has become a hot spot in tumor therapy,and many natural substances in nature contain compound components with anti-tumor ***,there is a lack of discussion on the synergistic anti-tumor effects of natural products in combination with chemotherapeutic drugs through reactive oxygen *** terms“natural products”,“reactive oxygen species”,“anti-tumor”,and“chemotherapy”were used to identify the synergistic effects of natural *** conducted a systematic literature search in PubMed and Web of Science databases for relevant research articles and reviews published in recent *** systematically summarized the studies related to anti-tumor active ingredients in natural compounds in the field of reactive oxygen species in recent years.A total of 77 relevant literatures were *** them,45 literatures containing various natural products such as terpenoids,flavonoids,alkaloids,*** anti-tumor effects by regulating reactive oxygen species levels,and 32 literatures regarding adjunctive role of natural products in anti-tumor *** this study,we found that natural products exert anti-tumor effects by elevating reactive oxygen species *** provides strong theoretical support for future clinical studies.

关键词： nature products tumor reactive oxygen species combination chemotherapy oxidative stress

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Transparent cap adjusted the stent placed for stenosis after endoscopic injection of esophageal varices:A case report

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World Journal of Clinical Cases 2024年第15期12卷 2614-2620页

作者： Fu-Long Zhang Jing Xu Yuan-dong Zhu Qian-Neng Wu Yan shi Lei Fang Dan Zhou hai Wang Chao-JunHuang Chun-Hua Zhou Qun Zhu Department of Gastroenterology Hangzhou Xixi hospitalHangzhou 310023Zhejiang ProvinceChina Department of Hepatopathy Hangzhou Xixi hospitalHangzhou 310023Zhejiang ProvinceChina

BACKGROUND The stent embedded in the esophageal mucosa is one of the complications after stenting for esophageal *** present a case of stent adjustment with the aid of a transparent cap after endoscopic injection of an esophageal varices *** SUMMARY A 61-year-old male patient came to the hospital with discomfort of the chest after the stent implanted for the stenosis because of endoscopic injection of esophageal *** gastroscopy was performed,and the stent embedded into the esophageal *** first,we pulled the recycling line for shrinking the stent,however,the mucosa could not be removed from the *** a forceps was performed to remove the mucosa in the stent,nevertheless,the bleeding form the mucosa was *** then,we used a transparent cap to scrape the mucosa along the stent,and the mucosa were removed successfully without *** A transparent cap helps gastroscopy to remove the mucosa embedded in the stent after endoscopic injection of the esophageal varices stent.

关键词： Stent Transparent cap Stenosis Endoscopic injection Esophageal varices Case report

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