检索结果-南通市图书馆

Computer Model of Phase Transformation From Hot-Deformed Austenite in Niobium Microalloyed Steels

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2007年第2期14卷 66-69页

作者： xu yun-bo yu yong-mei liu xiang-hua wang guo-dong State Key Lab of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

Based on thermodynamics and kinetics, a new mathematical model was developed to calculate the CCT diagrams and the transformation kinetics in low carbon niobium steels, in which the effect of deformation on the degree of supercooling was taken into account. The undercooling caused by deformation is the major reason for the increase of the starting transition temperature during continuous cooling. The critical cooling rate of bainite formation is within 2--5 ℃s for the studied niobium steels and deformation is suitable for the occurrence of pearlite. The ferrite volume fraction increases with the increase of the austenite boundary area, and decreases with the increase of the cooling rate. The calculated CCT diagrams and the volume fraction of each phase are in good agreement with the measurements.

关键词： low carbon niobium steel thermodynamics supercooling degree continuous cooling transformation computer model

Thermodynamic Calculation of Carbide Precipitate in Niobium Microalloyed Steels

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2006年第6期13卷 53-56页

作者： xu yun-bo yu yong-mei liu xiang-hua wang guo-dong State Key Lab of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

On the basis of regular solution sublattice model, thermodynamic equilibrium of austenite/carbide in Fe-Nb-C ternary system was investigated. The equilibrium volume fraction, chemical driving force of carbide precipitates and molar fraction of niobium and carbon in solution at different temperatures were evaluated respectively. The volume fraction of precipitates increases, molar fraction of niobium dissolved in austenite decreases and molar fraction of carbon increases with decreasing the niobium content. The driving force increases with the decrease of temperature, and then comes to be stable at relatively low temperatures. The predicted ratio of carbon in precipitates is in good agreement with the measured one.

关键词： microalloyed steel thermodynamic calculation phase equilibrium carbide prediction model

Deciphering fungal metabolon coupling tandem inverse-electrondemand Diels-Alder reaction and semipinacol rearrangement for the biosynthesis of spiro polycyclic alkaloids

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2025年第01期 288-296页

作者： Shuai liu Wen-Qiang xu Ying-Tong Di Man-Cheng Tang Ding-Kang Chen Ming-Ming Cao Yao-Wen Chang Hong-yu Tang Chun-Mao yuan Jun-bo Yang Zhi-Li Zuo Han guo Zi-Fei xu Ying Zeng yun-dong Wu Xiao-Jiang Hao Key Laboratory of Phytochemistry and Natural Medicines (Chinese Academy of Sciences) Kunming Institute of Botany Chinese Academy of Sciences University of Chinese Academy of Sciences Lab of Computational Chemistry and Drug Design State Key Laboratory of Chemical Oncogenomics Peking University Shenzhen Graduate School Shenzhen Bay Laboratory State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University State Key Laboratory of Functions and Applications of Medicinal Plants Guizhou Medical University Molecular Biology Experimental Center Germplasm Bank of Wild Species in Southwest China Kunming Institute of Botany Chinese Academy of Sciences yunnan Key Laboratory for Wild Plant Resources Kunming Institute of Botany Chinese Academy of Sciences Research Unit of Chemical Biology of Natural Anti-Virus Products Chinese Academy of Medical Sciences

In the intricate process of natural product biosynthesis, a metabolon can enhance metabolic flux by associating sequential enzymes. A fungal metabolon, comprising of flavin-dependent monooxygenase Spe F and P450 monooxygenase Spe G, is identified in the biosynthesis of spiro polycyclic alkaloids(+)-notoamide B and its diastereomer(+)-versicolamide B. Using notoamide E as a substance, Spe F/Spe G metabolon can control the stereoselectivity of its 2,3-epoxidation, followed by hydrogen atom ion at C-17 to generate reactive epoxide tau-m A with dienyl iminium unit. Subsequently,(+)-notoamide B and(+)-versicolamide B are produced via tandem nonenzymatic inverse-electron-demand Diels-Alder reaction and semipinacol rearrangement. This provides the first example of metabolon in the biosynthesis of spiro-prenylated indole alkaloids.

关键词：

同方期刊数据库

Added value of shear-wave elastography in the prediction of extracapsular extension and seminal vesicle invasion before radical prostatectomy

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2023年第2期25卷 259-264页

作者： Yi-Kang Sun Yang yu Guang xu Jian Wu yun-yun liu Shuai wang Lin dong Li-hua xiang Hui-Xiong xu Department of Medical Ultrasound Center of Minimally Invasive Treatment for TumorShanghai Tenth People’s HospitalUltrasound Research and Education InstituteClinical Research Center for Interventional MedicineSchool of MedicineTongji UniversityShanghai 200072China Department of Ultrasound Zhongshan HospitalInstitute of Ultrasound in Medicine and EngineeringFudan UniversityShanghai 200032China Department of Urology Shanghai Tenth People’s HospitalSchool of MedicineTongji UniversityShanghai 200072China

The purpose of this study was to analyze the value of transrectal shear-wave elastography(SWE)in combination with multivariable tools for predicting adverse pathological features before radical prostatectomy(RP).Preoperative clinicopathological variables,multiparametric magnetic resonance imaging(mp-MRI)manifestations,and the maximum elastic value of the prostate(Emax)on SWE were retrospectively *** accuracy of SWE for predicting adverse pathological features was evaluated based on postoperative pathology,and parameters with statistical significance were *** diagnostic performance of various models,including preoperative clinicopathological variables(model 1),preoperative clinicopathological variables+mp-MRI(model 2),and preoperative clinicopathological variables+mp-MRI+SWE(model 3),was evaluated with area under the receiver operator characteristic curve(AUC)*** was significantly higher in prostate cancer with extracapsular extension(ECE)or seminal vesicle invasion(SVI)with both P<*** optimal cutoff Emax values for ECE and SVI were 60.45 kPa and 81.55 kPa,*** of mp-MRI and SWE improved discrimination by clinical models for ECE(model 2 vs model 1,P=0.031;model 3 vs model 1,P=0.002;model 3 vs model 2,P=0.018)and SVI(model 2 vs model 1,P=0.147;model 3 vs model 1,P=0.037;model 3 vs model 2,P=0.134).SWE is valuable for identifying patients at high risk of adverse pathology.

关键词： extracapsular extension prostate cancer seminal vesicle invasion shear-wave elastography transrectal ultrasound

Modeling of kinetic characteristics of alkaline-surfactant-polymer-strengthened foams decay under ultrasonic standing wave

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2022年第4期19卷 1825-1839页

作者： Zhi-hua wang Xiao-yu liu Hong-Qi Zhang yong wang yun-Fei xu Bao-Liang Peng Yang liu Key Laboratory for Enhanced Oil&Gas Recovery of the Ministry of Education Northeast Petroleum UniversityDaqingHeilongjiang163318China Oil Recovery Plant No.3 PetroChina Daqing Oilfield Company LimitedDaqingHeilongjiang163113China Research Institute of Petroleum Exploration and Development PetroChinaBeijing100083China

Foaming issues are encountered at the stages in crude oil production, transportation, processing, especially in chemical flooding enhanced oil recovery(EOR) oilfields. These accumulated foams would cause a lot of trouble for downstream operation. The destruction of foams under ultrasonic has been increasingly paying attention in the background of green oilfield development. This study focuses on the decay kinetic characteristics of alkaline-surfactant-polymer-strengthened foams under the ultrasonic standing *** performance of the diverse foams was characterized. A decay kinetic model incorporating the energy correlation was developed and validated. The factors that affect the decay kinetic characteristics were discussed. The results indicated that the collapse rate and the collapse volume fraction decreased when the foam size decreased, the gas-liquid ratio decreased and the surface tension increased. Ultrasonic standing wave parameters have a significant impact on the decay behavior of the foam. both the ultrasonic frequency and ultrasonic amplitude were increased by 50%, the collapse volume fraction of foams increased by about 1.25 times in the identical irradiation time. The relative deviation between the measured results and the model prediction was less than 10%. The potential collapse mechanism was also explained using the principle of energy correlation of foam surface. This study is not only beneficial to provide a robust and rigorous way to defoam of produced liquid in the alkaline/surfactant/polymer(ASP)flooding EOR process but also meaningful to well understand the decay process of oil-based foams.

关键词： Foaming performance Energy correlation model Decay kinetic Collapse mechanism ASP flooding Ultrasonic standing wave

Dynamically tunable multiband plasmon-induced transparency effect based on graphene nanoribbon waveguide coupled with rectangle cavities system

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2022年第8期31卷 440-452页

作者： Zi-Hao Zhu bo-yun wang xiang Yan Yang liu Qing-dong Zeng Tao wang hua-Qing yu School of Physics and Electronic-information Engineering Hubei Engineering UniversityXiaogan 432000China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China

A dynamically tunable multiband plasmon-induced transparency(PIT) effect in a series of rectangle cavities coupled with a graphene nanoribbon waveguide system is investigated theoretically and numerically by tuning the Fermi level of the graphene rectangle cavity. A single-PIT effect is realized using two different methods: one is the direct destructive interference between bright and dark modes, and the other is the indirect coupling through a graphene nanoribbon waveguide. Moreover, dual-PIT effect is obtained by three rectangle cavities side-coupled with a graphene nanoribbon *** show that the magnitude of the dual-PIT window can be controlled between 0.21 and 0.74, and the corresponding group index is controlled between 143.2 and 108.6. Furthermore, the triple-PIT effect is achieved by the combination of bright–dark mode coupling and the cavities side-coupled with waveguide mechanism. Thus, sharp PIT windows can be formed, a high transmission is maintained between 0.51 and 0.74, and the corresponding group index is controlled between161.4 and 115.8. Compared with previously proposed graphene-based PIT effects, the size of the introduced structure is less than 0.5 μm2. Particularly, the slow light effect is crucial in the current research. Therefore, a novel approach is introduced toward the realization of optical sensors, optical filters, and slow light and light storage devices with ultra-compact,multiband, and dynamic tunable.

关键词： plasmon-induced transparency(PIT) graphene group index rectangle cavities

Recent progress in Heusler-type magnetic shape memory alloys

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2015年第8期34卷 527-539页

作者： Guang-hua yu yun-Li xu Zhu-Hong liu Hong-mei Qiu Ze-Ya Zhu xiang-Ping huang Li-Qing Pan Department of Materials Physics and Chemistry University of Science and Technology Beijing College of Science China Three Gorges University Department of Physics University of Science and Technology Beijing

Magnetic shape memory alloys(MSMAs), both in condensed matter physics and in material science, are one of the most extensive research subjects. They show prompt response to the external magnetic field and give rise to large strain and have fine reversibility. The well-known example is Heusler-type MSMAs, which possess excellent multifunctional properties and have potential applications in energy transducer, actuator, sensor, microelectromechanical system, and magnetic refrigerator. In this paper, it is shown the recent progress in magnetostructural transformation, magnetic properties, shape deformation, magnetocaloric effect as well as magnetic field-induced shape memory effect in Ni–Mn–Ga, Ni Mn Z(Z = In, Sn, Sb),and Ni Co Mn Z(Z = In, Sn, Sb, Al) Heusler-type *** remaining issues and possible challenges are briefly discussed.

关键词： Heusler alloy Magnetic shape memory alloy Martensi

Analysis of sex pheromone production and field trapping of the Asian corn borer(Ostrinia furnacalis Guenée)in Xinjiang,China

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2023年第4期22卷 1093-1103页

作者： DENG Jian-yu LAN Chen-yi-hang ZHOU Jun-xiang YAO yu-bo YIN Xiao-hui FU Kai-yun DING Xin-hua guo Wen-chao liu Wen wang Na Fumin wang The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province/Department of Plant Protection Advanced College of Agricultural SciencesZhejiang A&F UniversityHangzhou 311300P.R.China Key Laboratory of Integrated Pest Management on Crops in Northwestern Oasis Ministry of Agriculture and Rural Affairs/Institute of Plant ProtectionXinjiang Academy of Agricultural SciencesUrumqi 830091P.R.China Agricultural Technology Extension Center of Yining County Yining 835000P.R.China Division of Plant and Soil Sciences Davis College of AgricultureNatural Resources and DesignWest Virginia UniversityMorgantown 26506USA

Identifying the sex pheromone systems of local pest populations facilitates their management,especially for moth species that show significant geographic variation in sex pheromone *** investigated the pheromone production and behavioral responses of the Asian corn borer(Ostrinia furnacalis Guenée;ACB)in Xinjiang,*** ACB produces three compounds:(Z)-12-tetradecenyl acetate(Z12-14:Ac)and(E)-12-tetradecenyl acetate(E12-14:Ac)which are two sex pheromone compounds,and n-tetradecyl acetate(14:Ac)which has variable roles in mediating behavioral *** ratios of these three compounds produced in female gland are geographically distinct among different *** analysis of pheromone production showed that the proportions of Z12-14:Ac in the E/Z isomers(i.e.,Z and E12-14:Ac)and the proportions of 14:Ac in the ternary blend respectively averaged 60.46%(SD=5.26)and 25.00%(SD=7.37),with their probabilities normally or near-normally *** experiments in a cornfield indicated that deploying the E/Z isomers and the three compounds in rubber septa close to their gland ratios yielded the most captured males,while other ratios that deviated from the gland ratios showed reduced field *** ternary blend was significantly more attractive to males than the E/Z isomers in the field,indicating a functional role of 14:Ac as the third pheromone component used by the local ***,the dose-response test demonstrated that the application of the three compounds at dosages between 200 and 350μg attracted significantly more males compared to other ***,the characterization of this local ACB pheromone system provides additional information about its geographic variation and serves as a basis for optimizing the pheromone-mediated control of this pest in Xinjiang.

关键词： geographic variation Ostrinia furnacalis Asian corn borer sex pheromone pheromone titer field trapping

Subchronic Oral Toxicity Evaluation of Sodium Dehydroacetate: A 90-day Repeated Dose Study in Rats

在线全文

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2022年第4期35卷 296-311页

作者： FANG Jin liu Hai bo ZHI yuan FENG yong Quan wang Hui Ling CUI Wen Ming ZHANG Ji yue wang hua Li yu Zhou JIA xu dong NHC Key Laboratory of Food Safety Risk Assessment Chinese Academy of Medical Science Research Unit(2019RU014)China National Center for Food Safety Risk AssessmentBeijing 100021China

Objective The present study was undertaken to evaluate the subchronic oral toxicity of sodium dehydroacetate(DHA-Na)and to determine the point of departure(POD),which is a critical factor in the establishment of an acceptable dietary *** DHA-Na was administered once daily by gavage to Sprague–Dawley rats at dose levels of 0.0,31.0,62.0,and 124.0 mg/kg BW per day for 90 days,followed by a recovery period of 4 weeks in the control and 124.0 mg/kg BW per day *** outcome parameters were mortality,clinical observations,body weights,food consumption,hematology and clinical biochemistry,endocrine hormone levels,and ophthalmic,urinary,and histopathologic *** benchmark dose(BMD)approach was applied to estimate the *** Significant decreases were found in the 62.0 and 124.0 mg/kg BW groups in terms of the body weight and food utilization rate,whereas a significant increase was found in the thyroid stimulating hormone levels of the 124.0 mg/kg BW ***,the 95%lower confidence limit on the BMD of 51.7 mg/kg BW was modeled for a reduction in body *** The repeated-dose study indicated the slight systemic toxicity of DHA-Na at certain levels(62.0 and 124.0 mg/kg BW)after a 90-day oral exposure.

关键词： Sodium dehydroacetate Sub-chronic toxicity 90-day repeated oral dose test Benchmark dose Point of departure