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Simulation of Fluid Flow, Heat Transfer and Micro-Segregation in Twin-roll Strip Casting of Stainless Steel

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Journal of Materials Science & Technology 2006年第3期22卷 295-300页

作者： Xiaomin ZHANG zhengyi JIANG Xianghua liu Guodong WANG State Key Laboratory of Rolling Technology and Automation Northeastern University Shenyang 110004 China

In twin-roll strip casting process, metal flow and temperature distribution in the molten pool directly affect the stability of the process and the quality of products. In this paper, a 3D coupled thermal-flow fenite element modeling （FEM） simulation for twin-roll strip casting of stainless steel was performed. Influences of the pouring temperature and casting speed on the temperature fields were obtained from the numerical simulation. The micro-segregation of the solutes during the strip casting process of stainless steel was also simulated. A developed micro-segregation model was used to calculate the micro-segregation of solutes in twin-roll casting of stainless steel. The relationship between the solidus fraction in solidification and temperature was given, which was used to determine the LIT （liquid impermeable temperature）, ZST （zero strength temperature） and ZDT （zero ductility temperature） in the period of non-equilibrium solidification. The effect of temperature on the micro-segregation was discussed. According to the computational results, the solidification completion temperature in the twin-roll strip casting of stainless steel was then determined, which can provide a basis for controlling the location of solidification completion temperature and analysing the crack of the casting strip.

关键词： Casting speed Micro-segregation Twin-roll strip casting Simulation

TEM observation of sintered permanent magnetic strontium ferrite

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Rare Metals 2006年第z1期25卷 578-583页

Sintered permanent magnetic strontium ferrites were studied using transmission electron microscopy to investigate the microstructure morphology and its correlation with the magnetic properties. The present study shows that the microstructure of sintered permanent magnetic strontium ferrites is an important parameter in determining their magnetic properties. The microstructure morphology in low-performance ferrite magnet is obviously different from high-performance one. The magnetic properties of sintered permanent strontium ferrite depend strongly on the orientation degree of strong magnetic crystals. The presence of ferric oxide phase in ferrite magnet can deteriorate the magnetic properties. Moreover, proper quantities of crystal defects are beneficial to high coercive force due to the fixing of magnetic domain.

关键词： permanent magnetic strontium ferrite TEM Moiré pattern crystal defect

Reproductive biology of Hemitripterus villosus in the Bohai Strait,China

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Journal of Oceanology and Limnology 2024年第3期42卷 881-892页

作者： Ping SUN Song QIN zhengyi liu Longchuan ZHUANG Key Laboratory of Coastal Biology and Biological Resource Utilization Yantai Institute of Coastal Zone ResearchChinese Academy of SciencesYantai 264003China University of Chinese Academy of Sciences Beijing 100049China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China

To understand the reproductive biology of Hemitripterus villosus in the Bohai Strait,and fill the key knowledge gap in verifying reproductive seasonality and documenting gonadotropin dependent reproductive cycle of this species,a year-round detail study was conducted for the first *** total,263 individuals were randomly sampled off the coasts of the Bohai *** show that and the overall female-to-male ratio(1.35:1)did not differ significantly from the 1:1 sex *** length and weight relationship for females and males were regressed,depicting an isometric growth for both *** reproductive phases of the complete gonadotropin dependent reproductive cycle in both sexes were *** monthly variations in the gonadosomatic and hepatosomatic indexes for both sexes further indicated that this species spawns a single batch of eggs per year and the peak spawning period is from October to *** average diameter of eggs ranged from 2.10 to 3.57 *** length at first sexual maturity was 224.87 mm for females and 241.26 mm for *** positive relationships between absolute fecundity and fish size,and also gonadal weight were *** from the Bohai Strait exhibited smaller body size,smaller egg diameter,lower gonadosomatic index,lower absolute fecundity,and higher population extinction risk than the other populations’studied *** findings contribute to understanding the status of this isolated westernmost population,and we emphasize that more efficient protection measures for the species and control measures are urgently required to improve the coastal environment in the Bohai Strait.

关键词： Hemitripterus villosus Bohai Strait fecundity length at first maturity reproductive seasonality

Eff ects of temperature on photosynthetic performance and nitrate reductase activity in vivo assay in Gracilariopsis lemaneiformis (Rhodophyta)

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Journal of Oceanology and Limnology 2021年第1期39卷 362-371页

作者： Zhihai ZHONG zhengyi liu Longchuan ZHUANG Wanlin SONG Weizhou CHEN Yantai Institute of Coastal Zone Research Chinese Academy of SciencesYantai 264003China Shantou University Shantou 515063China

Gracilariopsis lemaneiformis is an economically-valued species and widely cultured in China at *** being acclimated to diff erent growth temperatures(15,20,25,and 30°C)for 7 days,the relative growth rate(RGR),nitrate reductase activity,soluble protein content and chlorophyll a fl uorescence of *** were *** show that RGR was markedly aff ected by temperature especially at 20°C at which *** exhibited the highest eff ective quantum yield of PSII[Y(II)]and lightsaturated electron transport rate(ETR max),but the lowest non-photochemical *** of growth temperature,the nitrate reductase activity increased with the incubation temperature from 15 to 30°*** addition,the greatest nitrate reductase activity was found in the thalli grown at 20°*** value of temperature coeffi cient Q10 of alga cultured in 15°C was the greatest among those of other temperatures *** indicate that the optimum temperature for nitrate reductase synthesis was relatively lower than that for nitrate reductase activity,and the relationship among growth,photosynthesis,and nitrate reductase activity showed that the optimum temperature for activity of nitrate reductase in vivo assay should be the same to the optimal growth temperature.

关键词： chlorophyll a fl uorescence Gracilariopsis lemaneiformis growth nitrate reductase activity

Transient expression of the enhanced green fluorescent protein(egfp) gene in Sargassum horneri

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Journal of Oceanology and Limnology 2019年第2期37卷 651-656页

作者： PANG Yunlong LI Yan liu zhengyi CUI Yulin QIN Song Key Laboratory of Coastal Biology and Biological Resource Utilization Yantai Institute of Coastal Zone Research Chinese Academy of Sciences Yantai 264003 China University of Chinese Academy of Sciences Beijing 101408 China Yantai Ocean Environmental Monitoring Central Station of State Oceanic Administration Yantai 264006 China

Sargassum horneri is a macroalga widespread in North Asia-Pacific region, and these years its bloom has caused huge damage to the environment and the economic in China. To make up the blank on genetic engineering research, a transient transformation system for the multicellular marine brown alga S . horneri was established in this research. The algae used in this research were collected from the Yellow Sea of China and verified as a same species S . horneri with analysis of molecular markers. The S . horneri parietal leaves were transformed with the enhanced green fluorescent gene as the reporter by micro-particle bombardment. The results show that green fluorescent protein (GFP) is an eff ective transgene reporter for S . horneri and that particle bombardment is a suitable method for transformation of S . horneri . Through selection of four diff erent promoters for EGFP and six groups’ bombardment characters, the highest transformation efficiency approximately 1.31% was got with the vector pEGFP-N1 at bombardment characters 900 spi and 6 cm distance. This research paves a way for the further research and application of S . horneri .

关键词： green fluorescent protein (GFP) particle bombardment Sargassum horneri transgenesis

A Gγ subunit promoter T-DNA insertion mutant——A1-412 of Magnaporthe grisea is defective in appressorium formation,penetration and pathogenicity

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Chinese Science Bulletin 2006年第18期51卷 2214-2218页

作者： LIANG Shen WANG zhengyi liu Pengjuan LI Debao Institute of Biotechnology Zhejiang University Hangzhou 310029 China

In our previous studies,a nonpathogenic mutant of Magnaporthe grisea,A1-412,which was defective in appressorium formation,penetration and infectious growth,was obtained by T-DNA insertional mutagenesis. Here we reported the identification and characterization of the corresponding gene. Se- quence analysis of the genomic DNA franking T-DNA isolated by TAIL-PCR technique showed that T-DNA was inserted into the promoter region of the predicted G protein γ-subunit gene MGG1 (for Magnaporthe grisea G protein Gamma subunit). MGG1 is predicted to encode a 93-aa protein with a typical G-protein gamma like domain (GGL) and C-terminal CAAX box. The amino-acid sequence of MGG1 is highly identical to the Gγ subunits of other filamentous fungi. Further phenotypic investigation of A1-412 showed that ex- ogenous cAMP could induce appressorium formation,although the formed appressoria were abnormal in shape and unable to penetrate onion epidermis or rice leaves. Moreover,few perithecia were observed when A1-412 was crossed with the appropriate mat- ing-type strain. The above phenotypes in A1-412 were partially complemented by reintroduction of the gene MGG1. Our results indicate that the G-protein gamma subunit MGG1 may be involved in regulating morphogenesis,mating and pathogenicity in M. grisea.

关键词：形态发生插入突变致病性病毒 T-DNA

Effects of Temperature and Light on Growth Rate and Photosynthetic Characteristics of Sargassum horneri

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Journal of Ocean University of China 2021年第1期20卷 101-110页

作者： WANG Yong ZHONG Zhihai QIN Song LI Jialin LI Jingjing liu zhengyi Key Laboratory of Marine Hazards Forecasting Ministry of Natural ResourcesHohai UniversityNanjing 210098China Yantai Institute of Coastal Zone Research Chinese Academy of SciencesYantai 264003China

The changing environmental factors exerted great influences on coastal macroalgal *** study the responses of the brown seaweed Sargassum horneri to temperature and light,*** was cultured under three temperatures(20,25 and 30℃)and three light intensities(30,60,and 120μmol photons m-2 s-1)for seven *** growth rate,chlorophyll a(Chl a)and carotenoids(Car)contents,chlorophyll fluorescence,and photosynthetic oxygen evolution rate were *** results show that the highest relative growth rate(RGR),maximal electron transport rate(rETRmax);the net photosynthetic rate(Pn)were observed at the lowest temperature(20℃)and highest light intensity(120μmol photons m-2 s-1);and the RGR and Pn were significantly inhibited by the highest temperature(30℃),especially at the lowest light intensity(30μmol photons m-2 s-1)(P<0.05).Additionally,the highest light intensity enhanced the non-photochemical quenching(NPQ)even under the highest temperature(30℃),indicating that the higher light intensity could induce photo-protection reaction of *** results suggest that the higher temperature and lower light intensity exerted negative influences on ***.

关键词： chlorophyll fluorescence parameter ocean warming oxygen electrode photosynthetic activity Sargassum horneri transparency

Comparison of the photo-acclimation potential of fl oating and benthic thalli of Sargassum horneri(Phaeophyta)during autumn and winter

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Journal of Oceanology and Limnology 2022年第1期40卷 195-205页

作者： Jingjing LI Yunlong PANG Song QIN zhengyi liu Zhihai ZHONG Wanlin SONG Longchuan ZHUANG Key Laboratory of Marine Hazards Forecasting Ministry of Natural ResourcesHohai UniversityNanjing 210098China Yantai Institute of Coastal Zone Research Chinese Academy of SciencesYantai 264003China Weihai Vocational College Weihai 264200China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China

Sargassum horneri is a foundational species and an important contributor to the fl oating seaweed stock along the northeastern coast of *** this study,benthic and fl oating thalli of *** were collected from Changdao Island(37°54′N,120°43′E),Bohai Bay,*** conducted an in-situ and an indoor experiment to study the acclimation potential in *** to abiotic conditions at sea surface in autumn and *** benthic and fl oating thalli were cultured in situ for two months(from October to December)at diff erent depths:0 m above sea level(masl)and 3 m below sea level(mbsl),and their growth rate,biochemical content,and photosynthetic performance were *** the fi rst month of culture,the relative growth rate of fl oating thalli was 2-fold greater than that of benthic thalli at 0 *** photosynthetic rate of most thalli was signifi cantly higher at 0 masl than at 3 *** the indoor experiments,fl oating and benthic thalli were exposed to high light intensity(400μmol photons/(m^(2)·s)photosynthetically active radiation(PAR))for 21 d,and their photo-acclimation capacities were *** high light intensity,the two types of thalli showed low maximum quantum yield(F_(v)/F_(m))and light utilisation effi ciency(α)but high light saturation point(E_(k)).Floating thalli showed higher photosynthetic rate and photoprotective ability than benthic thalli at high light *** eff ective quantum yield of photosystem II[Y(II)]of both types of thalli recovered after a 6-day treatment with low light intensity(40μmol photons/(m^(2)·s)).These fi ndings suggest that *** is highly acclimated to the sea surface environment,which possibly contributes to its rapid accumulation and long free-fl oating periods at the sea surface.

关键词： chlorophyll-a fl uorescence growth photosynthesis photosynthetic pigments Sargassum horneri

Analysis of genetic variation within and among Ulva pertusa (Ulvaceae,Chlorophyta) populations using ISSR markers

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Chinese Science Bulletin 2010年第8期55卷 705-711页

作者： ZHAO Jin JIANG Peng LI Nan WANG JinFeng liu zhengyi QIN Song Key Laboratory of Experimental Marine Biology Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Yantai Institute of Coastal Zone Research for Sustainable Development Chinese Academy of Sciences Yantai 264003 China College of Resources and Environmental Sciences Nanjing Agricultural University Nanjing 210095 China

Ulva pertusa is a native species to Asia along the western coast of Pacific Ocean,with new occurrence records in the eastern coast of Pacific,the northwest coast of Atlantic and the Mediterranean ***,little is known about its population genetic *** this study,twelve *** populations from 3 coastal areas of China:Qingdao,Yantai and Dalian,were applied to ISSR *** selected 4 ISSR primers amplified 120 polymorphic bands ***'s gene diversity (H) ranged from 0.0729 to 0.1496,and Shannon's information index (I) ranged from 0.1072 to *** diversity was greater within Qingdao populations (H=0.2069,I=0.3232).Analysis of molecular variance (AMOVA) showed the greatest variance within populations (68.57%),much less variance among populations (22.63%) and among areas (8.79%).Unweighted pair-group mean analysis (UPGMA) indicated that clustering of *** individuals mainly relates to their populations and geographic distances separating those *** differentiation and limited gene flow among *** populations were indicated by ISSR analysis.

关键词： ISSR分析遗传变异分析孔石莼人口 Shannon信息指数国内绿藻群体遗传结构