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Effects of process parameters on fragment and refinement of millimeter- grade coarse grains for 316LN steel during hot cogging

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Journal of Iron and Steel Research International 2017年第5期24卷 529-535页

作者： Da-shan Sui Hai-ming Zhang Hong-yang Zhu Zhe Zhu Zhen-shan Cui National Die & Mold CAD Engineering Research Center Shanghai Jiao Tong University Shanghai 200030 China shanghai Heavy machinery plant Shanghai 200245 China

The heterogeneous mixed-grain microstructure is a common defect for the heavy forging of 316LN austenitie stainless steel. Isothermal compression experiments were performed on a Gleeble-3500 thermo-mechanical simulator to investigate the effect of process parameters on the fragment and re- finement of millimeter-grade coarse grains （MCGs） during hot cogging. The experimental results in- dicate that the stress of MCG specimens is much larger than that of fine grain （FG） ones at 1150 ℃, while the stress difference between MCG and FG samples became smaller at 1200 ℃. Moreover, the MCGs can be well fragmented and refined under the condition of temperature of 1200 ℃, strain rate of 0.01 s-1 , and reduction rate of 50%. Meanwhile, numerical simulations were conducted to study the influences of temperature, strain and strain rate on microstructure evolution. The results of ex- periments and simulations comprehensively demonstrate that the MCG results in the increase of de- formation resistance and incompatibility of deformation, and it can be fragmented and refined at 1200 ℃ so that the plastic deformation energy decreases remarkably with the increase of temperature from 1 150 to 1200 ℃.

关键词： 316LN steel Hot deformation Coarse grain Microstrueture evolution Numerical simulation

A SOLUTION OF COSINE PRESSURES ON A HOLLOW CYLINDER AND THE LIMIT WHEN k→0

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Applied Mathematics and Mechanics(English Edition) 1993年第5期14卷 443-448页

作者：刘助柏齐作玉 Northeast Heavy machinery Institute Qiqihaer shanghai Heavy machinery plant Shanghai

A new stress function is found in this paper and then the problems of cosine pressures on a hollow cylinder are solved with the new stress function, which provides the basis for the solution of the problems of space symmetrical deformation of a hollow cylinder. When the pressures do not vary in the axial direction, that is, when the lame formulae can be deduced.

关键词： hollow cylinder cosine pressure analytic solution

Active fuel design A way to manage the right fuel for HCCI engines

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Frontiers in Energy 2016年第1期10卷 14-28页

作者： Zhen HUANG Zhongzhao LI Jianyong ZHANG Xingcai LU Junhua FANG Dong HAN Key Laboratory of Power machinery and Engineering Ministry of Education Shanghai Jiao Tong University Shanghai 200240 China

Homogenous charge compression ignition （HCCI） engines feature high thermal efficiency and ultralow emissions compared to gasoline engines. However, unlike SI engines, HCCI combustion does not have a direct way to trigger the in-cylinder combustion. Therefore, gasoline HCCI combustion is facing challenges in the control of ignition and, combustion, and operational range extension. In this paper, an active fuel design concept was proposed to explore a potential pathway to optimize the HCCI engine combustion and broaden its operational range. The active fuel design concept was realized by real time control of dual-fuel （gasoline and n-heptane） port injection, with exhaust gas recirculation （EGR） rate and intake temperature adjusted. It was found that the cylinder- to-cylinder variation in HCCI combustion could be effectively reduced by the optimization in fuel injection proportion, and that the rapid transition process from SI to HCCI could be realized. The active fuel design technology could significantly increase the adaptability of HCCI combustion to increased EGR rate and reduced intake temperature. Active fuel design was shown to broaden the operational HCCI load to 9.3 bar indicated mean effective pressure （IMEP）. HCCI operation was used by up to 70% of the SI mode load while reducing fuel consumption and nitrogen oxides emissions. Therefore, the active fuel design technology could manage the right fuel for clean engine combustion, and provide a potential pathway for engine fuel diversification and future engine concept.

关键词： active fuel design HCCI gasoline n-heptane engine combustion

Self-Recirculating Casing Treatment for a Radial Compressor

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Chinese Journal of Mechanical Engineering 2009年第4期22卷 567-573页

作者： XIAO Jun XU Wei GU Chuangang SHU Xinwei Key Laboratory for Power machinery and Engineering of Ministry of Education Shanghai Jiao Tong University Shanghai 200240 China

Casing treatment is a widely employed technique to increase the stall margins of turbomachineries. In the last several decades, many researches on casing treatment have been carded out. However, the mechanism of its expanding stall margins is still not very clear. Till now, most casing teatment schemes are designed for axial compressors, while the investigations on casing treatments in centrifugal compressors are rarely reported. Moreover, current investigation methods mainly focus on experiments, and perfect theoretic al analysis is not yet feasible. In order to study the effectiveness and further the mechanism of casing treatments in centrifugal compressors, in this paper, a computationally based investigation of the impact of the self-recireulating casing treatment on the performance of a radial compressor is carried out. The results indicate that, by casing bleed and injection, the casing treatment with inclined blades in the cavity expands the stall margin most. At low mass flows, the reversed flow through the cavity with inclined blades develops the counter swirl flow in front of the impeller inlet, which is considered to benefit increasing the pressure rise from the injection port to the bleed port and thereby augment the recirculating flow. At 120% design speed, the stall margin is larger than that at the design speed. However, the cost of extending the stall margin is the reduction of isentropic efficiency. A mended casing treatment by shifting the bleed port upstream is also studied. It is demonstrated that, relative to the original casing treatment, this mend can improve the efficiency evidently notwithstanding a little narrowing of the flow range.

关键词： self-recirculating casing treatment bleed injection stall margin

Foliar modifications induced by inhibition of polar transport of auxin

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Cell Research 1999年第1期9卷 27-35页

作者： NI DI AN LING JIAN WANG ZHI HONG XU ZHEN Ao XIA(shanghai Institute of plant Physiology, Chinese Academy of Sciences, shanghai 200032, China) 1shanghai Institute of plant Physiology Chinese Academy of Sciences Shanghai 200032 China 1shanghai Institute of plant Physiology Chinese Academy of Sciences Shanghai 200032 China 1shanghai Institute of plant Physiology Chinese Academy of Sciences Shanghai 200032 China 1shanghai Institute of plant Physiology Chinese Academy of Sciences Shanghai 200032 China

The effects of auxin polar transport inhibitors, 9-hydroxy-fluorene-9-carboxylic acid (HFCA); 2, 3, 5-triiodobenzoic acid (TIBA) and trans-cinnamic acid (CA)on leaf pattern formation were investigated with shoots formed from cultured leaf explants of tobacco and cultured pedicel explants of Orychophragmus violaceus, and the seedlings of tobacco and Brassica chinensis. Although the effective concentration varies with the inhibitors used, all of the inhibitors induced the formation of trumpet-shaped and/or fused leaves. The frequency of trumpet-shaped leaf formation was related to the concentration of inhibitors in the *** observation of tobacco seedlings showed that there was only one main vascular bundle and several minor vascular bundles in normal leaves of the control, but there were several vascular bundles of more or less the same size in the trumpet-shaped leaves of treated *** results indicated that auxin polar transport played an important role on bilateral symmetry of leaf growth.

关键词： Brassica Chinensis Orychophragmus violaceus Nicotiana tabacum auxin polar transport foliar modification

Signaling in Pollen Tube Growth： Crosstalk, Feedback, and Missing Links

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Molecular plant 2013年第4期6卷 1053-1064页

作者： Yuefeng Guan Jingzhe Guo Hui Li Zhenbiao Yang shanghai Center for plant Stress Biology and shanghai Institute of plant Physiology and Ecology Shanghai Institutes of Biological Sciences Chinese Academy of Sciences Shanghai 200032 China Center for plant Cell Biology and Department of Botany and plant Sciences University of California Riverside CA 92521 USA

Pollen tubes elongate rapidly at their tips through highly polarized cell growth known as tip growth. Tip growth requires intensive exocytosis at the tip, which is supported by a dynamic cytoskeleton and vesicle trafficking. Several signaling pathways have been demonstrated to coordinate pollen tube growth by regulating cellular activities such as actin dynamics, exocytosis, and endocytosis. These signaling pathways crosstalk to form a signaling network that coordinates the cellular processes required for tip growth. The homeostasis of key signaling molecules is critical for the proper elongation of the pollen tube tip, and is commonly fine-tuned by positive and negative regulations. In addition to the major signaling pathways, emerging evidence implies the roles of other signals in the regulation of pollen tube growth. Here we review and discuss how these signaling networks modulate the rapid growth of pollen tubes.

关键词： polarity pollen development reproductive biology signal transduction.

Towards low emissions and high thermal efficiency of gasoline compression ignition engine under high loads by modulating the fuel reactivity and injection strategy

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Science China(Technological Sciences) 2020年第1期63卷 96-104页

作者： JIANG ChenXu LI ZiLong QIAN Yong LU XingCai Key Lab for Power machinery and Engineering of MOE Shanghai Jiao Tong University

Gasoline compression ignition(GCI) is a practicable way to obtain low emissions and high thermal efficiency of gasoline-like fuels in internal combustion engines. In this paper, the research octane number(RON) and injection strategy were coordinated to optimize the GCI engine performance and emissions under high loads. The direct injection and port injection were used to achieve two injection strategies: direct injection(DI) and port injection plus direct injection(PIDI), and the primary reference fuels(PRF) with the RON of 60, 70, 80 and 90 were used. The results show that using lower RON fuels under high loads, DI mode can achieve higher efficiency, while PIDI mode can achieve lower combustion noise at an expense of slightly lower fuel economy. When the DI mode is converted to PIDI mode with a pre-injection ratio of 30%, using PRF70 under 12 bar and the exhaust gas recirculation(EGR) rate of 40%, the gross indicated thermal efficiency and the maximum pressure rise rate are reduced by 1% and by 2 bar/°CA, respectively, while the particle emissions also decrease significantly, thus achieving low emissions and high efficiency. However, under the same load and EGR rate, DI mode produces less regulated and unregulated emissions than PIDI mode. In addition, the effect of fuel RON was obvious, the lower RON fuels exhibit obvious three-stage heat release in PIDI mode, however, PRF90 with higher RON only exhibits two-stage heat release, and the peak value of the firststage heat release rate is also lower than those of other fuels.

关键词： gasoline compression ignition regulated and unregulated emissions injection strategy particle emissions fuel reactivity

The Basal Level Ethylene Response is Important to the Wall and Endomembrane Structure in the Hypocotyl Cells of Etiolated Arabidopsis Seedlings

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Journal of Integrative plant Biology 2012年第7期54卷 434-455页

作者： Chan Xu Xiaoyan Gao Xiaobin Sun Chi-Kuang Wen National KeyLaboratory of plant Molecular Genetics and National Center for plant Gene Research(shanghai) Institute of Plant Physiology and EcologyShanghai Institutes for Biological SciencesChinese Academy of Sciences300 Fenglin RdShanghai 200032China shanghai Applied Protein Technology ShanghaiChina

The sub-cellular events that occur during the ethylene-modulated cell elongation were characterized by examining the ultra-structure of etiolated Arabidopsis seedling hypocotyl cells. Preventing the basal level ethylene response facilitated cell elongation, and the cells exhibited wall loosening and separation phenotype. Nearby the wall separation sites were frequently associated with an increase in the cortical rough endoplasmic reticulum （rER） membranes, the presence of paramural bodies, and the circular Golgi formation. The cortical rER proliferation and circular Golgi phenotype were reverted by the protein biosynthesis inhibitor cycloheximide. The cortical rER membranes were longer when the ethylene response was prevented and shortened with elevated ethylene responses. Proteomic changes between wild type and the ethylene-insensitive mutant ethylene insensitive2 （ein2） seedling hypocotyls indicated that distinct subsets of proteins involving endomembrane trafficking, remodeling, and wall modifications were differentially expressed. FM4-64 staining supported the proteomic changes, which indicated reduced endocytosis activity with alleviation of the ethylene response. The basal level ethylene response has an important role in endomembrane trafficking, biological materials transport and maintenance of the endomembrane organization. It is possible that endomembrane alterations may partly associate with the wall modifications, though the biological significance of the alterations should be addressed in future studies.

关键词： ER proliferation cell walls circular Golgi endomembrane trafficking ethylene.

The pentatricopeptide repeat protein EMB1270 interacts with CFM2 to splice specific group Ⅱ introns in Arabidopsis chloroplasts

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Journal of Integrative plant Biology 2021年第11期63卷 1952-1966页

作者： Li Zhang Jingli Chen Liqun Zhang Ying Wei Yajuan Li Xinyun Xu Hui Wu Zhong‐Nan Yang Jirong Huang Fenhong Hu Weihua Huang Yong‐Lan Cui shanghai Key Laboratory of plant Molecular Sciences Development Center of Plant Germplasm ResourcesCollege of Life SciencesShanghai Normal UniversityShanghai 200234China

Chloroplast biogenesis requires the coordinated expression of chloroplast and nuclear ***, we show that EMB1270, a plastid-localized pentatricopeptide repeat(PPR) protein, is required for chloroplast biogenesis in Arabidopsis *** of EMB1270 led to embryo arrest,whereas a mild knockdown mutant of EMB1270 displayed a virescent phenotype. Almost no photosynthetic proteins accumulated in the albino emb1270 knockout mutant. By contrast, in the emb1270 knockdown mutant, the levels of ClpP1 and photosystem I(PSI) subunits were significantly reduced, whereas the levels of photosystem II(PSII) subunits were normal. Furthermore, the splicing efficiencies of the clpP1.2,ycf3.1, ndhA, and ndhB plastid introns were dramatically reduced in both emb1270 mutants. RNA immunoprecipitation revealed that EMB1270 associated with these introns in vivo. In an RNA electrophoretic mobility shift assay(REMSA), a truncated EMB1270 protein containing the 11 Nterminal PPR motifs bound to the predicted sequences of the clpP1.2, ycf3.1, and ndhA *** addition, EMB1270 specifically interacted with CRM Family Member 2(CFM2). Given that CFM2 is known to be required for splicing the same plastid RNAs, our results suggest that EMB1270 associates with CFM2 to facilitate the splicing of specific group II introns in Arabidopsis.

关键词： Arabidopsis thaliana CRM Family Member 2 chloroplast EMB1270 intron splicing pentatricopeptide repeat protein