期刊文献+
共找到14篇文章
< 1 >
每页显示 20 50 100
Water Soluble Propolis and Royal Jelly Enhance the Antimicrobial Activity of Honeys and Promote the Growth of Human Macrophage Cell Line 被引量:1
1
作者 Bratko Filipic Lidija Gradisnik +7 位作者 Eva Ruzic-Sabljic Brabara Trtnik Adriana Pereyra Domen Jaklic Rok Kopinc Jana Potokar Almin Puzic Hrvoje Mazija 《Journal of Agricultural Science and Technology(B)》 2016年第1期35-47,共13页
Due to the overuse and misuse of antibiotic, an increase in antibiotic resistance of pathogenic bacteria is evolving. Attention should be focused on natural alternatives to antibiotics, like propolis, royal jelly (R ... Due to the overuse and misuse of antibiotic, an increase in antibiotic resistance of pathogenic bacteria is evolving. Attention should be focused on natural alternatives to antibiotics, like propolis, royal jelly (R J) and honeys. They all have strong antibacterial properties due to the active substances they contain. This study investigated the effect of combination of water soluble propolis (WSP) Greitl20 or fresh royal jelly (F-RJ) (MiZigoj) and Forest honeys as antibacterial against Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Acinetobacter baumanii, Staphylococcus aureus, methicillin resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Streptococcus agalactiae and Candida albicans. These substances are also cell growth promoters for human macrophage (TLT) cell line. WSP Greitl20, F-RJ (M) and different Forest honeys were prepared in saline as 10% solutions. The antimicrobial activity was expressed as the minimal inhibitory concentration (MIC) in mg/mL. The growth promotion activity was measured at optical density (OD) 595 nm. The combination ofWSP Greitl20 with different Forest honeys is better than F-RJ (M) in same combination with different Forest honeys. The best antibacterial/antifungal activity was found with the combination of 10% WSP Greit 120 in the Forest honey (1:10) from Italy or Spain. When measuring the growth promoting activity of TLT cell line, the best activity was detected at the combination of 10% WSP Greitl20 in the Forest honey from Italy (GI3 = 0.796 ± 0.014 and GI5 = 1.133± 0.022). Antimicrobial and growth promoting activities are correlated and WSP-dependent. 展开更多
关键词 PROPOLIS royal jelly Forest honey antimicrobial activity human macrophage cell line cell growth promoting activity.
下载PDF
Expression of serine protease SNC19/matriptase and its inhibitor hepatocyte growth factor activator inhibitor type 1 in normal and malignant tissues of gastrointestinal tract 被引量:9
2
作者 Lei Zeng Jiang Cao Xing Zhang 《World Journal of Gastroenterology》 SCIE CAS CSCD 2005年第39期6202-6207,共6页
AIM: To provide the expression profile of serine protease SNC19/matriptase and its inhibitor hepatocyte growth factor activator inhibitor type 1 (HAI-1) in normal and malignant tissues of gastrointestinal tract at ... AIM: To provide the expression profile of serine protease SNC19/matriptase and its inhibitor hepatocyte growth factor activator inhibitor type 1 (HAI-1) in normal and malignant tissues of gastrointestinal tract at mRNA level for further study on their correlations with tumor progression and metastasis. METHODS: Total RNAs were prepared from 37 samples of colorectal cancer tissues, 40 samples of gastric cancer tissues, and their adjacent normal tissues. The expression of SNC19/matriptase and HAI-1 in these samples was detected by real-time fluorescent quantitative PCR using glyceraldehyde-3-phosphate dehydrogenase as internal standard, and the clinical significance for the correlation with clinicopathological parameters was evaluated. RESULTS: In gastric cancer tissues the expression of HAI-1 and SNC19/matriptase was significantly lower than that in the corresponding adjacent normal tissues (Z = -3.280, P= 0.006; Z= -4.651, P= 0.000). HAI-1:SNC19/matriptase ratio showed no difference between normal and malignant tissues (P〉0.05). Analysis of clinicopathological parameters showed decreased expression of HAI-1 and HAI-1:SNC19/ matriptase ratio associated with stage Ⅲ/Ⅳ gastric tumors as compared to stage Ⅰ/Ⅱ ones (Z= -2.140, P= 0.031; Z = -2.155, P = 0.031), and with lymph node-positive gastric cancer tissues as compared to lymph node-negative ones (Z = -2.081, P = 0.036; Z= -2.686, P = 0.006). The expression of SNC19/matriptase had no relationship with stages and lymph node metastasis (P〉0.05). The expression of HAI-1 and HAI-1:SNC19/matriptase ratio increased in well-differentiated gastric cancer tissues, but there was no statistical significance (P〉0.05). The difference of SNC19/matriptase expression was not significant in gastric cancer tissues of different histological differentiation status (P〉0.05). In colorectal cancer tissues, the expression of HAI-1 and SNC19/matriptase was also markedly lower than that in their adjacent normal tissues (Z= -3.100, P = 0.002; Z= -2.731, P = 0.006), whereas HAI-1:SNC19/matriptase ratio showed no difference. Decreased expression of HAI-1 was associated with increased invasive depth and lymph node metastasis, but there was no statistical significance (P〉0.05). The difference of SNC19/matriptase expression and HAI-1: SNC19/matriptase ratio was not significant in different stages and different lymph node metastasis status (P〉0.05). The expression of SNC19/matriptase, HAI-1 or HAI-1: SNC19/matriptase ratio showed no difference in colorectal cancer tissues of different histological differentiation status (P〉0.05). CONCLUSION: The expressions of SNC19/matriptase and its inhibitor HAI-1 are decreased in gastrointestinal cancer tissues compared to their normal counterparts, and the decreased expression of HAI-1 may correlate with invasion and lymph node metastasis. The possible mechanisms involved need to be further investigated. 展开更多
关键词 MATRIPTASE Hepatocyte growth factor activator inhibitor type 1 EXPRESSION Metastasis
下载PDF
Aberrant activation of latent transforming growth factor-β initiates the onset of temporomandibular joint osteoarthritis 被引量:16
3
作者 Liwei Zheng Caixia Pi +9 位作者 Jun Zhang Yi Fan Chen Cui Yang Zhou Jianxun Sun Quan Yuan Xin Xu Ling Ye Xu Cao Xuedong Zhou 《Bone Research》 CAS CSCD 2018年第4期383-392,共10页
There is currently no effective medical treatment for temporomandibular joint osteoarthritis(TMJ-OA) due to a limited understanding of its pathogenesis. This study was undertaken to investigate the key role of transfo... There is currently no effective medical treatment for temporomandibular joint osteoarthritis(TMJ-OA) due to a limited understanding of its pathogenesis. This study was undertaken to investigate the key role of transforming growth factor-β(TGF-β)signalling in the cartilage and subchondral bone of the TMJ using a temporomandibular joint disorder(TMD) rat model, an ageing mouse model and a Camurati–Engelmann disease(CED) mouse model. In the three animal models, the subchondral bone phenotypes in the mandibular condyles were evaluated by μCT, and changes in TMJ condyles were examined by TRAP staining and immunohistochemical analysis of Osterix and p-Smad2/3. Condyle degradation was confirmed by Safranin O staining, the Mankin and OARSI scoring systems and type X collagen(Col X), p-Smad2/3 a and Osterix immunohistochemical analyses. We found apparent histological phenotypes of TMJ-OA in the TMD, ageing and CED animal models, with abnormal activation of TGF-βsignalling in the condylar cartilage and subchondral bone. Moreover, inhibition of TGF-β receptor I attenuated TMJ-OA progression in the TMD models. Therefore, aberrant activation of TGF-β signalling could be a key player in TMJ-OA development. 展开更多
关键词 TMJ OA TMD Aberrant activation of latent transforming growth factor initiates the onset of temporomandibular joint osteoarthritis
下载PDF
The hypoxia-inducible factor-1α activates ectopic production of fibroblast growth factor 23 in tumor-induced osteomalacia 被引量:8
4
作者 Qian Zhang Michele Doucet +4 位作者 Ryan E Tomlinson Xiaobin Han L Darryl Quarles Michael T Collins Thomas L Clemens 《Bone Research》 SCIE CAS CSCD 2016年第2期85-90,共6页
Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome in which ectopic production of fibroblast growth factor 23 (FGF23) by non-malignant mesenchymal tumors causes phosphate wasting and bone fractures... Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome in which ectopic production of fibroblast growth factor 23 (FGF23) by non-malignant mesenchymal tumors causes phosphate wasting and bone fractures. Recent studies have implicated the hypoxia-inducible factor-la (HIF-la) in other phosphate wasting disorders caused by elevated FGF23, including X-linked hypophosphatemic rickets and autosomal dominant hypophosphatemia. Here we provide evidence that HIF-la mediates aberrant FGF23 in TIO by transcriptionally activating its promoter. Immunohistochemical studies in phosphaturic mesenchymal tumors resected from patients with documented TIO showed that HIF-la and FGF23 were co-localized in spindle- shaped cells adjacent to blood vessels. Cultured tumor tissue produced high levels of intact FGF23 and demonstrated increased expression of HIF-la protein. Transfection of MC3T3-E1 and Saos-2 cells with a HIF-la expression construct induced the activity of a FGF23 reporter construct. Prior treatment of tumor organ cultures with HIF-la inhibitors decreased HIF-la and FGF23 protein accumulation and inhibited HIF-la-induced luciferase reporter activity in transfected cells. Chromatin immunoprecipitation assays confirmed binding to a HIF-la consensus sequence within the proximal FGF23 promoter, which was eliminated by treatment with a HIF-la inhibitor. These results show for the first time that HIF-la is a direct transcriptional activator of FGF23 and suggest that upregulation of HIF-la activity in TIO contributes to the aberrant FGF23 production in these patients. 展开更多
关键词 The hypoxia-inducible factor-1 activates ectopic production of fibroblast growth factor 23 in tumor-induced osteomalacia HIF
下载PDF
Activation of epidermal growth factor receptor mediates myocardial ischemia/reperfusion arrhythmias in anaesthetized rats
5
作者 MEI Feng~2,JI Zhou-xiang~1,QIN Fu~1,LEI Yang~1,HUI Liu~1 (1.Department of Pharmacology,Tongji Medical College, Huazhong University of Science and Technology,Wuhan 4300074 2.Department of Anesthesiology,Union Hospital, Tongji Medical College,Huazhong University of Science and Technology,Wuhan 4300074) 《岭南心血管病杂志》 2011年第S1期222-222,共1页
Objectives Epidermal growth factor receptor (EGFR)is a receptor protein tyrosine kinase and plays a critical role in the development and function of the heart.Previous studies have demonstrated that EGFR is involved... Objectives Epidermal growth factor receptor (EGFR)is a receptor protein tyrosine kinase and plays a critical role in the development and function of the heart.Previous studies have demonstrated that EGFR is involved in regulating electrical excitability of the heart.The present study was designed to investigate whether EGFR activation would mediate myocardial arrhythmias induced by ischemia/reperfu- sion in anaesthetized rats.Methods and results Myocardial ischemia/reperfusion arrhythmias were induced by 10 min ligation of the left anterior descending coronary artery,followed by a 30 min reperfusion in anaesthetized rats.Incidence and severity of cardiac arrhythmias were significantly reduced by pretreatment with the EGFR kinase inhibitor AG556.Phosphorylation level of myocardial EGFR was increased during ischemia and at early reperfusion.Intramyocardial transfection of EGFR siRNA reduced EGFR mRNA and protein,and decreased the incidence of ventricular fibrillation induced by reperfusion.Interestingly,tyrosine phosphorylation levels of cardiac Na<sup>+</sup> channel(I<sub>Na</sub>) and L-type Ca<sup>2+</sup> channel(I<sub>Ca.l</sub>) were significantly increased at corresponding time points to the alteration of phosphorylated EGFR level during reperfusion.AG556 pretreatment countered the increased tyrosine phosphorylation level of Na<sup>+</sup> and L-type Ca<sup>2+</sup> channels induced by reperfusion.No significant alteration was observed in tyrosine phosphorylation levels of cardiac Kv4.2 and Kir2.1 channels during the cardiac ischemia/reperfusion. Conclusions These results demonstrate for the first time that EGFR plays an important role in the genesis of myocardial ischemia/reperfusion arrhythmias,which is likely mediated at least in part by enhancing tyrosine phosphorylation of cardiac Na<sup>+</sup> and L-type Ca<sup>2+</sup> channels. 展开更多
关键词 EGFR Activation of epidermal growth factor receptor mediates myocardial ischemia/reperfusion arrhythmias in anaesthetized rats
下载PDF
Control Effects of Bacillus subtilis DJ-6 and Pyraclostrobin Alone and in Combination Against Fusarium oxysporum 被引量:9
6
作者 吉沐祥 姚克兵 +3 位作者 李国平 吴祥 陈宏洲 庄义庆 《Agricultural Science & Technology》 CAS 2014年第11期2020-2025,共6页
[Objective] This study was conducted to screen a synergistic biological fungicide complex to control Fusarium wilt, reducing the use of chemical pesticides. [Method] The inhibitory effects of Bacil us subtilis DJ-6 an... [Objective] This study was conducted to screen a synergistic biological fungicide complex to control Fusarium wilt, reducing the use of chemical pesticides. [Method] The inhibitory effects of Bacil us subtilis DJ-6 and pyraclostrobin alone or in combination at five ratios against Fusarium oxysporum were detected by mea-suring mycelium growth rate in laboratory tests. The growth promotion and disease control effect of combined or single use of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 WP at 1∶1 000, 1∶2 000 and 1∶3 000 dilutions were detected in field trials. [Result] The EC50 values of combined use of B. subtilis DJ-6 and pyra-clostrobin at ratios of 1∶1, 1∶2, 1∶3, 1∶4 and 1∶5 against F. oxysporum were 5.311 5, 4.008 6, 3.570 6, 3.350 9 and 3.218 9 μg/ml, with the synergistic ratios (SR) of 2.28, 1.77, 1.53, 1.64, 1.11, among which the synergetic effect at 1∶1 was the best. The fungicidal activity of pyraclostrobin was greater than that of B. subtilis DJ-6 in laboratory tests. Field trials revealed that al the 1∶1 000, 1∶2 000 and 1∶3 000 dilu-tions of 20% pyraclostrobin·2×1011 cfu/g B. subtilis DJ-6 WP in combination, 1∶1 000 dilution of 1 ×1012 cfu/g B. subtilis DJ-6 WP and 1∶2 000 dilution of 250 g/L pyra-clostrobin EC promoted the growth of strawberry by increasing plant height, leaf petiole, leaf blade area and stem diameter. Among them, the treatments with 1∶1 000 and 1∶2 000 of 20% pyraclostrobin · 2×1011 cfu/g B. subtilis DJ-6 WP in combina-tion had better effects than other treatments. The control effects of al the treat-ments were measured 30 and 80 d after fungicide application. The control effects of 1∶1 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combina-tion were up to 100% and 93.11%, which were higher than those in al other treat-ments. The second highest control effects were found in the treatment with 1∶ 2 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combination, they were 92.49% and 86.49%, higher than those in other treatments except the 1∶1 000 dilution of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 in combination. The control effects of 1∶3 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combination were 82.61% and 72.42%, higher than those in treatment with 1∶1 000 dilution of 1×1012 cfu/g B. subtilis DJ-6 WP, but lower than those in treat-ment with 1∶2 000 dilution of 25% pyraclostrobin EC. [Conclusion] Al the results re-vealed that the combination use of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 WP at 1∶1 000 to 1∶2 000 dilution had better control effect against strawberry Fusarium wilt. 展开更多
关键词 Strawberry Fusarium wilt Bacil us subtilis DJ-6 Pyraclostrobin Use in combination Antibacterial activity Plant growth traits Field control effects
下载PDF
Axonal remodeling in the corticospinal tract after stroke: how does rehabilitative training modulate it? 被引量:9
7
作者 Naohiko Okabe Kazuhiko Narita Osamu Miyamoto 《Neural Regeneration Research》 SCIE CAS CSCD 2017年第2期185-192,共8页
Stroke causes long-term disability, and rehabilitative training is commonly used to improve the consecutive functional recovery. Following brain damage, surviving neurons undergo morphological alterations to reconstru... Stroke causes long-term disability, and rehabilitative training is commonly used to improve the consecutive functional recovery. Following brain damage, surviving neurons undergo morphological alterations to reconstruct the remaining neural network. In the motor system, such neural network remodeling is observed as a motor map reorganization. Because of its significant correlation with functional recovery, motor map reorganization has been regarded as a key phenomenon for functional recovery after stroke. Although the mechanism underlying motor map reorganization remains unclear, increasing evidence has shown a critical role for axonal remodeling in the corticospinal tract. In this study, we review previous studies investigating axonal remodeling in the corticospinal tract after stroke and discuss which mechanisms may underlie the stimulatory effect of rehabilitative training. Axonal remodeling in the corticospinal tract can be classified into three types based on the location and the original targets of corticospinal neurons, and it seems that all the surviving corticospinal neurons in both ipsilesional and contralesional hemisphere can participate in axonal remodeling and motor map reorganization. Through axonal remodeling, corticospinal neurons alter their output selectivity from a single to multiple areas to compensate for the lost function. The remodeling of the corticospinal axon is influenced by the extent of tissue destruction and promoted by various therapeutic interventions, including rehabilitative training. Although the precise molecular mechanism underlying rehabilitation-promoted axonal remodeling remains elusive, previous data suggest that rehabilitative training promotes axonal remodeling by upregulating growth-promoting and downregulating growth-inhibiting signals. 展开更多
关键词 stroke rehabilitative training axonal remodeling corticospinal tract motor map reorganization motor system neurotrophic factor functional compensation neural activity growth promoting signal growth inhibitory signal task-specific training
下载PDF
EFFECTS OF TGF-β_1 ON THE EXPRESSION OF PLASMINOGEN ACTIVATOR INHIBITOR TYPE 1 IN CULTURED HUMAN RENAL INTERSTITIAL FIBROBLASTS
8
作者 王伟铭 姚建 +3 位作者 石蓉 周同 陈楠 董德长 《Medical Bulletin of Shanghai Jiaotong University》 CAS 2000年第2期77-79,共3页
Objective To investigate the effects of transforming growth factor-β1 (TGF-β1 ) on the expression of plasminogen activator inhibitor type 1 (PAI-1 ) mRNA in renal interstitial fibrosis in vitro. Methods Human renal ... Objective To investigate the effects of transforming growth factor-β1 (TGF-β1 ) on the expression of plasminogen activator inhibitor type 1 (PAI-1 ) mRNA in renal interstitial fibrosis in vitro. Methods Human renal interstitial fibroblasts were isolated and cultured in vitro. The cells wers stimulated by TGF-β1 with different concentration (0 to 10ng/ml ) at different time (0 to 48h). The expression of PAI-1 mRNA was assayed by RT-PCR. Results TGF-β1, had dose-dependent and time-dependent effects on the expression of PAI-1 mRNA in renal interstitial fibroblasts. Conclusion TGF-β1 may partic- ipate in renal fibrosis with inducing the expression of PAI-1 mRNA in renal fibroblasts and affecting the synthesis and degradation of extracellular matrix (ECM). 展开更多
关键词 transforming growth factor-β1 renal interstitial fibroblasts plasminogen activator inhibitor type 1
下载PDF
Synthesis of novel 1,3-oxazole derivatives with insect growth-inhibiting activities 被引量:3
9
作者 Peng Guo Jun-Hai Huang +1 位作者 Qing-Chun Huang Xu-Hong Qian 《Chinese Chemical Letters》 SCIE CAS CSCD 2013年第11期957-961,共5页
Straightforward and direct synthesis of 2-substituted-5-oxazolecarbaldehydes was achieved by treating propargylamides with mercury(II)perchlorate as catalyst and ammonium cerium(IV)nitrate as oxidant agent through... Straightforward and direct synthesis of 2-substituted-5-oxazolecarbaldehydes was achieved by treating propargylamides with mercury(II)perchlorate as catalyst and ammonium cerium(IV)nitrate as oxidant agent through intramolecular cyclization.These structurally interesting outcomes beneft to synthesize2,5-disubstituted-1,3-oxazoles with armyworm growth regulating activities. 展开更多
关键词 Oxazole Mercury Catalyst growth inhibiting activity
原文传递
Turning weak into strong: on the CTAB-induced active surface growth 被引量:1
10
作者 Yonglong Zheng Jianpeng Zong +5 位作者 Ting Xiang Quan Ren Dongmeng Su Yuhua Feng Yawen Wang Hongyu Chen 《Science China Chemistry》 SCIE EI CSCD 2022年第7期1299-1305,共7页
Discovering new methods and principles in the inequivalent growth of equivalent facets is of great significance for going beyond symmetrical nanocrystals and for out-of-box exploration. In this work, we demonstrate th... Discovering new methods and principles in the inequivalent growth of equivalent facets is of great significance for going beyond symmetrical nanocrystals and for out-of-box exploration. In this work, we demonstrate that a middle ground exists between the traditional weak ligands and the strong ligands with unusual growth modes. By modifying the seed concentration during the growth of pentagonal Au nanorods, the typical weak ligand cetyltrimethylammonium bromide(CTAB) is made strong, leading to notches of restricted growth and even the active surface growth mode. In-depth investigation in the link between growth kinetics and ligand packing reveals the principle of their interplay —— that the on-off dynamics of the ligands only allows for a certain limit of materials deposition rate. Beyond this limit, the growth materials build up and are then diverted elsewhere, leading to inequivalent growth. The fact that a freshly grown surface has few ligands promotes the active surface growth, focusing the growth materials onto a few sites. We believe that the knowhow of interfering ligand packing via growth kinetics would offer a powerful tool of synthetic control, where the facet-and curvature-dependent ligand packing is expected to be useful synthetic handles. 展开更多
关键词 facet control ligand packing active surface growth Au deposition ligand dissociation
原文传递
Realizing Sustainable Economic Growth Through Activation of the Microeconomy
11
《World Economy & China》 SCIE 2000年第6期3-6,共4页
关键词 Realizing Sustainable Economic growth Through Activation of the Microeconomy
原文传递
Textile Industry to See Slow Growth Analysis of industrial production activities in the first four months
12
作者 Guo Yun 《纺织服装周刊》 2009年第23期7-7,共1页
Textile industry, a major driver of the Chinese economy, has fallen victim to the global credit crisis and weaker demand. In the first two months, the output, sale, investment and export of textile industry grew at a ... Textile industry, a major driver of the Chinese economy, has fallen victim to the global credit crisis and weaker demand. In the first two months, the output, sale, investment and export of textile industry grew at a slower pace than last year. But things began to pick up after that as the economy slowly begins to recover since March. Signif icant gains at that time will be hard to come by, and won’t be nearly enough to prevent other sizeable slippage in overall textile and apparel activity. 展开更多
关键词 In than Textile Industry to See Slow growth Analysis of industrial production activities in the first four months Graph
原文传递
Textile industry to see slow growth Analysis of industrial production activities in the first eight months
13
作者 Gracie Guo 《纺织服装周刊》 2008年第40期7-7,共1页
The textile sector,a major driver of the Chinese economy,has fallen victim to the global credit crisis and weaker demand.In the first eight months
关键词 Textile industry to see slow growth Analysis of industrial production activities in the first eight months
原文传递
Effects of tantalum on austenitic transformation kinetics of RAFM steel 被引量:2
14
作者 Jian-guo Chen Yong-chang Liu +2 位作者 Chen-xi Liu Bi-yu Yan Hui-jun Li 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2017年第7期705-710,共6页
The RAFM(reduced activation ferritic/martensitic)steels containing different tantalum contents(0wt.%,0.027wt.%,0.073wt.%)were designed and cast.Differential scanning calorimetry and optical microscopy were employe... The RAFM(reduced activation ferritic/martensitic)steels containing different tantalum contents(0wt.%,0.027wt.%,0.073wt.%)were designed and cast.Differential scanning calorimetry and optical microscopy were employed to explore the influence of tantalum content on the austenitic transformation of RAFM steels.The austenitic transformation kinetics was described by aphase-transformation model.The model,involving site saturation nucleation,diffusion-controlled growth and impingement correction,was established based on the classical Johnson-Mehl-Avrami-Kolmogorov model.The phase-transformation kinetics parameters,including D_0(pre-exponential factor for diffusion)and Q_d(activation energy for diffusion),were calculated by fitting the experimental data and the kinetic model.The results indicated that the average grain size is decreased with the increase of tantalum.The values of A_(c1) and A_(c3) (onset and finish temperature of austenitic transformation,respectively)are increased by increasing the tantalum content.The increase of tantalum caused the decrease of D_0.However,Q_d is increased with the increase of tantalum.In addition,as a carbides forming element,tantalum would reduce the carbon diffusion coefficient and slow down the austenitic transformation rate. 展开更多
关键词 RAFM steel Tantalum content Grain growth Austenitic transformation kinetics Activation energy
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部