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技术创新扩散模型的探析 被引量:5
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作者 谈骏渝 《重庆大学学报(自然科学版)》 EI CAS CSCD 北大核心 2006年第1期146-149,共4页
技术创新的扩散或转移是技术进步的重要阶段或标志.对Raz,刘文阁和朱稼兴分别提出或者修正的技术转移的受方状态的模型进行了分析和实证研究,指出S形模型仍是描述创新扩散的一种简单、实用、拟合程度较高的一种模型.进而对朱稼兴所修正... 技术创新的扩散或转移是技术进步的重要阶段或标志.对Raz,刘文阁和朱稼兴分别提出或者修正的技术转移的受方状态的模型进行了分析和实证研究,指出S形模型仍是描述创新扩散的一种简单、实用、拟合程度较高的一种模型.进而对朱稼兴所修正的模型进行了改进,得到了技术扩散中学习方技术发展状态的一个长期模型. 展开更多
关键词 技术创新 S形模型 扩散/转移 扩散源与学习方/供方与受方
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Effect of ultrasonic on structure and electrochemical performance of α-Ni(OH)_2 electrodes 被引量:2
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作者 张仲举 朱燕娟 +3 位作者 包杰 周卓均 叶贤聪 许庆盛 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第12期2654-2659,共6页
Al/Co co-doped α-Ni(OH)2 samples were prepared by either ultrasonic co-precipitation method (Sample B) or co-precipitation method (Sample A). The crystal structure and particle size distribution of the prepared... Al/Co co-doped α-Ni(OH)2 samples were prepared by either ultrasonic co-precipitation method (Sample B) or co-precipitation method (Sample A). The crystal structure and particle size distribution of the prepared samples were examined by X-ray diffraction (XRD) and laser particle size analyzer, respectively. The results show that Sample B has more crystalline defects and smaller average diameter than Sample A. The cyclic voltammetry and electrochemical impedance spectroscopy measurements indicate that Sample B has better electrochemical performance than Sample A, such as better reaction reversibility, lower charge-transfer resistance and better cyclic stability. Proton diffusion coefficient of Sample B is 1.96×10-10cm2/s, which is two times as large as that (9.78×10-11cm2/s) of Sample A. The charge-discharge tests show that the discharge capacity (308 mA·h/g) of Sample B is 25 mA·h/g higher than that of Sample A (283 mA·h/g). 展开更多
关键词 Al/Co co-doped α-Ni(OH)2 ultrasonic co-precipitation method proton diffusion coefficient charge-transfer resistance electrochemical performance
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The altered DNA methylation pattern and its implications in liver cancer 被引量:17
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作者 JingDeZHU 《Cell Research》 SCIE CAS CSCD 2005年第4期272-280,共9页
DNA methylation is the most intensively studied epigenetic phenomenon, disturbances of which result in changes ingene transcription, thus exerting drastic imparts onto biological behaviors of cancer. Both the global d... DNA methylation is the most intensively studied epigenetic phenomenon, disturbances of which result in changes ingene transcription, thus exerting drastic imparts onto biological behaviors of cancer. Both the global demethylation andthe local hypermethylation have been widely reported in all types of tumors, providing both challenges and opportunitiesfor a better understanding and eventually controlling of the malignance. However, we are still in the very early stage ofinformation accumulation concerning the tumor associated changes in DNA methylation pattern. A number of excellentrecent reviews have covered this issue in depth. Therefore, this review will summarize our recent data on DNA methy-lation profiling in cancers. Perspectives for the future direction in this dynamic and exciting field will also be given. 展开更多
关键词 DNA methylation EPIGENETICS liver cancer tumor staging and classification.
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PRELIMINARY APPLICATION OF WHOLE BODY DIFFUSION WEIGHTED IMAGING IN SCREENING METASTASIS 被引量:12
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作者 Yong-jing Guan Hua-wei Ling Ke-min Chen 《Chinese Medical Sciences Journal》 CAS CSCD 2008年第3期178-182,共5页
Objective To investigate the feasibility of whole body diffusion weighted imaging (WB-DWI) in screening metastasis. Methods WB-DWI was performed in 24 patients diagnosed with various types of primary tumors. The three... Objective To investigate the feasibility of whole body diffusion weighted imaging (WB-DWI) in screening metastasis. Methods WB-DWI was performed in 24 patients diagnosed with various types of primary tumors. The three-dimensional maximum intensity projection reconstruction and black-and-white flip technique were used to observe metastatic lesions, and the results were compared with those of bone scintigraphy. Results By WB-DWI scanning sequence at b = 800 s/mm2, all the bone lesions found by bone scintigraphy in the cohort were well identified, and other lesions of soft tissue and organs were also well demonstrated. Its screening capability was equivalent with bone scintigraphy in screening metastases in bones (P = 0.062). Conclusion WB-DWI was practicable with the parameter settings attempted in metastases screening. 展开更多
关键词 magnetic resonance imaging whole body diffusion weighted imaging apparent diffusion coefficient METASTASIS
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FEASIBILITY OF WHOLE BODY DIFFUSION WEIGHTED IMAGING IN DETECTING BONE METASTASIS ON 3.0T MR SCANNER 被引量:12
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作者 Xian Xu Lin Ma +5 位作者 Jin-shan Zhang You-quan Cai Bai-xuan Xu Liu-quan Chen Fei Sun Xing-gao Guo 《Chinese Medical Sciences Journal》 CAS CSCD 2008年第3期151-157,共7页
Objective To evaluate the feasibility of whole body diffusion weighted imaging (DWI) in bone metastasis detection using bone scintigraphy as comparison. Methods Forty-five patients with malignancy history were enrolle... Objective To evaluate the feasibility of whole body diffusion weighted imaging (DWI) in bone metastasis detection using bone scintigraphy as comparison. Methods Forty-five patients with malignancy history were enrolled in our study. All the patients received the whole body DWI and bone scintigraphy scan within 1 week. The magnetic resonance (MR) examination was performed on 3.0T MR scanner using embedded body coil. The images were reviewed separately by two radiologists and two nuclear medicine physicians, who were blinded to the results of the other imaging modality. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the two techniques for detecting bone metastasis were analyzed. Results A total of 181 metastatic lesions in 77 regions of 34 patients were detected by whole body DWI, and 167 metastatic lesions in 76 regions of 31 patients were identified by bone scintigraphy. The patient-based sensitivity and PPV of whole body DWI and bone scintigraphy were similar (89.5% vs. 81.6%, 97.1% vs. 91.2%), whereas, the patient-based specificity and NPV of whole body DWI were obviously higher than those of bone scintigraphy (85.7% vs. 57.1%, 60.0% vs. 36.4%). Ten regions negative in scintigraphy but positive in whole body DWI, mainly located in spine, pelvis, and femur; nine regions only detected by scintigraphy, mainly located in skull, sternum, clavicle, and scapula. The region-based sensitivity and specificity of whole body DWI were slightly higher than those of bone scintigraphy (89.5% vs. 88.4%, 95.6% vs. 87.6%). Conclusion Whole body DWI reveals excellent concordance with bone scintigraphy regarding detection of bone metastasis, and the two techniques are complementary for each other. 展开更多
关键词 neoplasm metastasis diffusion weighted imaging bone tissue SCINTIGRAPHY
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Infrared thin layer drying of saffron(Crocus sativus L.) stigmas:Mass transfer parameters and quality assessment 被引量:2
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作者 Mehdi Torki-Harchegani Davoud Ghanbarian +1 位作者 Vida Maghsoodi Ahmad Moheb 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第4期426-432,共7页
Saffron is the most precious and expensive agricultural product. A dehydration treatment is necessary to convert Crocus sativus L. stigmas into saffron spice. To the best of our knowledge, no information on mass trans... Saffron is the most precious and expensive agricultural product. A dehydration treatment is necessary to convert Crocus sativus L. stigmas into saffron spice. To the best of our knowledge, no information on mass transfer parameters of saffron stigmas is available in the literature. This study aimed at investigating the moisture transfer parameters and quality attributes of saffron stigmas under infrared treatment at different temperatures(60,70, …, 110 ℃). It was observed that the dehydration process of the samples occurred in a short accelerating rate period at the start followed by a falling rate period. The effective moisture diffusivity and convective mass transfer coefficient were determined by using the Dincer and Dost model. The diffusivity values varied from1.1103 × 10^-10m^2·s^-1to 4.1397 × 10^-10m^2·s^-1 and mass transfer coefficient varied in the range of 2.6433 × 10^-7–8.7203 × 10^-7m·s^-1. The activation energy was obtained to be 27.86 kJ·mol^-1. The quality assessment results showed that the total crocin content increased, when the temperature increased up to90 ℃ but, in higher temperatures, the amount of crocin decreased slightly. The total safranal content of the samples decreased slightly when drying temperature increased from 60 ℃ to 70 ℃ and then continuously increased up to 110 ℃. Also, the amount of picrocrocin increased from 83.1 to 93.3 as the drying temperature increased from 60 ℃ to 100 ℃. 展开更多
关键词 drying moisture Infrared expensive slightly convective varied dehydration spice convert
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FDI's Spillover Effects on China's Growth Quality
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作者 沈坤荣 傅元海 《China Economist》 2011年第1期12-20,共9页
Using panel data of 29 regions in China from 1999 to 2007, this paper presents a systematic evaluation of how FDI's spillover effects impact the quality of China's indigenous econotnic growth, Research outcomes sugg... Using panel data of 29 regions in China from 1999 to 2007, this paper presents a systematic evaluation of how FDI's spillover effects impact the quality of China's indigenous econotnic growth, Research outcomes suggest that technology transfers and diffusion have a positive effect on indigenous growth quality. Spitlover effects (mainly competition effect) have primarily negatively affected indigenous growth quality. The effect on indigenous growth quality is positive only in sub-samples with high foreign capital concentration and ,,hen the spillover effect is similar to the technology transfer and diffusion effect brought about by localization. It is also found that technology gaps, foreign capital concentration and value added ratio gaps are important factors affecting the impact of technology transfer and diffusion on indigenous economic growth. 展开更多
关键词 technology transfer and diffusion spillover effect economic growth quality
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Pentacene-based nanorods on Au(111) single crystals: Charge transfer, diffusion, and step-edge barriers
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作者 Sabine-Antonia Savu Sabine Abb +7 位作者 Simon Schundelmeier Jonathan D. Saathoff James M. Stevenson Christina Tonshoff Holger F. Bettinger Paulette Clancy M. Benedetta Casu Thomas Chasse 《Nano Research》 SCIE EI CAS CSCD 2013年第6期449-459,共11页
We investigate nanorod assemblies of two 64-substituted pentacenes, namely (2,3-X2-9,10-Y2)-substituted pentacenes with X -- Y = OCH3 (MOP) and with X = F, Y-- OCH3 (MOPF), grown on Au(111) single crystals. By... We investigate nanorod assemblies of two 64-substituted pentacenes, namely (2,3-X2-9,10-Y2)-substituted pentacenes with X -- Y = OCH3 (MOP) and with X = F, Y-- OCH3 (MOPF), grown on Au(111) single crystals. By using a multi-technique approach based on ultraviolet photoelectron spectroscopy X-ray photoelectron spectroscopy; and X-ray absorption, we find evidence for charge transfer screening at the interface with gold. Furthermore, the MOP and MOPF nanorods show a rough surface morphology, which was investigated with atomic force microscopy. We use molecular simulation techniques to investigate the energetic barriers to diffusion and to traverse step-edges to estimate their influence on the nanorod roughness. We find that barriers to surface diffusion on a terrace are anisotropic and that their direction favors the formation of nanorods in these materials. 展开更多
关键词 nanorod assembly substituted pentacene electronic structures/ processes/mechanisms organic electronics charge transfer diffusion and step-edge barrier
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