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41.
目的:分析乳头状肾细胞癌的cT影像,探讨其相对特异的CT表现。方法:回顾性分析10例经病理证实的乳头状肾细胞癌的临床、手术及CT资料。结果:全部病例均为单发肿块,位于右。肾7例,位于左肾3例,CT平扫肿瘤呈圆形或椭圆形,边缘清楚或欠清楚。病变长径1.0~4.5cm,平均2.5cm。瘤体小时(冬3cm)密度较均匀,无囊变和坏死:瘤体较大时(≥3cm)常出现坏死、囊变。肿瘤强化程度较低,三期呈渐进性轻度增强,特别是排泄期密度略降低。结论:与其他亚型。肾癌相比,乳头状肾细胞癌的cT表现有一定特征,多呈渐进性轻度强化,其确诊可为手术方式的选择提供依据。 相似文献
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当然随着社会生活的节奏继续加快,需求的多样性,市场竞争的加剧,国际合作的紧迫性,网络3G技术的普及,以及传统期刊管理的意识理念的不足,这些都给我国期刊事业的发展带来了新的挑战。测绘类的期刊也同样面临以上来自市场、技术、理念层面的诸多挑战。期刊永远是时代的记录者和践行者,改革已经毫无争议地成为期刊业高速发展的根本动力。测绘期刊业市场还有很多尚未开拓的领域,亟待去识别、去利用,调整策略,实现测绘期刊品牌化,国际化,服务个性化,盈利多样化,制度透明化,这些都是当前测绘期刊发展的机会。 相似文献
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There are two basic requirements for heavy-oil recovery processes: first, mobilize the bitumen, and second, have a drive mechanism
deliver the mobilized bitumen to a production wellbore. In situ combustion has the potential to be an important heavy-oil
recovery method. Before design of in situ combustion recovery processes can start, it is necessary as a first step to understand
the kinetics of various complex chemical reactions and determine kinetic constants associated with the reactions. Even with
modern reservoir simulation capabilities, this is a significant challenge. In this research, an Athabasca bitumen combustion
tube experiment, conducted by the ISC Research Group at the University of Calgary, was history matched by using a reservoir
thermal simulator to determine a set of kinetic parameters as well as the transport parameters for the system. The main results
of the history match was a match of air injection rate, bitumen and gas production volumes, average product gas compositions,
temperature profiles along the tube through time, and pressure. Gridding sensitivities were examined to determine if the derived
kinetic and transport parameters were dependent on gridblock size. The results revealed that the grid was refined enough to
sufficiently capture thermal, mass transfer, and reaction length scales. After this single match was achieved, the same constants
were used to successfully predict several other combustion tube experiments. The results suggest that the fuel (coke) for
high-temperature oxidation (HTO) originates mainly from low-temperature oxidation (LTO) and not from thermal cracking. This
implies that the major control on HTO is upstream oxygen transfer into the LTO region. If LTO does not occur, then a relatively
small amount of coke is deposited in the matrix due to thermal cracking and this may be insufficient to start or sustain HTO. 相似文献
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二氧化碳注入煤层多用途研究 总被引:1,自引:0,他引:1
为了减轻环境污染,提高煤层气产率,增加能源储备,根据煤层气地质学和生物气的基本理论,提出二氧化碳(CO2)注入煤层多种用途这一新观点。研究结果显示:煤对CO2具有很强的吸附能力,可将煤层作为CO2的储集层;煤具有优先吸附CO2而滞后吸附甲烷(CH4)的特性,向煤层注入CO2可大大提高煤层气的采收率;产甲烷菌具有利用CO2生成CH4的能力,新生成的CH4成为能源储备的有益补充。可见,CO2注入煤层不仅可有效减少温室气体的排放,强化煤层甲烷产出,而且为新能源生物CH4的生成提供了基质。 相似文献
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Stanley D. Brunn 《The Professional geographer》1997,49(3):364-371
A survey of 176 authors who published in the Annals between 1988 and 1993 provides insights into why authors submitted their research to the journal, what support they received, and the impacts of the publication on their careers. Most decided themselves to submit their work, and one-third received support from research grants; cartographic assistance and graduate assistants were less important. The major benefits of publishing in the Annals were visibility in one's department, contact with other geographers, and requests for reprints. Most authors presented their ideas at professional meetings prior to submission. Promotion and salary Inc.reases were benefits for women, assistant professors, associate professors, and physical geographers. Authors considered their articles as original examinations that yielded new results, contributed to theory, stimulated debate, and helped bridge gaps inside and outside of geography. These results are useful in helping individual authors and for administrators in identifying the kinds of research support needed by authors publishing in the Annals. 相似文献