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平面应力问题的结构拓扑优化 被引量:14
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作者 李芳 凌道盛 《浙江工业大学学报》 CAS 2000年第3期220-223,共4页
研究了结构拓扑优化设计问题 ,研究对象是二维平面结构。利用线弹性问题的进化方法 (ESO) ,针对结构拓扑优化设计所需单元网格密度较大 ,且优化过程需反复组建刚度矩阵的特点 ,提出了利用虚拟层合单元进行拓扑优化的方法。数值算例表明 ... 研究了结构拓扑优化设计问题 ,研究对象是二维平面结构。利用线弹性问题的进化方法 (ESO) ,针对结构拓扑优化设计所需单元网格密度较大 ,且优化过程需反复组建刚度矩阵的特点 ,提出了利用虚拟层合单元进行拓扑优化的方法。数值算例表明 ,此法简单有效 ,能够用于结构拓扑优化设计。 展开更多
关键词 虚拟层合单元 结构 平面应力问题 拓扑优化设计
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肺部周围型肿块CT引导下经皮穿刺活检病理对照研究 被引量:19
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作者 董其龙 李达志 +2 位作者 李天然 赖国祥 宋均娜 《介入放射学杂志》 CSCD 2004年第6期544-545,共2页
目的 了解CT引导下经皮穿刺活检对肺部周围型肿块的诊断价值。方法 对 5 5例肺部肿块行CT导向下经皮穿刺活检并与手术病理结果对比。结果  5 5例中 4 4例手术证实为肺癌 ,CT诊断与病理一致 4 0例 ,准确率为 90 .9% (4 0 4 4 ) ;5例... 目的 了解CT引导下经皮穿刺活检对肺部周围型肿块的诊断价值。方法 对 5 5例肺部肿块行CT导向下经皮穿刺活检并与手术病理结果对比。结果  5 5例中 4 4例手术证实为肺癌 ,CT诊断与病理一致 4 0例 ,准确率为 90 .9% (4 0 4 4 ) ;5例结核肉芽肿 ,准确率为 4 5 ;6例炎性假瘤 (包括 2例隐球菌性肉芽肿 ) ,准确率为 2 6 ;5 5例肺周围型肿块CT总正确诊断率为 83.6 % (4 6 5 5 )。结论 根据影像特征表现CT对肺癌的正确诊断较高 ,但对非肿瘤性肿块正确诊断率较低。CT导向经皮肺穿对肺部肿块诊断是十分有价值的方法 ,且安全可靠 ,对正确制定治病方案具有重要的指导作用。 展开更多
关键词 肺部肿块 经皮穿刺活检 周围型 肺部 CT引导 病理对照研究 CT导向 肉芽肿 肺癌 诊断
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加氢渣油催化裂化14集总动力学模型的建立 被引量:17
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作者 王建平 许先焜 +3 位作者 翁惠新 方向晨 胡长禄 韩照明 《化工学报》 EI CAS CSCD 北大核心 2007年第1期86-94,共9页
以加工加氢渣油的茂名石化3#重油催化裂化装置(RFCC)的工业数据为基础,针对加氢渣油的特点,提出了以渣油4组分作为划分原料集总的催化裂化14集总动力学模型,通过分步求解法求取动力学参数,并应用工业实测数据进行验证,验证结果表明该模... 以加工加氢渣油的茂名石化3#重油催化裂化装置(RFCC)的工业数据为基础,针对加氢渣油的特点,提出了以渣油4组分作为划分原料集总的催化裂化14集总动力学模型,通过分步求解法求取动力学参数,并应用工业实测数据进行验证,验证结果表明该模型不仅能较好地预测催化裂化产品分布,而且还能较准确预测主要产品性质,较好地反映了加氢渣油催化裂化反应规律,可为工业装置操作的优化提供指导。 展开更多
关键词 加氢渣油 催化裂化 动力学模型 集总
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大庆常压渣油催化裂解反应动力学模型研究 被引量:12
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作者 孟祥海 高金森 +1 位作者 徐春明 李丽 《化学反应工程与工艺》 CAS CSCD 北大核心 2003年第4期365-371,共7页
 针对大庆常压渣油催化裂解反应体系,建立了大庆常压渣油催化裂解五集总动力学模型,推导出了各集总组分在反应器出口处的浓度表达式,给出了一种用于求取集总模型参数的简单方法。结合实验数据,编程计算求取了该五集总反应网络的速率常...  针对大庆常压渣油催化裂解反应体系,建立了大庆常压渣油催化裂解五集总动力学模型,推导出了各集总组分在反应器出口处的浓度表达式,给出了一种用于求取集总模型参数的简单方法。结合实验数据,编程计算求取了该五集总反应网络的速率常数、指前因子和活化能,并对所建集总模型的预测效果进行了初步检验,结果表明该模型对催化裂解汽柴油、气体烷烃和气体烯烃具有较好的预测能力,短停留时间有利于多产低碳烯烃。 展开更多
关键词 常压渣油 催化裂解 反应动力学 物理模型 数学模型
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Low Temperature Reduction Degradation Characteristics of Sinter,Pellet and Lump Ore 被引量:14
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作者 WU Sheng-li LIU Xiao-qin ZHOU Qi XU Jian LIU Cheng-song 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2011年第8期20-24,共5页
The reduction degradation characteristics of typical sinter, pellet and lump ore were tested with the reducing gas conditions simulating two kinds of irowmaking processes. The results show that, in the same condition ... The reduction degradation characteristics of typical sinter, pellet and lump ore were tested with the reducing gas conditions simulating two kinds of irowmaking processes. The results show that, in the same condition of gas composition and temperature, the reduction degradation degree (RDI〈3.15mm) of sinter is high, RDI〈3.15mm of lump ore is low and RDI〈3.15 mm of pellet is in the middle level. With two kinds of gas composition simulating different iron-making processes, the reduction degradation indices (RDI) of three kinds of iron ores all present the tenden- cy of "inverted V-shape" in the temperature range from 450 to 650℃, and the RDI reach the maximum value at 550℃. The reduction degradation degrees of iron ores are extended when mixing the gas with hydrogen to increase the re duction potential, and the influence extent is discrepant for different iron ores. Colligating the increase amplitude of grains in small size fraction, the influence of reducing gas on lump ore is the greatest, the influence on sinter is the second, and the sensitivity of pellet on the reducing gas properties change is relatively small. As for the degradation form, lump ore and sinter both present the degradation ,of cracking, and the distribution of small grains generated from the cracking is in the range from 03 5 to 6. 3 mm uniformly. The lump ore presents surface cracking, while sin- ter presents integral cracking. The pellet presents the degradation of surface stripping, and the proportion of grains smaller than 0.5 mm is the highest, which is up to 90% in the grains smaller than 3.15 mm. 展开更多
关键词 SINTER PELLET lump ore low temperature reduction degradation characteristic gas property
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睾丸副睾肿块的CT和MRI表现 被引量:13
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作者 刘强 王良 +1 位作者 李亮 蔡杰 《医学影像学杂志》 2015年第11期1995-1998,2007,共5页
目的探讨睾丸副睾肿块的CT和MRI影像学表现。方法回顾性分析20例经手术病理证实的睾丸副睾肿块,其中3例行CT平扫及增强扫描,3例行CT直接增强,8例行MRI平扫及PWI动态增强,6例行MRI平扫,然后观察肿块的分布、形态大小、境界、内部结构、... 目的探讨睾丸副睾肿块的CT和MRI影像学表现。方法回顾性分析20例经手术病理证实的睾丸副睾肿块,其中3例行CT平扫及增强扫描,3例行CT直接增强,8例行MRI平扫及PWI动态增强,6例行MRI平扫,然后观察肿块的分布、形态大小、境界、内部结构、强化特点及周围侵犯转移情况及影像学显示方法,并与病理结果对比。结果病理结果示21个睾丸副睾肿块,睾丸肿块18例,副睾肿块2例,恶性肿块12例(精原细胞瘤5例,胚胎性癌3例,畸胎瘤1例,淋巴瘤1例,附睾横纹肌肉瘤1例,阴茎根部原始神经胚叶肿瘤1例),良性肿块8例(畸胎瘤1例,睾丸间质细胞瘤2例,非异性炎性肿块1例,结核1例,表皮样囊肿2例,单纯囊肿1例);恶性肿块4个局限睾丸,8个累及被膜及附睾,良性肿块1例累及附睾。影像学结果示恶性肿块直径平均大于50mm,肿块大多实性结节状,结节间纤维分隔,肿块强化不均匀,其中3例向周围侵犯及伴淋巴结转移;良性肿块直径平均小于20mm,肿块部分强化不均匀,较少伴淋巴结转移。MRI多序列及灌注检查,分辨肿块内、外组织成分,周围组织累及情况,鉴别肿块良、恶性方面优于CT检查。结论睾丸副睾肿块CT、MRI表现有一定特征,CT、MRI检查有助于诊断及鉴别诊断,对提示其良、恶性有意义。 展开更多
关键词 睾丸 副睾 肿块 磁共振成像 体层摄影术 X线计算机 诊断 良恶性
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体液回流针法配合耳尖放血治疗早期麦粒肿疗效及对疼痛程度和肿块大小的影响 被引量:13
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作者 刘路遥 罗十之 武玉言 《针灸临床杂志》 2018年第11期23-26,共4页
目的:分析体液回流针法配合耳尖放血治疗早期麦粒肿疗效及对其疼痛程度和肿块大小的影响。方法:选取于本院确诊治疗的早期麦粒肿患者64例,依照随机数字表法分为两组,各32例。对照组给予耳尖放血治疗,观察组在对照组基础上配合体液回流... 目的:分析体液回流针法配合耳尖放血治疗早期麦粒肿疗效及对其疼痛程度和肿块大小的影响。方法:选取于本院确诊治疗的早期麦粒肿患者64例,依照随机数字表法分为两组,各32例。对照组给予耳尖放血治疗,观察组在对照组基础上配合体液回流针法治疗。观察两组自觉症状改善程度、疼痛程度、肿块大小以及临床疗效,并统计不良反应发生率情况。结果:治疗后两组眼睑红肿、眼痒、结膜充血评分相对治疗前呈降低趋势,两组比较有统计学差异(P <0. 05);治疗后组间VAS评分、肿块相比,数据均低于治疗前,有统计学差异(P <0. 05),且治疗后观察组VAS评分及肿块指标数值均低于对照组,存在统计学差异(P <0. 05);观察组治疗总有效率明显高于对照组,差异具有统计学意义(P <0. 05);观察组不良反应发生率3. 13%,稍低于对照组6. 25%,两组比较P> 0. 05。结论:体液回流针法配合耳尖放血能够改善早期麦粒肿患者临床症状,减轻疼痛,缩小肿块,提高临床疗效。 展开更多
关键词 体液回流针法 耳尖放血 麦粒肿 疼痛 肿块
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Model test of the cutting properties of a shearer drum 被引量:12
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作者 LIU Song-yong DU Chang-long CUI Xin-xia CHENG Xue 《Mining Science and Technology》 EI CAS 2009年第1期74-78,共5页
According to similarity theory, we carried out a dimensional analysis of the shearer drum correlation parameters and built similarity criteria. Based on these, similarity models of shearer drums were developed. Simult... According to similarity theory, we carried out a dimensional analysis of the shearer drum correlation parameters and built similarity criteria. Based on these, similarity models of shearer drums were developed. Simultaneously, based on an estab- lished cutting testbed of the coal and rock, cutting tests of different pick arrangements of the drum models were carried out, where the compressive strength of the analogous cutting material was 2.48 MPa and the drum rotary speed 67.5 r/min. The variance, the mean values, maxima and mean maxima of the torque load were analyzed for different type drum models. Moreover, the relation-ships between the type of pick arrangements and the cutting lump coal percentage were studied. The results indicate that the load fluctuation of the sequence drum is larger than that of the punnett square drum in the cutting process and the lump coal percentage and economic benefits of the sequence drum are inferior to the punnett square drum. We conclude that the punnett square drum is superior to the sequence drum. 展开更多
关键词 similarity theory dimensional analysis similarity criteria cutting test lump coal percentage
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渣油催化裂化集总动力学模型的建立 被引量:9
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作者 李光明 翁惠新 《同济大学学报(自然科学版)》 EI CAS CSCD 1996年第2期198-202,共5页
根据集总指导原则,从渣油催化裂化的反应机理出发,建立了11集总渣油催化裂化的反应网络及相应的动力学模型.该模型简单可行,具有对不同原料的适用性和良好的拟合性,能适应对工业渣油催化裂化装置反应结果的预测,以实现工业过程... 根据集总指导原则,从渣油催化裂化的反应机理出发,建立了11集总渣油催化裂化的反应网络及相应的动力学模型.该模型简单可行,具有对不同原料的适用性和良好的拟合性,能适应对工业渣油催化裂化装置反应结果的预测,以实现工业过程的优化操作和设计. 展开更多
关键词 渣油 催化裂化 动力学模型 集总动力学 反应机理
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Lump Solutions and Interaction Phenomenon for (2+1)-Dimensional Sawada–Kotera Equation 被引量:9
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作者 黄丽丽 陈勇 《Communications in Theoretical Physics》 SCIE CAS CSCD 2017年第5期473-478,共6页
In this paper, a class of lump solutions to the (2+1)-dimensional Sawada–Kotera equation is studied by searching for positive quadratic function solutions to the associated bilinear equation. To guarantee rational lo... In this paper, a class of lump solutions to the (2+1)-dimensional Sawada–Kotera equation is studied by searching for positive quadratic function solutions to the associated bilinear equation. To guarantee rational localization and analyticity of the lumps, some sufficient and necessary conditions are presented on the parameters involved in the solutions. Then, a completely non-elastic interaction between a lump and a stripe of the(2+1)-dimensional Sawada–Kotera equation is obtained, which shows a lump solution is drowned or swallowed by a stripe soliton. Finally, 2-dimensional curves, 3-dimensional plots and density plots with particular choices of the involved parameters are presented to show the dynamic characteristics of the obtained lump and interaction solutions. 展开更多
关键词 lump solution interaction solution Hirota bilinear method (2+1)-dimensional Sawada–Kotera equation
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FDFCC工艺中重油提升管催化裂化反应动力学模型 被引量:9
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作者 吴飞跃 翁惠新 罗世贤 《石油学报(石油加工)》 EI CAS CSCD 北大核心 2008年第5期540-547,共8页
以国内首套FDFCC(灵活多效催化裂化)工业化装置——中国石化长岭分公司1#重油提升管催化裂化装置的标定数据为基础,根据催化裂化反应机理,针对提升管内重油催化裂化特点及产品应用需要,采用集总理论,合理简化反应网络,建立了重油12集总... 以国内首套FDFCC(灵活多效催化裂化)工业化装置——中国石化长岭分公司1#重油提升管催化裂化装置的标定数据为基础,根据催化裂化反应机理,针对提升管内重油催化裂化特点及产品应用需要,采用集总理论,合理简化反应网络,建立了重油12集总催化裂化反应动力学模型。该12个集总为:原料饱和分[SS],芳香分[SA],胶质及沥青质[SR],柴油[DI],汽油中饱和烃[GS]、烯烃[GO]、芳烃[GA],液化气中烷烃[LP]、丙烯[LO3]、丁烯[LO4],干气[DR]和焦炭[CK]。求取了56组动力学参数,并对不同原料、不同工况下的2组工业数据进行了验证。结果表明,模型能够预测重油提升管出口主要产品分布及其性质,相对误差均小于5%。本研究结果对FDFCC工业装置重油催化裂化提升管操作具有指导意义。 展开更多
关键词 重油催化裂化 FDFCC 集总 反应机理 动力学模型
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中温煤焦油加氢裂化集总动力学研究 被引量:11
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作者 孙晋蒙 刘鑫 +4 位作者 李冬 崔楼伟 李学坤 孙智慧 李稳宏 《石油学报(石油加工)》 EI CAS CSCD 北大核心 2014年第2期291-297,共7页
以集总动力学为建模思想,将中温煤焦油裂化反应网络按原料油四组分和产品油馏分为划分标准,归并为6个虚拟集总组分,考察了氢分压、液体体积空速、床层温度对中温煤焦油加氢裂化结果的影响,建立了中温煤焦油6集总加氢裂化动力学模型。在V... 以集总动力学为建模思想,将中温煤焦油裂化反应网络按原料油四组分和产品油馏分为划分标准,归并为6个虚拟集总组分,考察了氢分压、液体体积空速、床层温度对中温煤焦油加氢裂化结果的影响,建立了中温煤焦油6集总加氢裂化动力学模型。在Visual C++平台上,采用四阶变步长的Runge-Kutta法求解微分方程,采用变尺度法(B-F-G-S)获得函数最优化求解,并进行模型验证。结果表明,该模型预测相对误差小于3%,对中温煤焦油加氢裂化的产品分布具有良好的预测性,为煤焦油加氢工艺的进一步优化提供了依据。 展开更多
关键词 煤焦油 加氢裂化 集总 动力学模型
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提高汽、柴油收率的两段提升管催化裂化动力学模型研究及应用 被引量:10
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作者 刘熠斌 杨朝合 +1 位作者 山红红 刘清华 《石油学报(石油加工)》 EI CAS CSCD 北大核心 2007年第5期7-14,共8页
建立了提高汽、柴油收率的两段提升管催化裂化六集总动力学模型,根据小型提升管催化裂化装置的实验数据求取了动力学参数,并用Runge-Kuta方法对模型求解。模型对两段提升管催化裂化技术进行计算的结果表明,一段的反应深度影响产品的产... 建立了提高汽、柴油收率的两段提升管催化裂化六集总动力学模型,根据小型提升管催化裂化装置的实验数据求取了动力学参数,并用Runge-Kuta方法对模型求解。模型对两段提升管催化裂化技术进行计算的结果表明,一段的反应深度影响产品的产率和选择性,两段技术可以提高汽、柴油的产率以及选择性和柴/汽比,降低干气和焦炭产率。与单段提升管催化裂化技术相比,当转化率为80%时,两段技术汽、柴油产率提高6.65%,选择性提高8.31%,柴/汽比由单段的0.71提高到1.07;当转化率为90%时,两段技术汽、柴油产率提高20.85%,选择性提高23.19%,柴/汽比提高到0.89。采用两段提升管技术,以汽、柴油作为目的产物时,汽、柴油的最大产率比单段提升管技术提高11.65%,选择性提高2.09%;以汽、柴油+液化气为目的产物时,汽、柴油+液化气的最大产率提高8.69%,汽、柴油的选择性提高16.87%,液化气的选择性则下降了13.62%。 展开更多
关键词 两段提升管 催化裂化 集总 模型 产率 选择性
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Antidiastole Value of Three-dimensional Ultrasonography and Power Doppler between Uterine Parenchyma Lumps and Endometrial Cancer:A Retrospective Study 被引量:11
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作者 Yan ZHANG Jing CHEN +1 位作者 Zeng ZHEN Xiao-yan XU 《Current Medical Science》 SCIE CAS 2019年第5期816-819,共4页
Sometimes endometrial polyps,submucosal myomas,and endometrial cancer show similar findings under ultrasonography.The aim of this study was to assess the antidiastole value of blood flow parameters using three-dimensi... Sometimes endometrial polyps,submucosal myomas,and endometrial cancer show similar findings under ultrasonography.The aim of this study was to assess the antidiastole value of blood flow parameters using three-dimensional(3D)power Doppler ultrasonography angiography(PDA)between endometrial cancer and uterine parenchyma lumps.The data of the blood flow indices in 3D-PDA including the vascularization index(VI),flow index(FI),and vascularization flow index(VFI)in 40 patients with endometrial cancer and 41 patients with uterine parenchyma lumps(endometrial polyps and submucosal myomas)were retrospectively analysed and compared utilizing Virtual Organ Computer-aided AnaLysis(VOCAL)software.The results showed that all the blood flow parameters(VI,FI,VFI)were significantly higher in women with endometrial cancer than in those with uterine parenchyma lumps(P<0.001).The area under the curve of ROC of VI,FI,and VFI was 0.98,0.84,and 0.97,respectively.Thus,the best predictor of endometrial carcinoma was VI with a sensitivity of 97.0% and a specificity of 91.0%.The optimal cutoff value of VI was 4.06%.Our data demonstrated that all of the blood flow signal parameters(including VI,FI,and VFI)in 3D power Doppler ultrasonography had significant antidiastole values between endometrial cancer and uterine parenchyma lumps to assist clinicians in properly diagnosing patients. 展开更多
关键词 power DOPPLER three-dimensional ultrasound UTERINE PARENCHYMA lump ENDOMETRIAL CARCINOMA BLOOD flow signal parameter
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Interaction solutions to Hirota-Satsuma-Ito equation in (2+1)-dimensions 被引量:10
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作者 Wen-Xiu MA 《Frontiers of Mathematics in China》 SCIE CSCD 2019年第3期619-629,共11页
Abundant exact interaction solutions, including lump-soliton, lump-kink, and lump-periodic solutions, are computed for the Hirota-Satsuma-Ito equation in (2+1)-dimensions, through conducting symbolic computations with... Abundant exact interaction solutions, including lump-soliton, lump-kink, and lump-periodic solutions, are computed for the Hirota-Satsuma-Ito equation in (2+1)-dimensions, through conducting symbolic computations with Maple. The basic starting point is a Hirota bilinear form of the Hirota-Satsuma-Ito equation. A few three-dimensional plots and contour plots of three special presented solutions are made to shed light on the characteristic of interaction solutions. 展开更多
关键词 SYMBOLIC COMPUTATION lump SOLUTION INTERACTION SOLUTION
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Lump solutions to a generalized Bogoyavlensky-Konopelchenko equation 被引量:7
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作者 Shou-Ting CHEN Wen-Xiu MA 《Frontiers of Mathematics in China》 SCIE CSCD 2018年第3期525-534,共10页
A (2 + 1)-dimensional generalized Bogoyavlensky-Konopelchenko equation that possesses a Hirota bilinear form is considered. Starting with its Hirota bilinear form, a class of explicit lump solutions is computed thr... A (2 + 1)-dimensional generalized Bogoyavlensky-Konopelchenko equation that possesses a Hirota bilinear form is considered. Starting with its Hirota bilinear form, a class of explicit lump solutions is computed through conducting symbolic computations with Maple, and a few plots of a specific presented lump solution are made to shed light on the characteristics of lumps. The result provides a new example of (2 + 1)-dimensional nonlinear partial differential equations which possess lump solutions. 展开更多
关键词 Symbolic computation lump solution soliton theory
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Preliminary study on CT perfusion imaging in guiding biopsy of pulmonary lumps 被引量:7
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作者 KANG Li-qing SONG Zhao-wei +4 位作者 LI Zhong-xin YU Shu-jing LIU Feng-hai CHEN Yue-feng XING Rong-ge 《Chinese Medical Journal》 SCIE CAS CSCD 2009年第7期807-812,共6页
Background CT perfusion imaging (CTP) has been proved to be a powerful functional imaging technique. This study aimed to evaluate the value of CTP in guiding biopsy of pulmonary lumps. Methods A total of 147 patient... Background CT perfusion imaging (CTP) has been proved to be a powerful functional imaging technique. This study aimed to evaluate the value of CTP in guiding biopsy of pulmonary lumps. Methods A total of 147 patients with pulmonary lumps who had CT guided biopsies were enrolled in this study from February 2005 to June 2007. The patients were assigned to 3 groups: 33 cases guided by CTP as group 1, 45 cases guided by contrast-enhanced scan of CT as group Ⅱ, and 69 cases guided by plain scan of CT as group Ⅲ. Each group was subdivided into central and peripheral types according to the location of the lumps. The achievement ratio of biopsy, the accuracy in grouping, and grading of lung cancer, and the incidence of complication were compared. Results The total achievement ratios of biopsy from group Ⅰ to Ⅲ were 100% (33/33), 91% (41/45), and 80% (55/69) respectively, and the difference was statistically significant between group Ⅰ and Ⅲ (P 〈0.05). For the central type, they were 100% (18/18), 88% (15/17), and 79% (11/14) respectively, and the difference was also statistically significant between group Ⅰand Ⅲ (P 〈0.05). For the peripheral type, they were 100% (15/15), 93% (26/28), and 80% (44/55) respectivelies, and the difference was not statistically significant among the three groups. The total accuracies in grouping and grading of lung cancer from group Ⅰ to Ⅲ were 100% (27/27), 91% (31/34), and 72% (33/46) respectively, and the difference was statistically significant between group Ⅰ and Ⅲ and between group Ⅱ and Ⅲ (P 〈0.05). For the central type, they were 100% (16/16), 94% (16/17), and 70% (8/12) respectively, and the difference was statistically significant between group Ⅰ and Ⅲ (P〈0.05). For the peripheral type, they were 100% (11/11), 88% (15/17), and 72% (26/36) respectively, and the difference was statistically significant between group Ⅰ and Ⅲ (P 〈0.05). The total 展开更多
关键词 pulmonary lump tomography X-ray computerized perfusion imaging BIOPSY
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FCC汽油催化裂解生产低碳烯烃的动力学模型研究 被引量:9
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作者 刘熠斌 陈小博 杨朝合 《炼油技术与工程》 CAS 北大核心 2007年第3期5-9,共5页
针对催化裂化汽油催化裂解生产低碳烯烃的反应体系,建立了六集总动力学模型,推导出模型的解析解,利用小型提升管催化裂化试验装置的试验数据,采用最小二乘法求出了各集总之间的反应速率常数,并对所建立的模型进行了初步的检验,结果表明... 针对催化裂化汽油催化裂解生产低碳烯烃的反应体系,建立了六集总动力学模型,推导出模型的解析解,利用小型提升管催化裂化试验装置的试验数据,采用最小二乘法求出了各集总之间的反应速率常数,并对所建立的模型进行了初步的检验,结果表明计算值与试验值吻合良好,模型具有较好的预测能力。对乙烯、丙烯的产率及选择性的计算表明,随停留时间的延长,产率有所增加,但选择性基本不变。 展开更多
关键词 催化裂化汽油 催化裂解 低碳烯烃 集总 动力学模型
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半纤维素稀酸循环喷淋冲滤水解动力学 被引量:9
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作者 金强 张红漫 +3 位作者 徐锐 林增祥 郑荣平 赵晶 《化工学报》 EI CAS CSCD 北大核心 2011年第1期103-110,共8页
采用稀酸循环喷淋冲滤(dilute acid cycle spray flow-through,DCF)反应器在温和的条件下水解玉米秸秆半纤维素,分析了半纤维素稀酸水解产物组分,研究不同温度、硫酸浓度和时间对主要产物木糖浓度的影响。探讨了其水解反应机理并以酸催... 采用稀酸循环喷淋冲滤(dilute acid cycle spray flow-through,DCF)反应器在温和的条件下水解玉米秸秆半纤维素,分析了半纤维素稀酸水解产物组分,研究不同温度、硫酸浓度和时间对主要产物木糖浓度的影响。探讨了其水解反应机理并以酸催化反应机理为基础,把玉米秸秆半纤维素及其水解产物按化学组成和性质进行集总划分,并对反应网络进行合理简化,提出了一种半纤维素稀酸水解反应的简化集总动力学模型。通过参数估计求取动力学参数,建立集总动力学模型以预测半纤维素主要水解产物。结果表明,喷淋作用加快了半纤维素的连续解聚过程,从而使得木糖得率超过90%,而其降解产物糠醛等较少。得到的模型能较好预测不同条件下主要产物含量。通过改进的Arrhenius方程确定木糖生成和降解的活化能分别为107.1kJ·mol-1和102.2kJ·mol-1。 展开更多
关键词 半纤维素 玉米秸秆 循环喷淋 动力学 集总
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High-Order Soliton Solutions and Hybrid Behavior for the (2 + 1)-Dimensional Konopelchenko-Dubrovsky Equations
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作者 Xingying Li Yin Ji 《Journal of Applied Mathematics and Physics》 2024年第7期2452-2466,共15页
In this paper, the evolutionary behavior of N-solitons for a (2 + 1)-dimensional Konopelchenko-Dubrovsky equations is studied by using the Hirota bilinear method and the long wave limit method. Based on the N-soliton ... In this paper, the evolutionary behavior of N-solitons for a (2 + 1)-dimensional Konopelchenko-Dubrovsky equations is studied by using the Hirota bilinear method and the long wave limit method. Based on the N-soliton solution, we first study the evolution from N-soliton to T-order (T=1,2) breather wave solutions via the paired-complexification of parameters, and then we get the N-order rational solutions, M-order (M=1,2) lump solutions, and the hybrid behavior between a variety of different types of solitons combined with the parameter limit technique and the paired-complexification of parameters. Meanwhile, we also provide a large number of three-dimensional figures in order to better show the degeneration of the N-soliton and the interaction behavior between different N-solitons. 展开更多
关键词 Konopelchenko-Dubrovsky Equations Hirota Bilinear Method M-Order lump Solutions High-Order Hybrid Solutions Interaction Behavior
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