期刊文献+
共找到6,285篇文章
< 1 2 250 >
每页显示 20 50 100
微博信息生态链构成要素与形成机理 被引量:57
1
作者 马捷 孙梦瑶 +1 位作者 尹爽 韩朝 《图书情报工作》 CSSCI 北大核心 2012年第18期73-77,81,共6页
指出微博信息生态链的构成要素包括信息内容、信息人和传播路径。认为信息人分为信息生产者、信息传播者、信息组织者、信息消费者和信息分解者。信息人角色在微博信息生态链中频繁转换,并构成节点之间强关系、弱关系。论述微博信息生... 指出微博信息生态链的构成要素包括信息内容、信息人和传播路径。认为信息人分为信息生产者、信息传播者、信息组织者、信息消费者和信息分解者。信息人角色在微博信息生态链中频繁转换,并构成节点之间强关系、弱关系。论述微博信息生态链的形成受主观因素与客观因素的影响,构建微博信息生态链的形成机理图。 展开更多
关键词 微博 信息生态链 信息人 节点 构成要素 形成机理
原文传递
Molecular mechanism about lymphogenous metastasis of hepatocarcinoma cells in mice 被引量:47
2
作者 Li Hou Ying Li Yong-Hua Jia Bo Wang Yi Xin Mao-Ying Ling Shen Lü Department of Pathology,Dalian Medical University,Dalian 116027,Liaoning Province,ChinaDepartment of Biochemistry,Dalian Medical University,Dalian 116027,Liaoning Province,China 《World Journal of Gastroenterology》 SCIE CAS CSCD 2001年第4期532-536,共5页
AIM: To investigate the correlation between lymphogenous metastasis and matrix metalloproteinases (MMPs) activity and the expression of Fas ligand of tumor cells in lymph nodes. METHODS: Fifty-six inbred 615-mice were... AIM: To investigate the correlation between lymphogenous metastasis and matrix metalloproteinases (MMPs) activity and the expression of Fas ligand of tumor cells in lymph nodes. METHODS: Fifty-six inbred 615-mice were equally divided into 2 groups and inoculated with Hca-F and Hca-P cells. Their lymph node metastatic rates were examined. Growth fraction of lymphocytes in host lymph nodes was detected by flow cytometry. The Hca-F and Hca-P cells were cultured with extract of lymph node, liver or spleen. The quantity of MMPs in these supernatants was examined by zymographic analysis. The expression of Fas ligand, PCNA, Bcl-2 protein of Hca-F and Hca-P cells in the mice were examined by immunohistochemistry. The apoptosis signals of macro-phages in lymph nodes were observed with in situ DNA fragmentation. RESULTS: On the 28th day post-inoculation, the lymph node metastatic rate of HcaF was 80%(16/20), whereas that of Hca-P was 25%(5/20). The growth fraction of lymphocytes was as follows: in the Hca-F cells, the proliferating peak of lymphocytes appeared on the 14th day post inoculation and then decreased rapidly, while in HcaP cells, the peak appeared on the 7th day post inoculation and then kept at a high level. With the extract of lymph node, the quantity of the MMP-9 activity increased (P【0.01) and active MMP-9 and MMP-2 were produced by both Hca-F and Hca-P tumor cells, which did not produce MMPs without the extract of lymph node or with the extracts of the liver and spleen. The expression of Fas Ligand of Hca-F cells was stronger than that of Hca-P cells (P 【0.01). The expressions of PCNA and Bcl-2 protein of Hca-F cells in the tumors of inoculated area were the same as that of Hca-P cells. In situ DNA fragmentation showed that the positive signals of macrophages were around Hca-F cells. CONCLUSION: Secretion of MMPs which was associated with metastatic ability of Hca-F and Hca-P tumor cells depends on the environment of lymph nodes. The increased expression of Fas ligand protein of Hca-F tumor cells with 展开更多
关键词 Animals DNA Fragmentation Flow Cytometry Gelatinase A Gelatinase B Liver Neoplasms Experimental Lymph nodes Lymphatic Metastasis Macrophages Membrane Glycoproteins MICE Mice Inbred Strains Research Support Non-U.S. Gov't Tumor Cells Cultured
下载PDF
Colorectal cancer lymph node staining by activated carbon nanoparticles suspension in vivo or methylene blue in vitro 被引量:41
3
作者 Hong-Ke Cai Hai-Fei He Wei Tian Mei-Qi Zhou Yue Hu Yong-Chuan Deng 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第42期6148-6154,共7页
AIM:To investigate whether activated carbon nanoparticles suspension(ACNS) or methylene blue(MB) can increase the detected number of lymph nodes in colorectal cancer.METHODS:Sixty-seven of 72 colorectal cancer patient... AIM:To investigate whether activated carbon nanoparticles suspension(ACNS) or methylene blue(MB) can increase the detected number of lymph nodes in colorectal cancer.METHODS:Sixty-seven of 72 colorectal cancer patients treated at our hospital fulfilled the inclusion criteria of the study which was conducted from December 2010 to February 2012.Seven patients refused to participate.Eventually,60 patients were included,and randomly assigned to three groups(20 in each group):ACNS group(group A),MB group(group B) and non-stained conventional surgical group(group C).In group A,patients received subserosal injection of 1 mL ACNS in a 4-quadrant region around the mass.In group B,the main artery of specimen was identified and isolated after the specimen was removed,and 2 mL MB was slowly injected into the isolated,stretched and fixed vessel.In group C,no ACNS and MB were injected.All the mesentery lymph nodes were isolated and removed systematically by visually inspecting and palpating the adipose tissue.RESULTS:No difference was observed among the three groups in age,gender,tumor location,tumor diameter,T-stage,degree of differentiation,postoperative complications and peritoneal drainage retention time.The total number of detected lymph nodes was 535,476 and 223 in the three groups,respectively.The mean number of detected lymph nodes per patient was significantly higher in group A than in group C(26.8 ± 8.4 vs 12.2 ± 3.2,P < 0.001).Similarly,there were significantly more lymph nodes detected in group B than in group C(23.8 ± 6.9 vs 12.2 ± 3.2,P < 0.001).However,there was no significant difference between group A and group B.There were 50,46 and 32 metastatic lymph nodes dissected in 13 patients of group A,10 patients of group B and 11 patients of group C,without significant differences among the three groups.Eleven of the 60 patients had insufficient number of detected lymph nodes(< 12).Only one patient with T 4a rectal cancer had 10 lymph nodes detected in group B,the other 10 patients were all from group C.Based on 展开更多
关键词 NANOTECHNOLOGY Activated carbon nanoparticles suspension Methylene blue Lymph nodes Colorectal cancer
下载PDF
Incidental gallbladder cancer during laparoscopic cholecystectomy:Managing an unexpected finding 被引量:36
4
作者 Andrea Cavallaro Gaetano Piccolo +5 位作者 Vincenzo Panebianco Emanuele Lo Menzo Massimiliano Berretta Antonio Zanghì Maria Di Vita Alessandro Cappellani 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第30期4019-4027,共9页
AIM:To evaluate the impact of incidental gallbladder cancer on surgical experience.METHODS:Between 1998 and 2008 all cases of cholecystectomy at two divisions of general surgery,one university based and one at a publi... AIM:To evaluate the impact of incidental gallbladder cancer on surgical experience.METHODS:Between 1998 and 2008 all cases of cholecystectomy at two divisions of general surgery,one university based and one at a public hospital,were retrospectively reviewed.Gallbladder pathology was diagnosed by history,physical examination,and laboratory and imaging studies [ultrasonography and computed tomography(CT)].Patients with gallbladder cancer(GBC) were further analyzed for demographic data,and type of operation,surgical morbidity and mortality,histopathological classification,and survival.Incidental GBC was compared with suspected or preoperatively diagnosed GBC.The primary endpoint was diseasefree survival(DFS).The secondary endpoint was the difference in DFS between patients previously treated with laparoscopic cholecystectomy and those who had oncological resection as first intervention.RESULTS:Nineteen patients(11 women and eight men) were found to have GBC.The male to female ratio was 1:1.4 and the mean age was 68 years(range:45-82 years).Preoperative diagnosis was made in 10 cases,and eight were diagnosed postoperatively.One was suspected intraoperatively and confirmed by frozen sections.The ratio between incidental and nonincidental cases was 9/19.The tumor node metastasis stage was:pTis(1),pT1a(2),pT1b(4),pT2(6),pT3(4),pT4(2);five cases with stageⅠa(T1 a-b);two with stageⅠb(T2 N0);one with stage Ⅱa(T3 N0);six with stage Ⅱb(T1-T3 N1);two with stage Ⅲ(T4 Nx Nx);and one with stage Ⅳ(Tx Nx Mx).Eighty-eight percent of the incidental cases were discovered at an early stage(≤Ⅱ).Preoperative diagnosis of the 19 patients with GBC was:GBC with liver invasion diagnosed by preoperative CT(nine cases),gallbladder abscess perforated into hepatic parenchyma and involving the transversal mesocolon and hepatic hilum(one case),porcelain gallbladder(one case),gallbladder adenoma(one case),and chronic cholelithiasis(eight cases).Every case,except one,with a T1b or more advanced invasion underwent Ⅳb + Ⅴ wedge li 展开更多
关键词 Incidental gallbladder cancer Laparoscopic cholecystectomy Lymph nodes Hepatic resection Management Outcome
下载PDF
基于轴辐理论的现代区域物流网络节点选择 被引量:33
5
作者 海峰 阎欣 +1 位作者 丁灿 邵校 《计算机集成制造系统》 EI CSCD 北大核心 2012年第6期1299-1305,共7页
为充分发挥区域物流在区域经济发展中的作用,提出构建一种以轴辐式网络为模型的轴辐式区域物流网络,这种物流网络具有轴辐式网络规模经济、范围经济、密度经济和结构经济的特点;为确定轴辐式区域物流网络的节点等级,选择对物流影响较大... 为充分发挥区域物流在区域经济发展中的作用,提出构建一种以轴辐式网络为模型的轴辐式区域物流网络,这种物流网络具有轴辐式网络规模经济、范围经济、密度经济和结构经济的特点;为确定轴辐式区域物流网络的节点等级,选择对物流影响较大的变量,运用主成分分析法,通过最后的得分排名来确定节点等级;以湖北省为例,为确定湖北轴辐式区域物流网络的节点等级,选取对物流影响较大的八个指标,通过城市得分排名来确定物流节点的等级,并提出了对湖北物流网络的优化。 展开更多
关键词 轴辐理论 物流网络 节点 主成分分析 区域经济
下载PDF
基于ZigBee技术的远程无线温湿度测控系统的设计 被引量:32
6
作者 武风波 强云霄 《西北大学学报(自然科学版)》 CAS CSCD 北大核心 2008年第5期731-734,共4页
目的为实现工农业生产中对温湿度参数的远程无线实时测控。方法采用ZigBee技术的无线传感网络与GPRS网络相结合的体系结构,基于CC2430芯片设计无线传感节点,并开发其软件。结果通过ZigBee组网,进行测试,该湿温度无线测控系统具有稳定的... 目的为实现工农业生产中对温湿度参数的远程无线实时测控。方法采用ZigBee技术的无线传感网络与GPRS网络相结合的体系结构,基于CC2430芯片设计无线传感节点,并开发其软件。结果通过ZigBee组网,进行测试,该湿温度无线测控系统具有稳定的数据采集和传输质量。结论提高了系统的灵活性和可扩展性,可作为传感监控网络的后续研究平台。 展开更多
关键词 ZIGBEE技术 无线通信 无线传感网络 节点
下载PDF
小波包分解树结点与信号子空间频带的对应关系及其应用 被引量:27
7
作者 曾宪伟 赵卫明 盛菊琴 《地震学报》 CSCD 北大核心 2008年第1期90-96,共7页
小波包变换的Mallat分解算法可以把较宽的信号频带划分成相等带宽且互不重叠的窄频带,但由于信号子空间频带的频率大小并非按照分解树结点(node)编号的大小顺序排列,各个结点重构信号的频率范围不易判定.本文通过分析小波包变换的Malla... 小波包变换的Mallat分解算法可以把较宽的信号频带划分成相等带宽且互不重叠的窄频带,但由于信号子空间频带的频率大小并非按照分解树结点(node)编号的大小顺序排列,各个结点重构信号的频率范围不易判定.本文通过分析小波包变换的Mallat分解算法与分解滤波器的关系,设定频带编号与结点编号间进行二进制转化的运算规则,得到了小波包分解树结点与信号子空间频带的对应关系,然后通过模拟信号进行了验证.结果表明,本文给出的小波包信号子空间频带的排列规则是正确的. 展开更多
关键词 分解树 结点 信号子空间 频带
下载PDF
New ultrasound techniques for lymph node evaluation 被引量:26
8
作者 Xin-Wu Cui Christian Jenssen +2 位作者 Adrian Saftoiu Andre Ignee Christoph F Dietrich 《World Journal of Gastroenterology》 SCIE CAS 2013年第30期4850-4860,共11页
Conventional ultrasound(US)is the recommended imaging method for lymph node(LN)diseases with the advantages of high resolution,real time evaluation and relative low costs.Current indications of transcutaneous ultrasou... Conventional ultrasound(US)is the recommended imaging method for lymph node(LN)diseases with the advantages of high resolution,real time evaluation and relative low costs.Current indications of transcutaneous ultrasound and endoscopic ultrasound include the detection and characterization of lymph nodes and the guidance for LN biopsy.Recent advances in US technology,such as contrast enhanced ultrasound(CEUS),contrast enhanced endoscopic ultrasound(CE-EUS),and real time elastography show potential to improve the accuracy of US for the differential diagnosis of benign and malignant lymph nodes.In addition,CEUS and CE-EUS have been also used for the guidance of fine needle aspiration and assessment of treatment response.Complementary to size criteria,CEUS could also be used to evaluate response of tumor angiogenesis to anti-angiogenic therapies.In this paper we review current literature regarding evaluation of lymphadenopathy by new and innovative US techniques. 展开更多
关键词 LYMPH nodes ULTRASOUND ENDOSCOPIC ULTRASOUND LYMPH node METASTASIS LYMPHOMA
下载PDF
Magnetic resonance imaging staging of nasopharyngeal carcinoma in the head and neck 被引量:25
9
作者 Ann Dorothy King Kunwar Suryaveer Singh Bhatia 《World Journal of Radiology》 CAS 2010年第5期159-165,共7页
Magnetic resonance imaging (MRI) is the modality of choice for staging nasopharyngeal carcinoma in the head and neck. This article will review the patterns of primary and nodal spread on MRI with reference to the late... Magnetic resonance imaging (MRI) is the modality of choice for staging nasopharyngeal carcinoma in the head and neck. This article will review the patterns of primary and nodal spread on MRI with reference to the latest 7th edition of the International Union Against Cancer/American Joint Committee on Cancer staging system. 展开更多
关键词 LYMPH nodes Magnetic resonance imaging METASTASES NASOPHARYNGEAL carcinoma STAGING
下载PDF
Prediction of cervical lymph node metastases in papillary thyroid microcarcinoma by sonographic features of the primary site 被引量:23
10
作者 Xi Wei Meng Wang +9 位作者 Xiaoqing Wang Xiangqian Zheng Ying Li Yi Pan Yueguo Li Jiali Mu Yang Yu Dapeng Li Ming Gao Sheng Zhang 《Cancer Biology & Medicine》 SCIE CAS CSCD 2019年第3期587-594,共8页
Objective: To study the sonographic features of the primary site of papillary thyroid microcarcinoma(PTMC) for the prediction of cervical lymph node metastasis during preoperative diagnosis.Methods: A total of 710 PTM... Objective: To study the sonographic features of the primary site of papillary thyroid microcarcinoma(PTMC) for the prediction of cervical lymph node metastasis during preoperative diagnosis.Methods: A total of 710 PTMC patients between 2013 and 2016 with a diagnosis of cervical lymph node metastases were reviewed.We analyzed the sonographic features of the PTMC primary site to predict ipsilateral or central lymph node metastases in univariate and multivariate models.The ratio of abutment/perimeter of the PTMC primary site was utilized to evaluate cervical lymph node status.Results: Regarding clinical characteristics, multifocality and extrathyroidal extension were associated with cervical lymph node involvement.In the multivariate regression model, calcification and the abutment/perimeter ratio of lesions were evaluated as independent factors in level Ⅵ, ipsilateral or skip cervical lymph node metastases.The cut-off value of the ratio of abutment/perimeter of the PTMC primary site(25%) was significantly correlated with cervical lymph node metastases(P = 0.000).Conclusions: Independent sonographic features, including lesion size, lesion location, calcification, and the ratio of abutment/perimeter of the primary site, were associated with cervical lymph node metastases in PTMC patients. 展开更多
关键词 ULTRASONOGRAPHY THYROID LYMPH nodes METASTASIS evaluation
下载PDF
基于Delaunay剖分有限元网格结点和单元一体化生成方法 被引量:18
11
作者 杜群贵 邓达华 《计算机辅助设计与图形学学报》 EI CSCD 北大核心 1997年第1期60-65,共6页
首次将Delaunay三角剖分中产生结点和单元两个彼此独立的步骤合二为一,实现了利用Delaunay方法产生有限元网格结点和单元的自动化、一体化。较好地解决了产生有限元网格结点的困难。
关键词 DELAUNAY剖分 有限元网络 结点 单元 CAD
下载PDF
网络信息生态链的形成机理 被引量:22
12
作者 霍明奎 张向先 靖继鹏 《情报科学》 CSSCI 北大核心 2014年第12期3-7,共5页
首先对网络信息生态链的内涵进行数学表达;其次分析了网络信息生态链节点和节点关系的特性,从节点的形成、节点关系的形成两个角度阐释了网络信息生态链的形成过程;最后提炼了网络信息生态链的形成动力系统,描述出网络信息生态链的形成... 首先对网络信息生态链的内涵进行数学表达;其次分析了网络信息生态链节点和节点关系的特性,从节点的形成、节点关系的形成两个角度阐释了网络信息生态链的形成过程;最后提炼了网络信息生态链的形成动力系统,描述出网络信息生态链的形成机理。 展开更多
关键词 网络信息生态链 形成机理 节点 关系 形成动力
原文传递
网络时代的学习理论新进展:关联主义 被引量:21
13
作者 邱崇光 高安邦 《广东广播电视大学学报》 2010年第3期2-7,共6页
关联主义自2004年西蒙斯提出以来就备受关注。有人说它是数字时代的学习理论,也有人提出质疑。从关联主义提出的时代背景看,其时的行为主义、认知主义和建构主义三种主流学习理论学习观的局限性已面临着时代的挑战;而数字时代学习理论... 关联主义自2004年西蒙斯提出以来就备受关注。有人说它是数字时代的学习理论,也有人提出质疑。从关联主义提出的时代背景看,其时的行为主义、认知主义和建构主义三种主流学习理论学习观的局限性已面临着时代的挑战;而数字时代学习理论之关联主义,包括其对节点、连接和网络等基本概念的理解,对学习的解释及其八个基本原理等,为数字时代进一步探讨学习的本质提供了有益借鉴,找出学习理论研究发展的新方向。 展开更多
关键词 学习理论 关联主义 西蒙斯 节点 连接 网络
下载PDF
基于C8051F040的CAN总线通讯系统设计 被引量:18
14
作者 田奕 刘秀红 《现代电子技术》 2006年第15期29-30,33,共3页
作为一种很有前途的现场总线,CAN总线通信相对于一般的串行通信总线,他的实时性、可靠性和灵活性的特点更加突出。介绍了C8051F040内部集成的CAN控制器的使用方法,给出了以此芯片为核心的CAN总线智能节点通讯接口的硬件和软件设计,实际... 作为一种很有前途的现场总线,CAN总线通信相对于一般的串行通信总线,他的实时性、可靠性和灵活性的特点更加突出。介绍了C8051F040内部集成的CAN控制器的使用方法,给出了以此芯片为核心的CAN总线智能节点通讯接口的硬件和软件设计,实际的运行验证了设计的正确性。其设计通用性好、可靠性高、性价比高,具有广泛的应用前景。 展开更多
关键词 C8051F040 总线控制器 消息对象 节点
下载PDF
Prognostic impact of dissected lymph node count on patients with node-negative gastric cancer 被引量:21
15
作者 Chang-Ming Huang Jian-Xian Lin Chao-Hui Zheng Ping Li Jian-Wei Xie Bi-Juan Lin Hui-Shan Lu 《World Journal of Gastroenterology》 SCIE CAS CSCD 2009年第31期3926-3930,共5页
AIM:To investigate the long-term effect of the number of resected lymph nodes (LNs) on the prognosis of patients with node-negative gastric cancer.METHODS: Clinical data of 211 patients with gastric cancer, without no... AIM:To investigate the long-term effect of the number of resected lymph nodes (LNs) on the prognosis of patients with node-negative gastric cancer.METHODS: Clinical data of 211 patients with gastric cancer, without nodal involvement, were analyzed retrospectively after D2 radical operation. We analyzed the relationship between the number of resected LNs with the 5-year survival, the recurrence rate and the post-operative complication rate.RESULTS: The 5-year survival of the entire cohort was 82.2%. The total number of dissected LNs was one of the independent prognostic factors. Among patients with comparable depth of invasion, the larger the number of resected LNs, the better the survival (P<0.05). A cut-point analysis provided the possibility to detect a significant survival difference among subgroups. Patients had a better long-term survival outcomes with LN counts ≥15 for pT1-2, ≥20 for pT3-4, and ≥15 for the entire cohort. The overall recurrence rate was 29.4% within 5 years after surgery. There was a statistically significant, negative correlation between the number of resected LNs and the recurrence rate (P>0.01). The post-operative complication rate was 10.9% and was not signif icantly correlated with the number of dissected LNs (P>0.05).CONCLUSION: For node-negative gastric cancer, sufficient number of dissected LNs is recommended during D2 lymphadenectomy, to improve the long-term survival and reduce the recurrence. Suitable increments of the dissected LN count would not increase the post-operative complication rate. 展开更多
关键词 Stomach neoplasms Lymph nodes GASTRECTOMY LYMPHADENECTOMY Prognosis
下载PDF
Significant value of 18F-FDG-PET/CT in diagnosing small cervical lymph node metastases in patients with nasopharyngeal carcinoma treated with intensity-modulated radiotherapy 被引量:19
16
作者 Hao Peng Lei Chen +11 位作者 Ling-Long Tang Wen-Fei Li Yan-Ping Mao Rui Guo Yuan Zhang Li-Zhi Liu Li Tian Xu Zhang Xiao-Ping Lin Ying Guo Ying Sun Jun Ma 《Chinese Journal of Cancer》 SCIE CAS CSCD 2017年第12期757-766,共10页
Background: Little is known about the nature of metaistasis to small cervical lymph nodes(SCLNS) in the patients with nasopharyngeal carcinoma(NPC)examined by using 18-fluoro-2-deoxy-glucose(^(18)F-FDG) positron emiss... Background: Little is known about the nature of metaistasis to small cervical lymph nodes(SCLNS) in the patients with nasopharyngeal carcinoma(NPC)examined by using 18-fluoro-2-deoxy-glucose(^(18)F-FDG) positron emission tomography/computed tomography(PET/CT).The present study aimed to evaluate the diagnostic values of PET/CT in identifying metastasis in SCLNs in NPC patients.Methods: Magnetic resonance images(MRI) and PET/CT scans for 470 patients with newly diagnosed, non-distant metastatic NPC were analyzed. Metastatic rates of SCLNs were defined by the positive number of SCLNs on PET/CT scans and total number of SCLNs on MRI scans. Receiver operating characteristic curve was applied to compare PET/CT-determined stage with MRI-determined stage.Results: In total, 2082 SCLNs were identified, with 808(38.8%) ≥ 5 and < 6 mm in diameter(group A), 526(25.3%)≥ 6 and < 7 mm in diameter(group B),374(18.0%)≥ 7 and < 8 mm in diameter(group C), 237(11.4%) ≥8 and<9 mm in diameter(group D),and 137(6.5%) ≥ 9 and <10 mm in diameter(group E).The overall metastatic rates examined by using PET/CT for groups A, B,C,D, and E were 3.5%, 8.0%, 31.3%, 60.0%, and 83.9%, respectively(P< 0.001). In level IV/Vb, the metastatic rate for nodes ≥ 8 mm was 84.6%. PET/CT examination resulted in modification of N category and overall stage for 135(28.7%) and 46(9.8%) patients, respectively. The areas under curve of MRIdetermined and PET/CT-determined overall stage were 0.659 and 0.704 for predicting overall survival, 0.661 and 0.711 for predicting distant metastasis-free survival, and 0.636 and 0.663 for predicting disease-free survival.Conclusions: PET/CT was more effective than MRI in identifying metastatic SCLNs, and the radiologic diagnostic criteria for metastatic lymph nodes in level IV/Vb should be re-defined. 展开更多
关键词 NASOPHARYNGEAL carcinoma 18-fluoro-2-deoxy-glucose positron emission TOMOGRAPHY with computed TOMOGRAPHY (18F-PET/CT) Magnetic resonance image INTENSITY-MODULATED radiotherapy SMALL cervical LYMPH nodes
下载PDF
Air route network optimization in fragmented airspace based on cellular automata 被引量:18
17
作者 Shijin WANG Xi CAO +3 位作者 Haiyun LI Qingyun LI Xu HANG Yanjun WANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2017年第3期1184-1195,共12页
Air route network optimization,one of the essential parts of the airspace planning,is an effective way to optimize airspace resources,increase airspace capacity,and alleviate air traffic congestion.However,little has ... Air route network optimization,one of the essential parts of the airspace planning,is an effective way to optimize airspace resources,increase airspace capacity,and alleviate air traffic congestion.However,little has been done on the optimization of air route network in the fragmented airspace caused by prohibited,restricted,and dangerous areas(PRDs).In this paper,an air route network optimization model is developed with the total operational cost as the objective function while airspace restriction,air route network capacity,and non-straight-line factors(NSLF) are taken as major constraints.A square grid cellular space,Moore neighbors,a fixed boundary,together with a set of rules for solving the route network optimization model are designed based on cellular automata.The empirical traffic of airports with the largest traffic volume in each of the 9 flight information regions in China's Mainland is collected as the origin-destination(OD) airport pair demands.Based on traffic patterns,the model generates 35 air routes which successfully avoids 144 PRDs.Compared with the current air route network structure,the number of nodes decreases by 41.67%,while the total length of flight segments and air routes drop by 32.03% and 5.82% respectively.The NSLF decreases by 5.82% with changes in the total length of the air route network.More importantly,the total operational cost of the whole network decreases by 6.22%.The computational results show the potential benefits of the model and the advantage of the algorithm.Optimization of air route network can significantly reduce operational cost while ensuring operation safety. 展开更多
关键词 Air route network planning Airspace restriction Cellular automata Network capacity Optimization of nodes
原文传递
组合空腹梁中钢管剪键、钢助及砼板连接节点应力分析 被引量:16
18
作者 黄勇 金玉 +1 位作者 杨想红 杜德静 《贵州科学》 2005年第3期1-4,27,共5页
组合空腹板中剪力键、钢肋及混凝土板连接节点是结构的关键节点,本文建立了基于空间壳单元的有限元模型,对这类节点进行了理论分析,得到了节点区域的应力分布规律和变形特点。研究表明,节点区域内各构件的接触面附近,存在较大的应力集... 组合空腹板中剪力键、钢肋及混凝土板连接节点是结构的关键节点,本文建立了基于空间壳单元的有限元模型,对这类节点进行了理论分析,得到了节点区域的应力分布规律和变形特点。研究表明,节点区域内各构件的接触面附近,存在较大的应力集中现象。指出了应力集中的原因及解决措施。 展开更多
关键词 组合结构 组合空腹梁 节点 应力分布 剪力键
下载PDF
经略21世纪海上丝路:重要航线、节点及港口特征 被引量:19
19
作者 郑崇伟 孙威 +2 位作者 黎鑫 何方 陈璇 《海洋开发与管理》 2016年第1期4-13,共10页
为了更好地认识21世纪海上丝绸之路(简称"海上丝路"),文章对"海上丝路"涉及的重要航线、节点及港口的地理位置、气候状况、水文特征、商业价值、人文背景等进行梳理。重要航线、节点及港口的使用与管理作为"... 为了更好地认识21世纪海上丝绸之路(简称"海上丝路"),文章对"海上丝路"涉及的重要航线、节点及港口的地理位置、气候状况、水文特征、商业价值、人文背景等进行梳理。重要航线、节点及港口的使用与管理作为"海上丝路"建设的基础要素,是与造船能力并列的核心资源,三者之间环环相扣,构成"海上丝路"健康运营的完整体系。与沿"海上丝路"国家稳步推进航线、节点及港口的管理、开发与维护,打造坚实的战略支撑点、现代之"海上驿站",是成功实现我国资源多样化、产业走出去、贸易全球化的最佳路径之一,以此为契机,融入现有国际海洋法公约并在践行过程中制定利我的海上政策体制,助力"海之梦"、"中国梦"。 展开更多
关键词 海上丝绸之路 战略支撑点 海上驿站 航线 节点 港口
下载PDF
食用农产品供应链中节点间知识共享行为的演化博弈分析 被引量:19
20
作者 林挺 李杨 张亮 《科技管理研究》 CSSCI 北大核心 2015年第18期141-144,156,共5页
以演化博弈理论为指导,构建食用农产品供应链中上下游相邻节点间知识共享的演化博弈模型,得出节点间知识共享行为的动态演化过程,并对演化稳定策略和影响因素做出合理分析。研究表明,仅当各节点从知识共享中可获得的增益部分大于知识共... 以演化博弈理论为指导,构建食用农产品供应链中上下游相邻节点间知识共享的演化博弈模型,得出节点间知识共享行为的动态演化过程,并对演化稳定策略和影响因素做出合理分析。研究表明,仅当各节点从知识共享中可获得的增益部分大于知识共享成本时,双方才将维持稳定的知识共享策略状态;其中各节点间存在的知识所有量差距、获取知识的难易程度、以及彼此间共享过程中的诚信度都是知识共享行为的重要因素。 展开更多
关键词 食用农产品供应链 节点 知识共享 演化博弈
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部