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Heuristic Expanding Disconnected Graph:A Rapid Path Planning Method for Mobile Robots
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作者 Yong Tao Lian Duan +3 位作者 He Gao Yufan Zhang Yian Song Tianmiao Wang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第2期68-82,共15页
Existing mobile robots mostly use graph search algorithms for path planning,which suffer from relatively low planning efficiency owing to high redundancy and large computational complexity.Due to the limitations of th... Existing mobile robots mostly use graph search algorithms for path planning,which suffer from relatively low planning efficiency owing to high redundancy and large computational complexity.Due to the limitations of the neighborhood search strategy,the robots could hardly obtain the most optimal global path.A global path planning algorithm,denoted as EDG*,is proposed by expanding nodes using a well-designed expanding disconnected graph operator(EDG)in this paper.Firstly,all obstacles are marked and their corners are located through the map pre-processing.Then,the EDG operator is designed to find points in non-obstruction areas to complete the rapid expansion of disconnected nodes.Finally,the EDG*heuristic iterative algorithm is proposed.It selects the candidate node through a specific valuation function and realizes the node expansion while avoiding collision with a minimum offset.Path planning experiments were conducted in a typical indoor environment and on the public dataset CSM.The result shows that the proposed EDG*reduced the planning time by more than 90%and total length of paths reduced by more than 4.6%.Compared to A*,Dijkstra and JPS,EDG*does not show an exponential explosion effect in map size.The EDG*showed better performance in terms of path smoothness,and collision avoidance.This shows that the EDG*algorithm proposed in this paper can improve the efficiency of path planning and enhance path quality. 展开更多
关键词 Global path planning Mobile robot Expanding disconnected graph Edge node OFFSET
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Management of the late effects of disconnected pancreatic duct syndrome: A case report 被引量:1
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作者 Reiko Yamada Yuhei Umeda +8 位作者 Yasunori Shiono Hiroaki Okuse Naoki Kuroda Junya Tsuboi Hiroyuki Inoue Yasuhiko Hamada Kyosuke Tanaka Noriyuki Horiki Yoshiyuki Takei 《World Journal of Clinical Cases》 SCIE 2019年第9期1053-1059,共7页
BACKGROUND There have been few reports about the late effects of disconnected pancreatic duct syndrome(DPDS). Although few reports have described the recurrence interval of pancreatitis, it might be rare for recurrenc... BACKGROUND There have been few reports about the late effects of disconnected pancreatic duct syndrome(DPDS). Although few reports have described the recurrence interval of pancreatitis, it might be rare for recurrence to occur more than 5 years later.Herein, we describe a case of recurrence in an 81-year-old man after the treatment of walled-off necrosis(WON) with pancreatic transection 7 years ago.CASE SUMMARY An 81-year-old man visited our hospital with chief complaints of fever and abdominal pain 7 years after the onset of WON due to severe necrotic pancreatitis. His medical history included an abdominal aortic aneurysm(AAA),hypertension, dyslipidemia, and chronic kidney disease. Computed tomography(CT) scan showed that the pancreatic fluid collection(PFC) had spread to the aorta with inflammation surrounding it, and CT findings suggested that bleeding occurred from the vasodilation due to splenic vein occlusion. First, we attempted to perform transpapillary drainage because of venous dilation around the residual stomach and the PFC. However, pancreatic duct drainage failed because of complete main pancreatic duct disruption. Second, we performed endoscopic ultrasound-guided drainage. After transmural drainage, the inflammation improved and stenting for the AAA was performed successfully. The inflammation was resolved, and he has been free from infection for more than 2 years after the procedure.CONCLUSION This case highlights the importance of continued follow-up of patients for recurrence after the treatment of WON with pancreatic transection. 展开更多
关键词 Case report ENDOSCOPY NECROSIS PANCREAS Walled-off NECROSIS disconnected PANCREATIC DUCT SYNDROME
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Scattering of SH-wave from interface cylindrical elastic inclusion with a semicircular disconnected curve 被引量:1
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作者 赵嘉喜 齐辉 苏胜伟 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2008年第6期779-786,共8页
Scattering of SH wave from an interface cylindrical elastic inclusion with a semicircular disconnected curve is investigated. The solution of dynamic stress concentration factor is given using the Green's function an... Scattering of SH wave from an interface cylindrical elastic inclusion with a semicircular disconnected curve is investigated. The solution of dynamic stress concentration factor is given using the Green's function and the method of complex variable functions. First, the space is divided into upper and lower parts along the interface. In the lower half space, a suitable Green's function for the problem is constructed. It is an essential solution of the displacement field for an elastic half space with a semi-cylindrical hill of cylindrical elastic inclusion while bearing out-plane harmonic line source load at the horizontal surface. Thus, the semicircular disconnected curve can be constructed when the two parts are bonded and continuous on the interface loading the undetermined anti-plane forces on the horizontal surfaces. Also, the expressions of displacement and stress fields are obtained in this situation. Finally, examples and results of dynamic stress concentration factor are given. Influences of the cylindrical inclusion and the difference parameters of the two mediators are discussed. 展开更多
关键词 dynamic stress concentration factor (DSCF) a semicircular disconnected curve Green's function scattering of SH-wave
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Layer stacked SiO_(x) microparticle with disconnected interstices enables stable interphase and particle integrity for lithium-ion batteries
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作者 Yang Ren Xucai Yin +4 位作者 Lizhi Xiang Rang Xiao Hua Huo Geping Yin Chunyu Du 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第11期300-307,I0007,共9页
Severe mechanical fractu re and unstable interphase,associated with the large volumetric expansion/contraction,significantly hinder the application of high-capacity SiO_(x)materials in lithium-ion batteries.Herein,we ... Severe mechanical fractu re and unstable interphase,associated with the large volumetric expansion/contraction,significantly hinder the application of high-capacity SiO_(x)materials in lithium-ion batteries.Herein,we report the design and facile synthesis of a layer stacked SiO_(x)microparticle(LS-SiO_(x))material,which presents a stacking structure of SiO_(x)layers with abundant disconnected interstices.This LS-SiO_(x)microparticle can effectively accommodate the volume expansion,while ensuring negligible particle expansion.More importantly,the interstices within SiO_(x)microparticle are disconnected from each other,which efficiently prevent the electrolyte from infiltration into the interior,achieving stable electrode/-electrolyte interface.Accordingly,the LS-SiO_(x)material without any coating delivers ultrahigh average Coulombic efficiency,outstanding cycling stability,and full-cell applicability.Only 6 cycles can attain>99.92%Coulombic efficiency and the capacity retention at 0.05 A g^(-1)for 100 cycles exceeds99%.After 800 cycles at 1 A g^(-1),the thickness swelling of LS-SiO_(x)electrode is as low as 0.87%.Moreover,the full cell with pure LS-SiO_(x)anode exhibits capacity retention of 91.2%after 300 cycles at 0.2 C.This work provides a novel concept and effective approach to rationally design silicon-based and other electrode materials with huge volume variation for electrochemical energy storage applications. 展开更多
关键词 Lithium-ion batteries Silicon oxide Layer stacked structure disconnected interstices Coulombic efficiency
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First report of small cell lung cancer with PTHrP-induced hypercalcemic pancreatitis causing disconnected duct syndrome
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作者 Eric M Montminy Stephen W Landreneau Jordan J Karlitz 《World Journal of Clinical Oncology》 CAS 2017年第5期420-424,共5页
Here we report a patient diagnosed with small cell lung cancer after first presenting with parathyroid hormonerelated peptide-induced hypercalcemic pancreatitis and developed walled-off necrosis that resulted in disru... Here we report a patient diagnosed with small cell lung cancer after first presenting with parathyroid hormonerelated peptide-induced hypercalcemic pancreatitis and developed walled-off necrosis that resulted in disruption of the main pancreatic duct.Disconnected duct syndrome (DDS) is a rare syndrome that occurs when the main pancreatic duct exocrine flow is disrupted resulting in leakage of pancreatic enzymes and further inflammatory sequela.To date,no prior reports have described DDS occurring with paraneoplastic reactions.Diagnostic imaging techniques and therapeutic interventions are reviewed to provide insight into current approaches to DDS. 展开更多
关键词 disconnected DUCT SYNDROME PARATHYROID hormone-related peptide Hypercalcemic PANCREATITIS
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Constrained consensuses in disconnected topologies
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作者 Song Hai-Yu Yu Li +1 位作者 Hu Hong-Xiang Zhang Wen-An 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第2期581-590,共10页
This paper is concerned with the constrained consensuses problem for a group of agents in disconnected topologies. By dividing the communication topology into a combination of directed trees, some necessary and suffic... This paper is concerned with the constrained consensuses problem for a group of agents in disconnected topologies. By dividing the communication topology into a combination of directed trees, some necessary and sufficient conditions are derived for all the agents to asymptotically reach a single consensus and multiple consensuses, respectively. The obtained results indicate that arbitrary anticipant consensuses can be achieved, if additional constrained controllers are added to those agents with specific indexes. Some illustrative examples are provided to demonstrate the effectiveness of the proposed theoretical results. 展开更多
关键词 disconnected topologies single consensus multiple consensuses
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Hopping Parameter Expansion Technique in Noise Method for Disconnected Quark Loops
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作者 Jia-Liang Zhou Zhen Cheng +1 位作者 Guang-Yi Xiong Jian-Bo Zhang 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第4期16-19,共4页
We investigate the effectiveness of the hopping parameter expansion(HPE) combined with the Z(2) noise method in the calculation of the trace of the inverse of Wilson's Dirac operator and some other disconnected c... We investigate the effectiveness of the hopping parameter expansion(HPE) combined with the Z(2) noise method in the calculation of the trace of the inverse of Wilson's Dirac operator and some other disconnected contributions.A numerical comparison of the standard deviation for the Z(2) noise method and HPE with the Z(2) noise method is carried out. It is found that there are noise reductions in all the quantities we calculated using the HPE with the Z(2) noise method. For the trace of the inverse of Wilson's Dirac operator, the HPE can reduce the statistical error by about 60%. 展开更多
关键词 HPE Hopping Parameter Expansion Technique in Noise Method for disconnected Quark Loops
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Deep Foundation Pit Excavations Adjacent to Disconnected Piled Rafts: A Review on Risk Control Practice
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作者 Bantayehu Uba Uge Yuancheng Guo 《Open Journal of Civil Engineering》 2020年第3期270-300,共31页
Foundation pit excavation engineering is an old subject full of decision making. Yet, it still deserves further research due to the associated high failure cost and the complexity of the geological conditions and/or t... Foundation pit excavation engineering is an old subject full of decision making. Yet, it still deserves further research due to the associated high failure cost and the complexity of the geological conditions and/or the surrounding existing infrastructure around it. This article overviews the risk control practice of foundation pit excavation projects in close proximity to <span style="font-family:Verdana;">existing</span><span style="font-family:Verdana;"> disconnected piled raft. More focus is given to geotechnical aspects. The review begins with achievements to ensure excavation performance </span><span style="font-family:Verdana;">requirements,</span><span style="font-family:Verdana;"> and follows to discuss the complex </span><span style="font-family:Verdana;">soil structure</span><span style="font-family:Verdana;"> interaction involved among the fundamental components</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">: </span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">the retaining wall, mat, piles, cushion, and the soil. After bringing consensus points to practicing engineers and </span><span style="font-family:Verdana;">decision makers</span><span style="font-family:Verdana;">, it then suggests possible future research directions.</span></span></span></span> 展开更多
关键词 Deep Foundation Pit Excavation disconnected Piled Raft Foundation Risk Control Observational Method
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Calculation of disconnected quark loops in lattice QCD
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作者 Zhen Cheng Jian-Bo Zhang Guang-Yi Xiong 《Chinese Physics C》 SCIE CAS CSCD 2020年第3期52-58,共7页
Calculation of disconnected quark loops in lattice QCD is very time consuming.Stochastic noise methods are generally used to estimate these loops.However,stochastic estimation gives large errors in the calculations of... Calculation of disconnected quark loops in lattice QCD is very time consuming.Stochastic noise methods are generally used to estimate these loops.However,stochastic estimation gives large errors in the calculations of disconnected diagrams.We use the symmetric multi-probing source(SMP)method to estimate the disconnected quark loops,and compare the results with the Z(2)noise method and the spin-color explicit(SCE)method on a quenched lattice QCD ensemble with lattice volume 12^3×24 and lattice spacing a≈0.1 fm.The results show that the SMP method is very suitable for the calculation of pseudoscalar disconnected quark loops.However,the SMP and SCE methods do not have an obvious advantage over the Z(2)noise method in the evaluation of the scalar disconnected loops. 展开更多
关键词 lattice QCD Wilson matrix disconnected quark loops Z(2)noise method SMP method
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3redon-Illman cohomology with actions of ;otally disconnected groups
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作者 Peilin SHI Lingzhen DONG 《Frontiers of Mathematics in China》 SCIE CSCD 2015年第2期367-375,共9页
We study the Bredon-IUman cohomology with local coefficients for a G-space X in the case of G being a totally disconnected, locally compact group. We prove that any short exact sequence of equivariant local coefficien... We study the Bredon-IUman cohomology with local coefficients for a G-space X in the case of G being a totally disconnected, locally compact group. We prove that any short exact sequence of equivariant local coefficients systems on X gives a long exact sequence of the associated Bredon-Illman cohomology groups with local coefficients. 展开更多
关键词 Bredon-Illman cohomology with local coefficients group action totally disconnected group exact sequence
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RECOGNITION OF ESSENTIALLY DISCONNECTED BENZENOIDS
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作者 陈荣斯 S.J.CYVIN B.N.CYVIN 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 1992年第4期377-382,共6页
A benzenoid, or a benzenoid system, is a connected planar graph whose every interiorface is a regular hexagon. A peak (resp. valley) of a benzenoid is a vertex which lies above(resp. below) all its first neighbors. A ... A benzenoid, or a benzenoid system, is a connected planar graph whose every interiorface is a regular hexagon. A peak (resp. valley) of a benzenoid is a vertex which lies above(resp. below) all its first neighbors. A Kekulean benzenoid is a benzenoid with at least oneperfect matching. An essentially disconnected benzenoid is a Kekulean benzenoid which hassome fixed bonds. Essentially disconnected benzenoids have proved to be very useful incertain enumeration techniques for Derfect matching. Hence the problem of recognizing 展开更多
关键词 RECOGNITION OF ESSENTIALLY disconnected BENZENOIDS
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Endoscopic pancreatogastric anastomosis in the treatment of symptoms associated with inflammatory diseases of the pancreas
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作者 Mateusz Jagielski Eryk Bella Marek Jackowski 《World Journal of Gastrointestinal Endoscopy》 2024年第7期406-412,共7页
BACKGROUND The outflow of pancreatic juice into the duodenum is often impaired in pancreatic inflammatory diseases.The basis of interventional treatment in these cases is anatomical transpapillary access of the main p... BACKGROUND The outflow of pancreatic juice into the duodenum is often impaired in pancreatic inflammatory diseases.The basis of interventional treatment in these cases is anatomical transpapillary access of the main pancreatic duct during endoscopic retrograde cholangiopancreatography(ERCP),which ensures the physiological outflow of pancreatic juice into the lumen of the digestive tract.However,in some patients,anatomical changes prevent transpapillary drainage of the main pancreatic duct.Surgery is the treatment of choice in such cases.AIM To evaluate the effectiveness and safety of endoscopic pancreaticogastrostomy under endoscopic ultrasound(EUS)guidance.METHODS Retrospective analysis of treatment outcomes of all patients with acute or chronic pancreatitis who underwent endoscopic pancreatogastric anastomosis under EUS guidance in 2018-2023 at the Department of General,Gastroenterological and Oncological Surgery,Ludwik Rydygier Collegium Medicum in Bydgoszcz,Nicolaus Copernicus University in Toruń,Poland.RESULTS In 9 patients[7 men,2 women;mean age 53.45(36-66)years],endoscopic pancreatogastric anastomosis under EUS guidance was performed because of the lack of transpapillary access during ERCP.Narrowing of the main pancreatic duct at the head of the pancreas was observed in 4/9 patients(44.44%).Pancreatic fragmentation(disconnected pancreatic duct syndrome)was diagnosed in 3/9 patients(33.33%).In 2/9 patients(22.22%),narrowing of the pancreatoenteric anastomosis was observed after pancreaticoduodenectomy.Technical success of endoscopic pancreaticogastrostomy was observed in 8/9 patients(88.89%).Endotherapeutic complications were observed in 2/9 patients(22.22%).Clinical success was achieved in 8/9 patients(88.89%).The mean follow-up period was 451(42-988)d.Long-term success of endoscopic pancreatogastric anastomosis was achieved in 7/9 patients(77.78%).CONCLUSION Endoscopic pancreaticogastrostomy under EUS guidance is an effective and safe treatment method,especially in the absence of transpapillary access to the main pancreatic duct. 展开更多
关键词 PANCREATICOGASTROSTOMY Chronic pancreatitis Acute pancreatitis disconnected pancreatic duct syndrome Endotherapy
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Enhanced DDoS Detection Using Advanced Machine Learning and Ensemble Techniques in Software Defined Networking
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作者 Hira Akhtar Butt Khoula Said Al Harthy +3 位作者 Mumtaz Ali Shah Mudassar Hussain Rashid Amin Mujeeb Ur Rehman 《Computers, Materials & Continua》 SCIE EI 2024年第11期3003-3031,共29页
Detecting sophisticated cyberattacks,mainly Distributed Denial of Service(DDoS)attacks,with unexpected patterns remains challenging in modern networks.Traditional detection systems often struggle to mitigate such atta... Detecting sophisticated cyberattacks,mainly Distributed Denial of Service(DDoS)attacks,with unexpected patterns remains challenging in modern networks.Traditional detection systems often struggle to mitigate such attacks in conventional and software-defined networking(SDN)environments.While Machine Learning(ML)models can distinguish between benign and malicious traffic,their limited feature scope hinders the detection of new zero-day or low-rate DDoS attacks requiring frequent retraining.In this paper,we propose a novel DDoS detection framework that combines Machine Learning(ML)and Ensemble Learning(EL)techniques to improve DDoS attack detection and mitigation in SDN environments.Our model leverages the“DDoS SDN”dataset for training and evaluation and employs a dynamic feature selection mechanism that enhances detection accuracy by focusing on the most relevant features.This adaptive approach addresses the limitations of conventional ML models and provides more accurate detection of various DDoS attack scenarios.Our proposed ensemble model introduces an additional layer of detection,increasing reliability through the innovative application of ensemble techniques.The proposed solution significantly enhances the model’s ability to identify and respond to dynamic threats in SDNs.It provides a strong foundation for proactive DDoS detection and mitigation,enhancing network defenses against evolving threats.Our comprehensive runtime analysis of Simultaneous Multi-Threading(SMT)on identical configurations shows superior accuracy and efficiency,with significantly reduced computational time,making it ideal for real-time DDoS detection in dynamic,rapidly changing SDNs.Experimental results demonstrate that our model achieves outstanding performance,outperforming traditional algorithms with 99%accuracy using Random Forest(RF)and K-Nearest Neighbors(KNN)and 98%accuracy using XGBoost. 展开更多
关键词 Table 1(continued)OSI layer Possible DDoS attack Data link MAC Address Flooding Physical Cable disconnection JaMMING physical impersonation
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Design of Cold-Junction Compensation and Disconnection Detection Circuits of Various Thermocouples and Implementation of Multi-Channel Interfaces Using Them-A Secondary Publication
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作者 Hyeong-Woo Cha 《Journal of Electronic Research and Application》 2024年第1期93-105,共13页
Cold-junction compensation(CJC)and disconnection detection circuit design of various thermocouples(TC)and multi-channel TC interface circuits were designed.The CJC and disconnection detection circuit consists of a CJC... Cold-junction compensation(CJC)and disconnection detection circuit design of various thermocouples(TC)and multi-channel TC interface circuits were designed.The CJC and disconnection detection circuit consists of a CJC semiconductor device,an instrumentation amplifier(IA),two resistors,and a diode for disconnection detection.Based on the basic circuit,a multi-channel interface circuit was also implemented.The CJC was implemented using compensation semiconductor and IA,and disconnection detection was detected by using two resistors and a diode so that IA input voltage became-0.42 V.As a result of the experiment using R-type TC,the error of the designed circuit was reduced from 0.14 mV to 3μV after CJC in the temperature range of 0°C to 1400°C.In addition,it was confirmed that the output voltage of IA was saturated from 88 mV to-14.2 V when TC was disconnected from normal.The output voltage of the designed circuit was 0 V to 10 V in the temperature range of 0°C to 1400°C.The results of the 4-channel interface experiment using R-type TC were almost identical to the CJC and disconnection detection results for each channel.The implemented multi-channel interface has a feature that can be applied equally to E,J,K,T,R,and S-type TCs by changing the terminals of CJC semiconductor devices and adjusting the IA gain. 展开更多
关键词 R-type thermocouple(TC) Cold-junction compensation(CJC) TC disconnection detection Multi-channel interface circuit Sensor interface
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The Absurdity of Happy Days
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作者 杨樱 《英语广场(学术研究)》 2012年第8期36-38,共3页
Happy Days,one of Samuel Beckett's renowned works,is remarkable for its absurdity.The paper approaches the predominant feature from such aspects as fragmented characters,disconnected language,peculiar structure an... Happy Days,one of Samuel Beckett's renowned works,is remarkable for its absurdity.The paper approaches the predominant feature from such aspects as fragmented characters,disconnected language,peculiar structure and grotesque stagecraft. 展开更多
关键词 Happy Days ABSURDITY fragmented characters disconnected language peculiar structure grotesque stagecraft
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拓扑空间中的强半开集 被引量:6
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作者 艾为鸿 《江西教育学院学报》 2003年第3期8-10,共3页
 对拓朴空间中的强半开集进行了探讨,给出了它的等价刻划及一些特征性质,研究了它与半开集。
关键词 半开集 拓扑空间 特征性质 等价刻划 拓朴
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Study on Scavenging and Disconnecting Effects of Nitrosation Reaction by Extracts of Tetradium Ruticarpum and Glycyrrhizae
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作者 张成 王应江 +3 位作者 吴高箭 魏玉娴 董侯燕 颜亨梅 《Agricultural Science & Technology》 CAS 2014年第6期970-976,共7页
In order to investigate and compare the effects of Tetradium ruticarpum and Glycyrrhizae extracts in terms of scavenging sodium nitrite and inhibiting N-ni- troso compounds formation, the 1_9(3^3) orthogonal test wa... In order to investigate and compare the effects of Tetradium ruticarpum and Glycyrrhizae extracts in terms of scavenging sodium nitrite and inhibiting N-ni- troso compounds formation, the 1_9(3^3) orthogonal test was conducted to extract the active components. In addition, the capacities of scavenging sodium nitrite and of in- hibiting the N-nitroso compounds formation were measured to confirm the optimum condition of extracting. When the scavenging rate was considered as the main index, the maximum capacities of scavenging sodium nitrite by the extracts of Tetradi- urn ruticarpum and Glycyrrhizae were 0.836 5 and 0.558 0, respectively. Further- more, when the disconnection rate was considered as the main index, the maximum capacities of inhibiting the N-nitroso compounds formation by the extracts of Tetradi- urn ruticarpum and G/ycyrrhizae were 0.922 8 and 0.625 6, respectively. As a re- suit, the capacity of inhibiting nitrosation reaction by Tetradium ruticarpum was shown to be much stronger than G/ycyrrhizae, no matter the scavenging rate or the disconnection rate as the main index to be considered. 展开更多
关键词 Tetradium ruticarpum and Glycyrrhizae extracts Disconnecting effect Scavenging effect Sodium nitrite N-Nitro compounds
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S─闭对称拓扑分子格 被引量:10
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作者 王国俊 《延安大学学报(自然科学版)》 1994年第3期8-15,共8页
本文的目的是在对称拓扑分子格的框架下继续对我们于[13]中引入的S─闭性进行讨论。值得注意的是,M.Erne'于[1]中提出的所谓“翻译h”在对称格的情形是寸步难移的。
关键词 对称 拓扑分子格 S-闭空间
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TOPOLOGICAL CHARACTERIZATIONS OF THE EXTENDING PROPERTY OF RINGS
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作者 卢丹庆 武同锁 《Acta Mathematica Scientia》 SCIE CSCD 2010年第4期1086-1092,共7页
A commutative ring R is called extending if every ideal is essential in a direct summand of RR. The following results are proved: (1) C(X) is an extending ring if and only if X is extremely disconnected; (2) S... A commutative ring R is called extending if every ideal is essential in a direct summand of RR. The following results are proved: (1) C(X) is an extending ring if and only if X is extremely disconnected; (2) Spec(R) is extremely disconnected and R is semiprime if and only if R is a nonsingular extending ring; (3) Spec(R) is extremely disconnected if and only if R/N(R) is an extending ring, where N(R) consists of all nilpotent elements of R. As an application, it is also shown that any Gelfand nonsingular extending ring is clean. 展开更多
关键词 Extending Rings extremely disconnected prime spectrum
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对称拓扑分子格中的可数紧性
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作者 艾为鸿 《浙江科技学院学报》 CAS 2003年第4期199-201,218,共4页
在对称拓扑分子格中引入12种可数紧性的概念,着重指出了它们在极不连通的对称拓扑分子格中的内在联系。
关键词 对称拓扑分子格 可数紧性 拓扑学 开元 半开元 半闭元
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