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400t沿海货船更机改造
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作者 顾宣炎 《中国修船》 2001年第4期31-32,共2页
根据船东的需要以及“船舶规范”的要求 ,对 4 0 0t沿海货船进行更机改造 ,力求简单、少改动 ,考虑全面 ,设计合理 ,使该船更机后在营运中安全、可靠 ,达到预期的效果。
关键词 沿海货船 更机改造 船舶规范 船东要求 设计
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主机更机轴线校中一例
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作者 仇一平 《海运科技》 1996年第6期22-23,共2页
关键词 船舶 维修 更机 轴线校中
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HQ-Tree: A Distributed Spatial Index Based on Hadoop 被引量:5
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作者 FENG Jun TANG Zhixian WEI Mian XU Liming 《China Communications》 SCIE CSCD 2014年第7期128-141,共14页
In this paper,we propose a novel spatial data index based on Hadoop:HQ-Tree.In HQ-Tree,we use PR QuadTrec to solve the problem of poor efficiency in parallel processing,which is caused by data insertion order and spac... In this paper,we propose a novel spatial data index based on Hadoop:HQ-Tree.In HQ-Tree,we use PR QuadTrec to solve the problem of poor efficiency in parallel processing,which is caused by data insertion order and space overlapping.For the problem that HDFS cannot support random write,we propose an updating mechanism,called "Copy Write",to support the index update.Additionally,HQ-Tree employs a two-level index caching mechanism to reduce the cost of network transferring and I/O operations.Finally,we develop MapReduce-based algorithms,which are able to significantly enhance the efficiency of index creation and query.Experimental results demonstrate the effectiveness of our methods. 展开更多
关键词 spatial index QUADTREE HADOOP MAPREDUCE
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Precise large deviation result for heavy-tailed random sums and applications to risk theory
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作者 杨洋 林金官 《Journal of Southeast University(English Edition)》 EI CAS 2010年第3期498-501,共4页
The differences between two sequences of nonnegative independent and identically distributed random variables with sub-exponential tails and the random index are studied. The random index is a strictly stationary rene... The differences between two sequences of nonnegative independent and identically distributed random variables with sub-exponential tails and the random index are studied. The random index is a strictly stationary renewal counting process generated by some negatively associated random variables. Using a revised large deviation result of partial sums, the elementary renewal theorem and the central limit theorem of negatively associated random variables, a precise large deviation result is derived for the random sums. The result is applied to the customer-arrival-based insurance risk model. Some uniform asymptotics for the ruin probabilities of an insurance company are obtained as the number of customers or the time tends to infinity. 展开更多
关键词 precise large deviation random sum sub-exponential distribution renewal counting process customer-arrival-based insurance risk model
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Large Deviations for Random Sums on Some Kind of Heavy-tailed Classes in Risk Models 被引量:3
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作者 KONG Fan-chao WANG Jin-liang 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2006年第1期71-79,共9页
This paper is a further investigation into the large deviations for random sums of heavy-tailed,we extended and improved some results in ref. [1] and [2]. These results can applied to some questions in Insurance and F... This paper is a further investigation into the large deviations for random sums of heavy-tailed,we extended and improved some results in ref. [1] and [2]. These results can applied to some questions in Insurance and Finance. 展开更多
关键词 renewal risk model heavy-tailed distribution large deviation renewal counting process
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MicroRNAs in tumor stem cells
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作者 Xiaochen Hu Junqiang Yang +3 位作者 Ruijie Yang Ruina Yang Xinshuai Wang Shegan Gao 《The Chinese-German Journal of Clinical Oncology》 CAS 2015年第2期92-96,共5页
MicroRNAs (miRNAs) are a class of non-coding RNAs that are believed to have a significant role in tumorigenesis and cancer metastasis. Cancer stem cells play a major role in tumor recurrence, metastasis, and drug re... MicroRNAs (miRNAs) are a class of non-coding RNAs that are believed to have a significant role in tumorigenesis and cancer metastasis. Cancer stem cells play a major role in tumor recurrence, metastasis, and drug resistance. Research has shown that miRNAs can promote or inhibit the sternness of cancer stem cells and regulate the differentiation and self-renewal of cancer stem cells. In this article, the phenotype and regulatory mechanisms of miRNAs in cancer stem cells will be described, together with an explanation of their potential role in tumor diagnosis and treatment. 展开更多
关键词 MIRNAS tumor stem cells STERNNESS
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Finite element model updating for large span spatial steel structure considering uncertainties 被引量:4
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作者 滕军 朱焰煌 +2 位作者 周峰 李惠 欧进萍 《Journal of Central South University》 SCIE EI CAS 2010年第4期857-862,共6页
In order to establish the baseline finite element model for structural health monitoring,a new method of model updating was proposed after analyzing the uncertainties of measured data and the error of finite element m... In order to establish the baseline finite element model for structural health monitoring,a new method of model updating was proposed after analyzing the uncertainties of measured data and the error of finite element model.In the new method,the finite element model was replaced by the multi-output support vector regression machine(MSVR).The interval variables of the measured frequency were sampled by Latin hypercube sampling method.The samples of frequency were regarded as the inputs of the trained MSVR.The outputs of MSVR were the target values of design parameters.The steel structure of National Aquatic Center for Beijing Olympic Games was introduced as a case for finite element model updating.The results show that the proposed method can avoid solving the problem of complicated calculation.Both the estimated values and associated uncertainties of the structure parameters can be obtained by the method.The static and dynamic characteristics of the updated finite element model are in good agreement with the measured data. 展开更多
关键词 model updating UNCERTAINTY interval analysis multi-output support vector regression large span spatial steel structure
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Impact of different regeneration patterns of old-growth Chinese fir on quantity and quality of soil organic carbon
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作者 ZOU Shuang-quan YANG Zhi-jie +5 位作者 FAN Guang-kuo WANG Ping HE Zong-ming LIN Kai-min CAO Yong-kang XIAO Ling-ling 《Journal of Environmental Science and Engineering》 2009年第7期23-28,36,共7页
Chinese fir is one of the largest distributions of commercial forest plantation in South China. In this study, we chose the different regeneration patterns of Chinese fir for our researches, the results showed differe... Chinese fir is one of the largest distributions of commercial forest plantation in South China. In this study, we chose the different regeneration patterns of Chinese fir for our researches, the results showed different regeneration patterns affected both the quantity and quality of soil organic carbon. clear cutting followed by different regeneration in old-growth Chinese fir decreased the quantity of soil organic carbon both in artificial regeneration forest and natural regeneration forest, and both of them were significantly different with the old-growth Chinese fir forest (p〈0.05). The concentrations of soil organic carbon(SOC) and particulate organic carbon(POC) in natural regeneration forest were higher than those in artificial regeneration forest, and the difference was significant in the 0-5 cm layer (p〈0.05). Different regeneration patterns decreased forest SOC storage. Compared with the old-growth Chinese fir, SOC storage in 0-100 cm layer decreased by 7.09% and 13.27% in natural regeneration forest and artificial regeneration forest respectively, and the differences were both significant (p〈0.05). In addition, SOC storage in 0-100 cm layer of natural regeneration forest was 7.13% higher than that in artificial regeneration forest. 展开更多
关键词 Chinese fir regeneration pattern SOC POC
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Efficacy and safety of electroacupuncture for perimenopausal insomnia: a randomized controlled trial 被引量:3
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作者 Zhao Fei-yi Yan Hai-xia +2 位作者 Zhao Ying-xia Chen Si-han Xu Hong 《Journal of Acupuncture and Tuina Science》 CSCD 2019年第3期188-195,共8页
Objective: To observe the effectiveness and safety of electroacupuncture (EA) plus Luohua Anshen oral liquid for patients with perimenopausal insomnia. Methods: A total of 66 participants who met the inclusion criteri... Objective: To observe the effectiveness and safety of electroacupuncture (EA) plus Luohua Anshen oral liquid for patients with perimenopausal insomnia. Methods: A total of 66 participants who met the inclusion criteria were enrolled in the randomized controlled trial and allocated to a treatment group and a control group at a ratio of 1:1, with 33 cases in each group. Both groups were given Luohua Anshen oral liquid as a basic treatment. The treatment group was additionally given EA every other day, three times a week. Both groups were treated for four weeks and a four-week follow-up was conducted. The scores of Pittsburgh sleep quality index (PSQI), Kupperman index (KI) and traditional Chinese medicine sleep syndrome scale (TCMSSS) were recorded at pre- and post-treatment, and at the follow-up. Meanwhile, adverse effects were monitored and recorded. Results: After four-week treatment, the global scores of PSQI, KI and TCMSSS in both groups declined significantly (all P<0.05), and the decreases in the treatment group were more significant than those in the control group (allP<0.05). The global scores of PSQI, KI and TCMSSS in both groups at the follow-up visit were significantly different from the corresponding baseline (allP<0.05), while insignificantly different from those assessed at post-treatment (allP>0.05). The total effective rate was 93.9% in the treatment group, significantly higher than 72.2% in the control group (P<0.05). No significant adverse event was reported in this trial excepted one patient experienced slight dizziness in the first acupuncture treatment. Conclusion: EA plus Luohua Anshen oral liquid is safe for perimenopausal insomnia with satisfactory short- and long-term effectiveness, and it shows certain advantage compared with using Luohua Anshen oral liquid alone. 展开更多
关键词 Acupuncture Therapy ELECTROACUPUNCTURE INSOMNIA PERIMENOPAUSE CLIMACTERIC Acupuncture Medication Combined Randomized Controlled Trial
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Retrofit of Ressalat jacket platform (Persian Gulf) using friction damper device 被引量:1
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作者 Y. KOMACHI M. R. TABESHPOUR +1 位作者 A. A. GOLAFSHANI I. MUALLA 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2011年第9期680-691,共12页
A friction damper device (FDD) is used for vibration control of an existing steel jacket platform under seismic excitation. First, the damping is presented for vibration mitigation of structures located in seismically... A friction damper device (FDD) is used for vibration control of an existing steel jacket platform under seismic excitation. First, the damping is presented for vibration mitigation of structures located in seismically active zones. A new method for quick design of friction or yielding damping devices is presented. The effectiveness of the damping system employing such FDDs in a jacket platform is evaluated numerically. The influence of key parameters of the damping system on the vibration suppression of the offshore structure is studied in detail. To examine the vibration control effectiveness of the FDD for the jacket platform, performance of the controlled structure under the seismic forces is studied using numerical simulations. A parametric study is undertaken to discover the optimized slip load and brace area of the FDD. It is shown that the FDD is effective in mitigating the dynamic responses of the offshore platform structure. 展开更多
关键词 Jacket offshore platform Seismic retrofit Friction damper devices (FDDs)
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Task space control of free-floating space robots using constrained adaptive RBF-NTSM 被引量:11
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作者 GUO ShengPeng LI DongXu +1 位作者 MENG YunHe FAN CaiZhi 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第4期828-837,共10页
Trajectory tracking control of space robots in task space is of great importance to space missions, which require on-orbit manipulations. This paper focuses on position and attitude tracking control of a tree-floating... Trajectory tracking control of space robots in task space is of great importance to space missions, which require on-orbit manipulations. This paper focuses on position and attitude tracking control of a tree-floating space robot in task space. Since nei- ther the nonlinear terms and parametric uncertainties of the dynamic model, nor the external disturbances are known, an adap- tive radial basis function network based nonsingular terminal sliding mode (RBF-NTSM) control method is presented. The proposed algorithm combines the nonlinear sliding manifold with the radial basis function to improve control performance. Moreover, in order to account for actuator physical constraints, a constrained adaptive RBF-NTSM, which employs a RBF network to compensate for the limited input is developed. The adaptive updating laws acquired by Lyapunov approach guar- antee the global stability of the control system and suppress chattering problems. Two examples are provided using a six-link free-floating space robot. Simulation results clearly demonstrate that the proposed constrained adaptive RBF-NTSM control method performs high precision task based on incomplete dynamic model of the space robots. In addition, the control errors converge faster and the chattering is eliminated comparing to traditional sliding mode control. 展开更多
关键词 free-floating space robots task space radial basis function nonsingular terminal sliding mode
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Uniform tail asymptotics for the aggregate claims with stochastic discount in the renewal risk models
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作者 ZHU ChunHua GAO QiBing LIN JinGuan 《Science China Mathematics》 SCIE CSCD 2015年第5期1079-1090,共12页
Considering an insurer who is allowed to make risk-free and risky investments, as in Tang et al.(2010), the price process of the investment portfolio is described as a geometric L′evy process. We study the tail proba... Considering an insurer who is allowed to make risk-free and risky investments, as in Tang et al.(2010), the price process of the investment portfolio is described as a geometric L′evy process. We study the tail probability of the stochastic present value of future aggregate claims. When the claim-size distribution is of extended regular variation, we obtain an asymptotically equivalent formula which holds uniformly for all time horizons, and furthermore, the same asymptotic formula holds for the finite-time ruin probabilities. The results extend the works of Tang et al.(2010). 展开更多
关键词 renewal risk models ASYMPTOTICS Levy process UNIFORMITY extended regular variation
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