针对感应式电能传输(inductive power transfer,IPT)系统偏移造成输出电压不稳定和效率低下的问题,提出一种强抗偏移的S/SP补偿IPT系统,该系统在变耦合变自感和变耦合不变自感两种情况下均能保证较小的输出电压波动和较高的传输效率。首...针对感应式电能传输(inductive power transfer,IPT)系统偏移造成输出电压不稳定和效率低下的问题,提出一种强抗偏移的S/SP补偿IPT系统,该系统在变耦合变自感和变耦合不变自感两种情况下均能保证较小的输出电压波动和较高的传输效率。首先,基于Maxwell有限元仿真,分析罐型磁心松耦合变压器的磁通分布和磁场分布特性,总结不同方向偏移的参数变化规律。然后,提出一种提高系统抗偏移能力的S/SP补偿参数设计方法,得到相应的磁耦合机构设计准则,并结合磁仿真数据,通过数值计算方式求得系统输出波动和输入阻抗角的变化规律。最后,通过实验验证文中采用罐型磁心和新型S/SP补偿拓扑实现多方向偏移下高效率、低波动无线电能传输的可行性。在额定负载下,系统沿纵向和水平方向偏移的输出电压波动分别为2.7%和3.1%,传输效率维持在90.8%~94.3%。展开更多
Ports operating in the same geographical range face significant competition among them. In such setting, less competitive ports may continually lose patronage of shippers (indigenous to them) to adjacent ones with b...Ports operating in the same geographical range face significant competition among them. In such setting, less competitive ports may continually lose patronage of shippers (indigenous to them) to adjacent ones with better attributes. The extent of and determinants of inter-port competition in the West Africa's coast are of interest to port administrators/operators who risk losing significant portion of their domestic generated cargo traffic to competing neighbouring ports. In this paper, we explore the question of what port specific attributes serve as competitive basis for West Africa's coastal ports operating in proximity to the other. Through a survey, users of these ports were asked to identify port specific attributes which they consider when deciding which port to use for shipments making. To enrich our empirical model, data collected from the survey were augmented with secondary data (on the identified attributes) obtained from the respective ports. Statistical evidence from data analysis suggests that ports operating in proximity in the West Africa's coast compete on the basis of attributes that minimise costs for port users, viz: ships' pre-berthiig time, ship turnround time, crane efficiency and availability of cargo spaces (proxied by frequency of ship calls). Policy implications of the findings were discussed.展开更多
The functionally graded thermal barrier coatings (FG-TBCs) with 80%ZrO2-13%CeO2-7%Y2O3 (C-YSZ)/NiCoCrAlY were prepared using a recently developed supersonic plasma spraying(S-PS) with dual powder feed ports syst...The functionally graded thermal barrier coatings (FG-TBCs) with 80%ZrO2-13%CeO2-7%Y2O3 (C-YSZ)/NiCoCrAlY were prepared using a recently developed supersonic plasma spraying(S-PS) with dual powder feed ports system. The thermal shock experiment of FG-TBCs specimens was carried out by means of the automatic thermal cycle device, in which the samples were heated to 1200℃ by oxygen-acetylene flame jet then water-quenched to ambient temperature. The temperature—time curves of specimens and photographs can be watched on-line and recorded by a computer during the test. The results show that the totally 1mm-thick FG-TBCs have excellent thermal shock resistance due to the fact that the coatings have no any peeling-off after 200 thermal cycles. The microstructures and morphologies of FG-TBCs were characterized and analyzed by SEM.展开更多
The 21th century is a "quality century". Facing the s evere challenge about quality, all the developed industry countries attach impor tance to the research and education about quality project. With the deep...The 21th century is a "quality century". Facing the s evere challenge about quality, all the developed industry countries attach impor tance to the research and education about quality project. With the deepening of the reform of China and it’s joining to WTO, many industries and enterprises wi ll be confronted with severe challenge while being offered the opportunity to wa lk up to the world. The arrival of knowledge economy and web time has provided t he space for the innovation on enterprise management. It has also provided new m ethod and model for enterprise management, that is online management based on th e internet. The online management use an enterprise model including the goal of the enterprise and the scheme to carry out it to represent the whole operational of all the work. The online management is constructed on the integration of exp ert system, database, software and other technical models. How to scientifically manage the entire system of product, precisely master the condition of quantity and quality and analyze the rules of the change of produc t quality in order to carry out the overall control of quality, guarantee the go od condition of product as well as improve product quality and prolong it’s se rvice life was discussed in this thesis. Based on the above research the thesis also discussed how to develop the study on product quality information and const ruct it’s decision making support system. The concrete measures to improve peopl e’s concept of quality are also raised. Based on the type analysis, scientific management of product quality information should start from dynamic information of quality, instruction information as we ll as the information about the use, maintain, management and conservation of pr oduct, and induce them and further propose a design scheme of feedback system on product quality information, and then set up the blueprint of the information s ystem of product quality. This thesis included 7 chapters:1.the type of quality information;2.the content of quality information;3.the construction of the se nsitive web for transfering information, and collecting and transfering quality information rapidly and effectively;4.the way and procedure to transfer informa tion;5.the construction of quality information library for all phases; 6.the d isposal of quality information;7.the decision making support system of the mana gement of quality information;8.attach importance to three key factors on impro ving quality concept.展开更多
The market concentration of selected 24 container port/terminal in the Middle East region was evaluated. Data collected for 6 years (2009-2014), HHI (Herfindahl-Hirschman index technique) was used to analyse the m...The market concentration of selected 24 container port/terminal in the Middle East region was evaluated. Data collected for 6 years (2009-2014), HHI (Herfindahl-Hirschman index technique) was used to analyse the market behaviour and the movement of the market towards monopoly or to lead to PPC (pure and perfect competition). Based on the above, by analyzing the defined market data, it was found to be a promising market and tends to competition. Of course, this serves the interest of the client, which is the efficiency and speed of cargo handling safely and at the lowest cost.展开更多
In this paper, we developed performance assessment criteria to evaluate effects of compliance to ISPS Code's requirements on port/terminal operation in Nigeria. The primary data for the study were obtained from copie...In this paper, we developed performance assessment criteria to evaluate effects of compliance to ISPS Code's requirements on port/terminal operation in Nigeria. The primary data for the study were obtained from copies ofsurvey questionnaires administered to random sample of port users stratified by areas of specialisation. Hypotheses governing this study were based on the premise that additional port facilities provided and security measures adopted in compliance to ISPS code's requirements would have positive spillover effects on port operations. Evidence from data analysis indicated that compliance to ISPS code had positive effects on performance of operational performance of Nigeria ports. Similar effects were also observed inport users' satisfaction and profitability. The paper contributes by providing decision support framework for ports and terminals. monitoring and gauging outcomes of ISPS code administration in展开更多
港口吞吐量时序变化数据量较小且变化快,传统长短时记忆(long short term memory,LSTM)神经网络在此类数据上易出现过拟合,导致模型预测性能不佳。针对此问题,提出融合预训练与LSTM时序模型,通过预训练捕获任务领域的全局信息,再用LSTM...港口吞吐量时序变化数据量较小且变化快,传统长短时记忆(long short term memory,LSTM)神经网络在此类数据上易出现过拟合,导致模型预测性能不佳。针对此问题,提出融合预训练与LSTM时序模型,通过预训练捕获任务领域的全局信息,再用LSTM模型精确描述各个港口的吞吐量变化规律,以提升模型对全部港口吞吐量预测的准确性。以天津港等15个中大型港口过去21年的月吞吐量为实验数据,以BP(back propagation)、自回归积分滑动平均模型(autoregressive integrated moving average model,ARIMA)、传统LSTM等预测模型和目前流行的图神经网络(graph nerual network,GNN)-LSTM模型为比较基准进行仿真实验。结果表明:所提出的融合预训练的LSTM模型能有效解决LSTM神经网络的过拟合问题,整体预测准确率高于所有基准模型。与传统LSTM模型相比,基于预训练的LSTM的MAE指标平均降低45.2%,最多降低80.0%。展开更多
There are four distinctive features in Egypt’s port construction and maritime transportation:Egypt’s port construction and maritime transportation is a vital part of the international shipping system;maritime transp...There are four distinctive features in Egypt’s port construction and maritime transportation:Egypt’s port construction and maritime transportation is a vital part of the international shipping system;maritime transportation is an important backbone industry in Egypt;Egypt’s port construction propels its domestic economy and international interaction;and the capacity for ocean shipping still needs upgrading.China’s participation in Egypt’s port construction is,on one side,the further demand of China’s economic globalization,and on the other side,it is an outcome of the beneficial interactions between China and Egypt.Egypt’s port construction has started a new chapter ever since Abdel Fattah al Sisi assumed power.As opportunities and risks coexist in China’s participation in Egypt’s port construction,only when we are fully aware of the risks and make scientific decisions based on China’s own strengths can we effectively participate in Egypt’s port construction to yield a win-win result.展开更多
Under the guidance of Deng Xiao-ping’s strategic think-ing of openning to the outside world, the structure of om-nibearing openness has basically taken shape in China. Follow-
In connection with the port facilities spatial distribution feature and volume of relevant attributes, applying of GIS technology and computer technology to build an application system to administrate port facilities,...In connection with the port facilities spatial distribution feature and volume of relevant attributes, applying of GIS technology and computer technology to build an application system to administrate port facilities, makes it convenient for port facilities administrator to know well of port facilities location and execute management. In this paper, the application and development of GIS to port facilities is studied. The main idea to understand the system design, the frame structure and its technical structure; and to demonstrate facilities information data processing& management and system function by connection with development instance. The construction of the system will enable the port facilities GIS become daily management tools and play an important role to improve efficiency, and promote the intelligent and convenient managemen^t of port facilities.展开更多
This paper presents an analysis and validation by advanced system simulation of compact and low-cost six-port transceivers for future wireless local area networks (WLANs) operating at millimeter-wave frequencies. To...This paper presents an analysis and validation by advanced system simulation of compact and low-cost six-port transceivers for future wireless local area networks (WLANs) operating at millimeter-wave frequencies. To obtain realistic simulation results, a six-port model based on the measurement results of a fabricated V-band hybrid coupler, the core component, is used. A frequency-division multiplexing scheme is used by introducing four quadrature phase-shift keying (QPSK) channels in the wireless communication link. The data rate achieved is about 4 Gbit/s. The operating frequency is in the 60-64 GHz unlicensed band. Bit error rate (BER) results are presented, and a comparison is made between single-carrier and multicarrier architectures. The proposed wireless system can be considered an efficient candidate for millimeter-wave communication systems operating at quasi-optical data rates.展开更多
It is April 18th again,an unforgettable date for us. 20 Vears ago, liulinhai from China Ocean Shipping Company(COSCO), the first cargo ship anchored at Seattle. It ushered in a new chapter and therefore bullt up an oc...It is April 18th again,an unforgettable date for us. 20 Vears ago, liulinhai from China Ocean Shipping Company(COSCO), the first cargo ship anchored at Seattle. It ushered in a new chapter and therefore bullt up an ocean-crossing bridge of Sino-US shipping business. Over the past 20 yearS,ships of COSCO. which shuttled between China and the United States, carrying friendship between the two countries and best wishes for peace and development, promoted greatly the Sino-US trade.展开更多
文摘针对感应式电能传输(inductive power transfer,IPT)系统偏移造成输出电压不稳定和效率低下的问题,提出一种强抗偏移的S/SP补偿IPT系统,该系统在变耦合变自感和变耦合不变自感两种情况下均能保证较小的输出电压波动和较高的传输效率。首先,基于Maxwell有限元仿真,分析罐型磁心松耦合变压器的磁通分布和磁场分布特性,总结不同方向偏移的参数变化规律。然后,提出一种提高系统抗偏移能力的S/SP补偿参数设计方法,得到相应的磁耦合机构设计准则,并结合磁仿真数据,通过数值计算方式求得系统输出波动和输入阻抗角的变化规律。最后,通过实验验证文中采用罐型磁心和新型S/SP补偿拓扑实现多方向偏移下高效率、低波动无线电能传输的可行性。在额定负载下,系统沿纵向和水平方向偏移的输出电压波动分别为2.7%和3.1%,传输效率维持在90.8%~94.3%。
文摘Ports operating in the same geographical range face significant competition among them. In such setting, less competitive ports may continually lose patronage of shippers (indigenous to them) to adjacent ones with better attributes. The extent of and determinants of inter-port competition in the West Africa's coast are of interest to port administrators/operators who risk losing significant portion of their domestic generated cargo traffic to competing neighbouring ports. In this paper, we explore the question of what port specific attributes serve as competitive basis for West Africa's coastal ports operating in proximity to the other. Through a survey, users of these ports were asked to identify port specific attributes which they consider when deciding which port to use for shipments making. To enrich our empirical model, data collected from the survey were augmented with secondary data (on the identified attributes) obtained from the respective ports. Statistical evidence from data analysis suggests that ports operating in proximity in the West Africa's coast compete on the basis of attributes that minimise costs for port users, viz: ships' pre-berthiig time, ship turnround time, crane efficiency and availability of cargo spaces (proxied by frequency of ship calls). Policy implications of the findings were discussed.
文摘The functionally graded thermal barrier coatings (FG-TBCs) with 80%ZrO2-13%CeO2-7%Y2O3 (C-YSZ)/NiCoCrAlY were prepared using a recently developed supersonic plasma spraying(S-PS) with dual powder feed ports system. The thermal shock experiment of FG-TBCs specimens was carried out by means of the automatic thermal cycle device, in which the samples were heated to 1200℃ by oxygen-acetylene flame jet then water-quenched to ambient temperature. The temperature—time curves of specimens and photographs can be watched on-line and recorded by a computer during the test. The results show that the totally 1mm-thick FG-TBCs have excellent thermal shock resistance due to the fact that the coatings have no any peeling-off after 200 thermal cycles. The microstructures and morphologies of FG-TBCs were characterized and analyzed by SEM.
文摘The 21th century is a "quality century". Facing the s evere challenge about quality, all the developed industry countries attach impor tance to the research and education about quality project. With the deepening of the reform of China and it’s joining to WTO, many industries and enterprises wi ll be confronted with severe challenge while being offered the opportunity to wa lk up to the world. The arrival of knowledge economy and web time has provided t he space for the innovation on enterprise management. It has also provided new m ethod and model for enterprise management, that is online management based on th e internet. The online management use an enterprise model including the goal of the enterprise and the scheme to carry out it to represent the whole operational of all the work. The online management is constructed on the integration of exp ert system, database, software and other technical models. How to scientifically manage the entire system of product, precisely master the condition of quantity and quality and analyze the rules of the change of produc t quality in order to carry out the overall control of quality, guarantee the go od condition of product as well as improve product quality and prolong it’s se rvice life was discussed in this thesis. Based on the above research the thesis also discussed how to develop the study on product quality information and const ruct it’s decision making support system. The concrete measures to improve peopl e’s concept of quality are also raised. Based on the type analysis, scientific management of product quality information should start from dynamic information of quality, instruction information as we ll as the information about the use, maintain, management and conservation of pr oduct, and induce them and further propose a design scheme of feedback system on product quality information, and then set up the blueprint of the information s ystem of product quality. This thesis included 7 chapters:1.the type of quality information;2.the content of quality information;3.the construction of the se nsitive web for transfering information, and collecting and transfering quality information rapidly and effectively;4.the way and procedure to transfer informa tion;5.the construction of quality information library for all phases; 6.the d isposal of quality information;7.the decision making support system of the mana gement of quality information;8.attach importance to three key factors on impro ving quality concept.
文摘The market concentration of selected 24 container port/terminal in the Middle East region was evaluated. Data collected for 6 years (2009-2014), HHI (Herfindahl-Hirschman index technique) was used to analyse the market behaviour and the movement of the market towards monopoly or to lead to PPC (pure and perfect competition). Based on the above, by analyzing the defined market data, it was found to be a promising market and tends to competition. Of course, this serves the interest of the client, which is the efficiency and speed of cargo handling safely and at the lowest cost.
文摘In this paper, we developed performance assessment criteria to evaluate effects of compliance to ISPS Code's requirements on port/terminal operation in Nigeria. The primary data for the study were obtained from copies ofsurvey questionnaires administered to random sample of port users stratified by areas of specialisation. Hypotheses governing this study were based on the premise that additional port facilities provided and security measures adopted in compliance to ISPS code's requirements would have positive spillover effects on port operations. Evidence from data analysis indicated that compliance to ISPS code had positive effects on performance of operational performance of Nigeria ports. Similar effects were also observed inport users' satisfaction and profitability. The paper contributes by providing decision support framework for ports and terminals. monitoring and gauging outcomes of ISPS code administration in
文摘港口吞吐量时序变化数据量较小且变化快,传统长短时记忆(long short term memory,LSTM)神经网络在此类数据上易出现过拟合,导致模型预测性能不佳。针对此问题,提出融合预训练与LSTM时序模型,通过预训练捕获任务领域的全局信息,再用LSTM模型精确描述各个港口的吞吐量变化规律,以提升模型对全部港口吞吐量预测的准确性。以天津港等15个中大型港口过去21年的月吞吐量为实验数据,以BP(back propagation)、自回归积分滑动平均模型(autoregressive integrated moving average model,ARIMA)、传统LSTM等预测模型和目前流行的图神经网络(graph nerual network,GNN)-LSTM模型为比较基准进行仿真实验。结果表明:所提出的融合预训练的LSTM模型能有效解决LSTM神经网络的过拟合问题,整体预测准确率高于所有基准模型。与传统LSTM模型相比,基于预训练的LSTM的MAE指标平均降低45.2%,最多降低80.0%。
基金Research Project funded by China Ministry of Education Social Science Foundation entitled“The Coordination among Great Powers in the Middle East:China’s Participation in Hot Issues(No.16JJDGJW012)”.
文摘There are four distinctive features in Egypt’s port construction and maritime transportation:Egypt’s port construction and maritime transportation is a vital part of the international shipping system;maritime transportation is an important backbone industry in Egypt;Egypt’s port construction propels its domestic economy and international interaction;and the capacity for ocean shipping still needs upgrading.China’s participation in Egypt’s port construction is,on one side,the further demand of China’s economic globalization,and on the other side,it is an outcome of the beneficial interactions between China and Egypt.Egypt’s port construction has started a new chapter ever since Abdel Fattah al Sisi assumed power.As opportunities and risks coexist in China’s participation in Egypt’s port construction,only when we are fully aware of the risks and make scientific decisions based on China’s own strengths can we effectively participate in Egypt’s port construction to yield a win-win result.
文摘Under the guidance of Deng Xiao-ping’s strategic think-ing of openning to the outside world, the structure of om-nibearing openness has basically taken shape in China. Follow-
文摘In connection with the port facilities spatial distribution feature and volume of relevant attributes, applying of GIS technology and computer technology to build an application system to administrate port facilities, makes it convenient for port facilities administrator to know well of port facilities location and execute management. In this paper, the application and development of GIS to port facilities is studied. The main idea to understand the system design, the frame structure and its technical structure; and to demonstrate facilities information data processing& management and system function by connection with development instance. The construction of the system will enable the port facilities GIS become daily management tools and play an important role to improve efficiency, and promote the intelligent and convenient managemen^t of port facilities.
文摘This paper presents an analysis and validation by advanced system simulation of compact and low-cost six-port transceivers for future wireless local area networks (WLANs) operating at millimeter-wave frequencies. To obtain realistic simulation results, a six-port model based on the measurement results of a fabricated V-band hybrid coupler, the core component, is used. A frequency-division multiplexing scheme is used by introducing four quadrature phase-shift keying (QPSK) channels in the wireless communication link. The data rate achieved is about 4 Gbit/s. The operating frequency is in the 60-64 GHz unlicensed band. Bit error rate (BER) results are presented, and a comparison is made between single-carrier and multicarrier architectures. The proposed wireless system can be considered an efficient candidate for millimeter-wave communication systems operating at quasi-optical data rates.
文摘It is April 18th again,an unforgettable date for us. 20 Vears ago, liulinhai from China Ocean Shipping Company(COSCO), the first cargo ship anchored at Seattle. It ushered in a new chapter and therefore bullt up an ocean-crossing bridge of Sino-US shipping business. Over the past 20 yearS,ships of COSCO. which shuttled between China and the United States, carrying friendship between the two countries and best wishes for peace and development, promoted greatly the Sino-US trade.