计算机辅助统计过程控制(CA-SPC)是提高过程管理水平和质量的重要手段。在对CA-SPC进行需求分析与确定的基础上,进一步对用 MS EXCEL 2000来实现 CA－SPC的技术可行性进行了深入研究,并指出其优越性。描述了基于 MS EXCEL 2000的 CA－SP...计算机辅助统计过程控制(CA-SPC)是提高过程管理水平和质量的重要手段。在对CA-SPC进行需求分析与确定的基础上,进一步对用 MS EXCEL 2000来实现 CA－SPC的技术可行性进行了深入研究,并指出其优越性。描述了基于 MS EXCEL 2000的 CA－SPC系统功能结构,对应用流程进行了研究,对实现过程中的关键技术进行了说明。通过实际应用,实现了对生产过程质量状况进行分析、监控,并自动生成报表的功能。展开更多
Bioactive ceramic scaffolds HA·TCP, aimed to be applied in clinic, were evaluated both in vitro and in vivo models. HA·TCP was supposed as a completely biodegradable material and designed as a scaffold to be...Bioactive ceramic scaffolds HA·TCP, aimed to be applied in clinic, were evaluated both in vitro and in vivo models. HA·TCP was supposed as a completely biodegradable material and designed as a scaffold to be used for bone reconstruction or regeneration. Materials processing was proposed and physical properties as well as microstructure feature were characterized. Biological postulation of the relationship between seeding density and proliferation, and viability of human osteoblasts cultured on the porous HA·TCP were quantitatively measured. Bone reconstruction was investigated both in vitro and in vivo by using these biodegradable scaffolds with pore sizes ranged in 200400 μm in diameter. The degradable scaffold supported cellular proliferation of seeded osteoblasts on the scaffold and shown normal differentiated function in vitro. Seeding density is an important factor for cell attachment and proliferation expression and has been considerably discussed. Suitable pore size of the scaffolds is required if promotion of bone reconstruction is desired. Clinical trials show that HA·TCP scaffolds are successful applied for bone reconstruction and regeneration and can be completely degraded in human body in 12 months. This approach suggests the feasibility of using porous HA·TCP scaffold materials for the transplantation of autogenous osteoblasts to regenerate bone tissue.展开更多
Based on the Latin square design of statistics, the thickness of first boundary layer, the turbulence model and the cell number were taken as the three main factors of uncertainty in CFD （computational fluid dynamics...Based on the Latin square design of statistics, the thickness of first boundary layer, the turbulence model and the cell number were taken as the three main factors of uncertainty in CFD （computational fluid dynamics）. Total resistance of hull was calculated and the flow field around the hull was simulated by CFD method. Then, the influence of uncertainty factors on the hull resistance was discussed by regression analysis with trimmed mesh and overset mesh. Through a series of calculation and analysis, the optimal calculation method was put forward, and the relevant parameters of the calculation were determined. Thirdly, the total resistance of different speed was calculated by using these two kinds of grids, which were in good agreement with the experimental results. Finally, according to the ITTC recommended procedures, uncertainty analysis in CFD was carried out with the numerical results of the total resistance by three sets of grids with uniform refinement ratio rG = √2. Then the modified resistance was compared with the experimental result, which improved the accuracy of the resistance prediction.展开更多
To protect environment, and to comply with the IMO＇s （International Maritime Organization） newest regulations about ship＇s SOx emission. This thesis illustrates a closed recycling absorb system based on NaOH solut...To protect environment, and to comply with the IMO＇s （International Maritime Organization） newest regulations about ship＇s SOx emission. This thesis illustrates a closed recycling absorb system based on NaOH solution recycling particularly for SOx onboard. The goal is to use NaOH solution to absorb SOx, and reduce the damage the ships made towards environment. The thesis analyzes the main features that could influence the absorption of SOx on board, and the precipitations during the experiment. To reveal that NaOH solution is very highly effective and economic in absorption of SOx on ships by this experiment, and to set a theoretical basic fundamental for future application of alkali solution recycling absorption system for SOx.展开更多
This paper presents the results of a combined study of building energy consumption and the electricity production from PV modules integrated into a shading device, taking account of different site layouts. Various com...This paper presents the results of a combined study of building energy consumption and the electricity production from PV modules integrated into a shading device, taking account of different site layouts. Various combinations of surrounding building configurations and the tilt angles of the shading device （that determines the PV module orientation） are examined.展开更多
A single-phase modular multilevel inverter based photovoltaic system for grid connection is proposed. This photovoltaic system utilizes two conversion stages： a boost converter for tracking the maximum power point an...A single-phase modular multilevel inverter based photovoltaic system for grid connection is proposed. This photovoltaic system utilizes two conversion stages： a boost converter for tracking the maximum power point and a modular multilevel inverter used as an interfacing unit. The maximum power point tracking is achieved with a fuzzy logic controller, and the modular multilevel inverter regulates the DC link voltage and synchronizes the grid voltage and current in order to achieve unity power factor operation. The proposed system provides high dynamic performance and power quality injected into the grid. The validity of the proposed system is confirmed by simulations.展开更多
Performance of a three-phase shunt active power filter(SAPF)relies on the capability of the controller to track the reference current.Therefore,designing an accurate current controller is crucial to guarantee satisfac...Performance of a three-phase shunt active power filter(SAPF)relies on the capability of the controller to track the reference current.Therefore,designing an accurate current controller is crucial to guarantee satisfactory SAPF operation.This paper presents a model predictive current controller(MPCC)for a low-cost,four-switch,shunt active power filter for power quality improvement.A four-switch,B4,converter topology is adopted as an SAPF,hence offering a simple,robust,and low-cost solution.In addition,to further reduce overall cost,only two interfacing filter inductors,instead of three,are used to eliminate switching current ripple.The proposed SAPF model MPCC is detailed for implementation,where simulation and experimental results validate effectiveness of the proposed control algorithm showing a 20%improvement in total harmonic distortion compared with a conventional hysteresis band current controller.展开更多
文摘计算机辅助统计过程控制(CA-SPC)是提高过程管理水平和质量的重要手段。在对CA-SPC进行需求分析与确定的基础上,进一步对用 MS EXCEL 2000来实现 CA－SPC的技术可行性进行了深入研究,并指出其优越性。描述了基于 MS EXCEL 2000的 CA－SPC系统功能结构,对应用流程进行了研究,对实现过程中的关键技术进行了说明。通过实际应用,实现了对生产过程质量状况进行分析、监控,并自动生成报表的功能。
文摘Bioactive ceramic scaffolds HA·TCP, aimed to be applied in clinic, were evaluated both in vitro and in vivo models. HA·TCP was supposed as a completely biodegradable material and designed as a scaffold to be used for bone reconstruction or regeneration. Materials processing was proposed and physical properties as well as microstructure feature were characterized. Biological postulation of the relationship between seeding density and proliferation, and viability of human osteoblasts cultured on the porous HA·TCP were quantitatively measured. Bone reconstruction was investigated both in vitro and in vivo by using these biodegradable scaffolds with pore sizes ranged in 200400 μm in diameter. The degradable scaffold supported cellular proliferation of seeded osteoblasts on the scaffold and shown normal differentiated function in vitro. Seeding density is an important factor for cell attachment and proliferation expression and has been considerably discussed. Suitable pore size of the scaffolds is required if promotion of bone reconstruction is desired. Clinical trials show that HA·TCP scaffolds are successful applied for bone reconstruction and regeneration and can be completely degraded in human body in 12 months. This approach suggests the feasibility of using porous HA·TCP scaffold materials for the transplantation of autogenous osteoblasts to regenerate bone tissue.
文摘Based on the Latin square design of statistics, the thickness of first boundary layer, the turbulence model and the cell number were taken as the three main factors of uncertainty in CFD （computational fluid dynamics）. Total resistance of hull was calculated and the flow field around the hull was simulated by CFD method. Then, the influence of uncertainty factors on the hull resistance was discussed by regression analysis with trimmed mesh and overset mesh. Through a series of calculation and analysis, the optimal calculation method was put forward, and the relevant parameters of the calculation were determined. Thirdly, the total resistance of different speed was calculated by using these two kinds of grids, which were in good agreement with the experimental results. Finally, according to the ITTC recommended procedures, uncertainty analysis in CFD was carried out with the numerical results of the total resistance by three sets of grids with uniform refinement ratio rG = √2. Then the modified resistance was compared with the experimental result, which improved the accuracy of the resistance prediction.
文摘To protect environment, and to comply with the IMO＇s （International Maritime Organization） newest regulations about ship＇s SOx emission. This thesis illustrates a closed recycling absorb system based on NaOH solution recycling particularly for SOx onboard. The goal is to use NaOH solution to absorb SOx, and reduce the damage the ships made towards environment. The thesis analyzes the main features that could influence the absorption of SOx on board, and the precipitations during the experiment. To reveal that NaOH solution is very highly effective and economic in absorption of SOx on ships by this experiment, and to set a theoretical basic fundamental for future application of alkali solution recycling absorption system for SOx.
文摘This paper presents the results of a combined study of building energy consumption and the electricity production from PV modules integrated into a shading device, taking account of different site layouts. Various combinations of surrounding building configurations and the tilt angles of the shading device （that determines the PV module orientation） are examined.
文摘A single-phase modular multilevel inverter based photovoltaic system for grid connection is proposed. This photovoltaic system utilizes two conversion stages： a boost converter for tracking the maximum power point and a modular multilevel inverter used as an interfacing unit. The maximum power point tracking is achieved with a fuzzy logic controller, and the modular multilevel inverter regulates the DC link voltage and synchronizes the grid voltage and current in order to achieve unity power factor operation. The proposed system provides high dynamic performance and power quality injected into the grid. The validity of the proposed system is confirmed by simulations.
文摘Performance of a three-phase shunt active power filter(SAPF)relies on the capability of the controller to track the reference current.Therefore,designing an accurate current controller is crucial to guarantee satisfactory SAPF operation.This paper presents a model predictive current controller(MPCC)for a low-cost,four-switch,shunt active power filter for power quality improvement.A four-switch,B4,converter topology is adopted as an SAPF,hence offering a simple,robust,and low-cost solution.In addition,to further reduce overall cost,only two interfacing filter inductors,instead of three,are used to eliminate switching current ripple.The proposed SAPF model MPCC is detailed for implementation,where simulation and experimental results validate effectiveness of the proposed control algorithm showing a 20%improvement in total harmonic distortion compared with a conventional hysteresis band current controller.
