The crushing performance of printed circuit board (PCB) was studied on several crushers. The results show that PCB is a material which is difficult to crush. The crushing performance of PCB with disk crusher, especial...The crushing performance of printed circuit board (PCB) was studied on several crushers. The results show that PCB is a material which is difficult to crush. The crushing performance of PCB with disk crusher, especially vibration grinding, which has cut or impact action, excels that of jaw crusher or roller crusher. The PCB scrap is worthwhile to recycle using variety of modern characterization methods. When compared with natural resources, this material stream remains a rich precious metal and nonferrous metals. In PCB scrap, metals account for 47% of the total material composition, in which there exists 19.66% copper, 11.47% iron, 3.93% lead, 300 g/t gold and 510 kg/t silver, etc. In addition, the PCB scrap contains 27% of plastics and 26% of refractory oxides.展开更多
Objective To analyze the short-term outcomes of redo coronary artery bypass grafting(CABG) using on-pump and off-pump CABG techniques. Methods From January 2003 to August 2013, non-randomized 80 patients were treated ...Objective To analyze the short-term outcomes of redo coronary artery bypass grafting(CABG) using on-pump and off-pump CABG techniques. Methods From January 2003 to August 2013, non-randomized 80 patients were treated with redo CABG in the Department of Cardiac Surgery, Peking University Third Hospital. Among these patients, 40 underwent on-pump CABG technique(redo-ONCAB group) and 40 underwent off-pump CABG technique(redo-OPCAB group). Furthermore, transmyocardial laser revascularization was performed in high-risk patients who were not suitable to conventional grafting. Clinical data of the two groups were recorded and analyzed including operation time, coronary grafts, incomplete revascularization, postoperative ventilation, perioperative stroke, and low output syndrome, etc. Results There were no significantly differences in age, gender distribution, incidences of hypertension, stroke, and other clinical characteristics between redo-OPCAB group and redo-ONCAB group(all P>0.05), except for incidences of renal dysfunction and pulmonary disease(all P<0.05). The number of grafting vessels in the redo-ONCAB and redo-OPCAB groups was 2.1 ± 0.74 and 1.4 ±0.52 respectively. There was significant difference between the two groups(P=0.0243). Compared with the redo-ONCAB group, there was shorter operation time(P=0.0045), postoperative ventilation(P=0.0211) and intensive care unit stay(P=0.0400), as well as fewer use of platelet(P=0.0338) and blood transfusion(P=0.0034) in the redo-OPCAB group. The incidence of incomplete revascularization(P=0.0253) and the use of transmyocardial laser revascularization(P=0.0052) were higher in the redo-OPCAB group than those in the redo-ONCAB group(all P<0.05). However, no significant differences were showed for the incidence of the use of intra aortic balloon pump and continuous renal replacement therapy, perioperative stroke, low output syndrome, and in-hospital mortality between the two groups(all P>0.05). Conclusion Redo CABG is the safety and efficacy surgical procedure, and redo-OPCAB technique with better outcomes is commended especially in high-risk patients.展开更多
Physical methods show great potential and advantages on comprehensive reutilization of waste printed circuit boards (PCBs) because of lower investment and operation cost, higher efficiency and environment friendliness...Physical methods show great potential and advantages on comprehensive reutilization of waste printed circuit boards (PCBs) because of lower investment and operation cost, higher efficiency and environment friendliness. However, metals contained in fine fraction of PCBs cannot be recovered effectively by conventional equipments such as high tension electrostatic separator or shaking table. In the paper, this conundrum was resolved successfully with the enhanced Falcon SB concentrator. The separation mechanism of Falcon SB concentrator was analyzed and main factors affecting separation efficiency such as magnitude of rotation frequency of bowl, water counter pressure and slurry concentration of feed were studied and interaction of factors above also were investigated using Design-Expert software. Experiment results show that complete liberation degree and great difference of density between metals and nonmetals are suitable to recover metals from -74 μm PCBs using enhanced Falcon SB concentrator and 80.77 % integration efficiency can be achieved when slurry concentration of feed is 40 g/L with the water counter pressure of 0.01 MPa and rotation frequency of 50 Hz.展开更多
This paper divides the vertex set into several disjoined subsets and provides an optimal fault-tolerance routing algorithm based on the vertex set partition. This algorithm is efficient and convergent, in polynomial t...This paper divides the vertex set into several disjoined subsets and provides an optimal fault-tolerance routing algorithm based on the vertex set partition. This algorithm is efficient and convergent, in polynomial time, we can get the output if the vertex is given.展开更多
文摘The crushing performance of printed circuit board (PCB) was studied on several crushers. The results show that PCB is a material which is difficult to crush. The crushing performance of PCB with disk crusher, especially vibration grinding, which has cut or impact action, excels that of jaw crusher or roller crusher. The PCB scrap is worthwhile to recycle using variety of modern characterization methods. When compared with natural resources, this material stream remains a rich precious metal and nonferrous metals. In PCB scrap, metals account for 47% of the total material composition, in which there exists 19.66% copper, 11.47% iron, 3.93% lead, 300 g/t gold and 510 kg/t silver, etc. In addition, the PCB scrap contains 27% of plastics and 26% of refractory oxides.
文摘Objective To analyze the short-term outcomes of redo coronary artery bypass grafting(CABG) using on-pump and off-pump CABG techniques. Methods From January 2003 to August 2013, non-randomized 80 patients were treated with redo CABG in the Department of Cardiac Surgery, Peking University Third Hospital. Among these patients, 40 underwent on-pump CABG technique(redo-ONCAB group) and 40 underwent off-pump CABG technique(redo-OPCAB group). Furthermore, transmyocardial laser revascularization was performed in high-risk patients who were not suitable to conventional grafting. Clinical data of the two groups were recorded and analyzed including operation time, coronary grafts, incomplete revascularization, postoperative ventilation, perioperative stroke, and low output syndrome, etc. Results There were no significantly differences in age, gender distribution, incidences of hypertension, stroke, and other clinical characteristics between redo-OPCAB group and redo-ONCAB group(all P>0.05), except for incidences of renal dysfunction and pulmonary disease(all P<0.05). The number of grafting vessels in the redo-ONCAB and redo-OPCAB groups was 2.1 ± 0.74 and 1.4 ±0.52 respectively. There was significant difference between the two groups(P=0.0243). Compared with the redo-ONCAB group, there was shorter operation time(P=0.0045), postoperative ventilation(P=0.0211) and intensive care unit stay(P=0.0400), as well as fewer use of platelet(P=0.0338) and blood transfusion(P=0.0034) in the redo-OPCAB group. The incidence of incomplete revascularization(P=0.0253) and the use of transmyocardial laser revascularization(P=0.0052) were higher in the redo-OPCAB group than those in the redo-ONCAB group(all P<0.05). However, no significant differences were showed for the incidence of the use of intra aortic balloon pump and continuous renal replacement therapy, perioperative stroke, low output syndrome, and in-hospital mortality between the two groups(all P>0.05). Conclusion Redo CABG is the safety and efficacy surgical procedure, and redo-OPCAB technique with better outcomes is commended especially in high-risk patients.
基金Project 200360290015 supported by the Doctoral Program of Higher Education, China Ministry of Education
文摘Physical methods show great potential and advantages on comprehensive reutilization of waste printed circuit boards (PCBs) because of lower investment and operation cost, higher efficiency and environment friendliness. However, metals contained in fine fraction of PCBs cannot be recovered effectively by conventional equipments such as high tension electrostatic separator or shaking table. In the paper, this conundrum was resolved successfully with the enhanced Falcon SB concentrator. The separation mechanism of Falcon SB concentrator was analyzed and main factors affecting separation efficiency such as magnitude of rotation frequency of bowl, water counter pressure and slurry concentration of feed were studied and interaction of factors above also were investigated using Design-Expert software. Experiment results show that complete liberation degree and great difference of density between metals and nonmetals are suitable to recover metals from -74 μm PCBs using enhanced Falcon SB concentrator and 80.77 % integration efficiency can be achieved when slurry concentration of feed is 40 g/L with the water counter pressure of 0.01 MPa and rotation frequency of 50 Hz.
基金supported by the National Key R&D Program of China (No. 2017YFB1002503)the National Natural Science Foundation of China (No. 31470974+5 种基金 31800910)the Humanity and Social Science Youth Foundation of the Ministry of Education of China (No. 17YJC190015)the China Postdoctoral Science Foundation (No. 2016M602754 2018T111010)Major Project of Medicine Science and Technology of PLA China (No. AWS17J012)
基金This project is supported by National Natural Science Foundation of Chins （10371049） and Science Foundation of Three Gorges University
文摘This paper divides the vertex set into several disjoined subsets and provides an optimal fault-tolerance routing algorithm based on the vertex set partition. This algorithm is efficient and convergent, in polynomial time, we can get the output if the vertex is given.
