XY table automated assembly machines ensure time saving and quality improving in the electronics industry. Recently, due to the need of higher operation speeds and lighter machines in PCB （Printed Circuit Board） ass...XY table automated assembly machines ensure time saving and quality improving in the electronics industry. Recently, due to the need of higher operation speeds and lighter machines in PCB （Printed Circuit Board） assembly, a challenging problem has arisen which is the table positioning vibration. The high speed with the machine flexibility, make the positioning vibration inevitable although the inner control. The positioning vibration is to be reduced otherwise the machine becomes useless. Firstly, the machine is modeled, the positioning vibration is formulated, and then analyzed. Secondly, using the analysis, three direct control methods are identified to decrease the positioning vibration, they are based on the kinematics, dynamics, and operation of the machine. Thirdly, the methods are examined numerically to evaluate their efficiency. Lastly, the identified methods are discussed to conclude on their application. The results are a real contribution in the vibration control of XY table automated assembly machines, which is classified as industrial knowhow.展开更多
AIM: To evaluate the feasibility, reproducibility and efficacy of a new tissue anchoring device in a porcine survival model. METHODS: Gastrotomies were performed using a needle-knife and balloon dilator in 10 female Y...AIM: To evaluate the feasibility, reproducibility and efficacy of a new tissue anchoring device in a porcine survival model. METHODS: Gastrotomies were performed using a needle-knife and balloon dilator in 10 female Yorkshire pigs weighing 30-35 kg. Gastric closure was attempted using a new tissue anchoring device. The tightness of the closure was confirmed by means of air insufflation and the ability to maintain gastric distension with stability in peritoneal pressure measured with a Veress needle. All animals were monitored daily for signs of peritonitis and sepsis over 14 d. During necropsy, the peritoneal cavity and the gastric access site were examined.RESULTS: Transgastric access, closure and 14 d survival was achieved in all pigs. The mean closure time was 18.1 ± 19.2 min and a mean of 2.1 ± 1 devices were used. Supplementary clips were necessary in 2 cases. The closure time was progressively reduced (24.8 ± 13.9 min in the first 5 pigs vs 11.4 ± 5.9 min in the last 5, P = NS). At necropsy, the gastric access site was correctly closed in all cases with all brace-bars present. One device was misplaced in the mesocolon. Minimal adhesions were observed in 3 pigs and signs of mild peritonitis and adhesions in one. CONCLUSIONS: The use of this new tissue anchoring device in porcine stomachs is feasible, reproducible and effective and requires a short learning curve.展开更多
The design of selective and efficient covalent organic frameworks(COFs)based electrocatalysts with tunable morphology for efficient CO_(2) reduction reaction(CO_(2)RR)to CH_(4) is highly desirable.Here,two kinds of an...The design of selective and efficient covalent organic frameworks(COFs)based electrocatalysts with tunable morphology for efficient CO_(2) reduction reaction(CO_(2)RR)to CH_(4) is highly desirable.Here,two kinds of anthraquinone-based COFs(i.e.,AAn-COF and OH-AAn-COF)with tunable 1D superstructures(e.g.,nanofibers(NF)and hollow tubes(HT))have been produced via Schiff-base condensation reaction.Interestingly,a rarely reported nanosheet-based self-template mechanism and a nanosheet-crimping mechanism have been demonstrated for the production of COF-based nanofibers and hollow tubes,respectively.Besides,the obtained COF-based superstructures can be post-modified with transition metals for efficient CO_(2)RR.Specifically,AAn-COF-Cu(NF)and OH-AAn-COF-Cu(HT)exhibit superior faradaic-efficiency with CH_(4)(FECH_(4))of 77%(-128.1 mA cm^(-2),-0.9 V)and 61%(-99.5 mA cm^(-2),-1.0 V)in a flow-cell,respectively.Noteworthy,the achieved FECH_(4) of AAn-COF-Cu(NF)(77%)is the highest one among reported crystalline COFs.This work provides a general methodology in exploring morphology-controlled COFs for electrocatalytic CO_(2)RR.展开更多
文摘XY table automated assembly machines ensure time saving and quality improving in the electronics industry. Recently, due to the need of higher operation speeds and lighter machines in PCB （Printed Circuit Board） assembly, a challenging problem has arisen which is the table positioning vibration. The high speed with the machine flexibility, make the positioning vibration inevitable although the inner control. The positioning vibration is to be reduced otherwise the machine becomes useless. Firstly, the machine is modeled, the positioning vibration is formulated, and then analyzed. Secondly, using the analysis, three direct control methods are identified to decrease the positioning vibration, they are based on the kinematics, dynamics, and operation of the machine. Thirdly, the methods are examined numerically to evaluate their efficiency. Lastly, the identified methods are discussed to conclude on their application. The results are a real contribution in the vibration control of XY table automated assembly machines, which is classified as industrial knowhow.
基金Supported by A Grant from the Instituto de Salud Carlos III(PI08/90026)
文摘AIM: To evaluate the feasibility, reproducibility and efficacy of a new tissue anchoring device in a porcine survival model. METHODS: Gastrotomies were performed using a needle-knife and balloon dilator in 10 female Yorkshire pigs weighing 30-35 kg. Gastric closure was attempted using a new tissue anchoring device. The tightness of the closure was confirmed by means of air insufflation and the ability to maintain gastric distension with stability in peritoneal pressure measured with a Veress needle. All animals were monitored daily for signs of peritonitis and sepsis over 14 d. During necropsy, the peritoneal cavity and the gastric access site were examined.RESULTS: Transgastric access, closure and 14 d survival was achieved in all pigs. The mean closure time was 18.1 ± 19.2 min and a mean of 2.1 ± 1 devices were used. Supplementary clips were necessary in 2 cases. The closure time was progressively reduced (24.8 ± 13.9 min in the first 5 pigs vs 11.4 ± 5.9 min in the last 5, P = NS). At necropsy, the gastric access site was correctly closed in all cases with all brace-bars present. One device was misplaced in the mesocolon. Minimal adhesions were observed in 3 pigs and signs of mild peritonitis and adhesions in one. CONCLUSIONS: The use of this new tissue anchoring device in porcine stomachs is feasible, reproducible and effective and requires a short learning curve.
基金supported by the National Natural Science Foundation of China(21871141,21871142,21901122,22071109 and 92061101)the Natural Science Research of Jiangsu Higher Education Institutions of China(19KJB150011)+3 种基金China Postdoctoral Science Foundation(2018M630572 and 2019M651873)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX201171)Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Foundation of Jiangsu Collaborative Innovation Center of Biomedical Functional Materials.
文摘The design of selective and efficient covalent organic frameworks(COFs)based electrocatalysts with tunable morphology for efficient CO_(2) reduction reaction(CO_(2)RR)to CH_(4) is highly desirable.Here,two kinds of anthraquinone-based COFs(i.e.,AAn-COF and OH-AAn-COF)with tunable 1D superstructures(e.g.,nanofibers(NF)and hollow tubes(HT))have been produced via Schiff-base condensation reaction.Interestingly,a rarely reported nanosheet-based self-template mechanism and a nanosheet-crimping mechanism have been demonstrated for the production of COF-based nanofibers and hollow tubes,respectively.Besides,the obtained COF-based superstructures can be post-modified with transition metals for efficient CO_(2)RR.Specifically,AAn-COF-Cu(NF)and OH-AAn-COF-Cu(HT)exhibit superior faradaic-efficiency with CH_(4)(FECH_(4))of 77%(-128.1 mA cm^(-2),-0.9 V)and 61%(-99.5 mA cm^(-2),-1.0 V)in a flow-cell,respectively.Noteworthy,the achieved FECH_(4) of AAn-COF-Cu(NF)(77%)is the highest one among reported crystalline COFs.This work provides a general methodology in exploring morphology-controlled COFs for electrocatalytic CO_(2)RR.
