Directional motion of dust particles in a dusty plasma ratcnet is observed experimentally.The dusty plasma ratcnet consists of two concentric gears with asymmetric sawtooth.It is found that the sawtooth number affects...Directional motion of dust particles in a dusty plasma ratcnet is observed experimentally.The dusty plasma ratcnet consists of two concentric gears with asymmetric sawtooth.It is found that the sawtooth number affects the directional motion of dust particles along the saw channel.With the inerease of the sawtooth number,the particle velocity increases firstly and then decreases,and there is an optimum number of the sawtooth which could induce fast rotation of dust particles.The velocities of dust particles change as they are flowing along the saw channel.We also explore the force acting on the dust particle experimentally.展开更多
BACKGROUND During laparoscopic resection for colorectal cancer,there is controversy regarding whether the left colic artery(LCA)should be preserved at its origin.AIM To investigate the prognostic significance of prese...BACKGROUND During laparoscopic resection for colorectal cancer,there is controversy regarding whether the left colic artery(LCA)should be preserved at its origin.AIM To investigate the prognostic significance of preservation of the LCA in colorectal cancer surgery.METHODS Patients were divided into two groups.The high ligation(H-L)technique(refers to ligation performed 1 cm from the beginning of the inferior mesenteric artery)group consisted of 46 patients,and the low ligation(L-L)technique(refers to ligation performed below the initiation of the LCA)group consisted of 148 patients.Operative time,blood loss,lymph nodes with tumor invasion,postoperative complications and recovery time,recurrence rate,and 5-year survival rate were compared between the two groups.RESULTS The average number of lymph nodes detected in postoperative pathological specimens was 17.4/person in the H-L group and 15.9/person in the L-L group.There were 20 patients(43%)with positive lymph nodes(lymph node metastasis)in the H-L group and 60 patients(41%)in the L-L group.No statistical differences were found between the groups.Complications occurred in 12 cases(26%)in the H-L group and in 26 cases(18%)in the L-L group.The incidences of postoperative anastomotic complications and functional urinary complications were significantly lower in the L-L group.The 5-year survival rates in H-L and L-L groups were 81.7%and 81.6%,respectively,and relapse-free survival rates were 74.3%and 77.1%,respectively.The two groups were similar statistically.CONCLUSION Complete mesenteric resection combined with lymph node dissection around the inferior mesenteric artery root while preserving the LCA is a beneficial surgical approach during laparoscopic resection for colorectal cancer.展开更多
Anti-spiral waves are controlled in an oscillatory system by using a local inhomogeneity. The inhomogeneity acts as a wave source, and gives rise to the propagating plane waves, tt is found that there is a critical pa...Anti-spiral waves are controlled in an oscillatory system by using a local inhomogeneity. The inhomogeneity acts as a wave source, and gives rise to the propagating plane waves, tt is found that there is a critical pacemaking domain size below which no wave will be created at all. Two types of ordered waves （target waves and traveling waves） are created depending on the geometry of the local inhomogeneity. The competition between the anti-spiral waves and the ordered waves is discussed. Two different competition mechanisms were observed, which are related to the ordered waves obtained from different local inhomogeneities. It is found that traveling waves with either lower frequency or higher frequency can both eliminate the anti-spiral waves, while only the target waves with lower absolute value of frequency can eliminate the anti-spiral waves. This method also applies to outwardly rotating spiral waves. The control mechanism is intuitively explained and the control method is easily operative.展开更多
Using a dusty plasma ratchet,one can realize the rectification of charged dust particle in a plasma.To obtain the ratchet potential dominating the rectification,here we perform quantitative simulations based on a two-...Using a dusty plasma ratchet,one can realize the rectification of charged dust particle in a plasma.To obtain the ratchet potential dominating the rectification,here we perform quantitative simulations based on a two-dimensional fluid model of capacitively coupled plasma.Plasma parameters are firstly calculated in two typical cross sections of the dusty plasma ratchet which cut vertically the saw channel at different azimuthal positions.The balance positions of charged dust particle in the two cross sections then can be found exactly.The electric potentials at the two balance positions have different values.Using interpolation in term of a double-sine function from previous experimental measurement,an asymmetrical ratchet potential along the saw channel is finally obtained.The asymmetrical orientation of the ratchet potential depends on discharge conditions.Quantitative simulations further reproduce our previous experimental phenomena such as the rectification of dust particle in the dusty plasma ratchet.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11975089)the Program for National Defense Science and Technology Innovation Special Zone of Chinathe Program for Young Top-Notch Talents of Hebei Province of China.
文摘Directional motion of dust particles in a dusty plasma ratcnet is observed experimentally.The dusty plasma ratcnet consists of two concentric gears with asymmetric sawtooth.It is found that the sawtooth number affects the directional motion of dust particles along the saw channel.With the inerease of the sawtooth number,the particle velocity increases firstly and then decreases,and there is an optimum number of the sawtooth which could induce fast rotation of dust particles.The velocities of dust particles change as they are flowing along the saw channel.We also explore the force acting on the dust particle experimentally.
基金The study was reviewed and approved by Ethics Committee of Capital Medical University(Approval No.2021-001-2).
文摘BACKGROUND During laparoscopic resection for colorectal cancer,there is controversy regarding whether the left colic artery(LCA)should be preserved at its origin.AIM To investigate the prognostic significance of preservation of the LCA in colorectal cancer surgery.METHODS Patients were divided into two groups.The high ligation(H-L)technique(refers to ligation performed 1 cm from the beginning of the inferior mesenteric artery)group consisted of 46 patients,and the low ligation(L-L)technique(refers to ligation performed below the initiation of the LCA)group consisted of 148 patients.Operative time,blood loss,lymph nodes with tumor invasion,postoperative complications and recovery time,recurrence rate,and 5-year survival rate were compared between the two groups.RESULTS The average number of lymph nodes detected in postoperative pathological specimens was 17.4/person in the H-L group and 15.9/person in the L-L group.There were 20 patients(43%)with positive lymph nodes(lymph node metastasis)in the H-L group and 60 patients(41%)in the L-L group.No statistical differences were found between the groups.Complications occurred in 12 cases(26%)in the H-L group and in 26 cases(18%)in the L-L group.The incidences of postoperative anastomotic complications and functional urinary complications were significantly lower in the L-L group.The 5-year survival rates in H-L and L-L groups were 81.7%and 81.6%,respectively,and relapse-free survival rates were 74.3%and 77.1%,respectively.The two groups were similar statistically.CONCLUSION Complete mesenteric resection combined with lymph node dissection around the inferior mesenteric artery root while preserving the LCA is a beneficial surgical approach during laparoscopic resection for colorectal cancer.
基金ACKNOWLEDGMENT This work was supported by the National Natural Science Foundation of China （No.10647123）.
文摘Anti-spiral waves are controlled in an oscillatory system by using a local inhomogeneity. The inhomogeneity acts as a wave source, and gives rise to the propagating plane waves, tt is found that there is a critical pacemaking domain size below which no wave will be created at all. Two types of ordered waves （target waves and traveling waves） are created depending on the geometry of the local inhomogeneity. The competition between the anti-spiral waves and the ordered waves is discussed. Two different competition mechanisms were observed, which are related to the ordered waves obtained from different local inhomogeneities. It is found that traveling waves with either lower frequency or higher frequency can both eliminate the anti-spiral waves, while only the target waves with lower absolute value of frequency can eliminate the anti-spiral waves. This method also applies to outwardly rotating spiral waves. The control mechanism is intuitively explained and the control method is easily operative.
基金supported by the National Natural Science Foundation of China(Grant Nos.11975089 and 11875014)the Interdisciplinary Research Program of Natural Science of Hebei University(Grant No.DXK202010)the Hebei Natural Science Fund(Grant Nos.A2021201003 and A2021201010)。
文摘Using a dusty plasma ratchet,one can realize the rectification of charged dust particle in a plasma.To obtain the ratchet potential dominating the rectification,here we perform quantitative simulations based on a two-dimensional fluid model of capacitively coupled plasma.Plasma parameters are firstly calculated in two typical cross sections of the dusty plasma ratchet which cut vertically the saw channel at different azimuthal positions.The balance positions of charged dust particle in the two cross sections then can be found exactly.The electric potentials at the two balance positions have different values.Using interpolation in term of a double-sine function from previous experimental measurement,an asymmetrical ratchet potential along the saw channel is finally obtained.The asymmetrical orientation of the ratchet potential depends on discharge conditions.Quantitative simulations further reproduce our previous experimental phenomena such as the rectification of dust particle in the dusty plasma ratchet.
