使用高度为50 m的落管研究了Sn-20%(质量分数) Ni包晶合金在重力和微重力作用下的凝固行为。用金相显微镜(OM)观察了合金的凝固组织并使用图像处理软件IPP(Image Pro Plus)统计了样品中的初生相、包晶相以及终凝相的含量,使用能谱仪(EDS...使用高度为50 m的落管研究了Sn-20%(质量分数) Ni包晶合金在重力和微重力作用下的凝固行为。用金相显微镜(OM)观察了合金的凝固组织并使用图像处理软件IPP(Image Pro Plus)统计了样品中的初生相、包晶相以及终凝相的含量,使用能谱仪(EDS)和X射线衍射(XRD)仪分析了样品凝固组织中的成分分布和组成相。结果表明,Sn-20%Ni包晶合金的凝固以初生相在固液界面前沿形核、枝晶生长和包晶反应的形式进行,重力对初生相的生成和包晶反应都有显著的影响,在微重力作用下的微观组织配比、分布以及合金元素的分布都与在重力作用下明显不同。在重力的作用下残余初生相的含量和残余初生相和包晶相的总量总是比在重力作用下的低,而包晶相的含量则总是比在微重力作用下的高。同时,样品中溶质元素的分布与残余初生相和包晶相的总量的分布趋势基本一致。结果表明,微重力环境有利于Sn-20%Ni合金初生相的形核和长大,而重力环境则促进包晶反应,其原因与重力导致的浮力对流和晶核沉积有关。展开更多
Temperature distribution and variation with time has been considered in the analysis of the influences of the initial level of immersion of a horizontal metallic mesh tube in the liquid on combined buoyant and thermoc...Temperature distribution and variation with time has been considered in the analysis of the influences of the initial level of immersion of a horizontal metallic mesh tube in the liquid on combined buoyant and thermocapillary flow.The combined flow occurs along with the rising liquid film flow on the surface of a horizontal metallic mesh tube.Three different levels of immersion of the metallic mesh tube in the liquid have been tested.Experiments of 60 min in duration have been performed using a heating metallic tube with a diameter of 25 mm and a length of 110 mm,sealed outside with a metallic mesh of 178 mm by 178 mm,and distilled water.These reveal two distinct flow patterns.Thermocouples and infrared thermal imager are utilized to measure the temperature.The level of the liquid free surface relative to the lower edge of the tube is measured as angleθ.The results show that for a smallerθangle,or a low level of immersion,with a relatively low heating power,it is possible to near fully combine the upwards buoyant flow with the rising liquid film flow.In this case,the liquid is heated only in the vicinity of the tube,while the liquid away from the flow region experiences small changes in temperature and the system approaches steady conditions.For largerθangles,or higher levels of immersion,a different flow pattern is noticed on the liquid free surface and identified as the thermo-capillary(Marangoni)flow.The rising liquid film is also present.The higher levels of immersion cause a high temperature gradient in the liquid free surface region and promote thermal stratification;therefore the system could not approach steady conditions.展开更多
Objective To compare the outcomes after self-expanding metallic stent (SEMS) or transanal drainage tube (TDT) placement in patients with malignant large-bowel obstruction (MLBO). Methods Seventy-three patients with ML...Objective To compare the outcomes after self-expanding metallic stent (SEMS) or transanal drainage tube (TDT) placement in patients with malignant large-bowel obstruction (MLBO). Methods Seventy-three patients with MLBO from the clinical unit underwent SEMS (n = 51) or TDT (n = 22) placement from 2012 to 2017. The success rates of placement, clinical outcomes after decompression, complications, the time to resuming enteral nutrition (EN), Karnofsky performance status (KPS) scoring and the following-up therapeutic options were investigated. Results Technical success were achieved in 100% of patients in both groups. The clinical success rates were 98.0%(50/51) for SEMS and 95.5%(21/22) for TDT. No perforation was found in any group, while 3.9%(2/51) in the SEMS and 18.2%(4/22) in TDT group experienced displacement (P = 0.26). It took 2.1 IQR (0~2) days and 3 IQR (2~5) days to resume EN in the SEMS and TDT groups, respectively (P < 0.001). The KPS scores were significantly higher in patients implanted with SEMS (70, IQR 50~80) than in those with TDT (35, IQR 30~50)(P < 0.001). In the SEMS group, 37.3%(19/51) of patients underwent stenting as a bridge to surgery, 9.8%(5/51) for chemotherapy only and 52.9%(27/51) for palliation, while 40.9%(9/22), 0 and 59.1%(13/22) underwent placement for these reasons in the TDT group, respectively. The majority (6/9) of the patients who underwent TDT placement as a bridge to surgery required stoma creation, while only 31.6%(6/19) of those in the SEMS group needed a stoma (P = 0.080). In addition, anastomotic leakage was only found in the TDT group (2/9)(P = 0.10). Conclusion Both SEMS and TDT placement could provide clinical relief for MLBO. However, SEMS placement is associated with earlier EN, fewer complications, and benefits for the postoperative quality-of-life.展开更多
BACKGROUND Emergency surgical resection is a standard treatment for right-sided malignant colonic obstruction; however, the procedure is associated with high rates of mortality and morbidity. Although a bridge to surg...BACKGROUND Emergency surgical resection is a standard treatment for right-sided malignant colonic obstruction; however, the procedure is associated with high rates of mortality and morbidity. Although a bridge to surgery can be created to obviate the need for emergency surgery, its effects on long-term outcomes and the most practical management strategies for right-sided malignant colonic obstruction remain unclear.AIM To determine the appropriate management approach for right-sided malignant colonic obstruction.METHODS Forty patients with right-sided malignant colonic obstruction who underwent curative resection from January 2007 to April 2017 were included in the study.We compared the perioperative and long-term outcomes of patients who received bridges to surgery established using decompression tubes and those created using self-expandable metallic stents(SEMS). The primary outcome was the overall survival duration(OS) and the secondary endpoints were the diseasefree survival(DFS) duration and the preoperative and postoperative morbidity rates. Analysis was performed on an intention-to-treat basis.RESULTS There were 21 patients in the decompression tube group and 19 in the SEMS group. There were no significant differences in the perioperative morbidity rates of the two groups. The OS rate was significantly higher in the decompression tube group than in the SEMS group(5-year OS rate; decompression tube 79.5%,SEMS 32%, P = 0.043). Multivariate analysis revealed that the bridge to surgery using a decompression tube was significantly associated with the OS(hazard ratio, 17.41; P = 0.004). The 3-year DFS rate was significantly higher in thedecompression tube group than in the SEMS group(68.9% vs 45.9%; log-rank test,P = 0.032). A propensity score–adjusted analysis also demonstrated that the prognosis was significantly better in the decompression tube group than in the SEMS group.CONCLUSION The bridge to surgery using trans-nasal and trans-anal decompression tubes for right-sided malignant colonic obstruction is s展开更多
文摘使用高度为50 m的落管研究了Sn-20%(质量分数) Ni包晶合金在重力和微重力作用下的凝固行为。用金相显微镜(OM)观察了合金的凝固组织并使用图像处理软件IPP(Image Pro Plus)统计了样品中的初生相、包晶相以及终凝相的含量,使用能谱仪(EDS)和X射线衍射(XRD)仪分析了样品凝固组织中的成分分布和组成相。结果表明,Sn-20%Ni包晶合金的凝固以初生相在固液界面前沿形核、枝晶生长和包晶反应的形式进行,重力对初生相的生成和包晶反应都有显著的影响,在微重力作用下的微观组织配比、分布以及合金元素的分布都与在重力作用下明显不同。在重力的作用下残余初生相的含量和残余初生相和包晶相的总量总是比在重力作用下的低,而包晶相的含量则总是比在微重力作用下的高。同时,样品中溶质元素的分布与残余初生相和包晶相的总量的分布趋势基本一致。结果表明,微重力环境有利于Sn-20%Ni合金初生相的形核和长大,而重力环境则促进包晶反应,其原因与重力导致的浮力对流和晶核沉积有关。
基金supported by Science and Technology Development Program of Qinghai Province(2013-N-547).
文摘Temperature distribution and variation with time has been considered in the analysis of the influences of the initial level of immersion of a horizontal metallic mesh tube in the liquid on combined buoyant and thermocapillary flow.The combined flow occurs along with the rising liquid film flow on the surface of a horizontal metallic mesh tube.Three different levels of immersion of the metallic mesh tube in the liquid have been tested.Experiments of 60 min in duration have been performed using a heating metallic tube with a diameter of 25 mm and a length of 110 mm,sealed outside with a metallic mesh of 178 mm by 178 mm,and distilled water.These reveal two distinct flow patterns.Thermocouples and infrared thermal imager are utilized to measure the temperature.The level of the liquid free surface relative to the lower edge of the tube is measured as angleθ.The results show that for a smallerθangle,or a low level of immersion,with a relatively low heating power,it is possible to near fully combine the upwards buoyant flow with the rising liquid film flow.In this case,the liquid is heated only in the vicinity of the tube,while the liquid away from the flow region experiences small changes in temperature and the system approaches steady conditions.For largerθangles,or higher levels of immersion,a different flow pattern is noticed on the liquid free surface and identified as the thermo-capillary(Marangoni)flow.The rising liquid film is also present.The higher levels of immersion cause a high temperature gradient in the liquid free surface region and promote thermal stratification;therefore the system could not approach steady conditions.
文摘Objective To compare the outcomes after self-expanding metallic stent (SEMS) or transanal drainage tube (TDT) placement in patients with malignant large-bowel obstruction (MLBO). Methods Seventy-three patients with MLBO from the clinical unit underwent SEMS (n = 51) or TDT (n = 22) placement from 2012 to 2017. The success rates of placement, clinical outcomes after decompression, complications, the time to resuming enteral nutrition (EN), Karnofsky performance status (KPS) scoring and the following-up therapeutic options were investigated. Results Technical success were achieved in 100% of patients in both groups. The clinical success rates were 98.0%(50/51) for SEMS and 95.5%(21/22) for TDT. No perforation was found in any group, while 3.9%(2/51) in the SEMS and 18.2%(4/22) in TDT group experienced displacement (P = 0.26). It took 2.1 IQR (0~2) days and 3 IQR (2~5) days to resume EN in the SEMS and TDT groups, respectively (P < 0.001). The KPS scores were significantly higher in patients implanted with SEMS (70, IQR 50~80) than in those with TDT (35, IQR 30~50)(P < 0.001). In the SEMS group, 37.3%(19/51) of patients underwent stenting as a bridge to surgery, 9.8%(5/51) for chemotherapy only and 52.9%(27/51) for palliation, while 40.9%(9/22), 0 and 59.1%(13/22) underwent placement for these reasons in the TDT group, respectively. The majority (6/9) of the patients who underwent TDT placement as a bridge to surgery required stoma creation, while only 31.6%(6/19) of those in the SEMS group needed a stoma (P = 0.080). In addition, anastomotic leakage was only found in the TDT group (2/9)(P = 0.10). Conclusion Both SEMS and TDT placement could provide clinical relief for MLBO. However, SEMS placement is associated with earlier EN, fewer complications, and benefits for the postoperative quality-of-life.
文摘BACKGROUND Emergency surgical resection is a standard treatment for right-sided malignant colonic obstruction; however, the procedure is associated with high rates of mortality and morbidity. Although a bridge to surgery can be created to obviate the need for emergency surgery, its effects on long-term outcomes and the most practical management strategies for right-sided malignant colonic obstruction remain unclear.AIM To determine the appropriate management approach for right-sided malignant colonic obstruction.METHODS Forty patients with right-sided malignant colonic obstruction who underwent curative resection from January 2007 to April 2017 were included in the study.We compared the perioperative and long-term outcomes of patients who received bridges to surgery established using decompression tubes and those created using self-expandable metallic stents(SEMS). The primary outcome was the overall survival duration(OS) and the secondary endpoints were the diseasefree survival(DFS) duration and the preoperative and postoperative morbidity rates. Analysis was performed on an intention-to-treat basis.RESULTS There were 21 patients in the decompression tube group and 19 in the SEMS group. There were no significant differences in the perioperative morbidity rates of the two groups. The OS rate was significantly higher in the decompression tube group than in the SEMS group(5-year OS rate; decompression tube 79.5%,SEMS 32%, P = 0.043). Multivariate analysis revealed that the bridge to surgery using a decompression tube was significantly associated with the OS(hazard ratio, 17.41; P = 0.004). The 3-year DFS rate was significantly higher in thedecompression tube group than in the SEMS group(68.9% vs 45.9%; log-rank test,P = 0.032). A propensity score–adjusted analysis also demonstrated that the prognosis was significantly better in the decompression tube group than in the SEMS group.CONCLUSION The bridge to surgery using trans-nasal and trans-anal decompression tubes for right-sided malignant colonic obstruction is s
