在设计使用年限内,风力发电机组装配式预应力混凝土塔筒的疲劳问题非常突出,尤其在塔筒1/2高度以上区域。国内标准的疲劳验算公式是基于等幅疲劳2×10^(6)次的试验研究结果,而风力发电机组混凝土塔筒的疲劳次数在3×10^(8)以上...在设计使用年限内,风力发电机组装配式预应力混凝土塔筒的疲劳问题非常突出,尤其在塔筒1/2高度以上区域。国内标准的疲劳验算公式是基于等幅疲劳2×10^(6)次的试验研究结果,而风力发电机组混凝土塔筒的疲劳次数在3×10^(8)以上,故国内标准不适用风电机组混凝土塔筒的疲劳验算。而欧标Fib Model Code for Concrete Structures 2010(FIB规范)采用基于S-N曲线的Palmgren-Miner累积损伤方法进行混凝土疲劳验算,可以解决高次数的疲劳问题。介绍了FIB规范中混凝土塔筒常用的Ⅲ级和Ⅳ级设计方法,通过具体案例分析了混凝土塔筒疲劳承载力的影响因素。结果表明:提高混凝土强度等级和加大塔筒壁厚,可以有效提高塔筒的疲劳承载力。可为风力发电机组装配式预应力混凝土塔筒实际设计提供参考。展开更多
BACKGROUND Obstructed defecation syndrome(ODS) is a widespread disease in the world.Rectocele is the most common cause of ODS in females. Multiple procedures have been performed to treat rectocele and no procedure has...BACKGROUND Obstructed defecation syndrome(ODS) is a widespread disease in the world.Rectocele is the most common cause of ODS in females. Multiple procedures have been performed to treat rectocele and no procedure has been accepted as the gold-standard procedure. Stapled transanal rectal resection(STARR) has been widely used. However, there are still some disadvantages in this procedure and its effectiveness in anterior wall repair is doubtful. Therefore, new procedures are expected to further improve the treatment of rectocele.AIM To evaluate the efficacy and safety of a novel rectocele repair combining Khubchandani's procedure with stapled posterior rectal wall resection.METHODS A cohort of 93 patients were recruited in our randomized clinical trial and were divided into two different groups in a randomized manner. Forty-two patients(group A) underwent Khubchandani's procedure with stapled posterior rectal wall resection and 51 patients(group B) underwent the STARR procedure.Follow-up was performed at 1, 3, 6, and 12 mo after the operation. Preoperative and postoperative ODS scores and depth of rectocele, postoperative complications, blood loss, and hospital stay of each patient were documented. All data were analyzed statistically to evaluate the efficiency and safety of our procedure.RESULTS In group A, 42 patients underwent Khubchandani's procedure with stapled posterior rectal wall resection and 34 were followed until the final analysis. In group B, 51 patients underwent the STARR procedure and 37 were followed until the final analysis. Mean operative duration was 41.47 ± 6.43 min(group A) vs39.24 ± 6.53 min(group B). Mean hospital stay was 3.15 ± 0.70 d(group A) vs 3.14± 0.54 d(group B). Mean blood loss was 10.91 ± 2.52 mL(group A) vs 10.14 ± 1.86 m L(group B). Mean ODS score in group A declined from 16.50 ± 2.06 before operation to 5.06 ± 1.07 one year after the operation, whereas in group B it was17.11 ± 2.57 before operation and 6.03 ± 2.63 one year after the operation. Mean depth of rectocele decreased from 4.32 ± 0.96 cm(group A) vs 4.18 ± 0.95 cm(group B) preoperatively to 1.19 ± 0.43 cm(group A) vs 1.54 ± 0.82 cm(group B)one year after operation. No other serious complications, such as rectovaginal fistula, perianal sepsis, or deaths, were recorded. After 12 mo of follow-up, 30 patients'(30/34, 88.2%) final outcomes were judged as effective and 4(4/34,11.8%) as moderate in group A, whereas in group B, 30(30/37, 81.1%) patients' outcomes were judged as effective, 5(5/37, 13.5%) as moderate, and 2(2/37,5.4%) as poor.CONCLUSION Khubchandani's procedure combined with stapled posterior rectal wall resection is an effective, feasible, and safe procedure with minor trauma to rectocele.展开更多
The average temperature of frozen soil wall is an essential parameter in the process of design, construction, and safety manage- ment of artificial ground freezing engineering. It is the basis of calculating frozen s...The average temperature of frozen soil wall is an essential parameter in the process of design, construction, and safety manage- ment of artificial ground freezing engineering. It is the basis of calculating frozen soil＇s mechanical parameters, fiarther prediction of bearing capacity and, ultimately, safety evaluation of the frozen soil wall. Regarding the average temperature of sin- gle-row-piped frozen soil wall, this paper summarizes several current calculation methods and their shortcomings. Furthermore, on the basis of Bakholdin＇s analytical solution for the temperature field under straight single-row-piped freezing, two new calcula- tion models, namely, the equivalent trapezoid model and the equivalent triangle model, are proposed. These two approaches are used to calculate the average temperature of a certain cross section which indicates the condition of the whole frozen soil wall. Considering the possible parameter range according to the freezing pipe layout that might be applied in actual construction, this paper compares the average temperatures of frozen soil walls obtained by the equivalent trapezoid method and the equivalent tri- angle method with that obtained by numerical integration of Bakholdin＇s analytical solution. The results show that the discrepancies are extremely small and these two new approaches are better than currently prevailing methods. However, the equivalent triangle method boasts higher accuracy and a simpler formula compared with the equivalent trapezoid method.展开更多
An approach was presented for synthesis of semiconducting single-walled carbon nanotubes(SWNTs) by sulfur(S) doping with the method of graphite arc discharge. Raman spectroscopy, UV-vis-NIR absorption spectroscopy and...An approach was presented for synthesis of semiconducting single-walled carbon nanotubes(SWNTs) by sulfur(S) doping with the method of graphite arc discharge. Raman spectroscopy, UV-vis-NIR absorption spectroscopy and electronic properties measurements indicated the semconducting properties of the SWNTs samples. Simulant calculation indicated that S doping could induce convertion of metallic SWNTs into semiconducting ones. This strategy may pave a way for the direct synthesis of pure semiconducting SWNTs.展开更多
The boundary-layer receptivity under the interaction of free-stream turbu- lence （FST） and localized wall roughness is studied by the direct numerical simulation （DNS） and the fast Fourier transform. The results s...The boundary-layer receptivity under the interaction of free-stream turbu- lence （FST） and localized wall roughness is studied by the direct numerical simulation （DNS） and the fast Fourier transform. The results show that the Tollmien-Schlichting （T-S） wave packets superposed by a group of stability, neutral, and instability T-S waves are generated in the boundary layer. The propagation speeds of the T-S wave packets are calculated. The relation among the boundary-layer receptivity response, the amplitude of the FST, the roughness height, and the roughness width is determined. The results agree well with Dietz＇s experiments. The effect of the roughness geometries on the receptivity is also studied.展开更多
Although it was reported that the title of 5000th Sino-foreign joint venture in Beijing had been conferred on Wall’s, it nevertheless remained a strange name to most Beijingers. However, on one of the hottest days la...Although it was reported that the title of 5000th Sino-foreign joint venture in Beijing had been conferred on Wall’s, it nevertheless remained a strange name to most Beijingers. However, on one of the hottest days last summer, the name Wall’s was seen in the Beijing streets and lanes, the ice-cream kept in small glass refrigerated cases standing under red and blue umbrellas with the trademark of Wall’s on them. This展开更多
＂Writing’s on the Wall＂是＂007＂系列第24部电影《007：幽灵党》（Spectre）的主题曲,这首歌在2016年第88届奥斯卡颁奖典礼上摘得最佳原创歌曲大奖。2015年格莱美奖得主、英国歌手Sam Smith创作并献唱了这首歌。这是继英国最有成...＂Writing’s on the Wall＂是＂007＂系列第24部电影《007：幽灵党》（Spectre）的主题曲,这首歌在2016年第88届奥斯卡颁奖典礼上摘得最佳原创歌曲大奖。2015年格莱美奖得主、英国歌手Sam Smith创作并献唱了这首歌。这是继英国最有成就的男歌手之一Tom Jones录制1965年＂007＂电影的主题曲＂Thunderball＂之后，展开更多
The majority of patients affected by Crohn’s disease(CD)develop a chronic condition with persistent inflammation and relapses that may cause progressive and irreversible damage to the bowel,resulting in stricturing o...The majority of patients affected by Crohn’s disease(CD)develop a chronic condition with persistent inflammation and relapses that may cause progressive and irreversible damage to the bowel,resulting in stricturing or penetrating complications in around 50%of patients during the natural history of the disease.Surgery is frequently needed to treat complicated disease when pharmacological therapy failes,with a high risk of repeated operations in time.Intestinal ultrasound(IUS),a non-invasive,cost-effective,radiation free and reproducible method for the diagnosis and follow-up of CD,in expert hands,allow a precise assessment of all the disease manifestations:Bowel characteristics,retrodilation,wrapping fat,fistulas and abscesses.Moreover,IUS is able to assess bowel wall thickness,bowel wall stratification(echo-pattern),vascularization and elasticity,as well as mesenteric hypertrophy,lymph-nodes and mesenteric blood flow.Its role in the disease evaluation and behaviour description is well assessed in literature,but less is known about the potential space of IUS as predictor of prognostic factors suggesting response to a medical treatment or postoperative recurrence.The availability of a low cost exam as IUS,able to recognize which patients are more likely to respond to a specific therapy and which patients are at high risk of surgery or complications,could be a very useful instrument in the hands of IBD physician.The aim of this review is to present current evidence about the prognostic role that IUS can show in predicting response to treatment,disease progression,risk of surgery and risk of post-surgical recurrence in CD.展开更多
文摘在设计使用年限内,风力发电机组装配式预应力混凝土塔筒的疲劳问题非常突出,尤其在塔筒1/2高度以上区域。国内标准的疲劳验算公式是基于等幅疲劳2×10^(6)次的试验研究结果,而风力发电机组混凝土塔筒的疲劳次数在3×10^(8)以上,故国内标准不适用风电机组混凝土塔筒的疲劳验算。而欧标Fib Model Code for Concrete Structures 2010(FIB规范)采用基于S-N曲线的Palmgren-Miner累积损伤方法进行混凝土疲劳验算,可以解决高次数的疲劳问题。介绍了FIB规范中混凝土塔筒常用的Ⅲ级和Ⅳ级设计方法,通过具体案例分析了混凝土塔筒疲劳承载力的影响因素。结果表明:提高混凝土强度等级和加大塔筒壁厚,可以有效提高塔筒的疲劳承载力。可为风力发电机组装配式预应力混凝土塔筒实际设计提供参考。
文摘BACKGROUND Obstructed defecation syndrome(ODS) is a widespread disease in the world.Rectocele is the most common cause of ODS in females. Multiple procedures have been performed to treat rectocele and no procedure has been accepted as the gold-standard procedure. Stapled transanal rectal resection(STARR) has been widely used. However, there are still some disadvantages in this procedure and its effectiveness in anterior wall repair is doubtful. Therefore, new procedures are expected to further improve the treatment of rectocele.AIM To evaluate the efficacy and safety of a novel rectocele repair combining Khubchandani's procedure with stapled posterior rectal wall resection.METHODS A cohort of 93 patients were recruited in our randomized clinical trial and were divided into two different groups in a randomized manner. Forty-two patients(group A) underwent Khubchandani's procedure with stapled posterior rectal wall resection and 51 patients(group B) underwent the STARR procedure.Follow-up was performed at 1, 3, 6, and 12 mo after the operation. Preoperative and postoperative ODS scores and depth of rectocele, postoperative complications, blood loss, and hospital stay of each patient were documented. All data were analyzed statistically to evaluate the efficiency and safety of our procedure.RESULTS In group A, 42 patients underwent Khubchandani's procedure with stapled posterior rectal wall resection and 34 were followed until the final analysis. In group B, 51 patients underwent the STARR procedure and 37 were followed until the final analysis. Mean operative duration was 41.47 ± 6.43 min(group A) vs39.24 ± 6.53 min(group B). Mean hospital stay was 3.15 ± 0.70 d(group A) vs 3.14± 0.54 d(group B). Mean blood loss was 10.91 ± 2.52 mL(group A) vs 10.14 ± 1.86 m L(group B). Mean ODS score in group A declined from 16.50 ± 2.06 before operation to 5.06 ± 1.07 one year after the operation, whereas in group B it was17.11 ± 2.57 before operation and 6.03 ± 2.63 one year after the operation. Mean depth of rectocele decreased from 4.32 ± 0.96 cm(group A) vs 4.18 ± 0.95 cm(group B) preoperatively to 1.19 ± 0.43 cm(group A) vs 1.54 ± 0.82 cm(group B)one year after operation. No other serious complications, such as rectovaginal fistula, perianal sepsis, or deaths, were recorded. After 12 mo of follow-up, 30 patients'(30/34, 88.2%) final outcomes were judged as effective and 4(4/34,11.8%) as moderate in group A, whereas in group B, 30(30/37, 81.1%) patients' outcomes were judged as effective, 5(5/37, 13.5%) as moderate, and 2(2/37,5.4%) as poor.CONCLUSION Khubchandani's procedure combined with stapled posterior rectal wall resection is an effective, feasible, and safe procedure with minor trauma to rectocele.
基金supported by the National Natural Science Foundation of China (No. 50578120)the National High Technology Research and Development Program of China (863 Program) (No. 2006AA11Z118)
文摘The average temperature of frozen soil wall is an essential parameter in the process of design, construction, and safety manage- ment of artificial ground freezing engineering. It is the basis of calculating frozen soil＇s mechanical parameters, fiarther prediction of bearing capacity and, ultimately, safety evaluation of the frozen soil wall. Regarding the average temperature of sin- gle-row-piped frozen soil wall, this paper summarizes several current calculation methods and their shortcomings. Furthermore, on the basis of Bakholdin＇s analytical solution for the temperature field under straight single-row-piped freezing, two new calcula- tion models, namely, the equivalent trapezoid model and the equivalent triangle model, are proposed. These two approaches are used to calculate the average temperature of a certain cross section which indicates the condition of the whole frozen soil wall. Considering the possible parameter range according to the freezing pipe layout that might be applied in actual construction, this paper compares the average temperatures of frozen soil walls obtained by the equivalent trapezoid method and the equivalent tri- angle method with that obtained by numerical integration of Bakholdin＇s analytical solution. The results show that the discrepancies are extremely small and these two new approaches are better than currently prevailing methods. However, the equivalent triangle method boasts higher accuracy and a simpler formula compared with the equivalent trapezoid method.
基金supported by National Natural Science Foundation of China No.50730008Shanghai Science and Technology Grant No.0752nm015National Basic Research Program of China No.2006CB300406
文摘An approach was presented for synthesis of semiconducting single-walled carbon nanotubes(SWNTs) by sulfur(S) doping with the method of graphite arc discharge. Raman spectroscopy, UV-vis-NIR absorption spectroscopy and electronic properties measurements indicated the semconducting properties of the SWNTs samples. Simulant calculation indicated that S doping could induce convertion of metallic SWNTs into semiconducting ones. This strategy may pave a way for the direct synthesis of pure semiconducting SWNTs.
基金supported by the National Natural Science Foundation of China(No.11172143)the Research Innovation Program for College Graduates of Jiangsu Province(No.CXZZ13 0518)
文摘The boundary-layer receptivity under the interaction of free-stream turbu- lence （FST） and localized wall roughness is studied by the direct numerical simulation （DNS） and the fast Fourier transform. The results show that the Tollmien-Schlichting （T-S） wave packets superposed by a group of stability, neutral, and instability T-S waves are generated in the boundary layer. The propagation speeds of the T-S wave packets are calculated. The relation among the boundary-layer receptivity response, the amplitude of the FST, the roughness height, and the roughness width is determined. The results agree well with Dietz＇s experiments. The effect of the roughness geometries on the receptivity is also studied.
文摘Although it was reported that the title of 5000th Sino-foreign joint venture in Beijing had been conferred on Wall’s, it nevertheless remained a strange name to most Beijingers. However, on one of the hottest days last summer, the name Wall’s was seen in the Beijing streets and lanes, the ice-cream kept in small glass refrigerated cases standing under red and blue umbrellas with the trademark of Wall’s on them. This
文摘＂Writing’s on the Wall＂是＂007＂系列第24部电影《007：幽灵党》（Spectre）的主题曲,这首歌在2016年第88届奥斯卡颁奖典礼上摘得最佳原创歌曲大奖。2015年格莱美奖得主、英国歌手Sam Smith创作并献唱了这首歌。这是继英国最有成就的男歌手之一Tom Jones录制1965年＂007＂电影的主题曲＂Thunderball＂之后，
文摘The majority of patients affected by Crohn’s disease(CD)develop a chronic condition with persistent inflammation and relapses that may cause progressive and irreversible damage to the bowel,resulting in stricturing or penetrating complications in around 50%of patients during the natural history of the disease.Surgery is frequently needed to treat complicated disease when pharmacological therapy failes,with a high risk of repeated operations in time.Intestinal ultrasound(IUS),a non-invasive,cost-effective,radiation free and reproducible method for the diagnosis and follow-up of CD,in expert hands,allow a precise assessment of all the disease manifestations:Bowel characteristics,retrodilation,wrapping fat,fistulas and abscesses.Moreover,IUS is able to assess bowel wall thickness,bowel wall stratification(echo-pattern),vascularization and elasticity,as well as mesenteric hypertrophy,lymph-nodes and mesenteric blood flow.Its role in the disease evaluation and behaviour description is well assessed in literature,but less is known about the potential space of IUS as predictor of prognostic factors suggesting response to a medical treatment or postoperative recurrence.The availability of a low cost exam as IUS,able to recognize which patients are more likely to respond to a specific therapy and which patients are at high risk of surgery or complications,could be a very useful instrument in the hands of IBD physician.The aim of this review is to present current evidence about the prognostic role that IUS can show in predicting response to treatment,disease progression,risk of surgery and risk of post-surgical recurrence in CD.
