The porosity of titanium foams obtained from the space holder technique was theoretically analyzed in the cases of volume shrinking, retaining and expanding during sintering. The relationship between porosity and spac...The porosity of titanium foams obtained from the space holder technique was theoretically analyzed in the cases of volume shrinking, retaining and expanding during sintering. The relationship between porosity and spacer content was compared under different conditions. The kind of volume change of macropores during sintering was discussed. The results indicate that the relationship between porosity and spacer content depends on the decreased volume of macropores and the volume of micropores in cell-walls in the first case, while the porosity will be greater than the spacer content for the other two cases. It proves that the volume change of macropores during sintering decreases based on theory and practice.展开更多
We report a case of a 63-year-old male who experienced an iatrogenic sigmoid perforation repaired combining three endoscopic techniques.The lesion was large and irregular with three discrete perforations,therefore,we ...We report a case of a 63-year-old male who experienced an iatrogenic sigmoid perforation repaired combining three endoscopic techniques.The lesion was large and irregular with three discrete perforations,therefore,we decided to close it by placing one clip per perforation,and then connecting all the clips with two endoloops.Finally we chose to use a fibrin glue injection to obtain a complete sealing.Four days after the colonoscopy the patient underwent a laparoscopic right hemicolectomy due to evidence of a large polyp of the caecum with high grade dysplasia and focal carcinoma in situ.Inspection of the sigma showed complete repair of the perforation.This report underlines how a conservative approach,together with a combination of various endoscopic techniques,can resolve complicated iatrogenic perforations of the colon.展开更多
Colonic perforation during endoscopic diagnostic or therapeutic procedures,represents an uncommon occurrence even if,together with haemorrhage,it is still the most common complication of colonoscopy,with an incidence ...Colonic perforation during endoscopic diagnostic or therapeutic procedures,represents an uncommon occurrence even if,together with haemorrhage,it is still the most common complication of colonoscopy,with an incidence ranging between 0.1% and 2% of all colonoscopic procedures. The ideal treatment in these cases remains elusive as the endoscopist and the surgeon have to make a choice case by case,depending on many factors such as how promptly the rupture is identified,the condition of the patient,the degree of contamination and the evidence of peritoneal irritation. Surgical interventions both laparotomic and laparoscopic,and other medical non-operative solutions are described in the literature. Only three cases have been reported in the literature in which the endoscopic apposition of endoclips was used to repair a colonic perforation during colonoscopy. Ours is the first case that the perforation itself was caused by the improper functioning of a therapeutic device.展开更多
Undisturbed soil core with many macropores and disturbed soil core with onlyone macropore (diameter is 10 mm) were probed by X-ray computed tomography (CT). The size, number,shape and continuity of macropores in the t...Undisturbed soil core with many macropores and disturbed soil core with onlyone macropore (diameter is 10 mm) were probed by X-ray computed tomography (CT). The size, number,shape and continuity of macropores in the transverse and vertical sectionsof soil were characterizedusing CT scanning images. The probability densities of macropores in the transverse section of soilcore exhibited a logarithmic P distribution. Results indicated that CT scanning was a promisingnondestructive method for characterizing macropores in soils.展开更多
Objective. To explore an effective method of surgical management of craniopharyngioma. Subjects and methods. Fifty patients with craniopharyngioma had total andsubtotal tumor ectomy. There were 29 males and 21 females...Objective. To explore an effective method of surgical management of craniopharyngioma. Subjects and methods. Fifty patients with craniopharyngioma had total andsubtotal tumor ectomy. There were 29 males and 21 females, ranging in age from 15 to 56 years (mean 34.1 years). MR imaging showed that the tumors were locatedin the superior sellar region in 24 cases, in superior sella region and extended into the third ventricular floor in 19 cases, into parasella in 3 cases and down to intrasella in 4 cases. Complete cystic tumors were found in 5 cases, whilethe partial cystic tumor in 24 cases and complete solid tumors in 21 cases. Pterional approach was used in 48 patients and subfrontal approach in 2 patients. Great attention was paid to the preservation of the perforating arteries from thecarotid, posterior and anterior communicating and anterior choroidal arteries to the hypothalamic structures. The clinical outcome was evaluated according to the GOS scale.Results. Of the 50 patients surgically treated, 47 patients obtained total ectomy of the tumor and 3 patients with the secondary surgery had subtotal ectomy of the tumor. The pituitary stalk was preserved in 29(58%) patients, severed in 14 patients and unidentified in 7 patients. Forty-six patients regained a normal life; one patient needed assist in life. Of the 3 deaths, one patient died of diabetes insipidus, one of inhalation asphyxia, and another one of water and sodium disorders. Conclusion. Avoidance of the injury to the neural structures in the thirdventricular floor and preservation of the perforating arteries to hypothalamus are the key to achieve good surgical results in treating craniopharyngioma.展开更多
In several countries, the residual RHA （rice husk ash） has been produced in rice processing industries or in thermoelectric plants that use rice husk to generate heat and/or electrical energy, usually without burnin...In several countries, the residual RHA （rice husk ash） has been produced in rice processing industries or in thermoelectric plants that use rice husk to generate heat and/or electrical energy, usually without burning process control. This causes a reduction in the amorphous silica content of residual RHA, which distinguishes them from the RHA produced according to controlled burning process, which is totally amorphous and considered a highly reactive pozzolan. In this paper, the hydration products and the porous structure of binders paste were studied by replacing, in weight of 5%, 10% and 20% of Portland cement OPC （ordinary Portland cement）, by residual RHAs named A and B, which have high and low content of amorphous silica, respectively, using microstructure evaluation techniques as XRD （X-ray diffraction）, TG （thermogravimetric） tests and MIP （mercury intrusion porosimetry）. A reducing the size of the pores of the pastes was observed according to the increase of content replacement of RHA A and RHA B.展开更多
In order to meet the rapid needs of processing square hole in mechanical equipment, the paper expounds the square hole processing method： planetary wheel method, and analyze the principle of tooling structure and pro...In order to meet the rapid needs of processing square hole in mechanical equipment, the paper expounds the square hole processing method： planetary wheel method, and analyze the principle of tooling structure and process with computer graphics parameters design. The results that, as long as the appropriate parameters, using the above method not only can punch the square hole, can also be processed triangle, the five angle and hexagonal regular polygon holes. The square hole processing method can provide theoretical basis and engineering reliable reference for related engineering and technical personnel.展开更多
A new structural parameter of shelterbelts, above-ground density of biomass volume, was putforward in this paper. Its practicality in managements of the shelterbelts and its physical meaning of windreduction were expo...A new structural parameter of shelterbelts, above-ground density of biomass volume, was putforward in this paper. Its practicality in managements of the shelterbelts and its physical meaning of windreduction were expounded. Analytical relations between the new parameter and often-used parameters(permeability and porosity) were deduced. An example was given to show the application of the newparameter in the management of shelterbelts.展开更多
The design and synthesis of highly active non-noble metal oxide catalysts, such as transition- and rare-earth-metal oxides, have attracted significant attention because of their high efficiency and low cost and the re...The design and synthesis of highly active non-noble metal oxide catalysts, such as transition- and rare-earth-metal oxides, have attracted significant attention because of their high efficiency and low cost and the resultant potential applications for the degradation of volatile organic compounds(VOCs). The structure-activity relationships have been well-studied and used to facilitate design of the structure and composition of highly active catalysts. Recently, non-noble metal oxides with porous structures have been used as catalysts for deep oxidation of VOCs, such as aromatic hydrocarbons, aliphatic compounds, aldehydes, and alcohols, with comparable activities to their noble metal counterparts. This review summarizes the growing literature regarding the use of porous metal oxides for the catalytic removal of VOCs, with emphasis on design of the composition and structure and typical synthetic technologies.展开更多
基金Project(51174243)supported by the National Natural Science Foundation of ChinaProject(106112015CDJZR135502)supported by the Fundamental Research Funds for the Central Universities,China
文摘The porosity of titanium foams obtained from the space holder technique was theoretically analyzed in the cases of volume shrinking, retaining and expanding during sintering. The relationship between porosity and spacer content was compared under different conditions. The kind of volume change of macropores during sintering was discussed. The results indicate that the relationship between porosity and spacer content depends on the decreased volume of macropores and the volume of micropores in cell-walls in the first case, while the porosity will be greater than the spacer content for the other two cases. It proves that the volume change of macropores during sintering decreases based on theory and practice.
文摘We report a case of a 63-year-old male who experienced an iatrogenic sigmoid perforation repaired combining three endoscopic techniques.The lesion was large and irregular with three discrete perforations,therefore,we decided to close it by placing one clip per perforation,and then connecting all the clips with two endoloops.Finally we chose to use a fibrin glue injection to obtain a complete sealing.Four days after the colonoscopy the patient underwent a laparoscopic right hemicolectomy due to evidence of a large polyp of the caecum with high grade dysplasia and focal carcinoma in situ.Inspection of the sigma showed complete repair of the perforation.This report underlines how a conservative approach,together with a combination of various endoscopic techniques,can resolve complicated iatrogenic perforations of the colon.
文摘Colonic perforation during endoscopic diagnostic or therapeutic procedures,represents an uncommon occurrence even if,together with haemorrhage,it is still the most common complication of colonoscopy,with an incidence ranging between 0.1% and 2% of all colonoscopic procedures. The ideal treatment in these cases remains elusive as the endoscopist and the surgeon have to make a choice case by case,depending on many factors such as how promptly the rupture is identified,the condition of the patient,the degree of contamination and the evidence of peritoneal irritation. Surgical interventions both laparotomic and laparoscopic,and other medical non-operative solutions are described in the literature. Only three cases have been reported in the literature in which the endoscopic apposition of endoclips was used to repair a colonic perforation during colonoscopy. Ours is the first case that the perforation itself was caused by the improper functioning of a therapeutic device.
基金Project supported by the National Key Basic Research Support Foundation (NKBRSF) of China (No. G1999011803) the Knowledge Innovation Program of the Chinese Academy of Sciences (No. K2CX2-404)the Science and Technology Innovation Program of Hohai
文摘Undisturbed soil core with many macropores and disturbed soil core with onlyone macropore (diameter is 10 mm) were probed by X-ray computed tomography (CT). The size, number,shape and continuity of macropores in the transverse and vertical sectionsof soil were characterizedusing CT scanning images. The probability densities of macropores in the transverse section of soilcore exhibited a logarithmic P distribution. Results indicated that CT scanning was a promisingnondestructive method for characterizing macropores in soils.
文摘Objective. To explore an effective method of surgical management of craniopharyngioma. Subjects and methods. Fifty patients with craniopharyngioma had total andsubtotal tumor ectomy. There were 29 males and 21 females, ranging in age from 15 to 56 years (mean 34.1 years). MR imaging showed that the tumors were locatedin the superior sellar region in 24 cases, in superior sella region and extended into the third ventricular floor in 19 cases, into parasella in 3 cases and down to intrasella in 4 cases. Complete cystic tumors were found in 5 cases, whilethe partial cystic tumor in 24 cases and complete solid tumors in 21 cases. Pterional approach was used in 48 patients and subfrontal approach in 2 patients. Great attention was paid to the preservation of the perforating arteries from thecarotid, posterior and anterior communicating and anterior choroidal arteries to the hypothalamic structures. The clinical outcome was evaluated according to the GOS scale.Results. Of the 50 patients surgically treated, 47 patients obtained total ectomy of the tumor and 3 patients with the secondary surgery had subtotal ectomy of the tumor. The pituitary stalk was preserved in 29(58%) patients, severed in 14 patients and unidentified in 7 patients. Forty-six patients regained a normal life; one patient needed assist in life. Of the 3 deaths, one patient died of diabetes insipidus, one of inhalation asphyxia, and another one of water and sodium disorders. Conclusion. Avoidance of the injury to the neural structures in the thirdventricular floor and preservation of the perforating arteries to hypothalamus are the key to achieve good surgical results in treating craniopharyngioma.
文摘In several countries, the residual RHA （rice husk ash） has been produced in rice processing industries or in thermoelectric plants that use rice husk to generate heat and/or electrical energy, usually without burning process control. This causes a reduction in the amorphous silica content of residual RHA, which distinguishes them from the RHA produced according to controlled burning process, which is totally amorphous and considered a highly reactive pozzolan. In this paper, the hydration products and the porous structure of binders paste were studied by replacing, in weight of 5%, 10% and 20% of Portland cement OPC （ordinary Portland cement）, by residual RHAs named A and B, which have high and low content of amorphous silica, respectively, using microstructure evaluation techniques as XRD （X-ray diffraction）, TG （thermogravimetric） tests and MIP （mercury intrusion porosimetry）. A reducing the size of the pores of the pastes was observed according to the increase of content replacement of RHA A and RHA B.
文摘In order to meet the rapid needs of processing square hole in mechanical equipment, the paper expounds the square hole processing method： planetary wheel method, and analyze the principle of tooling structure and process with computer graphics parameters design. The results that, as long as the appropriate parameters, using the above method not only can punch the square hole, can also be processed triangle, the five angle and hexagonal regular polygon holes. The square hole processing method can provide theoretical basis and engineering reliable reference for related engineering and technical personnel.
基金Supported by the Doctorial Foundation of Liaoning province and the Project of Institute of Applied Ecology, Chinese Academy ofSciences.
文摘A new structural parameter of shelterbelts, above-ground density of biomass volume, was putforward in this paper. Its practicality in managements of the shelterbelts and its physical meaning of windreduction were expounded. Analytical relations between the new parameter and often-used parameters(permeability and porosity) were deduced. An example was given to show the application of the newparameter in the management of shelterbelts.
基金supported by the National High Technology Research and Development Program of China(2012AA062702)the strategic project of the Chinese Academy of Sciences(XDB05050000)
文摘The design and synthesis of highly active non-noble metal oxide catalysts, such as transition- and rare-earth-metal oxides, have attracted significant attention because of their high efficiency and low cost and the resultant potential applications for the degradation of volatile organic compounds(VOCs). The structure-activity relationships have been well-studied and used to facilitate design of the structure and composition of highly active catalysts. Recently, non-noble metal oxides with porous structures have been used as catalysts for deep oxidation of VOCs, such as aromatic hydrocarbons, aliphatic compounds, aldehydes, and alcohols, with comparable activities to their noble metal counterparts. This review summarizes the growing literature regarding the use of porous metal oxides for the catalytic removal of VOCs, with emphasis on design of the composition and structure and typical synthetic technologies.
