Water-blown polyurethane rigid foams are getting more and more attention,because the traditional blowing agent HCFC141b has already been abolished to prevent the ozone layer from destruction.However,the polyurethane r...Water-blown polyurethane rigid foams are getting more and more attention,because the traditional blowing agent HCFC141b has already been abolished to prevent the ozone layer from destruction.However,the polyurethane rigid foams blown by water have serious defects,i.e.friability and resulting lower adhesion strength.Thus,the purpose of this study is to resolve the problems by chemical plastication.The maleate was added to polyol-premix containing water or to polyisocyanate,with both of which maleate does not react.To prove the reaction when polyol-premix and polyisocyanate were mixed,the model composite was synthesized and analyzed by IR,NMR and ESI(MS).Furthermore,a series of water-blown polyurethane rigid foams added different amount maleate were successfully prepared.By testing impact strength and adhesion strength of the foams,the actual effect of adding maleate was obtained.展开更多
The investigation on bubble behavior in electric field helps to analyze the mechanism of electric enhancement of boiling heat transfer. Experiments were performed to investigate the bubble deformation in direct curre...The investigation on bubble behavior in electric field helps to analyze the mechanism of electric enhancement of boiling heat transfer. Experiments were performed to investigate the bubble deformation in direct current （DC） electric field with bubbles attached to the orifice. The air bubbles were slowly generated in the transformer oil pool at different orifices, so that the effect of flow on bubble shape was eliminated. The results showed that the bubbles were elongated and the departure volume decreased when the electric field was intensified. The major and minor axes, aspect ratio and departure volume increased with increasing the orifice diameter. Both the electric field and orifice size have great influence on bubble behavior. The bubble deformation was also simulated to compare with the experimental results. The numerical and experimental data qualitatively agree with each other.展开更多
Objective: To screen and clone differentially expressed genes of dermal papillae cells (DPC) with aggregative behavior, and to explore the molecular mechanism of their aggregation. Methods: Total RNAs were extracted f...Objective: To screen and clone differentially expressed genes of dermal papillae cells (DPC) with aggregative behavior, and to explore the molecular mechanism of their aggregation. Methods: Total RNAs were extracted from DPC with and without aggregative behavior and double strand cDNAs were synthesized by using SMART cDNA synthesis, respectively. The cDNA fragments of differentially expressed genes in DPCs with aggregative behavior were isolated by suppression subtractive hybridization. Positive clones were screened by PCR method and verified by cDNA dot blot, Northern blot and then analyzed through homologous retrieving. Results: A subtractive cDNA library of DPC with aggregative behavior has been successfully constructed. The result of screening and cloning of the library showed that, DPC with aggregative behavior could expresse genes related to homologous aggregation, proliferation and cycle control, including known genes (capping protein, paladin, vascular endothelial growth factor), hematopoietic stem/progenitor cells (HSPC) related clone (HSPC011 and HSPC016) and a new gene. Conclusion: The construction of subtracted library of DPC lays solid foundation for screening and cloning new and specific genes related to aggregative behavior of DPC. Several genes might be cooperatively involved in the homologous aggregation, proliferation and cycle control of DPC. Among these genes, capping protein and palladin might be closely related to the aggregative behavior of dermal papilla cells, and VEGF and HSPC related clone would be responsible for the status of higher proliferation of dermal papilla cells.展开更多
OBJECTIVE To enhance the understanding of Castleman’s disease (CD), and to improve its diagnosis and management. METHODS Clinical features and related information on diagnosis and treatment of 14 cases of CD were ret...OBJECTIVE To enhance the understanding of Castleman’s disease (CD), and to improve its diagnosis and management. METHODS Clinical features and related information on diagnosis and treatment of 14 cases of CD were retrospectively analyzed and the literature reviewed. RESULTS Based on the clinical classification, localized CD was found in 8 of the 14 cases. Both the results of lymph node biopsy and histopathology indicated they were a hyaline-vascular type. The multicentric type CD was detected in 6 cases, among which 4 were plasma cell type and 2 mixed type based on histopathologic examination. There were a variety of clinical situa-tions in the 14 cases, with a lack of specificity. They were previously misdiag-nosed as other diseases, and final diagnosis depended on a histopathologic examination. The 8 patients with localized CD underwent excision, without recurrence up to now. The 6 patients with multicentric-type CD were treated with glucocorticoids or combined chemotherapy, and all achieved remission. CONCLUSIONS CD has complicated clinical manifestations and is difficult to diagnose. Lymph node biopsy is important for early diagnosis. An optimal curative effect can be achieved with a suitable therapeutic option, based on histopathology and clinical classification.展开更多
The corrosion behavior of a titanium-5% tantalum alloy （Ti-STa） in hot nitric acid condensate was investigated to understand aging behavior ofreprocessing equipments. On the basis of long-term immersion tests, it wa...The corrosion behavior of a titanium-5% tantalum alloy （Ti-STa） in hot nitric acid condensate was investigated to understand aging behavior ofreprocessing equipments. On the basis of long-term immersion tests, it was determined that the corrosion of Ti-STa in nitric acid condensate is accelerated with an increase in the concentration. The corrosion rate was nearly constant during the immersion test and the coupons suffered from uniform corrosion. In addition, it is important to note that the nitric acid concentration in the condensate increased on addition of metal salts to the heated nitric acid solution. The larger valence of metal ions was contributed to the increase in the concentration of nitric acid condensate. Consequently, the metal salt in the heated nitric acid solution accelerates the corrosion of Ti-STa in the condensate. Therefore, the nitric acid condensate condition should be carefully considered for the corrosion environment of titanium and its alloys.展开更多
This paper shows that there are two different phases in economics. These are the primal and dual problems. In the primal problem phase, capital expenditures of private corporations grow, creating an impetus towards th...This paper shows that there are two different phases in economics. These are the primal and dual problems. In the primal problem phase, capital expenditures of private corporations grow, creating an impetus towards the maximization of profits. In this case, as Adam Smith once wrote, the ＂invisible hand of God＂ works to lead the economy to a significant growth. This paper defines the concept of economic growth, bubble economy and destruction of bubble economy. And this paper describes why bubble economy occurs and crashes. In the process, this paper shows that primal economy exists before bubble economy and dual economy exists after destruction of bubble economy.展开更多
文摘Water-blown polyurethane rigid foams are getting more and more attention,because the traditional blowing agent HCFC141b has already been abolished to prevent the ozone layer from destruction.However,the polyurethane rigid foams blown by water have serious defects,i.e.friability and resulting lower adhesion strength.Thus,the purpose of this study is to resolve the problems by chemical plastication.The maleate was added to polyol-premix containing water or to polyisocyanate,with both of which maleate does not react.To prove the reaction when polyol-premix and polyisocyanate were mixed,the model composite was synthesized and analyzed by IR,NMR and ESI(MS).Furthermore,a series of water-blown polyurethane rigid foams added different amount maleate were successfully prepared.By testing impact strength and adhesion strength of the foams,the actual effect of adding maleate was obtained.
基金the National Key Basic Research Program of China (G2000026301)Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, China
文摘The investigation on bubble behavior in electric field helps to analyze the mechanism of electric enhancement of boiling heat transfer. Experiments were performed to investigate the bubble deformation in direct current （DC） electric field with bubbles attached to the orifice. The air bubbles were slowly generated in the transformer oil pool at different orifices, so that the effect of flow on bubble shape was eliminated. The results showed that the bubbles were elongated and the departure volume decreased when the electric field was intensified. The major and minor axes, aspect ratio and departure volume increased with increasing the orifice diameter. Both the electric field and orifice size have great influence on bubble behavior. The bubble deformation was also simulated to compare with the experimental results. The numerical and experimental data qualitatively agree with each other.
文摘Objective: To screen and clone differentially expressed genes of dermal papillae cells (DPC) with aggregative behavior, and to explore the molecular mechanism of their aggregation. Methods: Total RNAs were extracted from DPC with and without aggregative behavior and double strand cDNAs were synthesized by using SMART cDNA synthesis, respectively. The cDNA fragments of differentially expressed genes in DPCs with aggregative behavior were isolated by suppression subtractive hybridization. Positive clones were screened by PCR method and verified by cDNA dot blot, Northern blot and then analyzed through homologous retrieving. Results: A subtractive cDNA library of DPC with aggregative behavior has been successfully constructed. The result of screening and cloning of the library showed that, DPC with aggregative behavior could expresse genes related to homologous aggregation, proliferation and cycle control, including known genes (capping protein, paladin, vascular endothelial growth factor), hematopoietic stem/progenitor cells (HSPC) related clone (HSPC011 and HSPC016) and a new gene. Conclusion: The construction of subtracted library of DPC lays solid foundation for screening and cloning new and specific genes related to aggregative behavior of DPC. Several genes might be cooperatively involved in the homologous aggregation, proliferation and cycle control of DPC. Among these genes, capping protein and palladin might be closely related to the aggregative behavior of dermal papilla cells, and VEGF and HSPC related clone would be responsible for the status of higher proliferation of dermal papilla cells.
文摘OBJECTIVE To enhance the understanding of Castleman’s disease (CD), and to improve its diagnosis and management. METHODS Clinical features and related information on diagnosis and treatment of 14 cases of CD were retrospectively analyzed and the literature reviewed. RESULTS Based on the clinical classification, localized CD was found in 8 of the 14 cases. Both the results of lymph node biopsy and histopathology indicated they were a hyaline-vascular type. The multicentric type CD was detected in 6 cases, among which 4 were plasma cell type and 2 mixed type based on histopathologic examination. There were a variety of clinical situa-tions in the 14 cases, with a lack of specificity. They were previously misdiag-nosed as other diseases, and final diagnosis depended on a histopathologic examination. The 8 patients with localized CD underwent excision, without recurrence up to now. The 6 patients with multicentric-type CD were treated with glucocorticoids or combined chemotherapy, and all achieved remission. CONCLUSIONS CD has complicated clinical manifestations and is difficult to diagnose. Lymph node biopsy is important for early diagnosis. An optimal curative effect can be achieved with a suitable therapeutic option, based on histopathology and clinical classification.
文摘The corrosion behavior of a titanium-5% tantalum alloy （Ti-STa） in hot nitric acid condensate was investigated to understand aging behavior ofreprocessing equipments. On the basis of long-term immersion tests, it was determined that the corrosion of Ti-STa in nitric acid condensate is accelerated with an increase in the concentration. The corrosion rate was nearly constant during the immersion test and the coupons suffered from uniform corrosion. In addition, it is important to note that the nitric acid concentration in the condensate increased on addition of metal salts to the heated nitric acid solution. The larger valence of metal ions was contributed to the increase in the concentration of nitric acid condensate. Consequently, the metal salt in the heated nitric acid solution accelerates the corrosion of Ti-STa in the condensate. Therefore, the nitric acid condensate condition should be carefully considered for the corrosion environment of titanium and its alloys.
文摘This paper shows that there are two different phases in economics. These are the primal and dual problems. In the primal problem phase, capital expenditures of private corporations grow, creating an impetus towards the maximization of profits. In this case, as Adam Smith once wrote, the ＂invisible hand of God＂ works to lead the economy to a significant growth. This paper defines the concept of economic growth, bubble economy and destruction of bubble economy. And this paper describes why bubble economy occurs and crashes. In the process, this paper shows that primal economy exists before bubble economy and dual economy exists after destruction of bubble economy.
