通过常规乳酸菌分离技术结合形态观察、生理生化试验,以及16S r DNA同源性分析等方法,从臭豆腐发酵卤水中分离获得7株戊糖片球菌分离株,并通过随机扩增多态性DNA技术构建了不同菌株的特征指纹图谱;以Caco-2细胞和固定化肠黏液蛋白质作...通过常规乳酸菌分离技术结合形态观察、生理生化试验,以及16S r DNA同源性分析等方法,从臭豆腐发酵卤水中分离获得7株戊糖片球菌分离株,并通过随机扩增多态性DNA技术构建了不同菌株的特征指纹图谱;以Caco-2细胞和固定化肠黏液蛋白质作为体外模型,研究了菌株的粘附能力,并探讨了菌株粘附能力与基因型以及表面疏水性、自凝聚能力等表型特征的相关性。结果显示,发酵卤水中的戊糖片球菌存在高度分子多样性,7个分离株中存在6种不同的指纹图谱模式,其中A5型菌株(F28-8和Y27-4)对Caco-2细胞和肠黏液蛋白质的粘附性最强,并显示了高度的疏水性(﹥90%)和较强的自凝聚能力(﹥25%)。相关性分析表明,戊糖片球菌表面疏水率和自凝聚率与Caco-2细胞粘附率测定结果呈显著正相关(r=0.900和0.792,P﹤0.05),但是与肠黏液蛋白质粘附率测定结果相关性不显著(r=0.426和0.700,P﹥0.05)。研究成果为建立高粘附性戊糖片球菌快速筛选方法及其体内定植和分布研究提供了依据。展开更多
Chitosan derived from crab shells, was used to prepare the graft polymer in aqueous solution with acrylamide (AM) and methacrylatoethyl trimethyl ammonium chloride (DMC) as raw materials and ceric ammonium nitrate...Chitosan derived from crab shells, was used to prepare the graft polymer in aqueous solution with acrylamide (AM) and methacrylatoethyl trimethyl ammonium chloride (DMC) as raw materials and ceric ammonium nitrate (CAN) as initiator. The flocculation ability of the resulting polymer (PCAD) was studied in waste water treatment experiments. Its properties were determined on the basis of the transmittance of waste water after flocculation. The effects of ehitosan and DMC content on PCAD's flocculation ability were studied. Floeculation experiments were also undertaken under various pH conditions. According to the experimental data, the flocculation ability could be improved when chitosan content decreased in the raw material, but the monomer conversion would decrease obviously. When the ehitosan's content was more than 65%, AM and DMC groups were less on each chitosan molecule. So PCAD's flocculation ability was poor. Similarly, high content of DMC would result in low monomer conversion and high flocculation ability. PCAD molecules with more DMC group had more positive charges. It was favorable to flocculation. However, monomer conversion would decrease with the increase of DMC content. The suitable conditions were that chitosan and DMC contents were 65% and 15-20%, respectively. The experiment data showed that PCAD had good flocculation ability under weak acidic condition. Its ability would be weakened by strong acidic or alkaline condition. The flocculation efficiency was the best at pH of 5.5 when PCAD's dosage was 8mg-Lk Compared with cationic polymer (the copolymer of AM and DMC, PAD), PCAD showed better flocculation ability under acid and neutral conditions, but worse ability under alkaline condition.展开更多
Compressive and flexural strength,fracture energy,as well as fatigue property of pervious cement concrete with either supplementary cementitious materials (SCMs) or polymer intensified,were analyzed.Test results show ...Compressive and flexural strength,fracture energy,as well as fatigue property of pervious cement concrete with either supplementary cementitious materials (SCMs) or polymer intensified,were analyzed.Test results show that the strength development of SCM-modified pervious concrete (SPC) differs from that of polymer-intensified pervious concrete (PPC),and porosity has little effect on their strength growth.PPC has higher flexural strength and remarkably higher flexural-to-compressive strength ratio than SPC at the same porosity level.Results from fracture test of pervious concrete mixes with porosity around 19.5% show that the fracture energy increases with increasing the dosage of polymer,reflecting the ductile damage features rather than brittleness.PPC displays far longer fatigue life than SPC for any given failure probability and at any stress level.It is proved that two-parameter Weibull probability function describes the flexural fatigue of pervious concrete.展开更多
Graft copolymerization is one of the most attractive methods to modify natural polymers. In this study, graft copolymerization of acylic acid onto chitosan in aqueous media by ceric ammonium nitrate was investigated. ...Graft copolymerization is one of the most attractive methods to modify natural polymers. In this study, graft copolymerization of acylic acid onto chitosan in aqueous media by ceric ammonium nitrate was investigated. The graft copolymerization reaction was carried out in a three necked flask maintained at 70+/-0.05 ℃ under nitrogen atmosphere in a homogeneous aqueous phase (containing a small potion of acetic acid) by using ceric ammonium nitrate as an initiator. Evidence of grafting was obtained. The synthetic conditions were systematically optimized through studying the influential factors on grafting. The effectiveness of each individual factor was investigated by calculating and monitoring the variations of the grafting parameters [like monomer conversation Cm, grafting efficiency (Ge) and viscosity]. Under optimum conditions monomer conversion of 100.5% and graft efficiency of 94% were obtained, at temperature of 70℃. Flocculating ability of the copolymerization product of chitosan was studied by using Kaolin suspension as the flocculating object. And the application of the product was applied in Huayue dyeing plant. The results indicate that the higher the viscosity is, the better the flocculating ability of the copolymerization product of chitosan will be. The flocculating percentage reaches 96.0%, when the concentration of the product is only 1.0 mg/L and pH fixed at 7.0. Suitable separating mixtures for the grafted copolymer were chosen and the investigation of flocculation ability of the grafted copolymer was carried out with the aim of developing a good flocculant for wastewater treatment. A test of treating dyeing wastewater with the grafted copolymer was carried out and showed that grafting of Acrylic Acid with chitosan has a high COD removal rate 75% to the dyeing wastewater when the concentration is only 6.0 mg/L.展开更多
Facing with the future increasingly changed economy environment, a company who wants to survive forever has to control the key point of owning person with ability and core competence. However, the main question needs ...Facing with the future increasingly changed economy environment, a company who wants to survive forever has to control the key point of owning person with ability and core competence. However, the main question needs to he solved is to design a motivational compensation system which not only have competence when compared with other companies but also have cohesive force for the staffand can evaluate them fairly. Salary should not just be the cost of paying for worker's labor but should have more functions to introduct them to obey orders and stimulate their activities. This essay has some reference to enrich the motivational compensation system by discussing the motivational plans in different period of a company and analyzing the actual working operation. This essay aims at applying present compensation theory to small and medium-sized enterprises to get some beneficial discoveries, concluding a compensation dcsign system which suits for the traits of small and medium-sized enterprises from the strategic level and technical level. As a result, we can improve our company's core competence.展开更多
Geopolymer-lightweight aggregate refractory concrete (GLARC) was prepared with geopolymer and lightweight aggregate. The mechanical property and heat-resistance (950 ℃) of GLARC were investigated. The effects of size...Geopolymer-lightweight aggregate refractory concrete (GLARC) was prepared with geopolymer and lightweight aggregate. The mechanical property and heat-resistance (950 ℃) of GLARC were investigated. The effects of size of aggregate and mass ratio of geopolymer to aggregate on mechanical and thermal properties were also studied. The results show that the highest compressive strength of the heated refractory concrete is 43.3 MPa,and the strength loss is only 42%. The mechanical property and heat-resistance are influenced by the thickness of geopolymer covered with aggregate,which can be expressed as the quantity of geopolymer on per surface area of aggregate. In order to show the relationship between the thickness of geopolymer covered with aggregate and the thermal property of concrete,equal thickness model is presented,which provides a reference for the mix design of GLARC. For the haydite sand with size of 1.18-4.75 mm,the best amount of geopolymer per surface area of aggregate should be in the range of 0.300-0.500 mg/mm2.展开更多
文摘通过常规乳酸菌分离技术结合形态观察、生理生化试验,以及16S r DNA同源性分析等方法,从臭豆腐发酵卤水中分离获得7株戊糖片球菌分离株,并通过随机扩增多态性DNA技术构建了不同菌株的特征指纹图谱;以Caco-2细胞和固定化肠黏液蛋白质作为体外模型,研究了菌株的粘附能力,并探讨了菌株粘附能力与基因型以及表面疏水性、自凝聚能力等表型特征的相关性。结果显示,发酵卤水中的戊糖片球菌存在高度分子多样性,7个分离株中存在6种不同的指纹图谱模式,其中A5型菌株(F28-8和Y27-4)对Caco-2细胞和肠黏液蛋白质的粘附性最强,并显示了高度的疏水性(﹥90%)和较强的自凝聚能力(﹥25%)。相关性分析表明,戊糖片球菌表面疏水率和自凝聚率与Caco-2细胞粘附率测定结果呈显著正相关(r=0.900和0.792,P﹤0.05),但是与肠黏液蛋白质粘附率测定结果相关性不显著(r=0.426和0.700,P﹥0.05)。研究成果为建立高粘附性戊糖片球菌快速筛选方法及其体内定植和分布研究提供了依据。
基金supported by Young Scientist Foundation (2008BS09001) from the Department of Science and Technology of Shandong Province
文摘Chitosan derived from crab shells, was used to prepare the graft polymer in aqueous solution with acrylamide (AM) and methacrylatoethyl trimethyl ammonium chloride (DMC) as raw materials and ceric ammonium nitrate (CAN) as initiator. The flocculation ability of the resulting polymer (PCAD) was studied in waste water treatment experiments. Its properties were determined on the basis of the transmittance of waste water after flocculation. The effects of ehitosan and DMC content on PCAD's flocculation ability were studied. Floeculation experiments were also undertaken under various pH conditions. According to the experimental data, the flocculation ability could be improved when chitosan content decreased in the raw material, but the monomer conversion would decrease obviously. When the ehitosan's content was more than 65%, AM and DMC groups were less on each chitosan molecule. So PCAD's flocculation ability was poor. Similarly, high content of DMC would result in low monomer conversion and high flocculation ability. PCAD molecules with more DMC group had more positive charges. It was favorable to flocculation. However, monomer conversion would decrease with the increase of DMC content. The suitable conditions were that chitosan and DMC contents were 65% and 15-20%, respectively. The experiment data showed that PCAD had good flocculation ability under weak acidic condition. Its ability would be weakened by strong acidic or alkaline condition. The flocculation efficiency was the best at pH of 5.5 when PCAD's dosage was 8mg-Lk Compared with cationic polymer (the copolymer of AM and DMC, PAD), PCAD showed better flocculation ability under acid and neutral conditions, but worse ability under alkaline condition.
基金Project(kfj080205)supported by Key Laboratory of Road Structure and Material of Ministry of Transport(Changsha),China
文摘Compressive and flexural strength,fracture energy,as well as fatigue property of pervious cement concrete with either supplementary cementitious materials (SCMs) or polymer intensified,were analyzed.Test results show that the strength development of SCM-modified pervious concrete (SPC) differs from that of polymer-intensified pervious concrete (PPC),and porosity has little effect on their strength growth.PPC has higher flexural strength and remarkably higher flexural-to-compressive strength ratio than SPC at the same porosity level.Results from fracture test of pervious concrete mixes with porosity around 19.5% show that the fracture energy increases with increasing the dosage of polymer,reflecting the ductile damage features rather than brittleness.PPC displays far longer fatigue life than SPC for any given failure probability and at any stress level.It is proved that two-parameter Weibull probability function describes the flexural fatigue of pervious concrete.
文摘Graft copolymerization is one of the most attractive methods to modify natural polymers. In this study, graft copolymerization of acylic acid onto chitosan in aqueous media by ceric ammonium nitrate was investigated. The graft copolymerization reaction was carried out in a three necked flask maintained at 70+/-0.05 ℃ under nitrogen atmosphere in a homogeneous aqueous phase (containing a small potion of acetic acid) by using ceric ammonium nitrate as an initiator. Evidence of grafting was obtained. The synthetic conditions were systematically optimized through studying the influential factors on grafting. The effectiveness of each individual factor was investigated by calculating and monitoring the variations of the grafting parameters [like monomer conversation Cm, grafting efficiency (Ge) and viscosity]. Under optimum conditions monomer conversion of 100.5% and graft efficiency of 94% were obtained, at temperature of 70℃. Flocculating ability of the copolymerization product of chitosan was studied by using Kaolin suspension as the flocculating object. And the application of the product was applied in Huayue dyeing plant. The results indicate that the higher the viscosity is, the better the flocculating ability of the copolymerization product of chitosan will be. The flocculating percentage reaches 96.0%, when the concentration of the product is only 1.0 mg/L and pH fixed at 7.0. Suitable separating mixtures for the grafted copolymer were chosen and the investigation of flocculation ability of the grafted copolymer was carried out with the aim of developing a good flocculant for wastewater treatment. A test of treating dyeing wastewater with the grafted copolymer was carried out and showed that grafting of Acrylic Acid with chitosan has a high COD removal rate 75% to the dyeing wastewater when the concentration is only 6.0 mg/L.
文摘Facing with the future increasingly changed economy environment, a company who wants to survive forever has to control the key point of owning person with ability and core competence. However, the main question needs to he solved is to design a motivational compensation system which not only have competence when compared with other companies but also have cohesive force for the staffand can evaluate them fairly. Salary should not just be the cost of paying for worker's labor but should have more functions to introduct them to obey orders and stimulate their activities. This essay has some reference to enrich the motivational compensation system by discussing the motivational plans in different period of a company and analyzing the actual working operation. This essay aims at applying present compensation theory to small and medium-sized enterprises to get some beneficial discoveries, concluding a compensation dcsign system which suits for the traits of small and medium-sized enterprises from the strategic level and technical level. As a result, we can improve our company's core competence.
基金Project(2009CB623201) supported by the National Basic Research Program of ChinaProject(G0510) supported by the Key Laboratory for Refractories and High-temperature Ceramics of Hubei Province, China
文摘Geopolymer-lightweight aggregate refractory concrete (GLARC) was prepared with geopolymer and lightweight aggregate. The mechanical property and heat-resistance (950 ℃) of GLARC were investigated. The effects of size of aggregate and mass ratio of geopolymer to aggregate on mechanical and thermal properties were also studied. The results show that the highest compressive strength of the heated refractory concrete is 43.3 MPa,and the strength loss is only 42%. The mechanical property and heat-resistance are influenced by the thickness of geopolymer covered with aggregate,which can be expressed as the quantity of geopolymer on per surface area of aggregate. In order to show the relationship between the thickness of geopolymer covered with aggregate and the thermal property of concrete,equal thickness model is presented,which provides a reference for the mix design of GLARC. For the haydite sand with size of 1.18-4.75 mm,the best amount of geopolymer per surface area of aggregate should be in the range of 0.300-0.500 mg/mm2.