笔者过往每当在品酒场合提到马其顿Republic of Macedonia这个小国家的葡萄酒时,经常出现很安静的场面。我自问表达能力尚算可以,听者又没有观天望地和东张西望,也看不见有人哈欠连连。啊,原来没多少人有注意到这个细小地方!也许你是看...笔者过往每当在品酒场合提到马其顿Republic of Macedonia这个小国家的葡萄酒时,经常出现很安静的场面。我自问表达能力尚算可以,听者又没有观天望地和东张西望,也看不见有人哈欠连连。啊,原来没多少人有注意到这个细小地方!也许你是看足球比赛的Fans。展开更多
To solve the problem of sealing between the barrel and the rubber ring of shell body during an launching process of aerodynamic extinguishing cannon, a rubber sealing model with bionic dimpled characteristics was esta...To solve the problem of sealing between the barrel and the rubber ring of shell body during an launching process of aerodynamic extinguishing cannon, a rubber sealing model with bionic dimpled characteristics was established based on the theory of bionic dimpled drag reduction and the principle of rubber sealing. In condition that the bionic dimpled characteristic diameters were 1, 2, 3, 4, and 5 mm, respectively, by numerical simulation, the influence of the installing compression of the rubber sealing ring on its surface stress and deformation was analyzed, and sealing performance of the rubber ring with different diameters of bionic dimpled was studied. The results show that the deformation of rubber ring appears prominent nonlinear characteristics when compression is increased from 1.5 mm to 2.5 ram. When the compression is 2.5 mm, the equivalent compression stress on the sealing areas of both sides of the rubber seal is greater than the working pressure of aerodynamic extinguishing cannon, which could meet the sealing requirement and would not cause leakage. So the rubber sealing ring with bionic dimpled surface possesses a good sealing characteristic and has no negative effect on the sealing of shell body; When the compression is 2.5 mm, the larger equivalent stress on the edge of sealing ring and the more even stress distribution in the high pressure area are generated due to the smaller compressive stress on the bionic dimple areas, which lays a foundation for the drag reduction characteristics of the shell body＇s rubber ring with bionic dimpled surface.展开更多
Aroma is an important component for characteristic of wine. β-glucosidase is an enzyme for enhancing wine aroma during fermentation and aging. The aim of this study was to evaluate β-glucosidase activities from 17 y...Aroma is an important component for characteristic of wine. β-glucosidase is an enzyme for enhancing wine aroma during fermentation and aging. The aim of this study was to evaluate β-glucosidase activities from 17 yeast strains. It was found that strain 71 B-1122 exhibited highest activity of β-glucosidase. The purified enzyme of this strain was characterized. The purified enzyme was added in Muscat must before wine making process. The must and wine were determined for volatile compounds by headspace-SPME/GC-MS and found that the hexyl acetate, linalool, phenethyl, nerol and geraniol compounds were significantly increased after treated with the enzyme. Sensory evaluation of the combined alcoholic fermentation and flavour enrichment of Muscat juice by adding of purified β-glucosidase enzyme showed well oenological properties especially aroma. Therefore, in producing wine, yeast strain selection and addition of β-glucosidase enzyme should be considered because they were important factors affecting wine aroma.展开更多
基金Project(51275102)supported by the National Natural Science Foundation of ChinaProject(159070220011)supported by the Science and Technology Innovative Research Programs Foundation of Harbin city,ChinaProject(HEUCF110702)supported by the Fundamental Research Funds for the Central Universities of China
文摘To solve the problem of sealing between the barrel and the rubber ring of shell body during an launching process of aerodynamic extinguishing cannon, a rubber sealing model with bionic dimpled characteristics was established based on the theory of bionic dimpled drag reduction and the principle of rubber sealing. In condition that the bionic dimpled characteristic diameters were 1, 2, 3, 4, and 5 mm, respectively, by numerical simulation, the influence of the installing compression of the rubber sealing ring on its surface stress and deformation was analyzed, and sealing performance of the rubber ring with different diameters of bionic dimpled was studied. The results show that the deformation of rubber ring appears prominent nonlinear characteristics when compression is increased from 1.5 mm to 2.5 ram. When the compression is 2.5 mm, the equivalent compression stress on the sealing areas of both sides of the rubber seal is greater than the working pressure of aerodynamic extinguishing cannon, which could meet the sealing requirement and would not cause leakage. So the rubber sealing ring with bionic dimpled surface possesses a good sealing characteristic and has no negative effect on the sealing of shell body; When the compression is 2.5 mm, the larger equivalent stress on the edge of sealing ring and the more even stress distribution in the high pressure area are generated due to the smaller compressive stress on the bionic dimple areas, which lays a foundation for the drag reduction characteristics of the shell body＇s rubber ring with bionic dimpled surface.
文摘Aroma is an important component for characteristic of wine. β-glucosidase is an enzyme for enhancing wine aroma during fermentation and aging. The aim of this study was to evaluate β-glucosidase activities from 17 yeast strains. It was found that strain 71 B-1122 exhibited highest activity of β-glucosidase. The purified enzyme of this strain was characterized. The purified enzyme was added in Muscat must before wine making process. The must and wine were determined for volatile compounds by headspace-SPME/GC-MS and found that the hexyl acetate, linalool, phenethyl, nerol and geraniol compounds were significantly increased after treated with the enzyme. Sensory evaluation of the combined alcoholic fermentation and flavour enrichment of Muscat juice by adding of purified β-glucosidase enzyme showed well oenological properties especially aroma. Therefore, in producing wine, yeast strain selection and addition of β-glucosidase enzyme should be considered because they were important factors affecting wine aroma.
