Nowadays, an increasing number of web applications require identification registration. However, the behavior of website registration has not ever been thoroughly studied. We use the database provided by the Chinese S...Nowadays, an increasing number of web applications require identification registration. However, the behavior of website registration has not ever been thoroughly studied. We use the database provided by the Chinese Software Develop Net (CSDN) to provide a complete perspective on this research point. We concentrate on the following three aspects: complexity, correlation, and preference. From these analyses, we draw the following conclusions: firstly, a considerable number of users have not realized the importance of identification and are using very simple identifications that can be attacked very easily. Secondly, there is a strong complexity correlation among the three parts of identification. Thirdly, the top three passwords that users like are 123456789, 12345678 and 11111111, and the top three email providers that they prefer are NETEASE, qq and sina. Further, we provide some suggestions to improve the quality of user passwords.展开更多
分离鉴定4℃冷藏条件下海鲈鱼的优势腐败菌,通过选择性培养基筛选获得单一菌株,对各菌株进行致腐能力的测定,确定冷藏海鲈鱼的优势腐败菌。对冷藏海鲈鱼的优势腐败菌进行菌落形态观察及部分生理生化实验、16S r DNA分子鉴定。结果表明,...分离鉴定4℃冷藏条件下海鲈鱼的优势腐败菌,通过选择性培养基筛选获得单一菌株,对各菌株进行致腐能力的测定,确定冷藏海鲈鱼的优势腐败菌。对冷藏海鲈鱼的优势腐败菌进行菌落形态观察及部分生理生化实验、16S r DNA分子鉴定。结果表明,有4株冷藏海鲈鱼优势腐败菌,其中1株为草莓假单胞菌(Pseu domonas fragi),1株为腐败希瓦氏菌(Shewanella putrefaciens),其余2株为假单胞菌(Pseudomonas sp.)。在4℃冷藏条件下,草莓假单胞菌的致腐能力最强,其次是腐败希瓦氏菌和假单胞菌。展开更多
通过采用匀浆、硫酸铵盐析、透析、DEAE-52阴离子交换层析、Sephacryl S-300凝胶层析等方法从海参体壁中分离纯化并得到了α-1,4淀粉酶。结果表明,该酶具有3条亚基链,分子质量约为420 k D;最适p H值为9.0,最适温度为80℃,90℃条件下保温...通过采用匀浆、硫酸铵盐析、透析、DEAE-52阴离子交换层析、Sephacryl S-300凝胶层析等方法从海参体壁中分离纯化并得到了α-1,4淀粉酶。结果表明,该酶具有3条亚基链,分子质量约为420 k D;最适p H值为9.0,最适温度为80℃,90℃条件下保温30 min后仍有38%以上的相对酶活性,因此,该酶是一种具有较高热稳定性的碱性高温淀粉酶。K+、Fe3+和Mn2+对其有较强的抑制作用,Cu2+和Ca2+对其有较强的激活作用。展开更多
基金supported by the Foundation for Key Program of Ministry of Education, China under Grant No.311007National Science Foundation Project of China under Grants No. 61202079, No.61170225, No.61271199+1 种基金the Fundamental Research Funds for the Central Universities under Grant No.FRF-TP-09-015Athe Fundamental Research Funds in Beijing Jiaotong University under Grant No.W11JB00630
文摘Nowadays, an increasing number of web applications require identification registration. However, the behavior of website registration has not ever been thoroughly studied. We use the database provided by the Chinese Software Develop Net (CSDN) to provide a complete perspective on this research point. We concentrate on the following three aspects: complexity, correlation, and preference. From these analyses, we draw the following conclusions: firstly, a considerable number of users have not realized the importance of identification and are using very simple identifications that can be attacked very easily. Secondly, there is a strong complexity correlation among the three parts of identification. Thirdly, the top three passwords that users like are 123456789, 12345678 and 11111111, and the top three email providers that they prefer are NETEASE, qq and sina. Further, we provide some suggestions to improve the quality of user passwords.
