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In recent years, the modern information technology, whose core includes the computer technology, network communication technology and the multimedia technology, has developed rapidly. It has become the important way to spread knowledge, and impacted deeply to the traditional teaching concept, teaching content, teaching process and teaching resource. This article elaborated the changes of the teaching process under the condition of the modern information technology and summarized the more extensive roles of the college teachers. Finally, it pointed out that teachers must improve their own quality, and constantly adapt to the role changes in practice, in order to promote the improvement of the teaching level.

Biomass pyrolysis and liquefaction technology needs inert carrier gas and high energy consumption. On the basis of analyzing its energy consumption and the using way of char and off-gas, energy in the pyrolysis and liquefaction system in CFB is optimized by using a part of pyrolysis gas for carrier gas and off-gas to burn to heat biomass raw material. Inert carrier gas and its heating and cooling energy consumption are saved and off-gas is used to heat biomass instead of to exhaust to air after this optimization.

The objective of this work presents the numerical investigations of the enhancement performance of an phase change cold storage unit which is used for an air conditioning system during the solidification (discharge) process under the boundary condition of heat flux. The shell-and-tube cold storage unit is a typical tube-foil arrangement composed of an energy storage. The aluminum foils are arranged orthogonal to the axis of the tubes, and phase change material (PCM) fills the space between foils and tubes while the heat transfer fluid flows inside the tubes. The buildings use nighttime cold accumulation in PCM and cool hot air during the daytime in summer. When the cooling load is lower than the nominal cooling capacity of the system, the cold storage unit can store extra cold energy of the system to cool the interior of the building. The development of the model for the cold storage enables a detailed analysis of heat transfer process. The effects of foils and parameters on the behaviour of the performance are examined. Results show that by reducing the foil pitch or increasing heat flux has a significant enhancement effect on the heat transfer process.

With the development of the information technology, database security draws more and more attention than before. It is desirable to store data in encrypted form to protect the sensitive data from various attacks. But the efficiency of DBMS will fall as the SQL clauses can not execute over the encrypted data directly. In this paper we propose a secure cipher index with great efficiency over the encrypted character data to improve the performance of the encrypted database. The radical idea is to map the character data in the database into its index value, and translate the SQL clauses into a usable form to execute over the index attribute. Hash key and confuse number are introduced to make the cipher index in security in our scheme. In this schema, the same character data in different rows has different index value and the index value has no statistical characteristic, so it can alleviate the problem of statistical attack and plain attack. When there is a query over the encrypted character attribute, we filter out the majority of useless tulpes through the index and only decrypt the remainder, which could reduce the decryption cost greatly and prevent the information leaking.

The encryption mechanism is the common method to protect the sensitive data in database from various attacks. But once the data in databases is encrypted, the efficiency of DBMS will fall. To enhance the security of the sensitive data and to improve the efficiency of the encrypted database, one effective method is to build index on the encrypted field, and firstly executes the query on the index to get fewer records to decrypt in this paper. This paper proposes an index mechanism of bucket index on the character data, which has close relationships with all of its characters. The index tries to translate the character string into a numeric data, on which the primary query will be processed to filtrate the records roughly. Only the rest records need to be decrypted, and it will save lots of time. So the cipher index can improve the query efficiency greatly.