The Preparation and Application of Chitosan Compound Flocculant

[Objective]The research aimed to study preparation and application of the environment-friendly compound flocculant.[Method]Chitosan（natural biological product,CTS）,ferric sulfate[Fe2（SO4） 3]and polymeric aluminum chloride（PAC） as the main raw materials,four kinds of environment-friendly flocculants were made to conduct flocculation treatment on the domestic wastewater of Wuhan Bioengineering Institute.COD and turbidity of the wastewater as the main indicators,influences of the compound flocculant formulation,flocculant dosage and pH on flocculation effect were studied.[Result]CTS/PAC and CTS/Fe2（SO4） 3 compound flocculants had better removal rates for COD and turbidity when compared with single inorganic flocculant.The best volume ratio of CTS/PAC was 1.0：5.0.The smallest dosage of CTS/PAC in each 500 ml of water sample was 4.0 ml.When pH was 7.2,removal rates of the COD and turbidity were respectively 78.5% and 98.4%,which rose by 36.5% and 21.5% respectively than that singly using PAC.[Conclusion]CTS/PAC was a kind of ideal compound flocculant and had better application prospect.

Clinical application of retrograde cerebral perfusion for brain protection during the surgery of ascending aortic aneurysm:50 cases report

Objective To assess retrospectively the effects of different protective methods on brain in ascending aortic aneurysm surgery. Methods In 65 patients, aneurysm was dissected to the aortic arch or right arch. To protect brain, deep hypotermic circulatory arrest ( DHCA.) combined with retrograde cerebral perfusion ( RCP) June 2003 Vol11 No2 through the superior vena cava ( n = 50) and simple DHCA ( n = 15) were used during the procedure. Blood samples for lactic acid level from the jugular vein were compared in both groups at different plase, and perfusion blood distribution and oxygen content difference between the perfused and returned blood were measured in some RCP patients. Results The DHCA time was 35.9 ± 8 min (10. 0 - 63. 0 min) and DHCA+ RCP time was 45.5 ± 17. 2 min (16. 0 - 81. 0 min)The resuscitationtime was 7.1 ± 1.6 h (4.4 - 9.4H)in DHCA patients and 5.4±2.2h(2.0-9.0 h)in RCP patients. Operation death was 3/15 in the DHCA group and 1/50 in the RCP patients. Central nervous complication

Systematic Approach for Web Protection Runtime Tools’Effectiveness Analysis

Web applications represent one of the principal vehicles by which attackers gain access to an organization’s network or resources.Thus,different approaches to protect web applications have been proposed to date.Of them,the two major approaches are Web Application Firewalls(WAF)and Runtime Application Self Protection(RASP).It is,thus,essential to understand the differences and relative effectiveness of both these approaches for effective decisionmaking regarding the security of web applications.Here we present a comparative study between WAF and RASP simulated settings,with the aim to compare their effectiveness and efficiency against different categories of attacks.For this,we used computation of different metrics and sorted their results using F-Score index.We found that RASP tools scored better than WAF tools.In this study,we also developed a new experimental methodology for the objective evaluation ofweb protection tools since,to the best of our knowledge,nomethod specifically evaluates web protection tools.

Simulation of propagation of the HPM in the low-pressure argon plasma

The propagation of the high-power microwave（HPM） with a frequency of 6 GHz in the lowpressure argon plasma was studied by the method of fluid approximation.The two-dimensional transmission model was built based on the wave equation,the electron drift-diffusion equations and the heavy species transport equations,which were solved by means of COMSOL Multiphysics software.The simulation results showed that the propagation characteristic of the HPM was closely related to the average electron density of the plasma.The attenuation of the transmitted wave increased nonlinearly with the electron density.Specifically,the growth of the attenuation slowed down as the electron density increased uniformly.In addition,the concrete transmission process of the HPM wave in the low-pressure argon plasma was given.

A Private User Data Protection Mechanism in TrustZone Architecture Based on Identity Authentication

In Trust Zone architecture, the Trusted Application（TA） in the secure world does not certify the identity of Client Applications（CA） in the normal world that request data access, which represents a user data leakage risk. This paper proposes a private user data protection mechanism in Trust Zone to avoid such risks. We add corresponding modules to both the secure world and the normal world and authenticate the identity of CA to prevent illegal access to private user data. Then we analyze the system security, and perform validity and performance tests.The results show that this method can perform effective identity recognition and control of CA to protect the security of private user data. After adding authentication modules, the data operation time of system increases by about0.16 s, an acceptable price to pay for the improved security.