针对ECC密码芯片的CPA分析研究

相关性功率分析（CPA）方法可有效地对加密的集成电路芯片进行攻击解密,它绕过了加解密算法繁琐的数学分析,从而获取密码和信息。应用CPA分析攻击嵌有椭圆曲线算法的芯片,搭建实验平台,获取加密时的电磁数据,并用统计学、密码分析学和信号处理的方法推导分析得出结论,从而成功破解加密系统。     

Highly enhanced bactericidal effects of medium chain fatty acids (caprylic,capric, and lauric acid) combined with edible plant essential oils (carvacrol,eugenol, β-resorcylic acid,trans-cinnamaldehyde,thymol, and vanillin) against Escherichia coli O157:H7

Medium chain fatty acids (MCFAs) and essential oils (EOs) are known to be natural antimicrobials, but their combined effects have not been fully investigated. The objective of the present study was to examine the bactericidal effects of various combined treatments of MCFAs [caprylic (CA), capric (CPA), and lauric acid (LRA)] and EOs [carvacrol (CAR), eugenol (EUG), β-resorcylic acid (RA), trans-cinnamaldehyde (TC), thymol (TM), and vanillin (VNL)]. Escherichia coli O157:H7, was treated with 1) control (2% ethanol), 2) MCFA alone, 3) EO alone, and 4) different combinations of MCFAs and EOs at 37 °C for 5 and 10 min. Synergistic bactericidal effects were observed with combined treatments; the log reduction in viable bacteria in response to the combined treatments was much greater than the sum of the effects of the two compounds applied individually. For example, individual treatment with 0.2 mM CPA (0.004%) and 0.4 mM RA (0.006%) for 5 min resulted in a negligible reduction in bacterial load (0.25 and 0.21 log reduction, respectively), whereas combined treatment at the same concentrations and for the same time reduced the bacterial population in the test sample to an undetectable level (initial population: 7.51 log CFU/ml; detection limit: 1 CFU/ml). The ranking of EOs showing the highest bacterial killing activities when combined with MCFAs was generally RA, CAR, TM > EUG > TC > VNL. All the antimicrobials used in this study are natural compounds that have been widely used in industry, so they are both consumer- and user-friendly. Combined treatment can overcome the disadvantages of MCFAs and EOs such as unpleasant odor and high cost because the required concentrations can be reduced. Our results indicate that the combined treatments used here could be successfully used to eliminate foodborne pathogens, significantly improving the microbiological safety of foods.     

注册会计师审计中常见的问题及对策

文章分析了注册会计师在进行审计时常见的如与被审计单位沟通等六个问题,并针对这些问题提出了相应的对策,以规避审计风险.     

注册会计师审计鉴证失真的成因及对策

由于审计制度本身的缺陷、对注册会计师监管不力、民事赔偿制度不完善、会计信息失真严重等多方面因素的影响，使得注册会计师审计鉴汪失真成为一个严重的社会问题。要解决注册会计师审计鉴征失真问题，需要采取不断完善审计制度、建立行业信用体系、执业规范、健全民事赔偿制度、提高会计信息质量等有力的措施，以提高审计质量。     

水泥净浆结粒水筛检测方法研究

由水筛法得到启示，提出了一套水泥净浆结粒的检测方法。通过研究水泥称量、水化温度、水泥细度、水灰比、石膏掺量和水化时间对结粒量的影响，探讨了该检测方法的可行性，并计算了结粒量的标准偏差。结果表明：该净浆结粒检测方法可靠性高，检测结果具有很好的稳定性和重现性；同时对于不同条件下的变化，能够充分反映水泥净浆结粒的变化规律，是研究净浆结粒的有效方法。     

影响会计诚信的因素分析

针对目前上市公司会计造假猖獗的严峻形势,提出解决问题的根本途径——建立诚信机制。诚信机制与法律法规有着相辅相成的关系,而会计诚信机制与三方面的因素有着密切的关系,即会计人员、经理人、中介机构。     

DES密码相关性功率分析中最小样本量计算

样本量是可以衡量设备抵 CPA攻击的重要指标,因此建立一种计算样本量的模型是很重要的.选择用统计学的方法通过计算样本量测定硬件的防护效果,这就可以让设计者在设计过程中通过计算了解设备抵御CPA的能力,还可以很容易地比较不同的防护方法,避免了由于产品不能有效抵 CPA攻击而进行的代价高昂的重复设计.     

In vivo Mutational Analysis of Highly Conserved Amino Acid Residues of the Small Subunit Cpa1p of the Carbamylphosphate Synthetase of Saccharomyces cerevisiae

The role of selected amino acid residues located in the putative catalytic domain and of two conserved histidine residues within the small subunit of the carbamylphosphate synthetase (CPS) specific to the arginine biosynthesis pathway of the yeast Saccharomyces cerevisiae was studied using site-directed mutagenesis to change all residues to aspartic acid. Carbamylphosphate synthesis catalysed by modified CPS was tested in vivo. The C264D, H307D and H349D mutants were unable to grow on minimal medium, indicating the importance of these three residues for efficient CPS activity, whereas, four other mutated residues located in the catalytic site (including a proline residue) do not affect the growth rate. These results in comparison to those obtained with the CPS of Escherichia coli, implicate residues Cys 264 and His 349 in the glutaminase catalytic activity, and His 307 in the binding of glutamine to the active site. Using these three defective mutants, we investigated the in vivo utilization of ammonia by CPS. C264D and H307D mutants are able to use ammonia as a substrate when provided in sufficiently high concentrations (up to 200 mm). The H349D mutant, however, did not grow even at ammonium sulfate concentrations above 400 mm, suggesting that this substitution is critical to NH₃-dependent CPS activity although the ammonia binding site is presumably located within the large subunit of the enzyme. © 1997 by John Wiley & Sons, Ltd.     

Determination of asphaltene precipitation using a new CPA-based equation of state

Asphaltene precipitation during natural depletion and miscible gas injection is a common problem in oilfields throughout the world. Therefore, predicting asphaltene phase behavior through thermodynamic modeling may help to control its precipitation and reduce the associated problems. In this work, a new modified cubic-plus-association (CPA) equation of state (EoS) was used to model asphaltene precipitation. This equation is based on a combination of a new physical part and an association term.

The new physical part has an evolved cubic equation of state with a new attractive term in this work. The results of the new modification of CPA EoS were compared with the experimental data of two oil samples (oil samples 1 and 2) that belonged to Moradi et al. The results showed that this modified CPA EoS can predict asphaltene precipitation with good accuracy.     

Electronic properties of Cu–Zn–Al alloys

The stability of Cu–Zn–Al was studied by total-energy calculations using the KKR–CPA method. Mixing and elastic and chemical energies, solubility lines, and Fermi surfaces were computed for the fcc and bcc structure. We find that the martensitic transformation can be considered as a transition from a disordered bcc to a disordered fcc structure. Fermi-surface nesting leads to DO₂₃ ordering while the van Hove singularities contribute to the instability of the fcc structure.