New upper solution bounds of the continuous algebraic Riccati matrix equation

By utilizing some linear algebraic techniques, new upper bounds of the solution of the continuous algebraic Riccati equation (CARE) are derived. According to the present bounds, iterative procedures are also developed for obtaining more precise estimations. Comparing with existing results, the obtained bounds are less restrictive.     

Testing multi-characteristic product capability indices

Recently, studies associated with testing the quality and performance of each process for a product with multi-characteristics are proposed more often. However, most studies are limited to discussing one single type of quality characteristic. Practically, a multi-characteristic product is potentially composed of three types: smaller-the-better, larger-the-better, and nominal-the-best. In this paper, we propose an integrated product capability index which considers these three different types of quality characteristics. According to the theory of testing hypothesis, we develop a testing procedure for the product capability index to judge whether the process capabilities of total quality characteristics meet the customers’ demands. In addition, the relationship between the product capability index and the yield of the entire product will be introduced. Finally, an example is provided as a practical application.     

Tunnel stability and arching effects during tunneling in soft clayey soil

A series of centrifuge model tests and numerical simulations of these tests were carried out to investigate the surface settlement troughs, excess pore water pressure generation, tunnel stability and arching effects that develop during tunneling in soft clayey soil. The two methods were found to provide consistent results of the surface settlement troughs, excess pore water generation, and the overload factors at collapse for both single and parallel tunneling. The arching ratio describes the evolution of the arching effects on the soil mass surrounding tunnels and can be derived from the numerical analysis. The boundaries of the arching zones for both single tunneling and parallel tunneling were determined. In addition, the boundaries of the positive and negative arching zones were also proposed.     

Reliability-based failure cause assessment of collapsed bridge during construction

Until now, in many forensic reports, the failure cause assessments are usually carried out by a deterministic approach so far. However, it may be possible for the forensic investigation to lead to unreasonable results far from the real collapse scenario, because the deterministic approach does not systematically take into account any information on the uncertainties involved in the failures of structures.Reliability-based failure cause assessment (reliability-based forensic engineering) methodology is developed which can incorporate the uncertainties involved in structural failures and structures, and to apply them to the collapsed bridge in order to identify the most critical failure scenario and find the cause that triggered the bridge collapse. Moreover, to save the time and cost of evaluation, an algorithm of automated event tree analysis (ETA) is proposed and possible to automatically calculate the failure probabilities of the failure events and the occurrence probabilities of failure scenarios. Also, for reliability analysis, uncertainties are estimated more reasonably by using the Bayesian approach based on the experimental laboratory testing data in the forensic report. For the applicability, the proposed approach is applied to the Hang-ju Grand Bridge, which collapsed during construction, and compared with deterministic approach.     

Automatic ultrastructure segmentation of reconstructed cryoEM maps of icosahedral viruses.

We present an automatic algorithm to segment all the local and global asymmetric units of a three-dimensional density map of icosahedral viruses. This approach is readily applicable to the structural analysis of a broad range of virus structures that are reconstructed using cryo-electron microscopy (cryo-EM) technique. Our algorithm includes three major steps operating on the three dimensional density map: the detection of critical points of the volumetric density function, the detection of global and local symmetry axes, and, finally, the boundary segmentation of all the asymmetric units. We demonstrate the efficacy of our algorithm and report our results on several experimental volumetric datasets, consisting of both reconstructed cryo-EM molecular density maps taken from the European Bioinformatics Institute archive, as well our own synthetically generated (blurred) maps calculated from X-ray resolution molecular structural data taken from the Protein Data Bank.     

Feasibility study on the use of polyallyldiglycol-carbonate cell dishes in TUNEL assay for alpha particle radiobiological experiments

In the present work, we have studied the feasibility of a method based on polyallyldiglycol-carbonate (PADC) films to investigate the effects of alpha particles on HeLa cervix cancer cells. Thin PADC films with thickness of about 20 μm were prepared from commercially available CR-39 films by chemical etching to fabricate custom-made petri dishes for cell culture, which could accurately record alpha particle hit positions. A special method involving “base tracks” for aligning the images of cell nuclei and alpha particle hits has been proposed, so that alpha particle transversals of cell nuclei can be visually counted. Radiobiological experiments were carried out to induce DNA damages, with the TdT-mediated dUTP Nick-End Labeling (TUNEL) fluorescence method employed to detect DNA strand breaks. The staining results were investigated by flow cytometer. The preliminary results showed that more strand breaks occurred in cells hit by alpha particles with lower energies. Moreover, large TUNEL positive signals were obtained even with small percentages of cells irradiated and TUNEL signals were also obtained from non-targeted cells. These provided evidence for the bystander effect.     

Structural characteristics and catalytic activities of nanocrystalline Ni-Mo-B coatings obtained by catalytic electroless reduction

The structures, chemical states of elements, and catalytic activities of Ni-Mo-B alloys with different molybdenum contents, which were obtained by catalytic electroless reduction of metal ions, were studied. The rates of the partial reactions (heterogeneous hydrolysis of dimethylamine borane, reduction of nickel ions, and evolution of molecular hydrogen) were found to make a bell-shaped curve when plotted versus the concentration of molybdate ions in solution. Original Russian Text ? V.M. Krutskikh, M.V. Ivanov, A.B. Drovosekov, E.N. Lubnin, B.F. Lyakhov, Yu.M. Polukarov, 2007, published in Zashchita Metallov, 2007, Vol. 43, No. 6, pp. 619–625.     

国家战略发展新能源股价长期走牛可期待

严峻的能源短缺、居高不下的原油价格、日益严重的环境问题已经成为制约中国经济、社会发展的瓶颈。改变现有的以化石能源为主的能源结构,     

Effect of alloying and heat treatment on the structure and tribological properties of nitrogen-bearing stainless austenitic steels under abrasive and adhesive wear

The effect of nitrogen, silicon, and aging modes on the structure, resistance to abrasive and adhesive wear, friction factor, and mechanical properties of nitrogen-bearing (0.27–0.83% N) chromium-manganese austenitic steels is studied. It is shown that it is possible to ensure a favorable combination of mechanical and tribological properties in such steels by choosing the appropriate chemical composition and aging mode. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5, pp. 9–18, May, 2007.     

Electron hydration energy: Nonempirical estimate

Based on the results of quantum chemical calculations, the energies of vertical (photoionization) electron removal from superficial and bulk water layers are estimated as 2.9 and 4.4 eV respectively. For the first time, a nonempirical estimate of the electron hydration energy is obtained, 2.6 eV, which characterizes the electron state both at the superficial and bulk hydration. To find these value, molecular cluster systems modeling the Bjerrum defects of the hydrogen-bond network of water localizing the additional electron were calculated. Typical ways of the reorganization of defects upon the electron removal are identified. Conditions under which the relaxation of defects is reversible upon the re-addition of the charge are determined. The pre-existence of defects is shown not to be an indispensable condition of the effective localization of excess electrons by water. Small distortions, as well as breakage, of the continuity of the hydrogen-bond network are sufficient. Original Russian Text ? Yu.V. Novakovskaya, 2007, published in Zashchita Metallov, 2007, Vol. 43, No. 2, pp. 139–151.