Interactive search for the global maximum of a function of many variables

This paper discusses a new algorithm to locate the global maximum of a function defined in a multidimensional rectangular domain. The number of dimensions is as large as, or even more than, 5 or 10. There are two important elements in this algorithm. One is the transformation of the object function in such a way that its global maximum corresponds to infinity while other secondary maxima are reduced to zero. Actually there is some departure from the ideal transformation because of possible overflow on the computer. This portion of the algorithm precedes the interactive (or conversational) use of a graphic display system. This interactive part makes the other element of the algorithm. A multidimensional point is represented as a curve on the display screen. By projecting numerous points in the multidimensional space to similarly numerous curves on the screen of the graphic display device, the human eye can make overall recognition much more efficiently than computers. This fact is exploited to reduce the problem to that of a set of unimodal peaks. Once the supporting domain for each of these peaks is separated by visual aid, one may leave the computer to handle the rest of the problem for itself. A number of numerical experiments are done and discussed to provide evidence regarding the feasibility of the proposed algorithm.     

侧链型液晶高分子的合成

讨论了4′甲氧基苯基—4(6″-丙烯酰氧已基)苯甲酸酯(MPAHA)和对氯甲基苯乙烯(CMS)共聚物以及CMS相应的肉桂酸酯衍生物乙烯基苯甲基肉桂酸酯(VBC)共聚物的合成。DSC和偏光显微镜分析表明:该共聚物具有热致变高分子的行为,并根据分子链中MPAHB链节含量的高低,其T_(?)和T_1值发生相应的变化。     

Spectral Phase Encoder Employing an Arrayed-Waveguide Grating and Phase-Shifting Structure

This letter reports a spectral phase encoder using an arrayed-waveguide grating (AWG) with phase-adjustable structure. It consists of the 12.5-GHz spacing eight-channel AWG phase-adjustable structure with deep trenches formed in the waveguides. The spectral phase encoding of optical short pulses at the repetition rate of 12.5 GHz using the AWG encoder was successfully demonstrated.     

Pulmonary edema associated with the Chinese medicine shosaikoto

A 45-year-old Japanese woman presented with a high fever, a nonproductive coughing, and severe dyspnea, and was admitted to another hospital. During the week prior to hospitalization, she had been given Shosaikoto for treatment of liver dysfunction of unknown etiology. Mycoplasma pneumonitis was initially suspected, so she was treated with antibiotics (clindamycin and minocycline) and received oxygen therapy. Pulmonary insufficiency worsened rapidly, and she was transferred to our hospital. On admission, a chest roentgenogram revealed bilateral alveolar infiltrates predominantly in the medial lung fields. Furosemide and high-dose methylprednisolone were immediately administered, but hypoxemia increased. When the PaO2 was 55.7 Torr while the patient breathed 100% oxygen, mechanical ventilation with positive end-expiratory pressure (PEEP) was started. Arterial blood-gas values improved dramatically, and the chest roentgenogram became clear. Our diagnosis of noncardiogenic pulmonary edema is based on the chest-roentgenographic findings, infiltration of inflammatory cells as seen in two lung-biopsy specimens and bronchoalveolar lavage fluid, the lack of findings of heart failure on physical examination and electrocardiography, and the good clinical response to PEEP. A positive lymphocyte stimulation test in response to Shosaikoto implicated this non-traditional herbal medicine as an etiologic factor in the non-cardiogenic pulmonary edema. Shosaikoto has been identified as the cause of interstitial pneumonia or eosinophilic pneumonia, but pulmonary edema associated with Shosaikoto has not been previously described. This case suggests that methylprednisolone treatment may be insufficient for Shosaikoto-induced pulmonary edema, and that mechanical ventilation with PEEP is very effective.     

Unstable fracture criterion in a power-law hardening material

A fracture criterion for a pre-cracked plate subjected to large deformation is presented in a power-law hardening material based on the energy conservation law. First Hencky equations are applied to a non-linear elastic model in a small strain to derive the criterion and the theory is extended to a large strain case with the aid of numerical analysis. The criterion is expressed as a relation between a crack length and a remote fracture strain, and it is identical with Griffith's criterion when the power exponent is unity.Large strain and stress fields near a crack tip are also assessed. Experiments with pre-cracked steel plates well verify the theory, that is, the criterion based on elastic analysis appears to apply to an actual plastic material. The transition from the brittle fracture to the present unstable ductile fracture and a physical implication of the reduction of area in tension test are discussed.

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Résumé On présente un critère de rupture pour une tôle préfissurée soumise à une grande déformation dans une matériau durcissant suivant une loi parabolique et en se basant sur une loi de propagation de l'énergie. Les premières équations de Hencky sont appliquées à un modèle élastique non linéaire pour des déformations de faible amplitude en vue de dériver un critère, et la théorie est étendue au cas des grandes déformations à l'aide d'analyse numérique. Le critère est exprimé comme une relation entre la longueur de la fissure et une déformation à la rupture lointaine, et il est identique au critère de Griffith lorsque l'exposant de la loi de durcissement du matériau est l'unité.Les déformations en amplitude et les champs de contrainte au voisinage de l'extrémité de la fissure sont également prises en considération. Des expériences réalisées avec des tôles d'acier préfissurées vérifient la théorie de manière satisfaisante, c'est-à-dire que le critère basé sur l'analyse élastique apparait applicable à un matériau se comportant de façon plastique. La transition de la rupture fragile à une rupture ductile instable et les implications physiques de la striction lors de l'essai de traction sont discutées.

     

Human nails analysis as biomarker of exposure to perfluoroalkyl compounds

Extensive human exposure to perfluoroalkyl compounds (PFAA) together with their persistence and various toxicities have arisen increasing concern. A noninvasive method would improve exposure assessment for large population, especially the children susceptible to contaminants. The aim of the study was to assess the use of PFAA measurements in human nails as a biomarker of exposure to PFAAs. Fingernail, toenail, and blood samples were collected from 28 volunteers. The PFAA concentrations were determined by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Six PFAA were detected in nails, with perfluorooctane sulfonate (PFOS) being the compound with the highest median concentration (33.5 and 26.1 ng/g in fingernail and toenail, respectively). Followed was perfluorononanoate (PFNA), with the median concentrations of 20.4 and 16.8 ng/g, respectively, in fingernail and toenail. Other PFAA detected were perfluorooctanoate (PFOA), perfluorodecanoate (PFDA), perfluorododecanoate (PFDoA), and perfluorotetradecanoate (PFTA), with median levels ranging between 0.19 and 8.94 ng/g. PFOS and PFNA concentrations in fingernail significantly correlated with those in serum. Fingernail PFOS and PFNA levels were 2.8 and 24.4 times, respectively, higher than the serum levels. The accumulation of PFAA in nails, together with its advantages in noninvasive sampling and ability of reflecting long-term exposure, made nails PFAA an attractive biomarker of exposure.