Sex pheromone of tomato fruit borer, Neoleucinodes elegantalis

Five candidate pheromone components were identified by analyzing pheromone gland extracts by gas chromatography (GC), coupled GC-electroantennographic detection (EAD), and coupled GC-mass spectrometry (MS): (E)-11-hexadecenol(E11–16 : OH), (Z)-11-hexadecenol (Z11–16 : OH),(E)-11-hexadecenal, (E)-11-hexadecenyl acetate, and (Z)-3,(Z)-6,(Z)-9-tricosatriene (Z3,Z6,Z9–23 : Hy). In electroantennogram (EAG) recordings, synthetic E11–16 : OH elicited stronger antennal responses at low doses than other candidate pheromone components. Field tests demonstrated that synthetic E11–16 : OH as a trap bait was effective in attracting males, whereas addition of Z11–16 : OH inhibited the males' response. Z3,Z6,Z9–23 : Hy strongly enhanced attractiveness of E11–16 : OH, but was not attractive by itself. A pheromone blend with synergistic behavioral activity of an alcohol (E11–16 : OH) and hydrocarbon (Z3,Z6,Z9–23 : Hy) component is most unusual in the Lepidoptera. The synthetic two-component pheromone is approximately 60 times more attractive than the female-produced blend and might facilitate the control of this pest.     

Assessing the reliability of ordered categorical scales using kappa-type statistics

Methods for the analysis of reliability of ordered categorical scales are discussed, focussing on the limitation of the single summary-weighted kappa coefficients. A symmetric matrix of kappa-type coefficients is suggested as an alternative. The method is proposed as being suitable for ordinal scale where there is no underlying continuum. Their application is illustrated using two data sets from reliability studies. If, instead, distances between categories can be specified, a weighted mean of the matrix terms can be used as a summary measure. This is equal to a weighted kappa coefficient with squared weights, provided distances between adjacent categories are equal. When a study design corresponds to a one-way random effects model, estimates of precision of kappa-type coefficient, including the coefficients described here, can be obtained using the delta-method, bootstrap resampling by subjects or jack-knifing by subjects. In the case of interobserver reliability studies, where there may be systematic differences between observers, the investigator may wish to generalise to a population of observers and subjects. In this case, jack-knifing by observer and subject is suggested. Empirical comparisons are made between standard error estimates based on the delta-method, on jack-knifing by subjects and a two-way jack-knife by subjects and observers. The results suggest that standard errors based on the delta-method or jack-knifing by subject alone may be overly precise.     

Fluoroscopic MR imaging at 0.064 Tesla

The authors developed a system for ultrafast magnetic resonance imaging (MRI) protocols at low field. The system design permits the acquisition of the raw data in the background while the reconstruction and display steps repeat as fast as they can in the foreground. The performance speeds depends partly on the desired use. By collecting raw data at a rate of 20 ms per echo with an echo delay of 9 ms, a complete data cycle for a 128x64 image takes 1.28 s. However, once half of that data is incorporated into the reconstruction, the image appears complete. Using this set of parameters the authors were able to get the rate of the recon/display loop to paint about two times per completed raw data cycle, showing an entirely new image at least once per second with an apparent frame rate of two per second. Interleaving of two or three orthogonal scans reduces the speed of update but provides better information. The authors discuss the system design for rapid scan/recon/display and demonstrate the image quality available at low field strength with scan times below one second.     

Assessment of response function in two PET scanners with and without interplane septa

The authors have assessed the response function both experimentally and theoretically for two commercial tomographs: CTI 931/08-12 and CTI 953B with and without interplane septa. Monte Carlo simulations were undertaken using the GEANT package from CERN. Spatial resolution (tomographic and axial) was calculated for line sources at various positions in the field of view. Sensitivity and scatter fraction (SF) were calculated for various source geometries as a function of energy discrimination. A very realistic response function in positron emission tomography (PET) is obtained by Monte Carlo methods, using global parameters to account for unsimulated phenomena such as scintillation light transport inside a detector block and its sharing among the various phototubes. Minor discrepancies remain for sensitivity and SF at high energy thresholds and may probably be explained by introducing the observed dispersion in the energy response for the various crystals within a detector block.     

A knowledge-based approach for 3-D reconstruction and labeling of vascular networks from biplane angiographic projections

An approach to the three-dimensional reconstruction of coronary arteries is presented. The principal objective is to show how modeling of a vascular network, together with algorithmic procedures, can lead to accurate 3-D structure and feature labeling. The labeling problem is stated directly within the 3-D reconstruction framework. The reconstruction ambiguities inherent to biplane techniques are solved by means of a knowledge base, modeling of the object, and heuristic rules. Feasibility in near-real situations has been demonstrated. The critical importance of the object 3-D reference to achieving the data and modeling matching is emphasized, and a way to deal with it is pointed out. The overall system implies an incremental development in methodologies and experiments. All of them have been elaborated and tested independently, and the most appropriate ones have been selected for integration into a modular system. All the stages of the process (calibration, segmentation, reconstruction, and display) are discussed, with the main focus on modeling. Examples of automatic reconstruction from a phantom are provided.     

添加钛对Al—Zn—Mg合金时效特性的影响

往Al-Zn-Mg合金中添加微量钛(0.04％),以便确定钛对这种合金的显微组织和时效特性的影响。发现钛能延迟析出动力学,并且在空气淬火时,能阻止溶质在晶界上偏析。低于G.P.区溶解温度,合金的硬化是由于形成位错环和G.P.区。超过G.P.区的溶解温度,硬化仅仅是由于形成析出物。这些结果用钛能降低溶质原子—空位集团的形成,以及引起锌和镁迁移率降低来解释。     

MICROSTRUCTURAL EVOLUTION OF HIGHLY UNDERCOOLED EUTECTIC Ni78.6Si21.4 ALLOY

A large undercooling level up to 550K （0.386Te） was achieved in eutectic Ni78.6Si21.4melt by the combination of molten-glass and cyclic superheating. A microcrystaUine structure is obtained at large undercooling. Surprisingly, the morphology of ct（Ni） phase transits from the non-faceted phaseto faceted phase at large undercooling of 390K. Based on the classical nucleation theory and transient nucleation theory, the process of microstructure evolution and competitive nucleation was analyzed, and the refinement of crystal structure is determined by the high nucleation rate under large undercooling.     

REACTIVE DIFFUSION BETWEEN Si AND NbC AT 1300℃

ＲＥＡＣＴＩＶＥＤＩＦＦＵＳＩＯＮＢＥＴＷＥＥＮＳｉＡＮＤＮｂＣＡＴ１３００℃Ｃ．Ｒ．Ｋａｏ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｃａｌＥｎｇｉｎｅｅｒｉｎｇＮａｔｉｏｎａｌＣｅｎｔｒａｌＵｎｉｖｅｒｓｉｔｙＣｈｕｎｇＬｉ，Ｔａｉｗａｎ）Ｊ．Ｗｏｏｄｆ...     

球状及蠕虫状石墨铸铁中石墨形成过程的观察

引言蠕虫状石墨铸铁的发展又进一步引起人们去研究铸铁的结晶过程以及了解那些在凝固过程中控制石墨生长形态的诸因素。一般认为蠕虫状石墨的形成是因为球状石墨衰退的结果,然而,蠕虫状石墨的生长模式却可能是更加接近片状石墨。对石墨的形核和长大过程的直接观察目前尚还不可能。因而对铸铁凝固早期各种形态石墨的研究一直进行得还不够充分。已有的研究表明球化剂的脱氧和脱硫作用改变了铁水和石墨的介面能,这对石墨的生长