Validating database updates

Individual facts in the real world are represented by tuples in database relations (instances), while universal (time-independent) facts are treated as semantic constraints regarding database relation schemata. One important role of these semantic constraints is their use as integrity constraints that must not be violated by update operations. Among these, static constraints are represented by assertions, which are extended relational calculi in which every tuple variable is bound over a relation, and become true in a consistent database. When an update has been made on a consistent database, it is necessary to ascertain if the updated database is still consistent. It can be done by evaluating all the assertions in the updated database, but this is very time consuming. If a given assertion is in one of some classes, it is possible to devise an efficient validation procedure, which before the update is actually applied determines if the update violates the given assertion. In many cases a simplified form can be found, by examining whose value the properness of the given update is determined. The existence of such an efficient procedure and simplified form depends on what class the given assertion belongs, and also on what type of the update is to be made on what relation. This paper presents a method of finding such a procedure and simplified form using several simple syntactical transformation rules regarding extended relational calculi. This method is based on several basic properties in prepositional logic and many-sorted predicate logic.     

Quantum beat spectroscopy on excitons in GaN

We present four wave mixing experiments on excitons in GaN. The four wave mixing transients exhibit strong modulations yielding a splitting of the A- and the B-exciton of 7.98 meV. In addition, we obtain a biexciton binding energy for A-excitons of 5.7 meV.     

Characterization of a mannose-containing glycoasparagine isolated from urine of a patient with aspartylglycosylaminuria (AGU)

Pimozide-induced inhibition of lever-pressing for brain stimulation in the lateral hypothalamic area was differentially restored by the centrally acting anticholinergic, dexetimide and by different dopaminergic drugs. In addition, a differential antagonism towards chlorpromazine-induced inhibition of self-stimulation was shown. The results indicate that anticholinergis (non-competitive antagonism) or drugs which enhance endogenous neuro-transmission by increased release or by uptake blockade (competitive antagonism) are able to reserve the neuroleptic-induced inhibition of self-stimulation more effectively than are receptor agonists.     

First observations of CO2 absorption spectra recorded in 2005 using an airship-borne FTS (GOSAT TANSO–FTS BBM) in the SWIR spectral region

This article describes the results of a field experiment performed to confirm the feasibility of measuring the solar spectra absorbed by carbon dioxide (CO₂) using a short wavelength infrared Fourier transform spectrometer (SWIR-FTS) installed onboard an airship. These airship-borne observations, conducted on 7 April 2005, represent the first aircraft-borne spectroscopic experiment on greenhouse gases (GHGs) in Japan and were performed as part of the Greenhouse Gases Observing Satellite (GOSAT) project. To develop and demonstrate an effective retrieval algorithm to derive CO₂ column amounts from spectroscopic observations, ground-surface scattered solar absorption spectra were observed by SWIR-FTS installed onboard the airship. This instrument is a breadboard model (BBM) of the Thermal and Near-infrared Sensor for Carbon Observation (TANSO) of GOSAT, which was successfully launched on 23 January 2009. The spectra of CO₂ observed using the BBM were compared with the simulated spectra calculated by a radiative transfer code based on airship-borne in situ measurement data, which were obtained at the time of FTS measurements. The two sets of spectra are in agreement within 5%, and we identified solutions to several technical problems related to the FTS instrument, thereby improving the signal-to-noise ratio (SNR).     

<Emphasis Type="Italic">In situ</Emphasis> analysis of high temperature characteristics of prismatic polymer lithium - ion batteries

A systematic approach to understanding the safety fundamentals of Li-ion batteries was undertaken. Firstly, we present thermal characterization experiments of charged prismatic polymer lithium-ion batteries (PLBs). These cells, at different state of charge (SOC), were tested inside an accelerated rate calorimeter (ARC) to determine the onset-of-thermal runaway (OTR) temperatures. In addition, the thermally activated components of these cells were followed by monitoring both the impedance (at 1 kHz) and the open circuit voltage (OCV) as a function of temperature. An increase in the impedance was observed at around 133 °C corresponding to the polyethylene separator shutdown. Secondly, an original in situac impedance measurement was performed over a wide range of frequencies instead of 1 kHz when the battery was heated from ambient to 130 °C. Resulting impedance spectra were modeled using an appropriate equivalent circuit. It is concluded that the high frequency and the low frequency semicircles observed in the impedance spectra are due to processes occurring the anode/electrolyte and cathode/electrolyte interfaces, respectively. The activation energy E _a was found in the ranges of 0.4–0.6 and 0.36–0.53 eV, for cathode and anode processes, respectively. In addition, it is assumed that change in the electrolyte composition is the main factor responsible for the rise in the cell impedance at high temperatures.     

Conversion of alkyl radicals to allyl radicals in irradiated single crystal mats of polyethylene

The decay of alkyl radicals, the conversion of alkyl radicals to allyl radicals and the trapping of allyl radicals in irradiated single crystal mats of polyethylene have been studied by electron spin resonance (e.s.r.). It has been suggested that in the crystal core alkyl radicals react with trans-vinylene double bonds and are converted into trans-vinylene allyl radicals; at the crystal surface, alkyl radicals react with vinyl end groups and are converted into allyl radicals with vinyl end groups. The decay of radical pairs and the formation of trans-vinylene double bonds are discussed.     

Free Volume of cis-1,4 polyisoprene/polybutadiene blends

Summary The number and radius of molecular order free space present in polybutadiene (PBD)/polyisoprene (PIP) blend were observed by positron life-time measurement, and apparent free volume fraction was estimated. The changes in the number and radius of the free space were not represented to be a linear function of blend composition. The apparent free volume fraction increased by mixing PBD with PIP and was approximated by a concave curve depicted against blend composition, even though the excess volume of mixing was proved to be negative. The change in the apparent free volume fraction was related to the variation of thermal expansion coefficient on blend composition. Received: 21 July 2000/Revised version: 21 August 2000/ Accepted: 24 August 2000     

水泥对新型耐酸料耐酸性能的研究

以石英砂为主要原料,水泥为结合系统,分别研究了不同水泥含量对新型耐酸料性能的影响.试样自然干燥24 h脱模后,再经110℃烘干24 h,在空气气氛中分别于500℃和800℃热处理3 h.检测各温度热处理后试样的体积密度、线变化率、抗折强度、耐压强度和耐酸性能,结果表明,制备新型耐酸料的最佳水泥含量为W(水泥)=6%.新型耐酸料的抗折强度随着水泥含量的增加而降低,耐压强度随着水泥含量的增加而增加.     

Design formula for involute profile shifted gears applied to a skew shaft gear-box

By the intermeshing of a pair of helical gears having different absolute helix angles, we can design a gear-box for non-parallel shafts. This paper presents an analytical formulation and a geometrically approximated formulation concerned with the minimum shaft distance and the skew shaft angle when involute profile shifting is applied in design. In order to approximate the calculated result of the analytically correct formulae, when using the practical formulae, the correction factors, especially important in the case of high skew shaft angle, are also provided.