Condensation von Benzaldehyd mit Oxysäuren

Ohne ZusammenfassungZum Schlusse erfüllen wir eine angenehme Pflicht, wenn wir dem verehrten Lehrer Herrn Hofrath Lieben, sowie Herrn Dr. C. Pomeranz den besten Dank für die freundliche Unterstützung aussprechen, die sie unserer Arbeit durch ihre Rathschläge angedeihen ließen.     

Free energy of transfer ofn-nitroalkanes fromn-octane to water at 25°C

Calorimetric determinations of the thermodynamics of transfer of nitromethane, nitroethane, 1-nitrobutane, 1-nitropentane, and 1-nitrohexane from n-octane to water at 25°C have been made. Transfer free energies calculated by four different models agree reasonably well with observations. Calculations indicate that the dipolar part of the transfer free energy depends only on the dipole moment and size of the-C?NO₂ group and is independent of the length of the alkyl chain in nitroalkanes.     

Search for scalar top quark production in p&pmacr; collisions at sqrt

We have searched for direct production of scalar top quarks at the Collider Detector at Fermilab in 88 pb(-1) of p&pmacr; collisions at sqrt[s] = 1.8 TeV. We assume the scalar top quark decays into either a bottom quark and a chargino or a bottom quark, a lepton, and a scalar neutrino. The event signature for both decay scenarios is a lepton, missing transverse energy, and at least two b-quark jets. For a chargino mass of 90 GeV/c(2) and scalar neutrino masses of at least 40 GeV/c(2), we find no evidence for scalar top production and present upper limits on the production cross section in both decay scenarios.     

Dijet production by double pomeron exchange at the fermilab tevatron

We report the first observation of dijet events with a double Pomeron exchange topology produced in &pmacr;p collisions at sqrt[s] = 1800 GeV. The events are characterized by a leading antiproton, two jets in the central pseudorapidity region, and a large rapidity gap on the outgoing proton side. We present results on jet kinematics and production rates, compare them with corresponding results from single diffractive and inclusive dijet production, and test factorization.     

Particle Approximations of the Score and Observed Information Matrix for Parameter Estimation in State–Space Models With Linear Computational Cost

Poyiadjis, Doucet, and Singh showed how particle methods can be used to estimate both the score and the observed information matrix for state–space models. These methods either suffer from a computational cost that is quadratic in the number of particles, or produce estimates whose variance increases quadratically with the amount of data. This article introduces an alternative approach for estimating these terms at a computational cost that is linear in the number of particles. The method is derived using a combination of kernel density estimation, to avoid the particle degeneracy that causes the quadratically increasing variance, and Rao–Blackwellization. Crucially, we show the method is robust to the choice of bandwidth within the kernel density estimation, as it has good asymptotic properties regardless of this choice. Our estimates of the score and observed information matrix can be used within both online and batch procedures for estimating parameters for state–space models. Empirical results show improved parameter estimates compared to existing methods at a significantly reduced computational cost. Supplementary materials including code are available.     

Interaction of silver halides with gelatin of like charge

Summary Interactions of gelatin with silver bromide and silver iodide sols of like charges have been studied as a function of gelatin concentration, pH, and addition of neutral electrolytes. Silver halide solsin statu nascendi and aged sols were used in the experiments. Solsin statu nascendi showed a scattering intensity maximum indicating coagulation, while aged sols did not. At higher pH values, the maximum appeared, if sufficient amounts of electrolyte and gelatin were present. It is suggested that gelatin reduces the effective surface charge density of the colloidal particles. Such silver halide sols of reduced charge are then coagulated by smaller amounts of electrolytes than the same sols in the absence of gelatin. For very large concentrations of gelatin, close to the gel point, coagulation occurred wheter sols were aged orin statu nascendi.

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Zusammenfassung Es wurde die Wechselwirkung zwischen Gelatine und AgBr- bzw. AgJ-Solen gleichen Ladungszeichens in Abhängigkeit von der Gelatinekonzentration, dem pH-Wert und der Konzentration an neutralen Elektrolyten untersucht. Zu den Untersuchungen wurden Solein statu nascendi und gealterte Sole verwendet. Bei Solenin statu nascendi trat ein Maximum in der Streuintensität auf, das Koagulationsvorgänge anzeigt; bei gealterten Solen wurde ein derartiges Maximum erst bei höherenPh-Werten beobachtet, wenn ausreichende Mengen an Elektrolyt und Gelatine vorhanden waren. Bei sehr hohen Gelatine-Konzentrationen (im Bereich um den Gelpunkt) tritt die Koagulation sowohl in gealterten wiein statu nascendi-Solen ein.Es wird angenommen, daß die Gelatine die wirksame Oberflächenladungsdichte der kolloidalen Partikel ver-ringert. Derartige Silberhalogenidesole mit verringerter Oberflächenladung werden dann durch geringere Mengen von Elektrolyt ausgefällt als dieselbe Sole bei Abwesenheit von Gelatine.

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With 8 figures

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Supported by the Federal Water Pollution Control Administration Grant WP-00815 and by the U. S. Army Research Office (Durham), Grant No. DA-ARO (D)-31-124-G 656.

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Presented at the 153. ACS National Meeting, Miami Beach, Florida, April 1967.

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Part of the M. S. Thesis byR. Nemeth