ALBERT

Notes: Summary . It is well known that for the comparison and combination of geodetic networks their heterogeneous datum definitions are well to be considered. Various algorithms have been developed for this purpose. As an alternative concept to deal with hybrid datum problems, the operator parallel sum of matrices is introduced in this paper. To begin with, a definition is given and some basic properties are explained. To demonstrate the usefulness of the operator, two practical applications are given. The first deals with the estimation of parameters describing the deformation of two networks which are to be compared to each other. The second one treats the estimation of parameters representing the heterogeneous datum definitions of two networks which are to be merged into a hybrid network. It will be shown that – regardless of the datum definitions of the preadjusted individual networks – the parallel sum of matrices can be used to simplify the algorithms applied for the estimation of those parameters.

Notes: Abstract. The polynomial interpolation of least squares and interpolation moving least squares based on control stations with known GPS (global positioning system) ellipsoidal heights and levelling orthometric heights are the most often used methods for the interpolation of the geoid heights. But in their applications there occur two problems: one lies in selecting the suitable polynomial parameters; the other in reducing the influences of some possibly abnormal data points. To solve both of the problems, without emphasizing a sound theoretical basis, a heuristic solution with the help of robust estimation technique and optimization criteria for the regression equation is presented. Through two actual numerical examples it is shown that the new solution concept is efficient and can be realized easily on computers.

Notes: The paper will present the methodology used to design optimized die coatings employed inmaterial forming processes in an effort to extend the life and effect efficient operation of the dies. Anoptimized die coating 'architecture' requires that the coating system be essentially non-wetting withthe material (metal, glass, polymer) being formed in the die, coupled with good wear and oxidationresistance Other factors, such as delaying the onset of thermal fatigue cracking (heat checking), andan acceptably low coefficient of friction. And, possibly, self-lubricating, also need to be consideredbased on the processing and forming conditions that include both liquid and solid materials. Manydifferent die coatings have and are being used with different levels of success. This paper presents thecurrent understanding that has been gained in laboratory testing, in-plant trials, and modeling in aneffort to generate a fundamental understanding of how such optimized die coating systems may bedesigned for specific forming operations and conditions, with examples based on dies used inaluminum pressure die casting, glass molding, and metal forming operations

Notes: We describe an approach for real-time studies of the transition-state dynamics of charge-transfer reactions. An application to the bimolecular reaction of benzene with iodine is reported. The measured 750±50 fs transient growth of the free I atom product elucidates the nature of the transition state and the mechanism for the dissociative charge-transfer reaction. The mechanism is formulated in relation to the impact geometry and the dative bonding, which are crucial to condense-phase and surface reactions, and is supported by molecular dynamics. © 1995 American Institute of Physics.

Notes: Emission spectra have been used to characterize the excitation-transfer reactions from Kr(5s',3P0) and Kr(5s,3P2) metastable atoms to 12CO and 13CO at 300 K. The most important products from the Kr(3P0) reactions are 12CO and 13CO(b 3Σ+,v'=0 and 1) and 12CO(a' 3Σ+,v'=34 and 35) and 13CO(a' 3Σ+,v'=35 and 36). The rotational distributions of the CO(a' 3Σ+) and CO(b 3Σ+,v'=1) levels are cold, but the CO(b 3Σ+,v'=0) distribution is rotationally excited. The populations in the 12CO(a',v'=34 and 35) levels are transferred to CO(b,v'=0) by collisions with He and the rate constants are 0.4–1.0×10−10 cm3 s−1. Emission spectra from the Kr(3P2) reaction identified 12CO(a',v'=23–26) and 13CO(a',v'=24–27) and CO(d 3Δ,v'=20 and 21) for both 12CO and 13CO as important products; the CO(d 3Δ,v'=20 and 21) states previously were identified by Tsuji and co-workers. The vacuum ultraviolet spectra from the Kr(3P2) reaction with 12CO and 13CO showed that CO(A 1Π) is a primary product and that it also is formed from CO(d 3Δ) and CO(a' 3Σ+) by collisions with He and Ar. The Kr(3P2)+CO reaction also generates some unassigned CO triplet state emission. The propensity for formation of 3Σ+ states rather than the e 3Σ− state of CO is discussed. An improved transition dipole function for the CO(b 3Σ+–a 3Π) transition is presented in the Appendix. © 1995 American Institute of Physics.

Notes: This paper in the series gives our full account of the preliminary results reported in a communication [Cheng, Zhong, and Zewail, J. Chem. Phys. 103, 5153 (1995)] on real-time femtosecond (fs) studies of the transition state of charge-transfer (CT) reactions, generally described as harpooning reactions. Here, in a series of experimental studies in a molecular beam, and with the help of molecular dynamics, we elucidate the microscopic elementary dynamics and the structure of the transition states for the isolated, bimolecular reaction of benzenes (electron donor) with iodine (electron acceptor). The transition state is directly reached by fs excitation into the CT state of the complex Bz⋅I2, and the dynamics is followed by monitoring the product build up or the initial transition-state decay. We further employed the fs resolution in combination with the kinetic-energy resolved time-of-flight and recoil anisotropy techniques to separate different reaction pathways and to determine the impact geometry. Specifically, we have studied: (1) the temporal evolution of the transition state (τ

Notes: The second metastable state of Kr, 5s′[1/2]0, was generated from the first metastable state, 5s[3/2]2, by optical pumping in a flow reactor. Under optimum conditions, the entire Kr(5s[3/2]2) concentration could be removed with more than 40% conversion to the Kr(5s′[1/2]0) state, which is stable in He carrier gas. The Kr(5s′[1/2]0) and Kr(5s[3/2]2) states have the Kr+(2P1/2) and Kr+(2P3/2) ion cores, respectively, as do the Kr+X−(D) and Kr+X−(B,C) states. The reactions of a series of fluorine-, chlorine-, and bromine-containing molecules, RX, with the Kr(5s′[1/2]0) and Kr(5s[3/2]2) atoms were studied by measuring the total quenching rate constants and by observing the KrX(B,C,D) product emission spectra. In contrast to the Kr(5s[3/2]2) atoms, which give KrX(B and C) products, the Kr(5s′[1/2]0) atoms have a high propensity to give KrX(D) plus a lesser amount of KrX(B), depending on the reagent, as products. Discrimination against KrX(C) formation by reactions of Kr(5s′[1/2]0) atoms is severe. The reactions with F2, NF3, and N2F4 exhibit the highest conservation of the Kr+(2P1/2) core, and these Kr(5s′[1/3]0) reactions give (approximately-greater-than)70% KrF(D). The total quenching constants of Kr(5s′[1/2]0) atoms generally are equal to those for Kr(5s[3/2]2), but the branching fractions for KrX* formation from Kr(5s′[1/2]0) atoms generally are smaller than for Kr(5s[3/2]2) atoms. A correlation diagram based on conservation of Kr+ ion-core state and Ω=0− is developed to discuss these trends and the reactions of the Xe(6s′[1/2]0 and 6s[3/2]2) atoms. Due to the absence of KrX(C–A) emission from the Kr(5s′[1/2]0) atom reactions, the KrX(B–A) and Kr(D–A) transitions could be observed and the radiative branching ratios to the X and A states were assigned. © 1996 American Institute of Physics.

Notes: The eastern Himalayan syntaxis, situated at the eastern terminus of the Himalayas, is the least-known segment of the Himalayas. Recent research in this area has revealed that the syntaxis consists of the Gangdise, the Yarlung Zangbo, and the Himalayan units, each of which is bounded by faults. The Himalayan unit, the northernmost exposed part of the Indian plate, mainly contains amphibolite facies rocks, marked by the assemblages staurolite+kyanite+plagioclase+biotite+muscovite±sillimanite and garnet+amphibole+plagioclase, in the south; to the north, low- to medium-pressure granulite grade pelitic gneisses and marbles are present and are characterized by the assemblages garnet+sillimanite+K-feldspar+plagioclase or antiperthite+biotite+quartz±spinel±cordierite±orthopyroxene in gneisses, and anorthite+diopside±wollastonite and plagioclase+diopside+quartz+phlogopite+calcite in marbles. Within this unit, the Namula thrust system is a series of moderately north-dipping structures that displaced the granulite facies rocks southwards over the amphibolite facies rocks. High-pressure granulites occur as relics within these granulite facies rocks and contain garnet–kyanite granulite and garnet clinopyroxenite. The peak assemblage of the garnet–kyanite granulite includes garnet (core part)+kyanite+ternary feldspar+quartz+rutile. Sillimanite+garnet (rim part)+K-feldspar+ oligoclase+ilmenite+biotite and spinel+albite+biotite or spinel+cordierite±orthopyroxene, which are coronas around sillimanite and garnet, are retrograde products of this peak assemblage. Another peak assemblage includes very-high-Ca garnet (CaO 32–34 wt%, Alm10±Grs〉80) and diopside (CaO 22–24 wt%), scapolite, meionite, quartz, and accessory Al-bearing titanite (Al2O3 4–4.5 wt%). The diopside has kink bands. Partial or complete breakdown of Ca-rich garnet during post-peak metamorphism produced pseudomorphs and coronas consisting of fine-grained symplectic intergrowths of hedenbergite and anorthite. Thermobarometric estimates in combination with reaction textures, mineral compositions, and recent experimental studies indicate that these peak assemblages were formed at P=c. 1.7–1.8 GPa, T =c. 890 °C, and the retrograde assemblages experienced near-isothermal decompression to P=0.5±0.1 GPa, T =850±50 °C. The whole-rock compositions indicate that marble and pelite are plausible candidates for the protoliths. These facts suggest the following (1) sedimentary rocks were transported to upper-mantle depths and equilibrated at those conditions to form these high-pressure granulites, which were then emplaced into the crust quickly. During the rapid exhumation of these rocks, the earlier high-pressure assemblages were overprinted by the later low- to medium-pressure assemblages, that is, the high-pressure granulite belt formed in the syntaxis. (2) The Namula thrust system is an important tectonic boundary in the syntaxis, or even in the Higher Himalaya more generally.