白光和红绿蓝光LED可调光源研制

为了提高LED光源色温和亮度的调节精度和准确度,结合色温由低向高变化时光色所呈现的渐变特点,提出了一种低色温白光LED灯珠、高色温白光LED灯珠加红绿蓝光LED灯珠补偿式调光的方法.将色温分成三个部分进行调节,每个部分选用不同的LED灯珠组合来进行调光.实验结果表明:不同组合情况下的LED光源的初始输出色温相对于目标值的偏差范围在1％以内;亮度可以在保证色温不变的情况下独立进行调节,初始输出值与目标值的偏差范围在1％以内;经过微调之后可以达到目标值;达到了色温和亮度独立调节的要求;光源发光稳定,不会因为长时间工作而影响调节精度.     

Nonlocal potentials and their exact and approximate local and velocity-dependent equivalents

We show that good approximations to the exact equivalent local potential (ELP) and damping factor of a nonlocal Perey-Buck potential can be calculated in the partial wave WKB approximation of Horiuchi. The exact ELP and damping factor are obtained by means of a method previously given by one of us. We also confirm that an approximate ELP proposed by Bauhoff et al. is of comparable accuracy as the Horiuchi approximation. Thesel-dependent ELP's exhibit reduced attraction in the interior and provide a test for higher order WKB approximations. We subsequently obtain an equivalent velocity dependent potential (EVDP) which is even exactly wave function equivalent to the original nonlocal potential. This almost local potential, unlike the trivial equivalent local potential, is smooth and well-behaved and is therefore particularly useful in nuclear reactions where the off-shell behaviour of the potential is important.     

Sites and tours in orthoalgebras and orthomodular lattices

A block of an orthoalgebra (or of an orthomodular lattice) is a maximal Boolean subalgebra. A site is the intersection of two distinct blocks. L is block (site)-finite if there are only finitely many blocks (sites). We introduce a certain type of subalgebra of an orthoalgebra which is a subortholattice if the orthoalgebra is an ortholattice (and therefore an orthomodular lattice) and which is block finite if the orthoalgebra is site finite. The construction yields a cover of a site-finite orthoalgebra or orthomodular lattice L by block-finite substructures of the same type and having the same center as L. Every site-finite orthomodular lattice is commutator finite.In memory of Charles H. Randall.     

Visualization and interferometry for cylindrical and spherical sample tomography and profilometry

A technique combining image processing and laser interferometry for visualizing and detecting the deformation of transparent cylindrical and spherical sample is proposed. This deformation includes geometric deformation such as volume transition in profilometry and physical deformation such as refractive index change in tomography. Phase contour lines are used for quantitative analysis and graphical representation of the deformation. This method allows us to visually detect the spatial variation of the deformation field and to evaluate the test quality such as misalignment of optical system. A theoretical analysis using phase contour map to characterize the deformation field is described in detail. A method using phase contour map to qualify the interferometric test is proposed. Analysis of test examples is carried out. Suggestions on using phase contour line method to ameliorate test system design are finally discussed.     

Atomic and electronic structures and stability of icosahedral nanodiamonds and onions

The relative stability of alternative carbon nanoparticles with icosahedral symmetry, such as diamond-like nanocrystallites and multiwalled fullerenes (onions), is investigated using the parametric model and the density functional tight-binding (DFTB) method. It is demonstrated that an increase in the size of particles and their hydrogenation favor the stabilization of diamond-like nanocrystallites. The formation of “intermediate” nanostructures consisting of diamond-like nanocrystallites inside the fullerene cage is revealed. The electronic spectra of icosahedral carbon nanoparticles are calculated.     

To old and new PDF and PFF

A short review of problems with parton distribution functions in nucleons, non-polarized and polarized, is given. The main part is devoted to the T-odd Collins fragmentation function and to the proton transversity distribution its possible measurements and its first experimental probe via spin asymmetries in semi-inclusive DIS. It is argued that the proton transversity distribution is close to the prediction of chiral quark soliton model could be successfully measured in future DIS experiments with longitudinally polarized target and the Collins analyzing power is linearly growing with z.     

Liberations and twists of real and complex spheres

We study the 10 noncommutative spheres obtained by liberating, twisting, and liberating +twisting the real and complex spheres $S_{\mathbb{R}}^{N-1},S_{\mathbb{C}}^{N-1}$. At the axiomatic level, we show that, under very strong axioms, these 10 spheres are the only ones. Our main results concern the computation of the quantum isometry groups of these 10 spheres, taken in an affine real/complex sense. We formulate as well a proposal for an extended formalism, comprising 18 spheres.     

Definitions and control of the CEP and CEO

The definitions of the carrier to envelope phase (CEP) and carrier to envelope offset (CEO) arc reviewed. It is pointed out that a unique separation of the field of an ultrashort pulse in a “carrier” and “envelope” is not always possible for ultrashort pulses. Another definition is proposed for pulses of a few optical cycles, that is not dependent on the notion of “carrier” and “envelope.” The carrier to envelope offset (CEO) is a frequency, generally defined as the ratio of the change in CEP between pulses, to the pulse (temporal) spacing. It is shown that the CEO exists for trains of long pulses, for which the CEP cannot be measured. Methods of measuring the CEO of a mode-locked laser are proposed. It is shown that MQW have a locking tendency on the CEO of two pulse trains.     

Structure and excitations in liquid and solid surfaces

After a short summary of the thermodynamics of surfaces, attention is focussed on recent progress in determining the static structure of liquid surfaces, and the connection with surface energy. This is discussed fully for simple insulating liquids. For simple metals, both in liquid and solid phases, a different approach is necessary, because the density profiles of both electrons and ions enter the discussion. This area is reviewed and the importance of experiments to measure electron and atomic density profiles near surfaces is stressed. Additionally, a discussion of the surface tension of transition metals is included.Electronic excitations associated with metal surfaces are then considered, as well as the atomic dynamics of both liquid and solid surfaces.     

Collective potentials and dipole and quadrupole giant resonances

The dynamic collective model is extended into the energy region immediately above the giant dipole resonances, i.e. into an energy region between 20 and 28 MeV. The total Hamiltonian is constructed and the dynamical problem is solved by diagonalizing the Hamiltonian in the basis of a five-dimensional harmonic oscillator. In schematical studies the splitting of giant quadrupole resonances is shown. For some elements the potential energy surfaces (PES) are constructed within the collective model developed by Gneuss et al. and the quadrupole resonances have been calculated in the framework of the dynamic collective model. In the last part the agreement with experimental data is shown.     

Spectral-Luminescent Characteristics and Photoprocesses in a Psoralen Sensitizer and its Isomers and Methoxysubstitutes

The quantum chemistry method of intermediate neglect of differential overlap (INDO) with spectroscopic parameterization is used to study the spectroscopic-luminescent and physical characteristics of psoralen and its isomers and methoxysubstitutes. Efficient intersystem conversion, which causes significant population of triplets, is observed for the examined compounds. Effects of isomerism and methoxysubstitution on the energy level diagram, photoelectron spectrum, and dipole moments are demonstrated. The efficiency of psoralen sensitizers is examined.     

激光熔覆NiCrBSi涂层组织及摩擦磨损性能

采用激光熔覆技术在H13钢表面制备了NiCrBSi合金涂层,利用OM,SEM,EDX和XRD等对熔覆层的微观组织进行了分析,测试了熔覆层的显微硬度和摩擦磨损性能。结果表明,激光熔覆层与基体形成了良好的冶金结合,熔覆层的组织主要由γ-Ni,Cr7C3和CrB等相组成。熔覆层显微硬度在650~850HV之间,明显高于H13钢基体的硬度。摩擦磨损实验表明,在相同的条件下,熔覆层的耐磨性比基体有了明显的提高,磨损体积减少了92.4%。通过对磨损后的试样进行粗糙度测试后表明,涂层具有更平滑的表面。     

Frequency of collisions between electrons and gas and vapor atoms and molecules

A resonant method based on the phenomenon of electron cyclotron resonance is used to determine the frequency of collisions between electrons and He, Ar atoms and H₂S, SO₂, H₂O, and CsCl molecules. Electron distribution over energy is measured under experimental conditions and the mean electron energy determined therefrom. Existing techniques of collision frequency measurement and calculation are discussed. Experimental dependences of reduced collision frequency on mean electron energy are obtained and the parameter E/N is compared to values presented in the literature.     

NOx formation and flame velocity profiles of iso- and n-isomers of butane and butanol

NO formation and flame propagation are studied in premixed flames of iso- and n-isomers of butane and butanol through experimental measurements and direct simulation of experimental profiles. The stabilized flame is realized through the impingement of a premixed combustible jet from a contraction nozzle against a temperature-controlled plate. The velocity field is obtained by means of Particle Image Velocimetry (PIV) and nitric oxide concentration profiles are measured using Planar Laser Induced Fluorescence (PLIF), calibrated using known NO seeding levels. It is found that NO formation in n- and iso-isomers is comparable under the conditions considered, except for rich butanol mixtures, whereby NO formation is higher for iso-butanol. Generally, less NO is formed in butanol flames than in the butane flames. The experiment is simulated by a 1D chemically reacting stagnation flow model, using literature models of C1–C4 hydrocarbons [Wang et al., 2010] and butanol combustion chemistry [Sarathy et al., 2009, 2012]. NO prediction is tested using two of these mechanisms with a previously-published NO_x submechanism added into the butane and butanol models. While a good level of agreement is observed in the velocity field prediction under lean and stoichiometric conditions, discrepancies exist under rich conditions. Greater discrepancies are observed in NO prediction, except for the C1–C4 mechanism which shows good agreement with the experiment under lean and stoichiometric conditions. The current study provides data for further development of mechanisms with NO_x prediction capabilities for the fuels considered here.     

Entanglement and decoherence: fragile and robust entanglement

The destruction of entanglement of open quantum systems by decoherence is investigated in the asymptotic long-time limit. For this purpose a general and analytically solvable decoherence model is presented which does not involve any weak-coupling or Markovian assumption. It is shown that two fundamentally different classes of entangled states can be distinguished and that they can be influenced significantly by two important environmental properties, namely, its initially prepared state and its size. Quantum states of the first class are fragile against decoherence so that they can be disentangled asymptotically even if coherences between pointer states are still present. Quantum states of the second type are robust against decoherence. Asymptotically they can be disentangled only if also decoherence is perfect. A simple criterion for identifying these two classes on the basis of two-qubit entanglement is presented.     

Two-photon total and elastic cross section and factorization

The total γγ hadronic cross section is described by factorization using the forward γp and pp elastic cross sections. The hadronic contribution to the elastic γγ cross section is estimated and is about 5 × 10 ⁶ of the total γγ cross section.     

Generalized Brillouin theorem and generalized forces in SCF and MC SCF theories and their Hartree-Fock limits

A formula for the change of energy is derived, valid for any infinitesimal change of the hamiltonian and the wave function in CI, SCF and MC SCF theories. A general form of MC Hartree-Fock equations is derived in a somewhat new form. A closed MC theory is defined and a condition of self-consistency is derived for this theory. The role of deorthogonalization of spin orbitals is discussed. The Hellmann-Feynman theorem and the generalized Brillouin theorem are rederived in a unique and simple way. It is shown that in the case of the closed MC SCF theory the Brillouin theorem derived by Levy and Berthier can be strengthened.

Formulae for generalized forces are derived, valid for closed-shell, openshell and multiconfigurational SCF theories also far from the Hartree-Fock limit.     

Computational and experimental analysis of pinch-off and scaling

Pinch-off and scaling during drop formation are studied using high-accuracy computation and ultrafast, high-resolution imaging. The interface of a water drop (viscosity mu is approximately 1 cP) is shown to overturn prior to breakup for the first time in experiments, well before the dynamics transitions from the potential flow (PF) to the inertial-viscous (IV) regime. A drop of 83% glycerol-water solution (mu is approximately 85 cP) is shown to exhibit a transition from the PF to the IV regime both computationally and experimentally. The computed value of the minimum neck radius in the latter case follows Eggers's universal solution until it becomes unstable.     

Hemodynamics and nonlinear acoustics: General approaches and solutions

Related problems of nonlinear acoustics and hemodynamics are discussed. Equations describing the propagation of pulse waves in elastic tubes taking into account the dependence of the cross-section, linear and nonlinear elasticity on the distance along the axis are obtained. It is shown that in narrowing tubes with their elasticity increasing shock fronts may be formed with the peak pressure increasing, and the peak speed decreasing. The analogous behavior was observed in experiments. The expression of the nonlinearity coefficient as a sum of the “geometrical” and “physical” nonlinearities having different signs is obtained. It is supposed that in a normally functioning system these nonlinearities compensate each other. The formation of the shock waves is the evidence of vascular pathology. It is shown that it is possible to restore the local heterogeneity of a vessel (the change of the cross-section or rigidity) on the basis of measurements of the reflected or transmitted wave. The principle of the action of the acoustic pump not containing mechanically moving parts is described.     

Optical and acoustic electron-phonon coupling in Ho and Tb dihydrides and dideuterides

We present detailed measurements of the electrical resistivity for terbium and holmium dihydrides and dideuterides. An analysis of the thermal variation, ?(T), permits to separate two contributions, one stemming from the acoustic or host metal ion vibration and a second which is related to the optical H (or D) vibrations and which is strongly isotope dependent. The thermal variations can be reasonably well represented by a Debye spectrum as concerns the acoustic phonons and by an Einstein spectrum as concerns the optical phonons. We find also that the strength of the electron-phonon coupling is much weaker for the optical phonons as compared to the acoustic ones, in agreement with recent estimates from the theory.