1×4 buried optical power splitter fabricated by Tl~+-Na~+ ion-exchange

A new 1×4 buried optical power splitter with curved Y-junction structure has been successfully designed by a beam propagation method (BPM) software and fabricated by two-step ion-exchange in glass. The optical qualities of the device are favorable in comparison with that obtained with dry etching fabrication techniques.     

Time dependent local field felt byμ + in MnO revealed by spin resonance method

By using the muon spin resonance method, the time dependent paramagnetic shift of the ⁺ in MnO was observed at 170 K, where the time-dependence was monitored by changing a timing of rf firing. The advantage of this method is that, compared to the usual transverseSR method, there is no problem associated with a loss of phase-coherence.We acknowledge Prof. T. Yamazaki and Dr. Y.J. Uemura for helpful discussions. This work was supported by the Grant-in-Aid of the Japanese Ministry of Education, Culture and Science.     

Temperature measurements inside an Er3+–Yb3+ co-doped fluoride crystal heated by a NIR laser diode and probed by red-to-green upconversion

The temperature of a transparent Cd_0.7Sr_0.3F₂: Er³⁺(4%)–Yb³⁺(6%) crystalline plate 0.3 mm thick heated by a near-infrared (974 nm) laser diode and probed by a red (652 nm) laser was accurately evaluated as a function of the infrared power absorbed by the Yb³⁺ ions.The green emission generated by the Er³⁺ ions directly excited by the red laser consists of three major lines (coming from three individual Stark levels in thermal equilibrium) whose intensities were measured according to the absorbed infrared power and the distance between the heated and probed volumes, to evaluate the heating induced by the excitation of Yb³⁺ and Er³⁺ ions at 974 nm by applying the Boltzmann's equation linking the populations of emitting levels to the temperature. In the case where the Yb³⁺ ions excited by the laser diode are situated at a distance of about 0.5 mm from the edge of the crystal and for an absorbed infrared power of 100 mw, the crystal's edge temperature is reaching 80 °C after 20 s of continuous excitation at 974 nm.     

Ion scattering (Me+ → Me) by monatomic films

Discusses the results of computer simulation of the scattering of metal ions low energy (E ₀ = 2–530 eV) films those metals (Me⁺ → Me) with thickness of few atomic layers on a crystalline substrate, conducted in the framework of the model of multi-particle interactions. The effect of conservation for scattered ions with large values of energy, depending from the film crystal structure, has been realized as in the case of scattering on monocrystalls [1]. It has been determined, that the 3–5 atomic layers coating can save the substrate surface from its interaction with bombarding ions in the energy region E ₀ up to 500 eV.     

μ+ diffusion in copper studied by zero field μSR

Diffusion of muons in high purity Cu was studied by the zero-fieldSR method at temperatures from 134 K down to 0.09 K. The experimental data show clear evidence that the muons still diffuse below 15 K; the measured diffusion rate has a minimum at around 15 K and seems to become independent of temperature below about 0.5 K.     

Radiattonal capture of neutrons by deuterons n + d →3H + λ and P-odd nuclear forces

P-odd polarizational phenomena are considered in the radiative capture of neutrons by deuterons: n + d ³H + . It is shown that, in the general case, 18 different P-odd asymmetries of the angular distribution of quanta arise in the collision of arbitrarily polarized neutrons with a deuteron target characterized by vector and tensor polarizations. The P-odd contribution to the density matrix of the quanta formed in the capture of polarized neutrons by unpolarized deuterons is determined by eight real structural functions, while the P-odd dependence of the Stokes parameters of the photons on the tensor polarization of the deuterons is characterized, in the general case, by ten structural functions. In slow-neutron capture, the number of P-odd correlations is reduced.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 23–26, March, 1987.     

Upconversion Luminescence of Eu3 + in NaYbF4∶ Tm3 + , Eu3 +Nanocrystals Induced by 980 nm Excitation

利用水热法制备得到NaYbF4∶0.01％Tm3+,20％ Eu3+上转换材料,利用X射线衍射分析、扫描电子显微镜及光谱测试技术分别对其进行了结构、形貌以及光谱性质的表征.在980 nm近红外激光激发下,得到了Eu3+的可见到紫外范围的上转换荧光发射.分析表明:共掺杂NaYbF4纳米材料中Tm3+到Eu3+离子的能量传递对布居Eu3+离子的激发态能级,获得Eu3+的上转换发光起着至关重要的作用.另外,在实验中首次获得了Eu3+对应于3P0→7Fj(j=0,1,2)能级跃迁的上转换光发射.     

Thin Film, Near-Surface and Multi-Layer Investigations by Low-Energy μ +SR

At the Paul Scherrer Institute (PSI, Villigen, Switzerland) the beam of low-energy positive polarised muons (LE-μ ⁺) with tunable energy between 0.5 and 30 keV allows the extension of the muon-spin-rotation technique (μSR) to studies on thin films and multi-layers (LE-μ ⁺SR). The range of these muons in solids covers the near-surface region up to implantation depths of about 300 nm. As a sensitive local magnetic probe with a complementary observational time window to other techniques LE-μ ⁺SR offers the unique possibility to gain new insights in these nano-scale objects. After outlining the current status of the LE-μ ⁺ beam line we demonstrate the potential of this new technique by presenting the results of recent experiments: i) the direct observation of non-local effects in a superconducting Pb film, ii) the oxygen isotope effect on the in-plane penetration depth in optimally doped , and iii) the first observation of the conduction electron spin polarisation in the Ag spacer of a Fe/Ag/Fe tri-layer.     

Saturation of counterterms by resonances inK ����e + e ? decays

The decaysK ⁺???? ⁺ e ⁺ e ^?,K _S???? ⁰ e ⁺ e ^? andK _L???? ⁰ e ⁺ e ^? are reinvestigated within the framework of chiral perturbation theory. The counterterms induced by strong, electromagnetic and weak interactions are determined assuming the resonance exchange. The weak deformation model, the factorization model and the largeN _c limit are used to create a weak Lagrangian. It is found that the results of the first two approaches depend on theH ₁ coupling, defined in the effective chiral Lagrangian of theO(p ⁴) order. The set of parameters used in the extended Nambu and Jona-Lasinio model can accommodeteK ⁺???? ⁺ e ⁺ e ^? decay rate within the factorization approach. The CP violatingK _L???? ⁰ e ⁺ e ^? decay rate is discussed.     

Joint creation of Z-boson and photons by colliding e+e− beams

Density matrix elements for a Z-boson created in the reaction e⁺+e^–Z+, are computed. Two reference frames are used in computations: the center-of-mass frame of the reaction e⁺+e^–Z+ with polarization states of the Z-boson specified by the polarization 4-vector with definite helicities, and the rest frame of the Z-boson. In both cases P-odd phenomena should stipulate particular combinations of the density matrix elements. The energy behavior of the total cross-section of the process e⁺+e^–Z+ is studied.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 3–6, September, 1982.     

Sensing of Zn2+ion by N-Furfurylsalicylaldimine Based on CHEF Process†

The recognition ability of N-Furfurylsalicylaldimine (HL) toward various cations (Pb²⁺, Hg²⁺, Ba²⁺, Cd²⁺, Ag⁺, Zn²⁺, Cu²⁺, Ni²⁺, Co²⁺, K⁺, Sr²⁺, and Na⁺) has been studied by UV–Vis and fluorescence spectroscopy. The compound showed highly selective fluorescence signaling behaviour for Zn²⁺ ions in methanol-water medium based on CHEF process and is capable of distinguishing Zn²⁺ from Cd²⁺ ion. From single crystal X-ray analysis it is revealed that a Zn²⁺ ion binds two ligand molecules through imine nitrogen and phenolate oxygen atom.

Monomode channel waveguide in KTiOPO4 crystal produced by Rb+ ion exchange combined with Si+ ion implantation

A novel ion exchanged channel KTiOPO₄ waveguide formation technique is introduced, which can avoid a metal mask being dissolved in an ion exchanged molten salt. Rb⁺ ion exchange (340°C, 30 min) was first applied to a KTP sample to produce a planar waveguide substrate, and then Si⁺ ion implantation (3.0 MeV and 1.5 MeV with doses of 1×10¹⁵ ions/cm² and 6×10¹⁴ ions/cm², respectively) was carried out to construct channel stripes on the planar waveguide surface that has been deposited by a specially designed photoresist mask. The two-dimensional cross sectional refractive index profile of the channel waveguide was reconstructed by considering the shape of the channel waveguide as well as the index distribution of the planar waveguide.     

Improvement on the breakdown voltage for silicon-on-insulator devices based on epitaxy-separation by implantation oxygen by a partial buried n~+-layer

A novel silicon-on-insulator (SOI) high-voltage device based on epitaxy-separation by implantation oxygen (SIMOX) with a partial buried n +-layer silicon-on-insulator (PBN SOI) is proposed in this paper.Based on the proposed expressions of the vertical interface electric field,the high concentration interface charges which are accumulated on the interface between top silicon layer and buried oxide layer (BOX) effectively enhance the electric field of the BOX (E_I),resulting in a high breakdown voltage (BV) for the device.For the same thicknesses of top silicon layer (10 μm) and BOX (0.375 μm),the E I and BV of PBN SOI are improved by 186.5% and 45.4% in comparison with those of the conventional SOI,respectively.     

XPS study of CeTbO3+δ synthesized by high pressure and temperature method

The samples of CeTbO₃₊ synthesized by high pressure and high temperature method were studied by XPS. It was found that Tb⁴⁺ ion began to transform to Tb³⁺ at about 600° C and Ce⁴⁺ to Ce³⁺ about 800° C. Single phase compound of CeTbO₃₊ having fluorite structure was formed at 1000° C, and in the compound the Ce ions had been in mixed valence state. Existence of Ce³⁺ ions in compounds could be detected with the shift of the 888 eV peak and the change of relative intensity of it to the 882 eV peak. The duration stability of CeTbO₃₊ synthesized by high pressure and temperature method was investigated.The project supported by National Natural Science Foundation of China     

Nonmesonic decay of the Λ-hyperon in hypernuclei produced by p + Au collisions

The β-delayed proton precursor ¹⁴⁹Yb was synthesized in the reaction ¹¹²Sn(⁴⁰Ca, 3n) and identified by using a proton-gamma coincidence measurements in combination with a helium-jet fast tape transport system. Its β-delayed proton spectrum was observed. The half-life of ¹⁴⁹Yb was determined to be 0.7±0.2 s. The 253, 101, and 365 keV γ transitions in ¹⁴⁷Dy, following β-delayed proton emission of ¹⁴⁸Ho decay, were reported for the first time. Received: 14 March 2001 / Accepted: 26 September 2001     

Medium effects in ΛK~+ pair production by 2.83 GeV protons on nuclei

We study ΛK~+ pair production in the interaction of protons of 2.83 GeV kinetic energy with C, Cu,Ag, and Au target nuclei in the framework of the nuclear spectral function approach for incoherent primary proton–nucleon and secondary pion–nucleon production processes, and processes associated with the creation of intermediate Σ~0K~+ pairs. The approach accounts for the initial proton and final Λ hyperon absorption, final K~+ meson distortion in nuclei, target nucleon binding, and Fermi motion, as well as nuclear mean-field potential effects on these processes.We calculate the Λ momentum dependence of the absolute ΛK~+ yield from the target nuclei considered, in the kinematical conditions of the ANKE experiment, performed at COSY, within the different scenarios for the Λ-nucleus effective scalar potential. We show that the above observable is appreciably sensitive to this potential in the low-momentum region. Therefore, direct comparison of the results of our calculations with the data from the ANKE-at-COSY experiment can help to determine the above potential at finite momenta. We also demonstrate that the two-step pion–nucleon production channels dominate in the low-momentum ΛK~+ production in the chosen kinematics and, therefore, they have to be taken into account in the analysis of these data.     

Selection of dipolar interaction by the “2 + 1” pulse train ESE

The new kind of electron spin echo (ESE), the “2 + 1” pulse train, is described. This method allows the measurement of dipole-dipole interactions between paramagnetic centers which are substantially weaker than those that can be measured by the ordinary two-pulse train. The dead time of ESE spectrometer response in this method is decreased to the duration of the first two pulses. The theory of dipole-dipole interaction in the ESE signal decay in the “2 + 1” pulse train is developed for different Flip rates and for different cases of spin spatial distribution. The theoretical data fit the experiment, carried out with model systems of H and D atoms, randomly distributed in the frozen solutions of sulfuric acid, and of biradicals. New data concerning the spatial distribution of radical clusters, resulting from y irradiation of the methanol, are given.     

Measurement of the rate of ν e+d → p+p+e − interactions produced by 8B solar neutrinos at the Sudbury Neutrino Observatory

Solar neutrinos from the decay of ⁸B have been detected at the Sudbury Neutrino Observatory (SNO) via the charged current (CC) reaction on deuterium and by the elastic scattering (ES) of electrons. The CC reaction is sensitive exclusively to ν _e, while the ES reaction also has a small sensitivity to ν _μ and ν _τ. The flux of ν _e from ⁸B decay measured by the CC reaction rate is φ ^CC(ν _e )=[1.75±0.07(stat.) _?0.11 ^+0.12 (syst.)×0.05(theor.)]×10⁶cm^?2s^?1. Assuming no flavor transformation, the flux inferred from the ES reaction rate is φ ^ES(ν _x )=[2.39±0.34(stat.) _?0.14 ^+0.16 (syst.)]×10⁶cm^?2s^?1. Comparison of φ ^CC(ν _e) to the Super-Kamiokande collaboration’s precision value of φ ^ES(ν _x) yields a 3.3σ difference, assuming the systematic uncertainties are normally distributed, providing evidence that there is a nonelectron flavor active neutrino component in the solar flux. The total flux of active ⁸B neutrinos is thus determined to be (5.44±0.99)×10⁶ cm^?2 s^?1, in close agreement with the predictions of solar models.