Humidity and particulate testing of a high-Q microcavity packaging comprising a UV-curable polymer and tapered fiber coupler

The high-Q maintenance of microcavities greatly challenges the microresonator-based practical application. In this paper, we analyze the theoretical model of the Q in the open air, indicating that the Q can be spoiled drastically in the open air. The Q spoiling factors are also demonstrated experimentally to show the Q spoiling which originated from the water and the particulate in the surroundings. Then we propose and realize the Q maintenance through constructing a sealed and packaged microcavity regime. In the packaged structure the Q decreases a little but a high Q larger than 10⁶ can be achieved continuously. Moreover, the sealed structure has good performance to maintain the high Q for a long time with the standard deviation about 10⁴, because the Q spoiling factors are isolated by the package layer. Additionally, the package also enhances the robustness. These merits can promote the practical application of the microcavities.     

Diffusion of oxygen vacancies in yttrium iron garnet investigated by dynamic conductivity measurements

In yttrium iron garnet, Y₃Fe₅O₁₂, the oxygen vacancy concentration at high temperatures depends on the partial oxygen pressure. Due to the electron donating nature of the vacancies, changes in the oxygen vacancy concentration can be measured by electrical conductivity measurements. We discuss a dynamic method for studying the diffusion of oxygen vacancies by measurements of the time dependence of the electrical conduction after a change in the oxygen partial pressure has taken place. It is shown that the interpretation of the measurements is straightforward if the relative change in conductivity remains small (? 10%). Measurements were performed on single crystals and on polycrystalline samples at temperatures 900–1400°C. The samples were made n-type by substitution with Si or p-type by substitution with Ca, Zn or Pb. The partial oxygen pressure was changed between 1 and 0.1 atm. For all samples the diffusion coefficient D of the oxygen vacancies can be represented by $\text{D = A}\text{exp}\text{(?}\text{Q}\text{kT}\text{)}$, where A = 8400 cm²s^?1 and Q = 2.90 eV. It is shown that the activation energy of 2.90 eV is due to the migration enthalpy of the vacancies only.     

Infrared absorptivity of the 9.6 μm ozone band as a function of spectral resolution and abundance

The i.r. absorptivity of the R-branch maximum (9.48 μm) of gaseous ozone was determined at 25°C as a function of spectral resolution and absorbance a/a total pressure of 735 torr of dry air. Ozone samples produced by a high voltage discharge in oxygen, and measured accurately by either a pressure or volume change, were spectroscopically measured in a 57741. environmental chamber at paths up to 69.17 m. A linear relation between spectral slit (Δv) and the ratio of the absorbances (R_v/p) of the observed absorption minimum between the R and Q branches to the absorption maximum of the R-branch was found for cm^-1 < Δv < 10cm^-1 and for absorption up to 48%. The i.r. absorptivity varied approx. 20% (from 3.9 to 4.8 cm^-1 STP) over the range of values for R_v/p studied. Absorptivity was weakly dependent on ozone abundance (w) for w?0.03 cm STP.     

High-resolution stimulated Raman spectroscopy of O2

High-resolution (0.002 cm^?1) stimulated Raman spectroscopy has been applied to the study of both normal and satellite Q branches of the fundamental vibrational band of molecular oxygen. Using a pulsed molecular free-expansion jet to adiabatically cool the oxygen sample, satellite Q branches at 1554 and 1558 cm^?1 that arise due to the splitting of the ³Σ_g ground state by spin-spin and spin-rotation interactions were completely resolved for the first time. Measured intensity ratios for the ${}^{\mathrm{<mtext>\Delta </mtext><mtext>N</mtext>}}\text{Δ}\text{J(J, N) =}{}^{\mathrm{Q}}\text{0(2, 1)}$ and ^QR(1, 1) lines, and for the ^QS(0, 1) and ^QP(2, 1) lines compare favorably with that for a coupling case intermediate between Hund's cases (a) and (b). Depolarization ratios, measured for a series of ^QQ-branch (unresolved) triplets, give a value 0.164 ± 0.004 for the depolarization ratio of the fundamental vibrational band.     

The trapping of K and Na atoms by a clean W(110) surface trajectory calculations

The fraction of K and Na atoms initially trapped by the W(110) surface has been measured as a function of the incident energy (0.5–15 eV) and as a function of the incident angle. The trapping probability equals one at low incident energies (E_i ? 0.5 eV) and decreases with increasing energy. The measurements show an increase of trapping with increasing angle of incidence θ_i (measured from the surface normal). Simultaneously the desorption energies Q_i were determined from the temperature dependence of the measured mean residence time on the W(110) surface. We obtained for K: Q_i = 2.05 ± 0.02 eV, and for Na: Q_i = 2.60 ± 0.04 eV.The trapping phenomenon at a solid surface was approximated in a theoretical way by calculating the in-plane trajectory of a projectile scattered from a diatomic surface-molecule. The important feature which showed up was the conversion of tangential to normal momentum of the projectile, and thus the inapplicability of cube models. As a function of the angle of incidence two regimes can be distinguished: at the smaller angles the scattering is governed by simultaneous interaction of the projectile with two neighbouring surface atoms, and at the higher angles of incidence the single particle interaction contributes most to the momentum transfer.     

Inelastic electron scattering from protons and deuterons at very low Q2

The total cross-section for production of hadrons by inelastic electron scattering at 3.2° from hydrogen and deuterium has been measured in the Q² range 0.015 GeV² to 0.1 GeV², at virtual photon energies ranging from 2 GeV to 8.5 GeV. The transition to photoproduction is observed to be smooth, the ratio σ_D/σ_H being about 1.85 in this range. No evidence is seen for a conjectured rapid Q²-dependence of this ratio at low Q².     

Spin Structure of the Nucleon at Low Q 2 Region

The spin structure of the nucleon can play a key testing ground for the Quantum Chromo-Dynamics(QCD) at wide kinematic ranges from smaller to large four momentum transfer Q ². It is far more challenging to understand the QCD at small Q ² region due to the non-perturbative nature. Jefferson Lab has been one of the major experimental facilities for the spin structure with its polarized electron beams and various polarized targets. A few QCD sum rules have been compared with the measured spin structure functions g ₁ and g ₂ at low Q ² and the most surprising results have been obtained for the spin polarizabilities, γ ₀ and δ _LT .     

Pressure broadening coefficients of transitions in the ν5 band of methyl bromide from fitting to Voigt and Galatry line profiles

Tuneable diode laser absorption spectroscopy has been used to measure the room temperature pressure broadening coefficients (γ) of rotational transitions in the v₅ fundamental band of methyl bromide (¹²CH₃⁷⁹Br and ¹²CH₃⁸¹Br) around 6.9 μm. Nitrogen, oxygen and self-broadening coefficients have been determined for 125 lines in the ^RQ₁, ^PQ₃, ^PQ₅, ^PQ₇ and ^PQ₈ branches and 49 P and R branch transitions. Line profiles within Q branches were recorded at incremental pressures of nitrogen and oxygen up to 15 Torr and fitted to a Voigt profile to yield the broadening coefficients. The nitrogen broadened data for 14 lines, chosen from the five Q branches, were also fitted with Galatry profiles. The line profiles of the P and R branch transitions were recorded for total nitrogen and oxygen pressures of up to 300 Torr and fitted to both Voigt and Galatry profiles. Within individual Q branches, nitrogen broadening coefficients were found to decrease monotonically with increasing J from 0.14 cm⁻¹ atm⁻¹ at low J to 0.09 cm⁻¹ atm⁻¹ at high J. The corresponding values for oxygen were approximately 25% smaller. Self-broadening coefficients were found to vary between 0.48 and 0.16 cm⁻¹ atm⁻¹ with a similar J dependence to the foreign gas broadening for J > 20. However, between J = 2 and J ≈ 20 the broadening coefficient was found to increase with J. The magnitude of the pressure broadening coefficient for P and R branch transitions was found to closely follow the J dependence measured for the Q branch lines.     

Quality factor of vibration of aluminum alloy disks

The quality factor Q of a quadrupole vibration at 20 kHz has been measured for circular disks of several aluminum alloys in the temperature range 4–300 K. Q = 4 × 10⁷ is obtained with disks of the 5056 alloy below 20 K.     

Near-barrier transfer and fusion of the systems33S +90,91,92Zr

Double differential cross sections of all prominent transfer channels have been measured in the systems³³S +^99,91,92Zr at two energies close to the nominal Coulomb barrier. In addition the fusion excitation functions of these systems have been measured below and around the barrier. The angular- andQ-distributions of the most important transfer reactions have been analysed in the framework of a simple semiclassical formalism. Particularly the two-nucleon transfer angular distributions exhibit strong multi step coupling effects which manifest themselves in reduced cross sections at large angles corresponding to close distances. From the angular distributions at forward angles, where a single step character of the transfer reaction can be assumed, approximate form factors have been extracted employing a first order perturbation theory. Within the uncertainties of a schematic coupled channels calculation the isotopic differences of the sub-barrier fusion enhancement can be understood on the basis of the isotopic differences of the transfer form factors andQ-values.     

Pressure broadening coefficients of ν5 fundamental band lines of CH3I at 7 μm measured by diode laser absorption spectroscopy

We have measured the room temperature pressure broadening coefficients, γ, of over 100 lines in five Q-branches of the ν₅ perpendicular band of methyl iodide (¹²CH₃I) using tuneable diode laser absorption spectroscopy. The profiles of individual lines in the ^PQ₂, ^PQ₄, ^PQ₅, ^PQ₆ and ^RQ₃ branches were recorded in a 1 m long White cell and at nitrogen or oxygen pressures up to 15 Torr. The lines were fitted to the Voigt profile to obtain the collision broadened line widths. Within individual Q-branches the broadening coefficients decreased monotonically with increasing J and for nitrogen broadening varied between 0.19 cm⁻¹ atm⁻¹ at low J and 0.12 cm⁻¹ atm⁻¹ at high J. The corresponding oxygen broadening coefficients were approximately 20% smaller. Self broadening coefficients were also measured for several of the Q-branches and found to be up to ∼4 times higher than the corresponding nitrogen broadening values.     

Mass measurement and spectroscopy of57Cu with the58Ni(14N,15C)-reaction

The mass of⁵⁷Cu has been measured with the⁵⁸Ni(¹⁴N,¹⁵C)-reaction at 150 MeV incident energy with theQ 3D-spectrometer. The reaction has been selected after a careful inspection of the DWBA-expression for the cross section with respect to the highest weighting factors for spins andl-transfer. Cross sections of several μb/sr have been obtained. TheQ-value has been measured to beQ ₀=?19.90 (4) MeV and the⁵⁷Cu mass excess is ?47 340 (40) keV. Four lines of excited states have been observed up to 5.7 MeV. These states have a structure of single particle character, since⁵⁷Cu consists of a doubly closed core with N=Z=28 and a proton outside, and states up to the 2d 5-shell are observed.     

Q branches in the rotational spectrum of HOC1

We have obtained the far-i.r. rotational spectrm of HOCI from 70–263 cm^?1. The most prominent features of the rotational spectrum are the Q branches, for which we have measured positions. Statistical strengths for the Q branches ave been calculated and μβ, the component of the dipole moment that allows Q branch transitions has been determined from P and R branch line intensities. We find μβ = 1.4 ± 0.2 D. We also calculate Q branch strengths and shifts at stratospheric temperature.     

Coverage effects under atomic chemisorption: Morse-potential modeling based on bond-order conservation

Our recent analytical Morse-potential model based on bond-order conservation has been extended to treat coverage (θ) effects on the heat of atomic chemisorption Q. For highly symmetric surfaces such as fcc(111), fcc(100), and bcc(100), explicit expressions for Q versus θ have been obtained projecting regularities of Q(θ) and of the overlayer structures, in encouraging agreement with experiment. In particular, the model predicts that Q should typically decrease with θ (though at very low θ, Q can sometimes increase) and that there may be some critical coverage θ_c<1 beyond which the second-order phase transition (hollow→bridge or on-top) will occur.     

The decay of 20 min179Re

The decay of 20 min¹⁷⁹Re has been studied by means of Ge(Li) and Si(Li) detectors and a magneticβ-ray spectrometer. From the measured positon endpoint aQ-value of 2690±50 keV has been deduced. The decay scheme given is supported by coincidence relations. Fast beta transitions (logft≈5.1) to levels at 720keV and 1680 keV in¹⁷⁹W can be explained by a three quasi-particle character for these states. Nilsson assignments to these and other levels are discussed.     

Experimental investigation and modeling of corona characteristics under lightning impulses

An experimental study is conducted on the corona characteristics under lightning impulses. The charge-voltage characteristics, i. e. the Q-U curves, are measured in a corona cage. The impulse waveshapes are varied to investigate their influence on the Q-U curves. Meanwhile, a corona model is proposed to compute the Q-U curves. The ionized zone is simplified as a cylindrosymmetric geometry and a one-dimensional subdivision is made in the radial direction. The Q-U curves can be given by performing an efficient computational procedure. The computed results are compared with the measured ones to check the validity of the model.     

The structure factor for liquid nitrogen and liquid oxygen from neutron scattering studies

The structure factor, S(Q), has been measured for liquid nitrogen at 77 K and liquid oxygen at 84 K by neutron diffraction over a range of momentum transfer, Q, from 0·3 to 7·3 Å^-1. In the case of oxygen a correction for magnetic scattering has been included.

The liquid structure factor for nitrogen compares well with that obtained from X-ray diffraction measurements but there are significant discrepancies in the case of oxygen. These may be partially attributed to uncertainty in the form factor for paramagnetic scattering.

The data have been analysed in terms of several different models for the orientational correlation between neighbouring molecules. The results are particularly sensitive to uncertainties in the absolute normalization of the data, the inter-nuclear distance for the molecular structure and Placzek corrections; the effect of these errors is considered in detail. It is shown that some form of orientation correlation must exist but its precise nature could not be obtained from the present data.     

The EMC effect — status and perspectives

Recent experimental results on the EMC effect are presented. The ratios of structure functions for nuclei and deuterium measured by the two muon experiments at CERN show a clear enhancement of a few percent forx<0.25. Atx below 0.05 substantial shadowing with littleQ ² dependence has been observed by a dedicated low angle experiment of the EMC. No significant nuclear mass dependence ofR=αL/αT has been seen in the SLAC experiment E 140. There are several indications that theQ ² evolution of nuclear structure functions deviates from the expectations of perturbative QCD and that the gluon distribution in nuclei is harder than in free nucleons. This is possibly caused by nucleon-nucleon correlations on the quark-gluon level. Many aspects of the EMC effect are presently being investigated by the high energy muon experiment of the NMC collaboration at CERN and a Drell-Yan experiment at FNAL. First results can be expected soon. They will help to develop a better understanding of nuclear effects in quark and gluon distributions.     

High-Q photonic crystal surface-mode cavities on crystalline SOI structures

High-Q side-coupled surface-mode cavities in two-dimensional (2D) photonic crystals on crystalline silicon-on-insulator (SOI) structures are demonstrated. One of the surface-mode cavities has the measured system Q factor and intrinsic Q factor of 6200 and 13,400, respectively. The experimental results show that the value of system Q factor is ten times and the intrinsic Q factor six times higher than those of similar structures on amorphous SOI structures, respectively, due to the intrinsic material loss is much lower for crystalline silicon. The Q factors of cavities can be further improved by spin-on-glass overlayers, for increasing the structural symmetry. After the spin-on-glass process, the system Q factor and the intrinsic Q factor become nearly twice higher. Meanwhile, the drop wavelengths are largely red-shifted.     

Zur Asymmetrie der Reaktion139La(n,α)136Cs mit polarisierten Neutronen

Experimental and theoretical investigations have been performed to determine the thermal conductivity of hydrogen in the temperature range between 2000 and 7000 °K. For this purpose the radial temperature distributions for various currents and theE-I-characteristic of a low current wall-stabilized hydrogen arc have been measured. In the dark region of the arc outside the bright core the temperature and the thermal conductivity between 2000 and 4500 °K were found by means of the schlieren technique. The electron temperature in the core of the arc results from spectroscopic measurements. The gas temperature has been calculated with a formula, derived from the kinetic theory of gases. Assuming a constant collision integralQ _eH ¹¹ the radial distribution of electric conductivity has been calculated according to Langevin's formula. The valueQ _eH ¹¹ =30·10^?16 cm₂ results by comparing the integrated conductance with the measured one. Since now the radial distribution of power input and the temperatures are known, the thermal conductivity between 4500 and 7000 °K can be determined as well. The total course of the heat conductivity shows a strong peak at the temperature of 3740 °K characteristic for the dissociation process.