Emission of nuclear quadrupole resonance from polycrystalline hexamethylenetetramine

The angular dependence of the nuclear quadrupole resonance (NQR) signal intensity emitted from polycrystalline hexamethylenetetramine has been analytically investigated for all directions for non-contact detection of chemicals by nuclear quadrupole resonance. The field pattern of the NQR signal from a column sample was measured. The emitted patterns were the same as that from a united single magnetic dipole, which fitted well to the estimation based on quadrupole principle axis system. This result is helpful to design an antenna for NQR remote detection.     

Fourier transform spectral study of BΣ-XΣ system of AlO

The spectrum of B²Σ⁺-X²Σ⁺ system of AlO has been recorded on BOMEM DA8 Fourier transform spectrometer at an apodized resolution of 0.05 cm⁻¹. Nineteen bands of the Δv = 1, 0, −1, and −2 sequences of this band system have been analyzed for the rotational structure. Out of which seven bands, viz. 3-2, 4-3, 2-3, 3-4, 4-5, 5-6 and 6-7 have been analyzed for the first time. The rotational lines of these 19 bands along with 20 earlier analyzed bands, a total of 7200 lines, have been fitted in a simultaneous least squares fit. The study has resulted in determining more precise vibrational and rotational constants of the two states. Because of the high resolution employed it became necessary to invoke H₀ and H₁ coefficients, and a fifth order term to explain the anomalous spin-doubling observed in the v″ = 5, 6 and 7 levels of the X²Σ⁺ state.     

Measurements of relative line strengths in N I multiplets for transition arrays 3s-np (n=3, 4, 5)

Applying the emission method, intensities of 60 spectral lines of neutral nitrogen (N I) belonging to 15 multiplets originating from 3s-np (n=3, 4, 5) transition arrays have been measured. A wall-stabilized arc, operated at atmospheric pressure in helium with some admixture of nitrogen was applied as the excitation source. From measured line intensities, relative line strengths within multiplets have been evaluated. For transitions with Δn=1 and 2, significantly larger discrepancies from LS coupling results are found if compared to transitions 3s-3p (Δn=0). The measured relative line strengths within 3s-3p multiplets are compared with older measurements, recent calculations and with the new data recommended by NIST.     

Spacetime Curvature is Important for Cosmology Constrained with Supernova Emissions

We investigate universe expansion models as functions of emission frequency ratio decline rather than redshift z, using the latest on-line, self-consistent data from 192 supernovae. We present results for simpler and some current models of cosmology, including those with dark energy (standard model) and a recent model correcting for the effect of a small time-dependent, emission frequency increase with lookback. This new model, with a gentle lookback decline of the Planck constant, and the standard model fit the data with similar confidence according to Bayesian Information Criteria. The standard model tends towards solutions high in matter density while remaining flat, but models without dark energy tend towards dilute universes with significant spacetime and curvature and a smaller Hubble constant. We conclude the normalized spacetime parameter, Ω _k , should not be ignored and it includes the combined contributions of huge spacetime magnitude and curvature.     

A method for characterising solids translational and rotational motions using Multiple-Positron Emission Particle Tracking (Multiple-PEPT)

Solid motion can be classified into translational motion and rotational motion; both play an important role in a wide range of engineering processes. While translational motion has been extensively studied in various systems, there is a lack of information on rotational motion, possibly due to a lack of appropriate experimental techniques. For a number of mixing processes involving heat transfer for solid–liquid mixtures, the heat transfer coefficient between solid and liquid is critical in determining process times and overall product characteristics, and is greatly dependent on both rotational and translational behaviours of the solids, which ideally need to be studied simultaneously. This paper presents a new technique, Multiple-Positron Emission Particle Tracking (Multiple-PEPT), which can follow multiple particles simultaneously through a considerable thickness of surrounding material. Both translational and rotational motions of the solid can be reconstructed. The accuracy of the method for the translational velocity was better than 10% while for the angular velocity 23% for speeds up to 0.25 m/s. Multiple-PEPT will therefore offer the possibility to study translational and rotational motions for a range of engineering systems. The potential applications of tracking solid translational and rotational motions are illustrated by an example of tracking a cubed potato in a rotating can.     

Gain of harmonic generation in high gain free electron laser

In a planar undulator employed free electron laser(FEL),each harmonic radiation starts from linear amplification and ends with nonlinear harmonic interactions of the lower nonlinear harmonics and the fundamental radiation.In this paper,we investigate the harmonic generation based on the dispersion relation driven from the coupled Maxwell-Vlasov equations,taking into account the effects due to energy spread,emittance,betatron oscillation of electron beam as well as diffraction guiding of the radiation field.A 3D universal scaling function for gain of the linear harmonic generation and a 1D universal scaling function for gain of the nonlinear harmonic generation are presented,which promise rapid computation in FEL design and optimization.The analytical approaches have been validated by 3D simulation results in large range.     

Multiparton collisions and multiplicity distribution in high-energy collisions

We discuss the multiplicity distribution for the highest accessible energies of pp- and -interactions from the point of view of multiparton collisions. The inelastic cross sections for single, σ₁, and multiple (double and, presumably, triple), σ₂ parton collisions are calculated from the analysis of experimental data on the multiplicity distribution up to Tevatron energies. It is found that σ₁ becomes energy independent while σ₂ increases with for GeV. The observed growth of p with multiplicity is attributed to the increasing role of multiparton collisions for the high-energy -inelastic interactions. σ₂₊₃ reproduces quite well the cross-section for the mini-jet production.     

电感耦合等离子体原子发射光谱法(ICP-AES)测定5XXX系铝合金中的高镁含量

采用电感耦合等离子体原子发射光谱法测定5XXX系铝合金中的高镁含量,选择20mL稀王水溶液溶解试样,以消除合金中的基体元素及其它共存元素的干扰为目标,选择测定镁含量的分析谱线为280.270nm。分别称取与分析试样基体近似的三种铝合金标准物质0.100 0g,按试样相同的溶解方法处理并定容至100mL,选择仪器工作条件,制作分析曲线,进行曲线校准,按照同样的方法对4个样品各测定6次,测定值的相对标准偏差均不大于0.59%,用标准加入法测得加标回收率在94.0%~104.0%,测定值和环己二胺四乙酸分离络合滴定法测定的5XXX系铝合金中的镁量结果一致。     

电感耦合等离子体发射光谱法测定高效复合孕育剂中铝、钙、钡

通过硝酸、氢氟酸和盐酸分解试料,高氯酸冒烟驱走硅和氟,最后用盐酸溶解盐类,应用电感耦合等离子体发射光谱(ICP-AES)法对高效复合孕育剂中铝、钙、钡进行测定,此方法能准确、快速地测定其含量,回收率在98%～103%之间,精密度、标准样品分析对照均取得了满意的结果。