Some features of the development of a deformation frequency- response vacuum gauge for measuring low absolute pressures

The article shows the tasks involved in developing a deformation frequency-response vacuum gauge for measuring low absolute pressures. The calculations of the parameters of the measuring transducer are given, which made it possible to create a competitive and inexpensive device.

Numerical Simulation of Unsteady Aerodynamic Performance of Novel Adaptive Airfoil for Vertical Axis Wind Turbine

The aerodynamic performance of the blade determines the power and load characteristics of a wind turbine. In this paper, numerical research of the active deformation of an airfoil with equal thickness camber line was carried out, which shows the great potential of this active flow control method to improve the flow field. The NACA0012 is taken as the reference airfoil, and the inflow wind speed is 9 m/s, the chord length of the airfoil is 0.4 m, and the Reynolds number is 2.5 × 105. The influence factors, such as deformation amplitude and deformation frequency on the aerodynamic performance, were studied at different attack angles before and after stall. Studies have shown that: firstly, at different angles of attack, different deformation amplitudes and frequencies have great influence on the aerodynamic performance of the active deformed airfoil. The active deformation can improve the aerodynamic performance of the airfoil in different degrees in deep stall and light stall regions. Secondly, a suitable deformation amplitude and deformation frequency can improve the aerodynamic performance of airfoil stably and effectively in light stall, which occurs when the deformation amplitude equals to 0.02c and the deformation frequency is lower than 2 Hz, and the maximum lift-drag ratio can be increased by about 25%. Before stall, when the deformation frequency is 2 Hz and amplitude is 0.10c, the airfoil will have a negative drag coefficient in the process of deformation, and the airfoil will produce a thrust which is similar to the energy capture of the flapping foil. This is an unexpected discovery in our research.

IR spectra of deuterated propene analogues of Zeise's salt

The IR absorption spectra (4 000-250 cm-1) of anhydrous K[(propene)PtCl3], using propene-2-d1 and propene-1,1-d2 as the ligands, were measured in KBr discs. A new weak band for the fundamental deformation frequency of the C-C=C skeleton softened by the coordination of the propenes was found around 400 cm-1, namely at 420, 417, and 375 cm-1 for d0, d1, and d2 species, resp. Vibrational couplings of the so-called ν(C=C) with other modes of the ligands is discussed.

The low frequency infrared and Raman spectroscopic studies of some uranyl complexes: the deformation frequency of the uranyl ion

A study of the low frequency vibrational spectra of compounds of the type L2UO2(NO3)2 (L = mono-dentate ligand), MUO2(NO3)3 (M = monovalent cation), and CS2UO2X4 (X = Cl or Br) has shown that the deformation frequency of the uranyl group occurs in the region 274–245 cm−1 but detailed assignments of the U—O (nitrate) frequencies are not given since it is shown that structurally related complexes do not necessarily give similar low frequency infrared (i.r.) and Raman spectra.

Infra-red and Raman spectra of single crystals of ice

In this paper a brief account is given of one of the main results of an investigation on the infra-red and Raman spectra of single crystals of ice carried out recently a the University of Michigan. The first aim was to see whether infra-red analyse could be used to discriminate between various proposals which have been pu forward for the positions of the hydrogen atoms in the hexagonal crystal lattic formed by the oxygen atoms. The second objective was to obtain a complete interpretation of the vibration spectrum of ice between 50 and 10000 cm - . Nothing will be said about the latter problem, since it is too complex to be discussed satisfactorily in a short paper. The infra-red spectrum of water vapour stretches from 0·7 cm -1 to well beyond 17000 cm -1 and it has been interpreted in great detail. The general explanation is shown in table 6. In the same table, the main features of the infra-red spectrum c ice are described. As might be expected, the very extended pure rotation line spectrum of the vapour is replaced by a relatively small number of bands, which arise from the hindered rotation and translation of the water molecules in ice (intermolecular vibrations). That the water molecule preserves its individuality i seen from the fact that the values of the intra-molecular fundamentals are ged only slightly in value in going from the vapour to the solid state, i. e. v 2 1595 to 1640 cm -1 and v 3 from 3755 to 3250 cm -1 . The third fundamental ( v 1 ) ry weak in absorption but strong in the Raman spectrum, examination of h shows that it has changed from 3651 cm -1 in the vapour to 3143 cm -1 in the state. Such changes are characteristic of molecules which become hydrogen-ded in the condensed phase, viz. a lowering of the stretching frequencies ( v 1 v 3 ) bout 10% and a similar increase in the deformation frequency ( v 2 ). In this the increase in the deformation frequency appears to be very small (2·5%), this may well be due to changes in certain anharmonic and interaction con-ts in going from the vapour to the solid state.

Spectra of sulphonyl derivatives. IV. Sulphonic esters

The symmetric and asymmetric SO2 stretching frequencies (1190, 1365 cm-1) and the SO2 deformation frequency (565 cm-1) in esters of arylsulphonic acids are similar to those for sulphonyl chlorides. A frequency of about 800 cm-1 can be correlated with the presence of the SO2.OR group and is probably the S-OR bond stretching vibration. The corresponding frequencies in methyl methane sulphonate are slightly lower. A doubling of some frequencies is attributed to the occurrence of rotational isomerism in the sulphonic ester group. The frequency noted by Ham and Hambly (1953b) and suggested as characteristic of aromatic sulphonyl derivatives corresponds to a very constant vibration 1098-1099 cm-1 in the aromatic esters studied.