日全食下城市热环境的变化特征分析

2009年7月22日,我国长江流域能很好地观测到一次千载难逢的日全食现象,且重庆是一个非常好的日全食观测点.作者观测了重庆地区7月21日及22日两天的室外气象数据(太阳辐射,空气温度,相对湿度等),基于实验观测数据,分析和探讨了日全食对室外热环境的影响.日全食当天,室外气温和地表温度随太阳辐射强度的减小而减小,空气温度...     

Guidelines for measuring solar radius with Baily beads analysis

By inspection of central eclipses videorecords, data of Baily beads timings are retrievable. Knowing the lunar limb profile at the moment of the eclipse we evaluate the excess or defect of solar limb when the Sun is assumed at its standard radius. Two procedures of data analysis are here presented: one based on limb heights and the other on times. While these methods are based upon Occult 4 software, they can be used with other ephemerides and new lunar profiles. The example of 2006 total eclipse data, with its remarkably negative value of ΔR= − 0.41“± 0.04”, is presented.     

Solar eclipse effects of 22 July, 2009 on the propagation of radio signals

The results of investigation of the variation of radio signal strengths during the solar eclipse on July 22, 2009 are reported in this paper. Observations of the radio signals transmitted from different radio stations at different frequencies and received at a particular observing site indicate a distinct change in signal strength around the time the eclipse umbra passes the propagation paths. The three types of variations in the eclipse day and particularly during its peak period are different from propagation under normal condition. The phenomena of signal variations, the noted “Inverted U-shape“ at one of the frequencies before the occurrence of the eclipse and 13 to 15 minutes time difference between the enhancement of the signal strength and the onset of eclipse are some interesting characteristics. The results are interpreted by ionospheric D-layer behavior at such times.     

Mixing layer height and meteorological measurements in Hefei China during the total solar eclipse of 22 July, 2009

Mixing layer height measurements with an elastic-backscattered lidar were carried out in Hefei, China, during the total solar eclipse of 22 July, 2009. The mixing layer height evolution is studied with the observation of changes in near-ground temperature, relative humidity and wind speed. The lidar emits the laser at the wavelengths of 532 and 355 nm, respectively, and obtains the backscattered signal with the resolution of 10 m. The whole eclipse witnessed the mixing layer change similar to that occurring during sunset. The results also show the mixing layer height decreased to 287 m rapidly during the total eclipse within only more than 1 min from the initial 354 m. The entrainment thickness reached the minimum of 43 m in the eclipse, indicating the weakening of the penetrative convection. Thereafter the thickness kept a constant value of 180 m. The temperature in the whole eclipse is uptrend, increasing only by 0.5 °C as a whole. The wind speed decreased and simultaneously the wind direction changed. The wind speed reached its minimum of 2 m/s at the end of the eclipse.     

New measurements with a torsion pendulum during the solar eclipse

During the solar eclipse of 11 July 1991 in Mexico the period of a torsion pendulum was measured in order to reexamine possible anomalies observed in previous experiments of this kind. In our experiment no significant change was found as the relative change in the period associated with the eclipse was less than 2.0×10^–6 (90% confidence). Results were similar to our previous ones made during the eclipse in 1990 in Finland when the Sun was much lower in the horizon. However, two small but distinct shifts were observed in the horizontal position of the pendulum wire which were well correlated with the beginning and the end of the eclipse.     

Observation of signals of VLF radio stations and VLF noise during the solar eclipse on March 29, 2006

Effects of the solar eclipse on March 29, 2006 on signals of VLF radio stations, regular radio-noise intensity in the VLF range 0.3–10 kHz, and the number of atmospherics registered in Yakutsk mainly from the western direction are considered. The full lunar shadow zone consistently shaded the daytime section of the radio-signal propagation path from the western coast of Africa to Altai. A multichannel parallel analyzer-recorder (operating in the frequency range 0.47–8.7 kHz), one-point thunderstorm direction-and-range finder (0.3–100 kHz), narrow-sector radio-noise direction finder (0.3–10 kHz), recorder of VLF radio-station signals, and broadband radio-noise recorder (0.3–100 kHz) were used for observations. Time synchronization of the recorder of VLF radio-station signals was carried out with the help of GPS-clocks. The effect was observed in radio-station signals, radio-noise, and number of atmospherics from a direction of (270 ± 20)°, counted from the north clockwise, in the last stage of the eclipse (∼11–12 UT), when the lunar shadow approached the night terminator and crossed the signal propagation path. The effect was manifested through a ∼20% gain of the received signals, ∼40% increase in the number of atmospherics, and radio-station phase changes. The registered effects are similar to those we observed during the eclipse on March 9, 1997. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 84–87, June, 2007.     

Feature of the multifractal structure of small-scale ionospheric turbulence during the solar eclipse of August 1, 2008

Using the method of radio sounding of the mid-latitude ionosphere by the satellite signals, we study the multifractal structure of small-scale ionospheric turbulence during a solar eclipse. The measured multipower and generalized multifractal spectra of small-scale ionospheric turbulence at the initial and closing stages of the eclipse turn out to be almost identical on the space radio paths with different orientations. This is indicative of a sufficiently high stability of the nonuniform spatio-temporal distribution of small-scale fluctuations of the ionospheric electron number density under conditions of geophysical disturbances due to global physical processes in the ionospheric plasma during a solar eclipse. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 52, No. 4, pp. 302–306, April 2009.     

IR spectra temperature changes and conformational structure of 4-butyl-4′-cyanobiphenyl

IR spectra of 4-butyl-4′-cyanobiphenyl in the liquid and solid-crystal states were measured in the 400–4000 cm^–1 region at 28–70°C. Changes of the spectra as a function of temperature are due to the conformational fluxionality of the molecules according to calculated IR spectra of the possible 4-butyl-4′-cyanobiphenyl conformers. Calculations were carried out using the method of fragments and the LEV-100 program package. Bands sensitive to the conformational changes in the molecular structure were found. IR spectra have been interpreted. Conclusions have been made about the conformations of the sample in the solid-crystal and liquid phases. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 3, pp. 325–333, May–June, 2009.     

Effect of annealing on structure and magnetic properties of Fe-N and Fe-Ti-N thin films

The structure and magnetic properties of Fe-N and Fe-Ti-N films have been studied as a function of annealing temperature T_a with a transmission electron microscope and a vibrating sample magnetometer. The as-prepared Fe-N films consist of the γ^′-Fe₄N and α^′′-Fe₁₆N₂ phases, and the Fe-Ti-N films are composed of the γ^′-Fe₄N, α^′′-Fe₁₆N₂, and TiN phases. The structural changes with annealing temperature in the Fe-N films are distinct. The α^′′-Fe₁₆N₂ decomposes into α+γ^′ phases in the Fe-N film annealed at about 300 °C, and it disappears in the film annealed at 350 °C. Annealing of the Fe-Ti-N films shows no structural changes between room temperature (RT) and 500 °C. The saturation magnetization 4πM_S and coercivity H_c of the Fe-N films change drastically with the annealing temperature T_a, whereas those of the Fe-Ti-N films do not change with T_a up to 500 °C. These results indicate that the additon of Ti may improve the thermal stability of Fe-N films. Recieved: 6 Juli 1998 / Accepted: 19 Oktober 1998 / Published online: 10 March 1999     

西藏日食太阳辐射观测研究

日食现象会对地球太阳辐射、大气气象以及人类活动等造成相应的影响。2020年6月21日（夏至）在西藏发生了一次日食现象,西藏阿里日环食最大食分达到了0.995,拉萨地区日偏食食分也高达0.953。两地日食均发生在当地正午前后。本研究利用罕见的日食出现机会,对西藏阿里和拉萨日食过程中的太阳光谱、太阳总辐射和太阳紫外线变化特征进行了同步观测研究。观测表明阿里日环食在当地正午（北京时间14:41分）前后持续了约3小时27分钟;拉萨日食出现时间比阿里滞后约26 min,持续时间比阿里短3分28秒。实地观测表明在日食期间,阿里光谱观测中最强单色（476.6 nm）光峰值从初亏（13:01分）时刻的1 669.234 mW·m-2·nm-1陡然衰减到食甚（14:44分）时刻的61.936 mW·m-2·nm-1,损失约96.0%;相应时刻太阳总辐射强度从1 221.217 W·m-2衰减到56.086 W·m-2,也损失约95.4%。拉萨日食期间最强单色（476.6 nm）光峰值从初亏（13:27分）时刻的1 563.876 mW·m-2·nm-1亏损到食甚（15:13分）时刻的26.391 mW·m-2·nm-1,亏损约98.3%;相应时刻太阳总辐射强度从1 605.663 W·m-2衰减到28.169 W·m-2,也亏损约98.2%。观测研究发现拉萨太阳紫外线B剂量率从初亏的60.8 W·m-2减弱到食甚的0.9 W·m-2值,减弱了98.5%。该次日食对西藏地面各种太阳辐射强度造成95%以上能量损失。     

Comparison of indigenously developed micro pulse polarization lidar with EZ lidar profiles

A Micro Pulse Polarization LIDAR (MPPL) has been designed and developed for aerosol and cloud studies at National Physical Laboratory, New Delhi, India (28° 35′ N, 77° 12′E) using a low-energy pico-second pulsed Nd:YAG laser at 532 nm and single PMT detector. This has been used for detecting depolarization characteristics with back-scatter coefficient of atmospheric aerosols and clouds. The back-scattered signals are detected at the emitted wavelength with co-polarization and cross-polarization discrimination with a mirror on stepper motor for aerosols and cloud. Data are obtained by MPPL and are inter-compared with a well-established commercial Leosphere made EZ LIDAR, industry standard at the same site and time, and the results are found to be in good agreement. In the present communication the back-scattered coefficient, aerosols optical depth, depolarization ratio etc. obtained using MPPL & EZ LIDAR are discussed in detail.     

Piezoelectric properties of oriented Z′ cuts of PZT-type ferroelectric ceramics

The piezoelectric and dielectric properties of oriented β°Z′ cuts (β=0, 15, 30, 45, 60°) of piezoelectric crystals of TsTS-83G (lead zirconate titanate) composite are studied. A static model is proposed for the case of a maximally polarized ceramic based on the conditions of complete and partial stability of the polar axes c with allowance for their nonuniform distribution for 180° and 90° domain reorientations. It is found that the TsTS-83G piezoelectric composite does not exhibit anisotropy in the piezoelectric coefficient d ₃₃ ^′ when the axis of the Z′ cut is rotated in the ZY plane relative to the XYZ coordinate system. Zh. Tekh. Fiz. 68, 75–79 (July 1998) Deceased.     

Laser optogalvanic spectroscopy of argon in the wavelength region 605–740 nm

Two-photon optogalvanic transitions in Ar glow discharge with Nd: YAG laser pumped dye laser excitation in the frequency range 13520–16520 cm⁻¹ has been studied using linear and circular polarization. The intensities of two-photon optogalvanic transitions are very sensitive to changes in the incident laser power which is not the case with one-photon transitions. Intensity ratio for circular and linear polarized light for two photon transitions 6s′[1/2]°1←4s[3/2]°2, 6s′[1/2]°0←4s[3/2]°2, and 5d[1/2]°0←4s[3/2]°2, 5d[1/2]°1←4s[3/2]°2 are quite different from the other two-photon transitions. This has been explained as due to near one photon resonance of 4p′[3/2]1 level for the first pair and 4p′[1/2]1 for the second pair of transitions. The ratio of optogalvanic intensity for circular to linear polarized light has been theoretically estimated and compared with the observed results.     

On production of η′ mesons in pp collisions close to threshold

The near threshold behaviour of the reaction cross section for pp→ppη^′, recently measured in experiments at COSY and SATURNE, is analyzed. The interaction in the pp as well as in the η^′ p final states is taken into account. The suppression of the total cross section for this process at excess energies Q < 3 MeV observed in these experiments is interpreted as an evidence for a strong repulsive η^′ p interaction. Received: 26 May 1999 / Revised version: 8 July 1999     

Effect of cloud on atmospheric ozone formation over Kolkata (22°34′N, 88°24′E), India

The paper presents the nature of variations of clouds and total ozone over Kolkata (22°34′N, 88°24′E), India. The low-level cloud over Kolkata has been noticed to occur for many days and nights, particularly in the months from June to September. The low level cloud occurrences were minimum in winter months. The effect of cloud occurrence on ozone concentration has been critically analyzed and explained. It has been observed that the concentration of ozone increased with the increase of cloud occurrence. The related possible chemical explanation for ozone production processes has been offered.     

Study of solar features causing GMSs with 250γ<<Emphasis Type="Italic">H</Emphasis><400γ

The effect of solar features on geospheric conditions leading to geomagnetic storms (GMSs) with planetary index,A ^P ≥ 20 and the range of horizontal component of the Earth’s magnetic fieldH such that 250γ <H < 400γ has been investigated using interplanetary magnetic field (IMF), solar wind plasma (SWP) and solar geophysical data (SGD) during the period 1978–99. Statistically, it is observed that maximum number of GMSs have occurred during the maximum solar activity years of 21st and 22nd solar cycles. A peculiar result has been observed during the years 1982, 1994 when sunspot numbers (SSNs) decrease very rapidly while numbers of GMSs increase. No distinct association between yearly occurrence of disturbed days and SSNs is observed. Maximum number of disturbed days have occurred during spring and rainy seasons showing a seasonal variation of disturbed days. No significant correlation between magnitude (intensity) of GMSs and importance ofH _α , X-ray solar flares has been observed. Maximum number of GMSs is associated with solar flares of lower importance, i.e., SF during the period 1978-93.H _α , X-ray solar flares occurred within lower helio-latitudes, i.e., (0–30)°N to (0–30)°S are associated with GMSs. NoH _α , X-ray solar flares have occurred beyond 40°N or 40°S in association with GMSs. In helio-latitude range (10–40)°N to (10–40)°S, the 89.5% concentration of active prominences and disappearing filaments (APDFs) are associated with GMSs. Maximum number of GMSs are associated with solar flares. Coronal mass ejections (CMEs) are related with eruptive prominences, solar flares, type IV radio burst and they occur at low helio-latitude. It is observed that CMEs related GMS events are not always associated with high speed solar wind streams (HSSWSs). In many individual events, the travel time between the explosion on the Sun and maximum activity lies between 58 and 118 h causing GMSs at the Earth.     

Charge-separated-state enhancement of the third-order optical nonlinearity of a photosensitizer-electron acceptor triad assembly

′ ,4^′′,4^′′′-tetrasulfonato-phthalocyanine/N-butyl-N^′-methylanthraquinone-4,4^′-bipyridinum dibromide assembly (ZnTsPc-V-AQ), was observed to be enhanced by ten times when the sample was optically pumped by a 355 nm pump beam. The enhancement of the nonlinearity was found to be due predominantly to the charge transfer between the two monomers of the supramolecule after optical excitation. Received: 2 July 1996     

IR study of the pressure-induced amorphization and recrystallization of europium molybdate

Drastic changes of the IR spectra of optical phonons in europium molybdate single crystal were observed after its hydrostatic compression: instead of a series of narrow lines, wide bands were observed and a new band appeared, which can be attributed to the formation of the high pressure phase. Stepped annealing at temperatures from 100 to 550°C transformed the europium molybdate subjected to pressure to the initial β′ phase, the high-pressure phase disappeared, and bands corresponding to the α phase appeared.     

Atomosphere boundary layer height determination and observation from ceilometer measurements over Hefei during the total solar on July 22,2009 eclipse

<正>Using an improved inflexion point method(IIPM),we investigate atmosphere boundary layer(ABL) height evolution over Hefei during the total solar eclipse on July 22,2009.A lidar ceilometer is used in ground-based observations.Estimations of ABL heights before,during,and after the solar eclipse are analyzed using the IIPM.Results indicate that the IIPM,which is less sensitive to background noise,is more suitable in detecting ABL height and temporal evolution.Data demonstrate that the total solar eclipse resultes in a decrease in ABL height,indicating a suppression of turbulence activity,similar to that observed during the sunset hours.Changes in ABL height are associated with a slow change in temperature,indicating a significant weakening of penetrative convection and a time lag between ABL response and the reduction in solar radiation.     

Tuning of the emission color of organic electroluminescent devices by exciplex formation at the organic solid interface

′ ,4^′′-tris(3-methylphenylphenylamino)triphenylamine, 1,3,5-tris[(4-diphenylaminophenyl)phenylamino]benzene, N, N^′-bis(3-methylphenyl)-N, N^′-diphenyl-[1,1^′-biphenyl]-4,4^′-diamine, and 4,4^′,4^′′-tri(N-carbazolyl)triphenylamine, emitted bright light resulting from the exciplex formed at the solid interface between TPOB and the hole-transporting material. The exciplex formation was evidenced by the measurements of the photoluminescence spectra and lifetimes of the mixture of an equimolar amount of TPOB and each of the hole-transporting materials. Tuning of the emission color from greenish blue to orange was attained by varying the ionization potential of the hole-transporting material for the fixed electron-transporting material of TPOB. Received: 27 July 1998/Accepted: 28 July 1998