Far-infrared surveys of the sky

A series of far-infrared surveys of the sky is searching for thermal radiation from interstellar grains and for other localized sources of far-infrared radiation. A balloon-borne germanium bolometer, cooled by liquid helium, is used in association with a telescope and spectral filters. During two initial flights the response to a black-body source was mainly between 300 and 360 microns. Approximately half the celestial sphere was surveyed, including most of the northern Milky Way. The angular resolution was 2 degrees. Moon was the only source of thermal radiation detected. The upper limit on the differential flux, relative to background, from other sources was 2 x 10(-23) watt per square centimeter per hertz, corresponding to an antenna temperature of 0.6 degrees K in the Rayleigh-Jeans approximation, or 10 degrees K for a black body.     

Jovian Atmosphere: Structure and Composition between the Turbopause and the Mesopause

The occultation of the star Beta Scorpii by Jupiter was observed at high time resolution in three wavelength channels. The results imply a temperature of 220 degrees K at an altitude in the Jovian atmosphere corresponding to 10(14) molecules per cubic centimeter, and temperature fluctuations of 2 degrees to 10 degrees K over vertical scales of 2 to 10 kilometers. They suggest that the vertical eddy diffusion coefficient near the turbopause has a lower limit of 7 x 10(5)K square centimeters per second, and that the turbopause lies above the altitude where the density is 5 x 10(13) molecules per cubic centimeter. Below the turbopause, the ratio of hydrogen to helium is consistent with cosmic abundances.     

Low-energy charged particle environment at jupiter: a first look

The low-energy charged particle instrument on Voyager was designed to measure the hot plasma (electron and ion energies greater, similar 15 and greater, similar 30 kiloelectron volts, respectively) component of the Jovian magnetosphere. Protons, heavier ions, and electrons at these energies were detected nearly a third of an astronomical unit before encounter with the planet. The hot plasma near the magnetosphere boundary is predominantly composed of protons, oxygen, and sulfur in comparable proportions and a nonthermal power-law tail; its temperature is about 3 x 10(8) K, density about 5 x 10(-3) per cubic centimeter, and energy density comparable to that of the magnetic field. The plasma appears to be corotating throughout the magnetosphere; no hot plasma outflow, as suggested by planetary wind theories, is observed. The main constituents of the energetic particle population ( greater, similar200 kiloelectron volts per nucleon) are protons, helium, oxygen, sulfur, and some sodium observed throughout the outer magnetosphere; it is probable that the sulfur, sodium, and possibly oxygen originate at 1o. Fluxes in the outbound trajectory appear to be enhancedfrom approximately 90 degrees to approximately 130 degrees longitude (System III). Consistent low-energy particle flux periodicities were not observed on the inbound trajectory; both 5-and 10-hour periodicities were observed on the outbound trajectory. Partial absorption of > 10 million electron volts electrons is observed in the vicinity of the Io flux tube.     

X-ray Structure of the Cygnus Loop

X-ray emission from the Cygnus Loop was observed in the energy region around 0.2 to 1 kiloelectronvolt with a collector that focused x-rays along one dimension while scanning across the nebula. The total integrated intensity is 1.3x 10(-8) erg per square centimeter per second. The one-dimensional x-ray structure has the same angular size-about 3 degrees-as the outermost boundaries of the optical filaments. There is no increase in x-ray emission at the center of the nebula nor at the strong feature that is seen in certain radio maps. The x-ray spectrum is consistent with thermal radiation from a hot plasma at a temperature of about 4 x 10(6) degrees K with evidence for a line at 19 angstroms corresponding to the 2p-->1s transition of O VIII.     

微波快速合成钙锰矿的影响因素

以通O2氧化Mn(OH)2制备的水钠锰矿为前驱物,采用微波加热合成钙锰矿,并探讨微波的功率、反应温度、时间和pH值等条件对钙锰矿形成的影响。结果表明:一定微波条件下可快速合成粒径均一、结晶度较好的钙锰矿。当微波辐照功率大于150 W时,随着微波功率升高,合成钙锰矿所需时间缩短,600 W功率下20min即可快速得到钙锰矿;温度越高合成钙锰矿所需时间也越短,体系温度为100℃时不能生成钙锰矿,但升高到140℃时,20min即可合成出钙锰矿;在酸性条件下合成钙锰矿的转化率低,而中性和碱性条件下钙锰矿的形成速度快、转化率高、结晶度好。     

Solar cycle variation of exospheric temperatures Mars and venus: a prediction for mariner 6 and 7

Calculations have been made to determine the effects of variations in the extreme ultraviolet solar radiation on the upper atmospheres of mars and Venus. The results indicate that the exospheric temperature from 300 degrees K to 600 degrees K during the solar cycle, with a corresponding range on Venus of 450 degrees K to 850 degrees K. At the present time, the temperature of the Martain exosphere should be approximately 500 degrees K.     

Anisotropy of the cosmic blackbody radiation

The universe is filled with thermal radiation having a current temperature of 2.75 K. Originating in the very early universe, this radiation furnishes strong evidence that the Big Bang cosmology best describes our expanding universe from an incredibly hot, compacted early stage until now. The model can be used to extrapolate our physics backward in time to predict events whose effects might be observable in the 2.75 K radiation today. The spectrum and isotropy are being studied with sophisticated microwave radiometers on the ground, in balloons, and in satellites. The results are as predicted by the simple theory: the spectrum is that of a blackbody (to a few percent) and the radiation is isotropic (to 0.01 percent) except for a local effect due to our motion through the radiation. However, a problem is emerging. Primordial fluctuations in the mass density, which later became the great clusters of galaxies that we see today, should have left an imprint on the 2.75 K radiation-bumpiness on the sky at angular scales of about 10 arc minutes. They have not yet been seen.     

Galaxies and the Universe: Properties of the universe are revealed by the rotation of galaxies and their distribution in space

A brief review is given of what the study of galaxies has taught us about properties of the universe. It is assumed that the universe started from a general "explosion," and that the general expansion observed today, as well as the 3 degrees K blackbody radiation, are consequences of this explosion. The present average density in the universe is probably close to the critical value of 10(-29) g/cm(3). Only about 3 percent of this is contained in galaxies; the rest consists probably of intergalactic gas at a temperature between 10(5) and 10(6) degrees K. Observations in our own galaxy indicate that this intergalactic gas is still flowing into it.     

Electrical activity during the 2006 Mount St. Augustine volcanic eruptions

By using a combination of radio frequency time-of-arrival and interferometer measurements, we observed a sequence of lightning and electrical activity during one of Mount St. Augustine's eruptions. The observations indicate that the electrical activity had two modes or phases. First, there was an explosive phase in which the ejecta from the explosion appeared to be highly charged upon exiting the volcano, resulting in numerous apparently disorganized discharges and some simple lightning. The net charge exiting the volcano appears to have been positive. The second phase, which followed the most energetic explosion, produced conventional-type discharges that occurred within plume. Although the plume cloud was undoubtedly charged as a result of the explosion itself, the fact that the lightning onset was delayed and continued after and well downwind of the eruption indicates that in situ charging of some kind was occurring, presumably similar in some respects to that which occurs in normal thunderstorms.     

A 0.5-million-year record of millennial-scale climate variability in the north atlantic

Long, continuous, marine sediment records from the subpolar North Atlantic document the glacial modulation of regional climate instability throughout the past 0.5 million years. Whenever ice sheet size surpasses a critical threshold indicated by the benthic oxygen isotope (delta18O) value of 3.5 per mil during each of the past five glaciation cycles, indicators of iceberg discharge and sea-surface temperature display dramatically larger amplitudes of millennial-scale variability than when ice sheets are small. Sea-surface temperature oscillations of 1 degrees to 2 degreesC increase in size to approximately 4 degrees to 6 degreesC, and catastrophic iceberg discharges begin alternating repeatedly with brief quiescent intervals. The glacial growth associated with this amplification threshold represents a relatively small departure from the modern ice sheet configuration and sea level. Instability characterizes nearly all observed climate states, with the exception of a limited range of baseline conditions that includes the current Holocene interglacial.     

微波辐射对水稻生长发育的影响

对3个水稻纯系种子进行6个不同微波辐射时间处理,观察微波辐射对水稻生长发育状况的影响和生物效应.结果表明,水稻种子的发芽率随辐射处理时间的增加而明显降低,而分蘖数则有所增加;微波辐射处理使供试材料的播始历期比对照减少2～7d.大部分的微波辐射处理均不利于协调桂R225、明恢63的产量构成因素,降低了两个品种的单株产量;单次微波辐射70s 以及每次微波辐射50s、重复3次共150s的处理有利于协调特B每穗总粒数、结实率和千粒重的发展,因而提高了其单株产量.因此,不同微波辐射处理对不同水稻纯系的生长发育的生物效应是不同的,试验结果可为水稻辐射诱变育种提供依据.     

A search for intergalactic hydrogen in the virgo cluster

A fixed-horn antenna having a beam 10 degrees by 10 degrees , and a switched-load radiometer with traveling-wave-maser preamplifier were used to observe the 21-cm spectrum of the Virgo cluster of galaxies. An upper limit to the antenna temperature is 0.024 degrees K relative to regions outside the cluster with filters whose width is 2 Mc/sec. If the excitation temperature of the intergalactic hydrogen is enough greater than the background continuum radiation so that absorption can be ignored, and if the velocity spectrum is that defined by the galaxies, the density of optically thin neutral hydrogen in the cluster does not exceed that outside of the cluster by an amount that gives 5.6 x 10(12) solar masses in the cluster.     

基于伪逆学习算法的地基微波辐射计反演算法研究

利用兰州大学半干旱气候与环境观测站(SACOL站)2009-2010年的地基微波辐射计亮温资料和榆中站探空资料,基于伪逆学习算法建立了应用于地基微波辐射计温度、相对湿度和水汽密度反演的神经网络(PIFN),并将反演结果与地基微波辐射计自带反演产品进行了对比,研究了伪逆学习算法在地基微波辐射计气象要素反演算法本地化的应用效果.结果表明:PIFN反演的温度、相对湿度和水汽密度的均方根误差的最大值分别为6.41K,31.21%和1.5g/m3,地基微波辐射计温度、相对湿度和水汽密度产品的均方根误差最大值分别为11.93K,53.18%和3.06g/m3,与微波辐射计自带神经网络反演结果在不同高度层进行比较可以看出PIFN对2～10km、1～7km和0～3km的大气温度、相对湿度和水汽密度廓线的反演均有明显改善,伪逆学习算法能够应用于地基微波辐射计气象要素的反演算法的本地化.     

Mercury: the dark-side temperature

The planet Mercury was observed before, during, and after the inferior conjunctions of 29 September 1969 and 9 May 1970 at wavelengths of 3.75, 4.75, 8.6, and 12 microns. The average dark-side temperature is 111 degrees +/- 3 degrees K. The thermal inertia of the surface required to fit this temperature is close to that for the moon and indicates that Mercury and the moon have very similar top surface layers.     

Mariner 9 s-band martian occultation experiment: initial results on the atmosphere and topography of Mars

A preliminary analysis of 15 radio occultation measurements taken on the day side of Mars between 40 degrees S and 33 degrees S has revealed that the temperature in the lower 15 to 20 kilometers of the atmosphere of Mars is essentially isothermal and warmer than expected. This result, which is also confirmed by the increased altitude of the ionization peak of the ionosphere, can possibly be caused by the absorption of solar radiation by fine particles of dust suspended in the lower atmosphere. The measurements also revealed elevation differences of 13 kilometers and a range of surface pressures between 2.9 and 8.3 millibars. The floor of the classical bright area of Hellas was found to be about 6 kilometers below its western rim and 4 kilometers below the mean radius of Mars at that latitude. The region between Mare Sirenum and Solis Lacus was found to be relatively high, lying 5 to 8 kilometers above the mean radius. The maximum electron density in the ionosphere (about 1.5 x 10(5) electrons per cubic centimeter), which was found to be remarkably constant, was somewhat lower than that observed in 1969 but higher than that observed in 1965.     

Radio science investigations of the saturn system with voyager 1: preliminary results

Voyager 1 radio occultation measurements of Titan's equatorial atmosphere successfully probed to the surface, which is provisionally placed at a radius of 2570 kilometers. Derived scale heights plus other experimental and theoretical results indicate that molecular nitrogen is the predominant atmospheric constituent. The surface pressure and temperature appear to be about 1.6 bars and 93 K, respectively. The main clouds are probably methane ice, although some condensation of nitrogen cannot be ruled out. Solar abundance arguments suggest and the measurements allow large quantities of surface methane near its triple-point temperature, so that the three phases of methane could play roles in the atmosphere and on the surface of Titan similar to those of water on Earth. Radio occultation measurements of Saturn's atmosphere near 75 degrees south latitude reached a maximum pressure of 1.4 bars, where the temperature is about 156 K. The minimum temperature is about 91 K near the 60-millibar pressure level. The measured part of the polar ionosphere of Saturn has a peak electron concentration of 2.3 x 10(4) per cubic centimeter at an altitude of 2500 kilometers above the 1-bar level in the atmosphere, and a plasma scale height at the top of the ionosphere of 560 kilometers. Attenuation of monochromatic radiation at a wavelength of 3.6 centimeters propagating obliquely through Saturn's rings is consistent with traditional values for the normal optical depth of the rings, but the near-forward scattering of this radiation by the rings indicates effective scattering particles with larger than expected diameters of 10, 8, and 2 meters in the A ring, the outer Cassini division, and the C ring, respectively. Preliminary analysis of the radio tracking data yields new values for the masses of Rhea and Titan of 4.4 +/- 0.3 x 10(-6) and 236.64 +/- 0.08 x 10(-6) times the mass of Saturn. Corresponding values for the mean densities of these objects are 1.33 +/- 0.10 and about 1.89 grams per cubic centimeter. The density of Rhea is consistent with a solar-composition mix of anhydrous rock and volatiles, while Titan is apparently enriched in silicates relative to the solar composition.     

Radio rotation period of jupiter

The results of observations of Jupiter at 18 megacycles per second indicate that the apparent rotation period drifts cyclically about a constant mean value. The most probable drift period appears to be 11.9 years, Jupiter's orbital period. The mean rotation period during one orbital period is about 0.3 second longer than that of the system III (1957.0) period. This is in close agreement with the rotation period deduced from decimetric observations and probably represents the true rotation period of the magnetic field. The cyclic drift in the rotation period of source A at 18 megacycles per second is explained on the basis of beaming of the escaping radiation at an angle 6 degrees north of the magnetic equator. The apparent rotation period of source A depends on the rate of change of the Jovicentric declination of Earth.     

Empirical models of the electron temperature and density in the nightside venus ionosphere

Empirical models of the electron temperature and electron density of the late afternoon and nightside Venus ionosphere have been derived from Pioneer Venus measurements acquired between 10 December 1978 and 23 March 1979. The models describe the average ionosphere conditions near 18 degrees N latitude between 150 and 700 kilometers altitude for solar zenith angles of 80 degrees to 180 degrees . The average index of solar flux was 200. A major feature of the density model is the factor of 10 decrease beyond 90 degrees followed by a very gradual decrease between 120 degrees and 180 degrees . The density at 150 degrees is about five times greater than observed by Venera 9 and 10 at solar minimum (solar flux approximately 80), a difference that is probably related to the effects of increased solar activity on the processes that maintain the nightside ionosphere. The nightside electron density profile from the model (above 150 kilometers) can be reproduced theoretically either by transport of 0(+) ions from the dayside or by precipitation of low-energy electrons. The ion transport process would require a horizontal flow velocity of about 300 meters per second, a value that is consistent with other Pioneer Venus observations. Although currently available energetic electron data do not yet permit the role of precipitation to be evaluated quantitatively, this process is clearly involved to some extent in the formation of the nightside ionosphere. Perhaps the most surprising feature of the temperature model is that the electron temperature remains high throughout the nightside ionosphere. These high nocturnal temperatures and the existence of a well-defined nightside ionopause suggest that energetic processes occur across the top of the entire nightside ionosphere, maintaining elevated temperatures. A heat flux of 2 x 10(10) electron volts per square centimeter per second, introduced at the ionopause, is consistent with the average electron temperature profile on the nightside at a solar zenith angle of 140 degrees .     

Survival of mouse embryos frozen to -196 degrees and -269 degrees C

Mouse embryos survived freezing to -196 degrees C. Survival required slow cooling (0.3 degrees to 2 degrees C per minute) and slow warming (4 degrees to 25 degrees C per minute). Depending on the specific rates used, 50 to 70 percent of more than 2500 frozen and thawed early embryos developed into blastocysts in culture after storage at -196 degrees C for up to 8 days. When approximately 1000 of the survivors, including some frozen to -269 degrees C (4 degrees K), were transferred into foster mothers, 65 percent of the recipients became pregnant. More than 40 percent of the embryos in these pregnant mice gave rise to normal, living full-term fetuses or newborn mice.     

A high-efficiency power cycle in which hydrogen is compressed by absorption in metal hydrides

A high-efficiency power cycle is proposed in which molecular hydrogen gas is used as a working fluid in a regenerative closed Brayton cycle. The hydrogen gas is compressed by an absorption-desorption cycle on metal hydride (FeTiH(x)) beds. Low-temperature solar or geothermal heat (temperature about 100 degrees C) is used for the compression process, and high-temperature fossil fuel or nuclear heat (temperature about 700 degrees C) supplies the expansion work in the turbine. Typically, about 90 percent of the high-temperature heat input is converted to electricity, while about 3 kilowatts of low-temperature heat is required per kilowatt of electrical output.