Voyager 1 in the foreshock, termination shock, and heliosheath

Voyager 1 (V1) began measuring precursor energetic ions and electrons from the heliospheric termination shock (TS) in July 2002. During the ensuing 2.5 years, average particle intensities rose as V1 penetrated deeper into the energetic particle foreshock of the TS. Throughout 2004, V1 observed even larger, fluctuating intensities of ions from 40 kiloelectron volts (keV) to >/=50 megaelectron volts per nucleon and of electrons from >26 keV to >/=350 keV. On day 350 of 2004 (2004/350), V1 observed an intensity spike of ions and electrons that was followed by a sustained factor of 10 increase at the lowest energies and lesser increases at higher energies, larger than any intensities since V1 was at 15 astronomical units in 1982. The estimated solar wind radial flow speed was positive (outward) at approximately +100 kilometers per second (km s(-1)) from 2004/352 until 2005/018, when the radial flows became predominantly negative (sunward) and fluctuated between approximately -50 and 0 km s(-1) until about 2005/110; they then became more positive, with recent values (2005/179) of approximately +50 km s(-1). The energetic proton spectrum averaged over the postshock period is apparently dominated by strongly heated interstellar pickup ions. We interpret these observations as evidence that V1 was crossed by the TS on 2004/351 (during a tracking gap) at 94.0 astronomical units, evidently as the shock was moving radially inward in response to decreasing solar wind ram pressure, and that V1 has remained in the heliosheath until at least mid-2005.     

Voyager 1 explores the termination shock region and the heliosheath beyond

Voyager 1 crossed the termination shock of the supersonic flow of the solar wind on 16 December 2004 at a distance of 94.01 astronomical units from the Sun, becoming the first spacecraft to begin exploring the heliosheath, the outermost layer of the heliosphere. The shock is a steady source of low-energy protons with an energy spectrum approximately E(-1.41 +/- 0.15) from 0.5 to approximately 3.5 megaelectron volts, consistent with a weak termination shock having a solar wind velocity jump ratio r=2.6(-0.2)(+0.4). However, in contradiction to many predictions, the intensity of anomalous cosmic ray (ACR) helium did not peak at the shock, indicating that the ACR source is not in the shock region local to Voyager 1. The intensities of approximately 10-megaelectron volt electrons, ACRs, and galactic cosmic rays have steadily increased since late 2004 as the effects of solar modulation have decreased.     

Electron plasma oscillations upstream of the solar wind termination shock

Electron plasma oscillations have been detected upstream of the solar wind termination shock by the plasma wave instrument on the Voyager 1 spacecraft. These waves were first observed on 11 February 2004, at a heliocentric radial distance of 91.0 astronomical units, and continued sporadically with a gradually increasing occurrence rate for nearly a year. The last event occurred on 15 December 2004, at 94.1 astronomical units, just before the spacecraft crossed the termination shock. Since then, no further electron plasma oscillations have been observed, consistent with the spacecraft having crossed the termination shock into the heliosheath.     

Magnetic fields at uranus

The magnetic field experiment on the Voyager 2 spacecraft revealed a strong planetary magnetic field of Uranus and an associated magnetosphere and fully developed bipolar masnetic tail. The detached bow shock wave in the solar wind supersonic flow was observed upstream at 23.7 Uranus radii (1 R(U) = 25,600 km) and the magnetopause boundary at 18.0 R(U), near the planet-sun line. A miaximum magnetic field of 413 nanotesla was observed at 4.19 R(U ), just before closest approach. Initial analyses reveal that the planetary magnetic field is well represented by that of a dipole offset from the center of the planet by 0.3 R(U). The angle between Uranus' angular momentum vector and the dipole moment vector has the surprisingly large value of 60 degrees. Thus, in an astrophysical context, the field of Uranus may be described as that of an oblique rotator. The dipole moment of 0.23 gauss R(3)(U), combined with the large spatial offset, leads to minimum and maximum magnetic fields on the surface of the planet of approximately 0.1 and 1.1 gauss, respectively. The rotation period of the magnetic field and hence that of the interior of the planet is estimated to be 17.29+/- 0.10 hours; the magnetotail rotates about the planet-sun line with the same period. Thelarge offset and tilt lead to auroral zones far from the planetary rotation axis poles. The rings and the moons are embedded deep within the magnetosphere, and, because of the large dipole tilt, they will have a profound and diurnally varying influence as absorbers of the trapped radiation belt particles.     

Initial pioneer venus magnetic field results: dayside observations

Initial observations by the Pioneer Venus mangnetometer in the sunlit ionosphere reveal a dynamic ionosphere, very responsive to external solar-wind conditions. The localtions of the bow shock and ionosphere are variable. The strength of the magnetic field just olutside the ionopause is in approximate pressure balance with the thermal plasma of the ionosphere and changes markedly from day, to day in response to changes in solar wind pressure. The field strength in the ionosphere is also variable from day to day. The field is often weak, at most a few gammas, but reaching many tens of gammas for periods of the order of seconds. These field enchantments are interpreted as due to the passage of spacecraft through flux ropes consisting of bundles of twisted field lines surrounded by the ionospheric plasma. The helicity of the flux varies through the flux tube, with lows pitch angles on the inside and very lage angles in the low-field outer edges of the ropes. These ropes may have external or internal sources. Consistent with previous results, the average position of the bow shock is much closer to the planet than would be expected if the solar wnd were completely deflected by the planet. In total, these observations indicate that the solar wind plays a significant role in the physics of the Venus ionosphere.     

杀虫剂对不同蔬菜上小菜蛾毒力及种群动态的影响

通过毒力测定和田间调查,测定了甘蓝、小白菜上的小菜蛾幼虫对敌敌畏、高效氯氰菊酯、阿维菌素的药剂敏感性,以及阿维菌素作用下的不同蔬菜品种上的小菜蛾幼虫的种群动态。结果表明,不同年份、不同蔬菜品种上的小菜蛾对不同杀虫剂的药剂敏感性存在差异。2003年敌敌畏对甘蓝上小菜蛾LC50与2004年的之间没有差异,但2005年的LC50明显高于2003年,但在各调查的年份,小白菜上的小菜蛾对敌敌畏的药剂敏感性没有差异,从蔬菜品种来看,只有在2005年,敌敌畏对甘蓝上小菜蛾的LC50大于小白菜;在各个调查年份,高效氯氰菊酯对甘蓝上小菜蛾的药剂敏感性没有差异,只有2005年高效氯氰菊酯对小白菜上小菜蛾的LC50明显高于2003年,高效氯氰菊酯对甘蓝上小菜蛾的LC50与小白菜上的没有差异;2003年阿维菌素对甘蓝和小白菜上的小菜蛾LC50与2004年之间没有差异,但2005年的LC50明显高于2003年;在调查的各个年份,阿维菌素对甘蓝上小菜蛾的LC50与小白菜上的没有差异。施用阿维菌素对小菜蛾田间种群有明显抑制作用。施用1次阿维菌素的菜田中,虫量回升缓慢,最高值虫量仅约为对照菜田最高峰时的一半;施用阿维菌素2次的菜田中,虫量相对较低,仅在第2次药前有一个小高峰;在甘蓝和小白菜菜田中,小菜蛾幼虫种群数量动态基本一致,但甘蓝菜田的小菜蛾数量明显高于小白菜菜田。     

Electron temperatures and densities in the venus ionosphere: pioneer venus orbiter electron temperature probe results

Altitude profiles of electron temperature and density in the ionosphere of Venus have been obtained by the Pioneer Venus orbiter electron temperatutre probe. Elevated temperatutres observed at times of low solar wind flux exhibit height profiles that are consistent with a model in which less than 5 percent of the solar wind energy is deposited at the ionopause and is conducted downward through an unmagnetized ionosphere to the region below 200 kilomneters where electron cooling to the neutral atmosphere proceeds rapidly. When solar wind fluxes are higher, the electron temperatures and densities are highly structured and the ionopause moves to lower altitudes. The ionopause height in the late afternoon sector observed thus far varies so widely from day to (day that any height variation with solar zenith angle is not apparent in the observations. In the neighborhood of the ionopause, measuremnents of plasma temperatures and densities and magnetic field strength indicate that an induced magnetic barrier plays an important role in the pressure transfer between the solar wind and the ionosphere. The bow, shock is marked by a distinct increase in electron current collected by the instrument, a featutre that provides a convenient identification of the bow shock location.     

10%苯丁锡EC防治柑桔红蜘蛛效果研究

2004—2005年在湖南安乡、醴陵进行了10％苯丁锡EC防治柑桔红蜘蛛的田间药效试验。结果表明,在红蜘蛛发生期用10％苯丁锡EC200—250mg／kg喷雾,药后1d的校正防效均在70．7％以下;药后3d的校正防效为87．2％-92．4％,药后7d的校正防效均在92．7％以上,药后15d的校正防效为95．3％-98．8％,药后30d的校正防效为82．0％-93．9％,优于或相当于对照药剂15％哒螨灵EC用75mg／kg处理的效果。     

渤海天津近海海域重金属年际变化分析

根据2001-2005年天津近岸海域水质监测数据,对重金属含量随时间尺度发生的变化进行了分析,结果表明:2004年重金属Cu的含量最高.检测的5 a中,2004年的重金属Zn,Pb污染最为严重,到2005年时污染得到了有效控制;在这5 a中,Pb含量的波动很大,受到严重的人为干扰.2001-2005年Ⅰ类海水Cd的含量最大,污染最为严重并且变化不显著,需要加强治理;重金属Hg在Ⅰ类海区的污染状况与Cd类似.     

膜上灌对春小麦产量及产量构成因素的效应分析

从2004年到2005年在甘肃省张掖市甘州区二十里堡乡七号村进行了膜上灌春小麦调亏效应研究.结果表明,在膜上灌水的方式下覆膜处理的耗水量为460.1 mm,比对照减少了310.3 mm,但比对照增产1 363.69 kg/hm2,增收1 817.1元/hm2,水分利用效率提高了6.0 kg/(mm.hm2);在同一水分条件下,覆膜处理比露地处理增产54.22%,增收3 400.6元/hm2,水分利用效率提高了4.67 kg/(mm.hm2).覆膜处理具有明显的节水增产效应,开花后干物质积累量,茎、叶、穗等器官营养物质的分配、转换均高于露地处理,且产量达最高.     

An x-ray nebula associated with the millisecond pulsar B1957+20

We have detected an x-ray nebula around the binary millisecond pulsar B1957+20. A narrow tail, corresponding to the shocked pulsar wind, is seen interior to the known Halpha bow shock and proves the long-held assumption that the rotational energy of millisecond pulsars is dissipated through relativistic winds. Unresolved x-ray emission likely represents the shock where the winds of the pulsar and its companion collide. This emission indicates that the efficiency with which relativistic particles are accelerated in the postshock flow is similar to that for young pulsars, despite the shock proximity and much weaker surface magnetic field of this millisecond pulsar.     

Plasma observations at venus with galileo

Plasma measurements were obtained with the Galileo spacecraft during an approximately 3.5-hour interval in the vicinity of Venus on 10 February 1990. Several crossings of the bow shock in the local dawn sector were recorded before the spacecraft passed into the solar wind upstream from this planet. Although observations of ions of the solar wind and the postshock magnetosheath plasmas were not possible owing to the presence of a sunshade for thermal protection of the instrument, solar wind densities and bulk speeds were determined from the electron velocity distributions. A magnetic field-aligned distribution of hotter electrons or ;;strahl' was also found in the solar wind. Ions streaming into the solar wind from the bow shock were detected. Electron heating at the bow shock, 相似文献   

白僵菌和绿僵菌不同菌株对橙斑白条天牛幼虫的致病力

橙斑白条天牛是福建省杨树的一种新害虫,应用不同球孢白僵菌(Beauveria bassiana)和金龟子绿僵菌(Metarhizium anisopliae)菌株对橙斑白条天牛幼虫进行致病力测定,旨在筛选出感染该虫的高致病力菌株,为生物防治提供新的资源。结果表明,接种后,该天牛幼虫的累积死亡率随时间的延长而逐渐增高,接种绿僵菌Ma1291-2和Ma1775菌株14 d后,幼虫的校正死亡率分别为91.69%和86.50%;接种白僵菌BbDp-06菌株14 d后,幼虫校正死亡率达71.05%。绿僵菌Ma1291-2和Ma1775菌株对该幼虫的LT50分别为5.73和5.39 d,白僵菌BbDp-06菌株的LT50为8.02 d。Ma1291-2菌株对该幼虫的LC50为3.82×104孢子.mL-1,白僵菌BbDp-06菌株的LC50为3.88×104孢子.mL-1。说明绿僵菌对该幼虫的致病力较强,尤其是Ma1291-2和Ma1775菌株,在橙斑白条天牛的生物防治中将有较好的应用价值。     

Magnetic field studies by voyager 1: preliminary results at saturn

Magnetic field studies by Voyager 1 have confirmed and refined certain general features of the Saturnian magnetosphere and planetary magnetic field established by Pioneer 11 in 1979. The main field of Saturn is well represented by a dipole of moment 0.21 +/- 0.005 gauss-R(s)(3) (where 1 Saturn radius, R(s), is 60,330 kilometers), tilted 0.7 degrees +/- 0.35 degrees from the rotation axis and located within 0.02 R(s) of the center of the planet. The radius of the magnetopause at the subsolar point was observed to be 23 R(s) on the average, rather than 17 R(s). Voyager 1 discovered a magnetic tail of Saturn with a diameter of approximately 80 R(s). This tail extends away from the Sun and is similar to type II comet tails and the terrestrial and Jovian magnetic tails. Data from the very close flyby at Titan (located within the Saturnian magnetosphere) at a local time of 1330, showed an absence of any substantial intrinsic satellite magnetic field. However, the results did indicate a very well developed, induced magnetosphere with a bipolar magnetic tail. The upper limit to any possible internal satellite magnetic moment is 5 x 10(21) gauss-cubic centimeter, equivalent to a 30-nanotesla equatorial surface field.     

Magnetic field studies by voyager 2: preliminary results at saturn

Further studies of the Saturnian magnetosphere and planetary magnetic field by Voyager 2 have substantiated the earlier results derived from Voyager 1 observations in 1980. The magnetic field is primarily that of a centered dipole (moment = 0.21 gauss-RS(3); where one Saturn radius, RS, is 60,330 kilometers) tilted approximately 0.8 degrees from the rotation axis. Near closest approach to Saturn, Voyager 2 traversed a kronographic longitude and latitude range that was complementary to that of Voyager 1. Somewhat surprisingly, no evidence was found in the data or the analysis for any large-scale magnetic anomaly in the northern hemisphere which could be associated with the periodic modulation of Saturnian kilometric radiation radio emissions. Voyager 2 crossed the magnetopause of a relatively compressed Saturnian magnetosphere at 18.5 RS while inbound near the noon meridian. Outbound, near the dawn meridian, the magnetosphere had expanded considerably and the magnetopause boundary was not observed until the spacecraft reached 48.4 to 50.9 RS and possibly beyond. Throughout the outbound magnetosphere passage, a period of 46 hours (4.5 Saturn rotations), the field was relatively steady and smooth showing no evidence for any azimuthal asymmetry or magnetic anomaly in the planetary field. We are thus left with a rather enigmatic situation to understand the basic source of Saturnian kilometric radiation modulation, other than the small dipole tilt.     

Infrared observations of the saturnian system from voyager 2

During the passage of Voyager 2 through the Saturn system, infrared spectral and radiometric data were obtained for Saturn, Titan, Enceladus, Tethys, Iapetus, and the rings. Combined Voyager 1 and Voyager 2 observations of temperatures in the upper troposphere of Saturn indicate a seasonal asymmetry between the northern and southern hemispheres, with superposed small-scale meridional gradients. Comparison of high spatial resolution data from the two hemispheres poleward of 60 degrees latitude suggests an approximate symmetry in the small-scale structure, consistent with the extension of a symmetric system of zonal jets into the polar regions. Longitudinal variations of 1 to 2 K are observed. Disk- averaged infrared spectra of Titan show little change over the 9-month interval between Voyager encounters. By combining Voyager 2 temperature measurements with ground-based geometric albedo determinations, phase integrals of 0.91 +/- 0.13 and 0.89 +/- 0.09 were derived for Tethys and Enceladus, respectively. The subsolar point temperature of dark material on Iapetus must exceed 110 K. Temperatures (and infrared optical depths) for the A and C rings and for the Cassini division are 69 +/- 1 K (0.40 +/- 0.05), 85 +/- 1 K (0.10 +/- 0.03), and 85 +/- 2 K (0.07 +/- 0.04), respectively.     

利用诱集寄主苘麻防治B型烟粉虱的研究

【目的】 利用烟粉虱对寄主植物苘麻的嗜好趋性,研究棉花和大豆田的苘麻诱杀B型烟粉虱的技术体系。【方法】设计了不同播种期、种植方式和配套施药方法来研究苘麻对烟粉虱的诱集防治效果。【结果】在棉花和大豆的整个生长期间，苘麻对烟粉虱均有极显著的诱集作用，但不同播期苘麻的诱集效果差别明显。在棉花和大豆生长早期，烟粉虱最先在早播的苘麻上发生，诱集效果达85.2%；中播和晚播苘麻对棉花和大豆生长中、后期的烟粉虱诱集效果显著，分别达到93.3%和95.4%。苘麻植株在田间分散程度和诱集效果呈正相关，单棵插花种植苘麻的诱集效果分别是片状种植和条带种植苘麻的7倍和3倍。配套施药试验结果表明，苘麻喷洒25%阿克泰水分散粒剂、5%锐劲特悬浮剂、25%扑虱灵可湿性粉剂、10%高渗高效氯氰菊酯乳油和25%高渗辛硫磷乳油7 d 后对烟粉虱成虫和幼虫的防治效果分别为21.76%～97.57%和27.02%～74.77%，以阿克泰和锐劲特防治效果最佳。【结论】基于播种期、种植方式和配套合理的药剂防治的苘麻诱集方法对生态调控棉田和大豆田中的烟粉虱发挥了积极的作用。     

Resonant tunneling in the quantum Hall regime: measurement of fractional charge

In experiments on resonant tunneling through a "quantum antidot" (a potential hill) in the quantum Hall (QH) regime, periodic conductance peaks were observed as a function of both magnetic field and back gate voltage. A combination of the two periods constitutes a measurement of the charge of the tunneling particles and implies that charge deficiency on the antidot is quantized in units of the charge of quasi-particles of the surrounding QH condensate. The experimentally determined value of the electron charge e is 1.57 x 10(-19) coulomb = (0.98 +/- 0.03) e for the states v = 1 and v = 2 of the integer QH effect, and the quasi-particle charge is 5.20 x 10(-20) coulomb = (0.325 +/- 0.01)e for the state v = (1/3) of the fractional QH effect.     

我国有机食品研究专题文献的特征分析

采用文献计量学的方法,对我国1994年～2009年有机食品文献总量、年代分布、期刊分布、合作度和合作率以及论文研究主题进行了研究,以揭示16年中有机食品研究领域的文献分布特征,分析我国有机食品研究的现状和特点。研究结果表明：（1）有机食品的研究高峰期在2001年～2004年,2005年以后回落,进入了相对稳定期;（2）发表有机食品专题文献的期刊比较分散,尚未形成本领域的核心期刊群;（3）有机食品研究的课题以中小课题居多;（4）有机食品研究大致可分为有机食品生产技术、指标研究论文;宏观政策、战略及综述;法律、法规以及国家和国际标准;基本概念介绍;市场及经济;新闻消息报道6大主题,但缺乏理论性的研究。     

梨树液体授粉稳定剂与营养剂的综合效应

为了提高山西省梨树产区的坐果率及果实品质,试验以液体授粉为途径,通过授粉营养剂与稳定剂的筛选与配合,形成了提高梨树坐果的技术配方.结果表明:(1)以稀土为介质的液体授粉的稳定剂不同程度地提高了坐果率,其中处理A2显著高于处理A3,处理A3又明显高于处理A1、人工点授粉和常规液体授粉处理.(2)以氨基酸为主要成分的液体授粉营养剂也提高了坐果率,其中处理B1、B2显著高于常规液体授粉和点授粉,其坐果率提高了22%～25%.(3)综合处理A2B2的坐果效应最为明显,花后10d的坐果率达到61.8%～70.6%,同时,处理A3B1、A2B1、A3B1的坐果率也达到50%左右,显著高于常规液体授粉对照.(4)综合液体授粉处理后,A2B1、A3B1处理连续两年显著提高了成熟果实的酯类芳香物质含量,果肉可溶性固形物含量有一定增加,处理间果肉蛋白质的在2005年达到差异显著水平.因此,以稀土和氨基酸为辅助物质的液体授粉技术能够显著提高梨树坐果率,并一定程度上改善了果实品质,可以在山西省梨树生产上示范应用.