The atmosphere of the primitive earth and the prebiotic synthesis of organic compounds.

The prebiotic synthesis of organic compounds using a spark discharge on various simulated prebiotic atmospheres at 25 degrees has been studied. Methane mixtures contained H2 + CH4 + H2O + N2 + NH3 with H2/CH4 molar ratios from 0 to 4 and pNH3 = 0.1 torr. A similar set of experiments without added NH3 was performed. The yields of amino acids (1.2 to 4.7% based on the carbon) are approximately independent of the H2/CH4 ratio and the presence of added NH3, and a wide variety of amino acids are obtained. Mixtures of H2 + CO + H2O + N2 and H2 + CO2 + H2O + N2, with and without added NH3, all give about 2% yields of amino acids at H2/CO and H2/CO2 ratios of 2 to 4. For the H2/CO and H2/CO2 ratios less than 1, the yields fall off drastically to as low as 10(-3)%. Glycine is almost the only amino acid produced from CO and CO2 atmospheres. These results show that the maximum yield is about the same for the three carbon sources at high H2/carbon ratios, but that CH4 is superior at low H2/carbon ratios. In addition, CH4 gives a much greater variety of amino acids than either CO or CO2. If it is assumed that amino acids more complex than glycine were required for the origin of life, then these results indicate the need for CH4 in the primitive atmosphere. The yields of cyanide and formaldehyde parallel the amino acid results, with yields of HCN and H2CO as high as 13% based on the carbon. Ammonia is also produced from N2 in experiments with no added NH3 in yields as high as 4.9%. These results show that large amounts of NH3 would have been synthesized on the primitive earth by electric discharges. The amount of ammonia formed by hydrolysis of HCN and various nitriles may have exceeded that formed directly in electric discharges.     

Organic solids produced from simple C/H/O/N ices by charged particles: applications to the outer solar system.

CH4, CO, and CO2 are all potential one-carbon molecular repositories in primitive icy objects. These molecules are all found in the Comet Halley coma, and are probable but, (except for CH4 detected on Triton and Pluto) undetected subsurface constituents in icy outer solar system objects. We have investigated the effects of charged particle irradiation by cold plasma discharge upon surfaces of H2O:CH4 clathrate having a 200:1 ratio, as well as upon ices composed of H2O plus C2H6 or C2H2 (sometimes plus NH3) which are also plausible constituents. These materials color and darken noticeably after a dose 10(9) - 10(10) erg cm-2, which is deposited rapidly (< or = 10(4) yr.) in solar system environments. The chromophore is a yellowish to tan organic material (a tholin) which we have studied by UV-VIS reflection and transmission, and IR transmission spectroscopy. Its yield, -1 C keV-1, implies substantial production of organic solids by the action of cosmic rays and radionuclides in cometary crusts and interiors, as well as rapid production in satellite surfaces. This material shows alkane bands which Chyba and Sagan have shown to well match the Halley infrared emission spectrum near 3.4 microns, and also bands due to aldehyde, alcohol and perhaps alkene/aromatic functional groups. We compare the IR spectral properties of these tholins with the spectra of others produced by irradiation of gases and ices containing simple hydrocarbons.     

Radiation-induced syntheses in cometary simulated models.

The behavior of an aqueous-dominant multicomponent cometary model is examined at high doses of ionizing radiation. The system is composed of a water mixture of HCN (0.2 mol dm-3), CH3CN (0.04 mol dm-3), C2H5CN (0.02 mol dm-3), CH3OH (0.12 mol dm-3) and HCO2H (0.01 mol dm-3. It was exposed to gamma rays at doses up to 18.5 MGy. The chemical kinetic database used in the computer treatment of experimental data consists of 79 reactions. A complex mixture of products has been synthesized: gases, amino acids, carboxylic acids and polymeric material. The results suggest that the pristine material in cometary nuclei may have been chemically altered by the action of cosmic rays and embedded radionuclides.     

LiNi0.8Co0.15Al0.05O2(NCA)正极材料的磷酸表面改性

针对新一代空间型号产品对储能电源提出的更高需求,提出采用表面改性的方法提升LiNi0.8Co0.15Al0.05O2（NCA）正极材料在锂离子电池中的循环稳定性。通过采用磷酸（H3PO4）对NCA正极材料进行表面处理,H3PO4会与NCA颗粒表面的含锂碱性物质发生反应,从而在NCA颗粒表面生成稳定且导电性良好的Li3PO4界面层。循环以及阻抗测试结果表明,经H3PO4表面处理的NCA材料组装电池循环50次后电池容量为170.5mA·h/g,容量保持率达到94%以上,界面阻抗得到抑制。H3PO4表面处理有效抑制了NCA颗粒表面碱性残留对电化学性能的不良影响,提升了界面稳定性,获得了更好的循环性能。     

Comparison of vertical E × B drift velocities and ground-based magnetometer observations of DELTA H in the low latitude under geomagnetically disturbed conditions

In the present work, we analyzed the daytime vertical E × B drift velocities obtained from Jicamarca Unattended Long-term Ionosphere Atmosphere (JULIA) radar and ΔH component of geomagnetic field measured as the difference between the magnitudes of the horizontal (H) components between two magnetometers deployed at two different locations Jicamarca, and Piura in Peru for 22 geomagnetically disturbed events in which either SC has occurred or Dst_max < ?50 nT during the period 2006–2011. The ΔH component of geomagnetic field is measured as the differences in the magnitudes of horizontal H component between magnetometer placed directly on the magnetic equator and one displaced 6–9° away. It will provide a direct measure of the daytime electrojet current, due to the eastward electric field. This will in turn gives the magnitude of vertical E × B drift velocity in the F region. A positive correlation exists between peak values of daytime vertical E × B drift velocity and peak value of ΔH for the three consecutive days of the events. It was observed that 45% of the events have daytime vertical E × B drift velocity peak in the magnitude range 10–20 m/s and 20–30 m/s and 20% have peak ΔH in the magnitude range 50–60 nT and 80–90 nT. It was observed that the time of occurrence of the peak value of both the vertical E × B drift velocity and the ΔH have a maximum (40%) probability in the same time range 11:00–13:00 LT. We also investigated the correlation between E × B drift velocity and D_st index and the correlation between delta H and D_st index. A strong positive correlation is found between E × B drift and D_st index as well as between delta H and D_st Index. Three different techniques of data analysis – linear, polynomial (order 2), and polynomial (order 3) regression analysis were considered. The regression parameters in all the three cases were calculated using the Least Square Method (LSM), using the daytime vertical E × B drift velocity and ΔH. A formula was developed which indicates the relationship between daytime vertical E × B drift velocity and ΔH, for the disturbed periods. The E × B drift velocity was then evaluated using the formulae thus found for the three regression analysis and validated for the ‘disturbed periods’ of 3 selected events. The E × B drift velocities estimated by the three regression analysis have a fairly good agreement with JULIA radar observed values under different seasons and solar activity conditions. Root Mean Square (RMS) errors calculated for each case suggest that polynomial (order 3) regression analysis provides a better agreement with the observations from among the three.     

F2 layer characteristics and electrojet strength over an equatorial station

The data presented in this work describes the diurnal and seasonal variation in hmF2, NmF2, and the electrojet current strength over an African equatorial station during a period of low solar activity. The F2 region horizontal magnetic element H revealed that the Solar quiet Sq(H) daily variation rises from early morning period to maximum around local noon and falls to lower values towards evening. The F2 ionospheric current responsible for the magnetic field variations is inferred to build up at the early morning hours, attaining maximum strength around 1200 LT. The Sq variation across the entire months was higher during the daytime than nighttime. This is ascribed to the variability of the ionospheric parameters like conductivity and winds structure in this region. Seasonal daytime electrojet (EEJ) current strength for June solstice, March and September equinoxes, respectively had peak values ranging within 27–35 nT (at 1400 LT) , 30–40 nT (at 1200 LT) and 35–45 nT (at 1500 LT). The different peak periods of the EEJ strength were attributed to the combined effects of the peak electron density and electric field. Lastly, the EEJ strength was observed to be higher during the equinoxes than the solstice period.     

Complex organics in laboratory simulations of interstellar/cometary ices.

We present the photochemical and thermal evolution of both non-polar and polar ices representative of interstellar and pre-cometary grains. Ultraviolet photolysis of the non-polar ices comprised of O2, N2, and CO produces CO2, N2O, O3, CO3, HCO, H2CO, and possibly NO and NO2. When polar ice analogs (comprised of H2O, CH3OH, CO, and NH3) are exposed to UV radiation, simple molecules are formed including: H2, H2CO, CO2, CO, CH4, and HCO (the formyl radical). Warming produces moderately complex species such as CH3CH2OH (ethanol), HC(=O)NH2 (formamide), CH3C(=O)NH2 (acetamide), R-CN and/or R-NC (nitriles and/or isonitriles). Several of these are already known to be in the interstellar medium, and their presence indicates the importance of grain processing. Infrared spectroscopy, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, and gas chromatography-mass spectrometry demonstrate that after warming to room temperature what remains is an organic residue composed primarily of hexamethylenetetramine (HMT, C6H12N4) and other complex organics including the amides above and polyoxymethylene (POM) and its derivatives. The formation of these organic species from simple starting mixtures under conditions germane to astrochemistry may have important implications for the organic chemistry of interstellar ice grains, comets and the origins of life.     

Production of nitrogen oxides by lightning and coronae discharges in simulated early Earth, Venus and Mars environments.

We present measurements for the production of nitrogen oxides (NO and N2O) in CO2-N2 mixtures that simulate different stages of the evolution of the atmospheres of the Earth, Venus and Mars. The nitrogen fixation rates by two different types of electrical discharges, namely lightning and coronae, were studied over a wide range in CO2 and N2 mixing ratios. Nitric oxide (NO) is formed with a maximum energy yield estimated to be ~1.3 x 10(16) molecule J-1 at 80% CO2 and ~1.3 x 10(14) molecule J-1 at 50% CO2 for lightning and coronae discharges, respectively. Nitrous oxide (N2O) is only formed by coronae discharge with a maximum energy yield estimated to be ~1.2 x 10(13) molecule J-1 at 50% CO2. The pronounced difference in NO production in lightning and coronae discharges and the lack of formation of N2O in lightning indicate that the physics and chemistry involved in nitrogen fixation differs substantially in these two forms of electric energy.     

利用WACCM-3模式对平流层动力、热力场及微量化学成分季节变化的数值模拟研究

利用美国NCAR最新的化学-气候耦合模式WACCM-3对平流层风场、温度场以及平流层臭氧等多种微量气体成分(O3, CH4, N2O, H2O, HCl, HNO3)的季节变化进行了数值模拟, 并使用ECMWF再分析资料与美国UARS卫星 搭载的HALOE, MLS, CLAES等探测器的观测资料, 对模式输出的动力、热力及化学成分浓度的气候平均值进行了验证. 结果表明, 在气候平均海表温度值驱动下, WACCM-3模式能够很好地再现ECMWF资料中平流层纬向平均风场与温度场的季节变化. 模拟结果中平流层化学成分的经向-垂直分布及其季节变化与卫星观测结果基本一致. 模式的动力、热力场在极地平流层以及热带对流层顶等区域存在一定的偏差. 这些偏差对于微量气体成分分布 的模拟具有一定影响, 特别是南半球冬(7月)、春(10月)季节南极平流层低层极夜 急流偏强, 造成极地地区附近的输送障碍增强, 从而导致CH4, N2O, H2O浓度比观测偏低. 此外, WACCM-3缺少热带平流层风场的准两年振荡(QBO) 机制, 这对于热带平流层东风急流以及低纬度平流层O3, CH4, N2O, H2O等成分经向输送的模拟结果也有一定影响.      

A study of chemical systems using signal flow graph theory.

Photochemistry of giant planets and their satellites is characterized by numerous reactions involving a lot of chemical species. In the present paper, chemical systems are modeled by signal flow graphs. Such a technique evaluates the transmission of any input into the system (solar flux, electrons ... ) and gives access to the identification of the most important mechanisms in the chemical system. This method is applied to the production of hydrocarbons in the atmospheres of giant planets. In particular, the production of C2H6 in the atmosphere of Neptune from the photodissociation of CH4 is investigated. Different pathways of dissociation of CH4 are possible from L alpha radiation. A chemical system containing 14 species and 30 reactions including these different pathways of dissociation is integrated. The main mechanism of production of C2H6 is identified and evaluated for each model of dissociation. The importance of various reaction pathways as a function of time is presented.     

考虑倍率的平流层飞艇储能电池建模与分析

准确掌握储能电池的实际电量是确保平流层飞艇实现长航时飞行的关键因素之一。首先，建立了平流层飞艇能源系统仿真模型，对能量输入和消耗进行动态分析。随后，对储能电池进行不同电流倍率的充放电测试，采用多项式拟合的方法，根据测试数据建立了储能电池充放电过程中荷电状态(SOC)、剩余放电时间(RDT)、剩余充电时间(RCT)的分析模型。最后，结合能源系统能量输入、消耗模型和储能电池模型进行飞行模拟仿真，获取各部分变化数据，与已有试验数据进行量化对比分析。结果表明:所构建储能电池模型在SOC、RDT、RCT的计算误差分别小于3%、1.5%、1.5%，能够准确反映电池工作过程中SOC、RDT、RCT的变化，可为平流层飞艇平台制定优化的飞行策略提供量化支撑。      

The electrolytical processes in dirty ices: implications for origin and chemistry of minor bodies and related objects.

Many moonlike bodies (M approximately or = 1 Moon) beyond the Martian orbit contain large amounts of dirty ice (approximately 50%) forming thick mantle with the solid phase thermal convection. When a body moves through the inter- or nearplanetary magnetized plasma, electric current is generated in the body and its environment. The current passing through a dirty ice containing up to 10% of organic admixtures produces a lot of electrochemical effects which have a profound impact on its composition. At this stage one can hardly say something definite concerning changes experienced by organics. The changes must occur inevitably and can be of a rather unexpected and far-reaching nature, so deserving a close study. Another obvious effect is a volumetric electrolysis of ice containing alien inclusions. The electrolysis products accumulate in ice in the form of a solid solution which is capable of detonation at 15-20 wt.% of 2H2 + O2. If M > or = 1 Moon (Galilean satellites, Titan), the body loses in explosion a part of its mass in the form of vapor and ice fragments (=short-period comet nuclei), whereas if M < or = 0.2 Moon, the body breaks up totally (the Main Belt asteroids origin approximately 3.9 Byr ago). 2H2 + O2 containing cometary nuclei are capable of burning or suffer new explosions when receiving an additional energy. The combustion in the sublimation products containing also light organics and 2H2 + O2 explains unexpected energetics and nearnuclear chemistry of Comet P/Halley (e.g. great abundances of negative and positive ions, atomic carbon, CO over CO2, origin of CHON particles etc) and its distant outbursts correlated, possibly, with the Solar activity. Thus the electrochemical processes in the dirty ice with organics, along with its subsequent thermal, radiative etc. processing, open up new potentials for explanation and prediction of quite unexpected discoveries.     

Biogeochemical evidence of microbial activity on Mars.

We suggest a new interpretation of the data on so-called SNC meteorites and delta 13C values of the calcium carbonate minerals and organic matter discovered in them. The delta 13C value of calcite (up to 15 ppt) is accounted for by the microbial reaction CO2 + H2 ---> CH4 + H2O. Methane-forming bacteria also synthesize organic carbon (in the form of biomass) from CO2, and this process is accompanied by 12C fractionation. Therefore, the organic carbon of SNC meteorites is enriched with 12C (delta 13C as low as -35 ppt). The environmental conditions under which the calcite of SNC meteorites was formed were favorable for the activity of methanogens.     

Space observations of comets during solar flares: A possible explanation for comet brightness outbursts

Problems connected with mechanisms for comet brightness outbursts as well as for gamma-ray bursts remain open. Meantime, calculations show that irradiation of a certain class of comet nuclei, having high specific electric resistance, by intense fluxes of energetic protons and positively charged ions with kinetic energies more than 1 MeV/nucleon, ejected from the Sun during strong solar flares, can produce a macroscopic high-voltage electric double layer with positive charge in the subsurface zone of the nucleus, during irradiation times of the order of 10–100 h at heliocentric distances around 1–10 AU. The maximum electric energy accumulated in such layer will be restricted by the electric discharge potential of the layer material. For comet nuclei with typical radii of the order of 1–10 km the accumulated energy of such natural electric capacitor is comparable to the energy of large comet outbursts that are estimated on the basis of ground based optical observations. The impulse gamma and X-ray radiation together with optical burst from the comet nucleus during solar flares, anticipated due to high-voltage electric discharge, may serve as an indicator of realization of the processes above considered. Multi-wavelength observations of comets and pseudo-asteroids of cometary origin, having brightness correlation with solar activity, using ground based optical telescopes as well as space gamma and X-ray observatories, during strong solar flares, are very interesting for the physics of comets as well as for high energy astrophysics.     

Observational evidence for chromospheric footpoint penetration of nonthermal electrons during two well-observed flares

Recent advances have enabled simultaneous Hα and X-ray observations with substantially improved spatial, spectral, and temporal resolution. In this paper we study two events observed as part of a coordinated observing program between the Solar Maximum Mission and Sacramento Peak Observatory: the flares of 1456 UT, 7 May 1980 and 1522 UT, 24 June 1980. Using recently-developed physical models of static flare chromospheres, and corresponding theoretical Hα line profiles, we can distinguish effects of intense nonthermal electron heating from those of high conduction and pressure from the overlying flare corona. Both flares show the signature of intense chromospheric heating by fast electrons, temporally correlated with X-ray light curves at E > 27keV, and spatially associated with X-ray emission sites at E >62; 16 keV. Interpreting the Hα line profile observations using the theoretical Hα line profiles, we infer values of the thick-target input power contained in nonthermal electrons that are observationally indistinguishable (within a factor of 2–3) from those inferred from the X-ray data. Although these events are small, the energy flux values are large: of order 10¹¹ ergs cm^?2 s^?1 above 20 keV.     

The multi-wavelength study of the effect of energetic particle beams on the chromospheric emission in the 25th July 2004 solar flare

We present the multi-wavelength study of short-term variations of Hα line emission located in multiple kernels on the both sides from magnetic neutral line in the 25th July 2004 solar flare observed by VTT (Tenerife). The HXR and Hα emission in the kernels 1 and 3 is close spatially and temporally while in kernels 4 and 7 there is only delayed Hα emission observed tens seconds after HXR in the kernels 1 and 3. The locations of Hα kernels 1, 3, 4 and 7 are on the opposite sides from the magnetic neutral line. The temporal variations of Hα emission in kernels 1 and 3 coincide within 5 s with the HXR photon emission. The latter is found to have double power law photon spectra, which were corrected to a single power law with the turning point technique accounting for Ohmic losses and collisions. The Hα emission is fit by full non-LTE simulations in an atmosphere heated by an electron beam with the parameters derived from the HXR emission. The combination of radiative, thermal and non-thermal mechanisms of excitation and ionization of hydrogen atoms is considered. The temporal evolution of simulated Hα emission in the kernel 3 fits rather well the two observed intensity increases: the first at the flare onset (13:38:39–13:39:30 UT) caused by pure non-thermal excitation by beam electrons and the second one appearing after 13:40:00 UT because of a hydrodynamic heating. The observed close temporal correlation or delay of Hα emission with HXR emission points out to the precipitation either of electron (kernels 1 and 3) or protons (4 and 7).     

Atomic structure of the doubly ionized titanium Ti III ion

In this work, the atomic structure of Ti III is calculated using two methods, the Thomas-Fermi–Dirac-Amaldi (TFDA) method using the AUTOSTRUCTURE (AS) atomic structure code and the pseudo-relativistic Hartree–Fock (HFR) method using the Cowan (CW) atomic structure code. We used the terms and levels generated by the 19 configurations: 3p⁶ 3d², 3dns (n = 4–7), 3dnp (n = 4–7), 3dnd (n = 4–7), 3d nf (n = 4–7), 3p⁶ 4s²,3p⁶ 4s4p. Our calculated values are compared with available experimental and theoretical results and new theoretical data of our own are obtained.     

HCN formation under electron impact: experimental studies and application to Neptune's atmosphere.

Laboratory experiments simulating organic synthesis in Neptune's atmosphere have been performed. We have submitted to a spark discharge gaseous mixtures containing 9 mbar of molecular nitrogen and 3 mbar of methane (the p(N2)/p(CH4) ratio is compatible with upper limits in Neptune's stratosphere) with varying quantities of molecular hydrogen. The spark discharge is used to model the energetic electrons produced by the impact of cosmic rays on the high atmosphere of Neptune. HCN is synthesized in the described experimental conditions, even with a low mixing ratio of molecular nitrogen. Studying the variation of HCN production with the initial composition of the gas mixture and extrapolating to high mixing ratio of molecular hydrogen allows to estimate HCN production in Neptune's atmosphere. The computed HCN production flux is 7x10(7) m-2 s-1, which is two orders of magnitude lower than the value predicted by chemical models for an internal source of N atoms. The major uncertainty in our extrapolation is the energetic distribution of electrons, implicitly assumed comparable in the discharge and in Neptune's atmosphere. We note that this distribution is also a source of uncertainty in chemical models. The chemical mechanism responsible for the local formation of HCN in the stratosphere probably occurs in the reactor too. We propose a simple characterization of the spark discharge. We thus link the molecular nitrogen dissociation cross section by electron impact to the measured parameters of the experiments (current, voltage, initial partial pressures) and to the resulting HCN partial pressures. However, other laboratory experiments with larger hydrogen pressures, requiring a more powerful electric source, have to be performed to yield a value of the cross section.     

空间燃料电池电源子系统输出性能的仿真与试验验证

为了系统性地研究质子交换膜燃料电池电源子系统的输出特性与电堆压力、电堆温度之间的关系,首先建立电堆的数学模型,在Matlab/Simulink中进行仿真,研究输入与输出的关系;其次针对航天应用设计相匹配的燃料电池变换器（FCDR）,将其与电堆的输出端接在一起进行仿真,研究电堆的输入对FCDR的输出特性的影响,当负载发生变化时,检验FCDR对维持母线电压稳定输出的能力;最后对电堆和电堆系统的仿真进行试验测试,证明仿真的正确性,从而对空间燃料电池电源系统有更深一步的认识,为整个电源系统的设计打下坚实的基础。     

The 1980 April 12 flare and transient: Report on progress in interpretation

A multidisciplinary study of this solar-interplanetary event is summarized by two main points: this flare was an incident in a process that began days before the flare, and continued after the flare; and the chain of events can be interpreted most simply in terms of energy input over scales of time and space that are large compared to the flare seen in the light of Hα. In support of these points, 5 aspects of the flare are described here: (1) hours before the flare, slow changes in coronal structure were associated with radio continuum emission, suggesting large-scale magnetic-field changes and the presence of energetic electrons; (2) long-lived X-ray loops require sustained energy input for at least an hour after the flare start; (3) interplanetary disturbance near earth is probably related to this limb flare, although the (expected) absence of a shock makes identification uncertain; (4) the coronal mass ejection overlay decaying magnetic field; (5) speed derived from frequency drift of the type II radio burst in the low corona, and from the travel time of the disturbance to 1 a.u., are about twice as great as the observed speed of the coronal mass ejection and of the disturbed solar-wind speed.