The AMPTE UKS Three-Dimensional Ion Experiment

This instrument measures the three-dimensional (3-D) distribution function of positive ions at the UKS. Novel electrostatic analyzers using 2600 turning angle cover all viewing angles as the spacecraft rotates. The instrument has sufficient resolution to measure the solar wind as well as giving full 3-D coverage within a spin period. The operation of the experiment and organization of the data are synchronized to the spacecraft spin. A sample of the real-time data showing magnetospheric boundary crossings is presented.     

PET: a proton/electron telescope for studies of magnetospheric,solar, and galactic particles

The proton/electron telescope (PET) on SAMPEX (Solar, Anomalous, and Magnetospheric Particle Explorer) is designed to provide measurements of energetic electrons and light nuclei from solar, Galactic, and magnetospheric sources. PET is an all solid-state system that will measure the differential energy spectra of electrons from ~1 to ~30 MeV and H and He nuclei from ~20 to ~300 MeV/nucleon, with isotope resolution of H and He extending from ~20 to ~80 MeV/nucleon. As SAMPEX scans all local times and geomagnetic cutoffs over the course of its near-polar orbit, PET will characterize precipitating relativistic electron events during periods of declining solar activity, and it will examine whether the production rate of odd nitrogen and hydrogen molecules in the middle atmosphere by precipitating electrons is sufficient to affect O₃ depletion. In addition, PET will complement studies of the elemental and isotopic composition of energetic heavy (Z>2) nuclei on SAMPEX by providing measurements of H, He, and electrons. Finally, PET has limited capability to identify energetic positrons from potential natural and man-made sources     

The Atacama Large Millimeter/Submillimeter Array

The Atacama Large Millimeter/Submillimeter Array (ALMA) is an international radio telescope under construction in the Atacama Desert of northern Chile. ALMA is situated on a dry site at 5000 m elevation, allowing excellent atmospheric transmission over the instrument wavelength range of 0.3-10 mm. ALMA will consist of two arrays of high-precision antennas. One, of up to 64 12-m-diameter antennas, is reconfigurable in multiple patterns ranging in size from 150 m up to ~ 15 km. A second array is composed of a set of four 12-m and 12 7-m antennas operating in one of two closely packed configurations ~ 50 m in diameter. The instrument will provide both interferometric and total-power astronomical information on atomic, molecular, and ionized gas and dust in the solar system, our galaxy, and the nearby to high-redshift universe. In this paper, we outline the scientific drivers, technical challenges, and planned progress of ALMA.     

An 11-bit high-resolution and adjustable-range CMOS time-to-digital converter for space science instruments

An 11-bit time-to-digital converter (TDC) with high time resolution implemented in CMOS VLSI is presented. The TDC operates with a wide and clock-adjustable resolution of LSB = 50 ps to 1 ns, and with good power supply, temperature, and environmental effects compensation. The dead time of the measurement is as low as 0.5 /spl mu/s and the event rate can be as high as 1 MEvents/s. The power dissipation is a function of event rate and clock frequency; the TDC dissipates <10 mW at an event rate of 100 kEvents/s and LSB=100 ps. The TDC was incorporated in a complete time-of-flight (TOF) system on a chip that in addition included front-end analog signal processing. The TOF chip is already flying onboard the HENA (High Energy Neutral Atoms) instrument of the IMAGE NASA mission, launched in 2000, and is part of many other instruments such as particles, X-ray, and the laser altimeter of the Messenger spacecraft.     

The Pioneer Venus Orbiter Plasma Analyzer Experiment

The plasma analyzer experiment on the Pioneer Venus Orbiter was designed to determine the basic characteristics of the plasma environment of Venus and the nature of the solar wind interaction at Venus. The plasma analyzer experiment is an electrostatic energy-per-unit charge (E/Q) spectrometer which measures ions and electrons. There is a curved plate electrostatic analyzer system with multiple collectors. The experiment obtains the three dimensional plasma distribution function. Some of the scientific objectives of the instrument are briefly discussed, the general characteristics of the experiment are summarized, and some of the analyses based on the data are presented.     

The Mass-Separating Ion Spectrometer on the AMPTE Ion-Release Module

Mass-Separating Ion Spectrometer (MSIS) flown on the Ion Release Module of the AMPTE Mission was derived from a similar instrument (MASSWE) proposed and accepted for the United States spacecraft of the International Solar Polar Mission (Ulysses). It features an energy-per-charge range of 0.5 V to 14 kV, two separate systems for particle detection, each with a field of view of approximately 3° X 36°, and is distinguished from previously flown instruments by imaging capabilities in mass per charge which are employed for simultaneously detecting the ion species H+, 4He2+, 16O6+, 4He+, (7Li+; 56Fel0+; 56Fe8+), (16O2+; 56Fe7+; 56Fe6+), 16O+, (3He2+, or 137Ba+). Three different measurement modes make possible the adaption to low-energy particle measurements in an ion-release cloud, solar-wind investigations, and magnetospheric plasma measurements.     

The Medium-Energy Particle Analyzer (MEPA) on the AMPTE CCE Spacecraft

The medium-energy particle analyzer (MEPA) was designed to measure the spectra and composition of magnetospheric particle populations from 10 keV per nucleon (for oxygen) to more than 6 MeV The instrument provides for high background rejection and a geometry tactor large enougn (10-2 cm2 * sr) to be sensitive to rare natural species and tracer ions beyond geosynchronous orbit, while having the ability to operate without saturation in the very high flux regions of the inner magnetosphere. The MEPA telescope measures time of flight and thus velocity of energetic ions from a thin front foil to a rear solid-state total-energy detector, determining the incident ion mass. The telescope is capable of isotopic resolution of hydrogen and helium, of elemental resolution up through oxygen, and can resolve major species and groups to beyond iron with 32-sector angular resolution and temporal resolution of 0.2-24 s. MEPA represents a new and extremely promising technology for space-particle instrumentation in that it has the capability of measuring low-energy heavy ions with high efficiency while discriminating against high natural fluxes of protons.     

MEMS可调谐平顶窄带光学滤波器

设计了一种基于MEMS技术的可调谐光学滤波器,它通过光栅将输入的宽带光信号色散展开,以一个MEMS扭镜选择将对应滤波器通带的光信号反射至输出端,从而实现光学滤波和波长调谐功能。滤波器的输入端采用单模光纤,输出端采用多模或者少模光纤,可以实现窄带且平顶的通带特性。经过参数优化,仿真分析得结果显示,采用多模/少摸光纤输出的两种滤波器,其0.5 dB和25 dB带宽分别为0.95 nm/0.29 nm和1.39 nm/0.69 nm,分别满足100 GHz和50 GHz信道间隔的DWDM系统要求。由于输出端采用多模或者少摸光纤,从该滤波器输出的光信号不能继续在单模光纤中传输,只能由光探测器接收,因此该滤波器一般应用于全光网络节点中的下载端口。     

Terra MODIS on-orbit spectral characterization and performance

The Moderate Resolution Imaging Spectroradiometer (MODIS) protoflight model onboard the National Aeronautics and Space Administration's Earth Observing System Terra spacecraft has been in operation for over five years since its launch in December 1999. It makes measurements using 36 spectral bands with wavelengths from 0.41 to 14.5 /spl mu/m. Bands 1-19 and 26 with wavelengths below 2.2 /spl mu/m, the reflective solar bands (RSBs), collect daytime reflected solar radiance at three nadir spatial resolutions: 0.25 km (bands 1-2), 0.5 km (bands 3-7), and 1 km (bands 8-19 and 26). Bands 20-25 and 27-36, the thermal emissive bands, collect both daytime and nighttime thermal emissions, at 1-km nadir spatial resolution. The MODIS spectral characterization was performed prelaunch at the system level. One of the MODIS onboard calibrators, the Spectroradiometric Calibration Assembly (SRCA), was designed to perform on-orbit spectral characterization of the MODIS RSB. This paper provides a brief overview of MODIS prelaunch spectral characterization, but focuses primarily on the algorithms and results of using the SRCA for on-orbit spectral characterization. Discussions are provided on the RSB center wavelength measurements and their relative spectral response retrievals, comparisons of on-orbit results with those from prelaunch measurements, and the dependence of center wavelength shifts on instrument temperature. For Terra MODIS, the center wavelength shifts over the past five years are less than 0.5 nm for most RSBs, indicating excellent stability of the instrument's spectral characteristics. Similar spectral performance has also been obtained from the Aqua MODIS (launched in May 2002) SRCA measurements.     

Effect of alkali treatment on the spectral response of silicon-nanowire solar cells

The effect of alkali treatment of Si nanowires (SiNWs) on the spectral response of solar cells was investigated using monochromatic incident photon-to-electron conversion efficiency spectroscopy. SiNWs were prepared on a substrate by metal-assisted etching and were then treated with NaOH/isopropanol. The results show that alkali treatment of SiNWs for 30 s obviously improved the cell conversion efficiency. This was attributed to enhancement of the red light response and a decrease in surface reflectivity from 6% to ~2%. However, SiNW alkali treatment led to poor blue light response, which is a major limiting factor for efficient SiNW solar cells. To improve the photovoltaic properties of SiNW cells, a near-complete response over the whole solar spectrum is essential.     

MAST: a mass spectrometer telescope for studies of the isotopiccomposition of solar, anomalous, and galactic cosmic ray nuclei

The mass spectrometer telescope (MAST) on SAMPEX (Solar, Anomalous, and Magnetospheric Particle Explorer) is designed to provide high-resolution measurements of the isotopic composition of energetic nuclei from He to Ni (Z=2 to 28) over the energy range from ~10 to several hundred MeV/nucleon. During large solar flares MAST will measure the isotopic abundances of solar energetic particles to determine directly the composition of the solar corona, while during solar quiet times MAST will study the isotopic composition of galactic cosmic rays. In addition, MAST will measure the isotopic composition of both interplanetary and trapped fluxes of anomalous cosmic rays, believed to be a sample of the nearby interstellar medium     

390.60nm激光作用下Si(CH3)4的多光子解离与硅原子的(1+1)电离

在390.60nm的紫外激光作用下，利用超声分子束技术与飞行时间（TOF）质谱仪相结合的方法研究了气相四甲基硅分子多光子电离（MPI）的TOF质谱，在较低能量的激光作用下主要检测到了Si(CH3)^ 、Si^ 、C2^ 等离子的信号，有时甚至只检测到了Si^ 离子的信号：在较高能量的激光作用下主要检测到Si(CH3)^ n(n=1,2,3,4)、Si^ 、C2^ 甚至还有SiC3^ ,SiC2^ 等离子的信号。据此并结合以前得到的结论，讨论了四甲基硅分子可能的MPI过程。得出了Si^ 主要来自于Si(CH3)4的多光子解离－Si原子的（1＋1）电离、Si(CH3)n^ (n=1,2,3)的（3＋1）电离、Si(CH3)^ 4来自于Si(CH3)4的（3＋1）电离的结论。     

Optimization of a-Si:H absorber layer grown under a low pressure regime by plasma-enhanced chemical vapor deposition: Revisiting the significance of the p/i interface for solar cells

In this study, we revisited the significance of the p/i interface for hydrogenated amorphous silicon (a-Si:H) solar cells. Initially, intrinsic and extrinsic (p and n type) a-Si:H layers were grown in a low pressure regime (0.5–0.1 Torr) using the conventional RF plasma-enhanced chemical vapor deposition process and their opto-electronic properties were optimized for the fabrication of p–i–n a-Si:H solar cells. Subsequently, we obtained new insights in terms of the activation energy and band gap at the p/i interface in these solar cells. The absorber layers deposited at pressures of 0.23 Torr and 0.53 Torr had the highest photosensitivity with a band absorption edge at ~700 nm. Furthermore, the photosensitivity was shown to be correlated with the estimated diffusion length, which effectively defined the carrier transport within the solar cell layers. Moreover, the cell efficiency increased from 1.53% to 5.56% due to the improved p/i interface as well as the higher photosensitivity of the intrinsic/absorber layer.     

Nanostructured Alkaline‐Cation‐Containing δ‐MnO2 for Photocatalytic Water Oxidation

Oxygen evolution from water is one of the key reactions for solar fuel production. Here, two nanostructured K‐containing δ‐MnO₂ are synthesized: K‐δ‐MnO₂ nanosheets and K‐δ‐MnO₂ nanoparticles, both of which exhibit high catalytic activity in visible‐light‐driven water oxidation. The role of alkaline cations in oxygen evolution is first explored by replacing the K⁺ ions in the δ‐MnO₂ structure with H⁺ ions through proton ion exchange. H‐δ‐MnO₂ catalysts with a similar morphology and crystal structure exhibit activities per surface site approximately one order of magnitude lower than that of K‐δ‐MnO₂, although both nanostructured H‐δ‐MnO₂ catalysts have much larger Brunauer–Emmett–Teller (BET) surface areas. Such a low turnover frequency (TOF) per surface Mn atom might be due to the fact that the Ru²⁺(bpy)₃ sensitizer is too large to access the additional surface area created during proton exchange. Also, a prepared Na‐containing δ‐MnO₂ material with an identical crystal structure exhibits a TOF similar to that of the K‐containing δ‐MnO₂, suggesting that the alkaline cations are not directly involved in catalytic water oxidation, but instead stabilize the layered structure of the δ‐MnO₂.     

Analysis of Complete Organic Semiconductor Devices by Laser Desorption/Ionization Time‐of‐Flight Mass Spectrometry

In this contribution, it is shown that the method of laser‐desorption/ionization time‐of‐flight mass spectrometry (LDI‐TOF‐MS) is a powerful technique for analyzing complete organic devices, such as organic light‐emitting diodes (OLEDs) or organic solar cells. LDI‐TOF‐MS has the potential to analyze fully processed organic devices without special pretreatment such as dissolving the device, peeling off the metal cathode, or using additional matrix materials. Thus, devices may be analysed as they are with a minimum of measurement artefacts. It is demonstrated that the method allows an analysis of complex organic multilayer devices, their composition, and incorporated impurities. It even allows possible electrochemical reaction products caused by device degradation to be analyzed. Thus, LDI‐TOF‐MS has major advantages compared to measurements of dissolved samples. As an example, the identification of all of the materials used in a complete OLED is shown. Furthermore, a detailed chemical analysis of long‐term driven OLEDs, including the detection of degradation products, is presented. From these data, several degradation mechanisms can be distinguished.     

8-羟基喹啉铝本征薄膜的制备与性质研究

8-羟基喹啉铝属于有机半导体材料,在太阳能电池应用领域有较为广阔的应用前景。为了研究8-羟基喹啉铝载流子输运动力学信息,在恒温条件下制备了8-羟基喹啉铝薄膜,采用X射线衍射分析方法对薄膜的性质进行了分析,采用渡越时间方法对影响其载流子迁移率的实验条件进行了理论分析和实验验证。结果表明,在308K~338K温度范围内,8-羟基喹啉铝的载流子输运规律符合浅陷阱模型;取样电阻小于15kΩ及光脉冲能量低于3.5μJ时,载流子渡越时间保持恒定,测试结果可靠。这一结果对有机太阳能电池的制备是有帮助的。     

镧掺杂钛酸铋钠钾系无铅压电陶瓷的制备工艺

利用XRD、SEM等技术分析方法,研究了工艺条件对[(Na0.5Bi0.5)0.82(K0.5Bi0.5)0.18]1-xLaxTiO3(x=0~0.1)无铅压电陶瓷的物相组成、显微结构和压电性能的影响。结果表明:提高合成温度至870~900℃有利于主晶相的形成;在1130℃下烧结可得到高致密样品。同时研究了极化工艺条件对材料压电性能的影响:极化温度保持在80~100℃之间,极化电场强度为4MV/m可以得到较好的压电性能。     

High‐efficiency GaInP/GaAs/GaInNAs solar cells grown by combined MBE‐MOCVD technique

Triple‐junction GaInP/GaAs/GaInNAs solar cells with conversion efficiency of ~29% at AM0 are demonstrated using a combination of molecular beam epitaxy (MBE) and metal‐organic chemical vapor deposition (MOCVD) processes. The bottom junction made of GaInNAs was first grown on a GaAs substrate by MBE and then transferred to an MOCVD system for subsequent overgrowth of the two top junctions. The process produced repeatable cell characteristics and uniform efficiency pattern over 4‐inch wafers. Combining the advantages offered by MBE and MOCVD opens a new perspective for fabrication of high‐efficiency tandem solar cells with three or more junctions. Copyright © 2016 John Wiley & Sons, Ltd.     

The Plasma Instrument for AMPTE IRM

The AMPTE IRM plasma instrument package consists of three sensors. Two of them measure complete 3-D velocity-distribution functions of ions and electrons every spacecraft revolution (i.e., 4.35 s). The third sensor is a retarding potential analyzer (RPA) for low-energy electron measurements. The 3-D measurements consist of countrates at 30 energies and 128 angles evenly distributed over the 4xr solid-angle sphere. The energy range is 15 eV-30 keV for electrons and 20 eV/q-40 keV/q for ions. The RPA extends the electron measurements to lower energies. Three microcomputers within the experinent perform extensive on-board data-processing functions. Two of them compute the moments (density, velocity, temperature tensor, and heat flux vector) of the distribution functions of ions and electrons in real time. The third compresses the RPA data and computes an indication for the spacecraft potential.