Ion cyclotron resonance spectroscopy. Cyclotron double resonance provides a new technique for the study of ion-molecule reaction mechanisms

Ion cyclotron resonance spectroscopy yields information on many aspects of ion-molecule chemistry. The method is ideally suited for experiments involving ion energies below several electron volts, and hence provides a valuable complement to other techniques (27). eyclotron double resonance is uniquely suitable for establishing relationships between reactant ions and their product ions in complex ion-molecule reaction sequences. The double-resonance experiments with isotopic species yield information on reaction mechanisms and the nature of intermediate species. Ion-molecule reactions which occur at low energies are quite sensitive to the nature of functional groups and the details of molecular structure (28). Reactions of ions or neutral molecules with specific reagents in the cyclotron spectrometer can thus be used to characterize unknown species. Once the systematic ion-molecule chemistry of useful reagents has been worked out, it should be possible to proceed in a manner directly analogous to classical chemical methods. Suppose, for example, that reagents A(+), B(+), C(+), and D(+) each have characteristic reactions with different functional groups. Then these reagents can all be mixed with an unknown neutral species, X, and each of the reactions, X + A(+) --> ?, X + B(+) --> ?, . . . . can be examined. In contrast to solution chemistry, all the reagents can be added simultaneously to the unknown, since each of the specific reactions can be examined by cyclotron double resonance. The reactions which occur, the species synthesized , and the products of degradation then characterize X. The same methodology can be applied to characterize an unknown ionic epecies X(+), through use of neutral reagents A, B, C, and D. For example, proton transfer reactions to neuteal species have been applied in studying ions of mass 45 produced from various sources (29). The order of the proton affinities of the neutral reagent molecules are as follows: NH(3) isobutylene propene. Ions of mass 45 can be produced by the protonation of ethylene oxide (see structure III), the protonation of acetaldehyde (see structure IV), and the fragmentation of dimethyl ether (see structure V). Those ions might be expected to have, respectively, the three structures: Proton transfer from the mass-45 ions from sources III and IV to NH(3) and to isobutylene occurs readily, but not proton transfer to propene. For the ion from source V, proton transfer to NH3 occurs, but not proton transfer to isobutylene or propene. Thus the proton transfer reactions to various neutral reagents demonstrate that the mass-45 ions from the various sources are different. This example is only a rudimentary version of an approach to the characterization of unusual ionic species; niore sophisticated applications can follow when the systematic chemistry of more reagents is available. This approach should be ideal for comparing nonclassical carbonium ions produced by different routes. Some very interesting ionic species are produced by rearrangements in the fragmentation of molecules, following electron impact. Such molecular rearrangements frequently result in the fragmentation of an ion radical to another ion radical with the elimination of a small neutral species (30). It should be possible to run these reactions in reverse to check the postulated mechanisms. An interesting result of the systematic study of proton transfer to various functional groups is the finding that the proton affinity of various amines and pyridine is extremely high (31). Species such as VI and VII: might be expected to be very stable; they are in fact so stable that they are unreactive with respect to subsequent chemistry at the charge center. Thus, if there are other functional groups on the ion, the important reactions should occur at these functional groups. It should be possible to design species for which the presence of the charge has little influence on the reactivity of a neutral functional group. In this case the charge functions simply as an inert label which makes the study of neutral-neutral reactions accessible by cyclotron resonance: Various routes for development of the basic technique also appear to be very promising. Echo phenomena following sequences of pulsed excitation have been observed in electron cyclotron resonance (32). Analogous transient phenomena should also occur in ion cvclotron resonances (33). Pulsed-cyclotron-resonance techniques of course have intriguing analogies to nuclear-magnetic-resonance spin-echo experiments (34) and may be the technique of choice for making accurate measurements of ion-molecule-reaction cross sections as a function of energy for low ion energies. Finally, many ion-molecule reactions yield products in excited electronic states (35). For example, the reaction N(2)- + CO --> N(2) + CO- (46) has been studied by beam techniques (36). A straightforward procedure is to observe optical emission from the cyclotron spectrometer by placing a window at the end of the cyclotron cell (37). The emission can be analyzed with a crude set of optical filters, or with a high-speed spectrograph. Optical emission from the cyclotron cell can of course originate from many sources. The radiation from a specific excited product ion can be selected by a radio-frequency-optical double-resonance experiment. If, in the generai reaction A+ + B --> *C+ + D, (47) ion A+ is irradiated at its cyclotron resonance frequency, the number density of optical emitters *C+ is changed. If the irradiating frequency is modulated, then the number of optical emitters will be modulated, so that the intensity of emission from *C+ will also be modulated. When the optical emission from *C+ is analyzed in a spectrograph with a photoelectric cell, the output of the photoelectric cell can be detected with a phase sensitive detector referenced to the modulation frequency. This highly specific modulation-detection scheme should discriminate against other sources of light in the cyclotron cell.     

射频电磁波生物学效应实验系统的研制

设计和研制了一套用于研究电磁波非热效应的实验系统。该系统综合了工程上的TEM小室、开阔场地测量屏蔽室和微波暗室的优点，能产生一个具有极端的宽带特征、分布均匀、易于测量的电磁场区域，对周围的人或设备无害或无干扰。     

抗生素在马铃薯组织培养中抑菌效果的研究

利用不同种类不同浓度抗生素添加至不同方式处理下的MS培养基中进行对比,观察培养基及瓶苗抑菌情况,试验表明不经高温高压灭菌,直接添加抗生素的培养基,抑菌效果最好。抗生素是一种长效、广谱、高活性新型组织培养专用防污染杀菌剂,通过试验进而得到最适合马铃薯组织培养扩繁脱毒苗的培养基。     

Phencyclidine-induced immunodepression

Phencyclidine ("PCP" or "angel dust") and some of its derivatives are psychotomimetic drugs that have been used in general anesthesia for some time. This drug blocks potassium ion channels in brain tissue, and there is a specific PCP binding to lymphocytes. In a study of the effects of this drug on immunocyte function, it was found that humoral and cellular immune responses in vitro were depressed when immunocytes were treated with PCP before biological assay. This finding has implications for PCP abuse and also for the use of its derivative in general anesthesia, where it may contribute to postoperative infection.     

准连续植物组织电压频率响应特性的研究

采用宽频域交流阻抗技术研究准连续植物组织的电压频率特性。选取不同厚度的土豆片为研究对象,在100KHz～25MHz范围内测量其电压随交变电场频率变化的特性。通过对数据的处理和分析,得到如下结论：在工作电压1V时,对应同一厚度的土豆组织,输出电压总体上随频率的增加而增加;但是在频率103～104Hz中间出现一个极小值;在同一频率下,土豆片厚度对输出电压影响不大。从而揭示出生物组织的组分和内在结构的复杂性及其在不同频率的交变电场中电学性质的复杂性。     

Archean microfossils showing cell division from the swaziland system of South Africa

A newly discovered population of organic walled microstructures from the Swaziland System, South Africa, is considered to be biological on the following grounds: (i) the structures are carbonaceous and occasionally have internal organic contents; (ii) the population has a narrow unimodal size frequency distribution (average diameter, 2.5 micrometers; range, 1 to 4 micrometers); (iii) the structures are not strictly spherical, but are commonly flattened and folded like younger microfossils; (iv) the sedimentary context is consistent with biogenic origins; and (v) various stages of binary division are clearly preserved.     

我国对硒的生物学意义的研究进展

硒是生物的必需营养元素，具有多种生理功能。在生物体内：无机硒被转化成有机硒组分而充分发挥其作用。在低硒地区，补硒有利于提高生物的硒营养水平，本文综述了近些年来我国对硒的生物学功能及应用的研究进展。     

离子束介导玉米DNA后受体小麦当代群体的生物学效应

以6份玉米品种的全基因组DNA为供体,以4份普通小麦品种为受体,借助于低能离子束介导技术完成异源遗传物质的转移,对其介导试验的当代群体的特异性进行了观察鉴定。结果表明,经过离子束注入处理后试验材料的成苗率明显地降低,这是低能离子所导致的生物学效应之一。在所有的试验材料的生育前期和中期,在每一个处理的群体内主要农艺性状上没有表现出明显的差异,而在生育后期,被处理材料的大部分农艺性状与对照没有显著差异,仅仅在4个性状,即植株的生长势、穗型、主茎分蘖状态和单穗变异上,被处理材料表现出一定的变异特征。尽管离子束注入处理和直接浸泡外源DNA的处理也会导致其当代群体内出现突变株,但其群体内的突变株数量比较少,突变率比较低。经过离子束介导处理所导致的生物学效应最明显,其群体内的突变株数量比较多,突变率比较高。     

Detection of SO in Io's exosphere

The Galileo orbiter's close pass by Io in 1995 produced evidence for extensive mass loading of the plasma torus through the ionization of SO2. On 11 October 1999, Galileo passed even closer to Io, this time across the upstream side relative to the flow of magnetospheric plasma that corotates with Jupiter. On the first flyby, ion cyclotron waves gave direct evidence for the production of SO2+ ions. On the second flyby, ion cyclotron waves associated with SO+ were stronger and more persistent. Moreover, SO+ emissions were seen closer to Io than SO2+ emissions, suggesting that the exosphere was spatially inhomogeneous. The location of the waves suggests a fan-shaped region of ion pickup extending in the anti-Jupiter direction. Because the wave spectra were different even where the 1995 and 1999 trajectories crossed, we infer that Io's exosphere is temporally variable.     

Ultrastrong coupling of the cyclotron transition of a 2D electron gas to a THz metamaterial

Artificial cavity photon resonators with ultrastrong light-matter interactions are attracting interest both in semiconductor and superconducting systems because of the possibility of manipulating the cavity quantum electrodynamic ground state with controllable physical properties. We report here experiments showing ultrastrong light-matter coupling in a terahertz (THz) metamaterial where the cyclotron transition of a high-mobility two-dimensional electron gas (2DEG) is coupled to the photonic modes of an array of electronic split-ring resonators. We observe a normalized coupling ratio, Ω/ω(c) = 0.58, between the vacuum Rabi frequency, ?, and the cyclotron frequency, ω(c). Our system appears to be scalable in frequency and could be brought to the microwave spectral range with the potential of strongly controlling the magnetotransport properties of a high-mobility 2DEG.     

量子盘中氢化杂质束缚磁极化子的性质

采用Lee-Low-Pines变换法和Tokuda改进的线性组合算符法研究了外磁场和温度对量子盘中氢化杂质束缚强耦合磁极化子性质的影响,推导出了束缚磁极化子振动频率λ和声子平均数（N）随温度T,外磁场回旋频率ωc,电子-声子耦合强度α,介电常数比η和电子速率u的变化规律.结果表明,磁极化子的振动频率λ随电子-声子耦合强度α,介电常数比η,电子的速率u和外磁场回旋频率ω.的增加而增大,随温度T的升高和量子盘厚度L的增加而减小;磁极化子的声子平均数（N）随电子-声子耦合强度α,介电常数比η和外磁场回旋频率ωc的增加而增大,随温度T的升高和电子速率u的增加而减小,随量子盘厚度L的增加而振荡减小.     

Emission of coherent THz radiation from superconductors

Compact solid-state sources of terahertz (THz) radiation are being sought for sensing, imaging, and spectroscopy applications across the physical and biological sciences. We demonstrate that coherent continuous-wave THz radiation of sizable power can be extracted from intrinsic Josephson junctions in the layered high-temperature superconductor Bi2Sr2CaCu2O8. In analogy to a laser cavity, the excitation of an electromagnetic cavity resonance inside the sample generates a macroscopic coherent state in which a large number of junctions are synchronized to oscillate in phase. The emission power is found to increase as the square of the number of junctions reaching values of 0.5 microwatt at frequencies up to 0.85 THz, and persists up to approximately 50 kelvin. These results should stimulate the development of superconducting compact sources of THz radiation.     

黄酒中生物胺的测定

[目的]为测定黄酒中生物胺的含量寻求一种快速、简单、灵敏的检测方法。[方法]以丹磺酰氯为衍生剂,室温离子液体作为萃取、富集、衍生介质来测定黄酒中生物胺的含量。[结果]用室温离子液体[HMIM]PF6为介质来衍生、萃取和富集黄酒中的生物胺。通过试验得出比较理想的衍生条件:衍生剂量1.5 ml,硼砂缓冲液的pH 9.10,硼砂缓冲液量为2.0 ml,1.0 ml[HMIM]PF6离子液,超声时间为30 min。所得出的6种生物胺回收率为87.5%～109.8%,相对标准偏差为0.75%～3.21%,检出限量为0.005～0.025μg/ml。该方法将衍生、萃取和富集3个步骤集于一体,大大简化了试验,离子液体可有效促进分离,稳定性良好,所建立的方法线性范围良好。[结论]以丹磺酰氯为衍生剂,室温离子液体作为萃取、富集、衍生介质来测定生物胺的含量,是测定黄酒及其他饮料中痕量生物胺含量的一种快速、简单、灵敏的检测方法。     

Satellite ionosonde records: resonances below the cyclotron frequency

Resonant responses observed by the topside ionosonde in the Canadian satellite Alouette II are examined. In addition to the well-known plasma resonances, several subsidiary resonances are identified below the electron cyclotron frequency. Their patterns of occurrence are not consistent with a suggested explanation of induced magnetic dipole radiation; rather they appear to result from harmonic stimulation of the plasma resonances and beat-frequency generation.     

离子束的生物效应及应用

概述了离子束的产生,作用于生物组织的原初过程以及在诱变育种和一物工程上的应用等,并对离子束生物效应研究中存在的问题发展方向进行了分析。     

氮离子束注入和钴60伽玛辐射对大豆生物学效应研究初报

[目的] 探索氮离子束注入和钴60伽玛辐射对大豆的生物学效应,为大豆诱变育种提供依据。[方法]14份大豆品种或高代稳定品系干种子按4×10^16、6×10^16和8×10^16N^＋/cm^2 3个剂量和能量30 Kev氮离子束注入,35份大豆品种或高代稳定品系干种子按100、150和200 Gy 3个剂量和剂量率1.6 Gy/Min钴60伽玛辐射,以未处理作对照,考察大豆主要农艺性状和产量,采用近红外透射光谱法测定大豆籽粒品质。[结果]8×10^16N^＋/cm^2氮离子束注入和150 Gy钴60伽玛辐射对大豆农艺性状的突变效果明显。氮离子束注入和钴60伽玛辐射诱变蛋白质含量增加的材料占总材料份数的57.1%-78.6%,但6×10^16N^＋/cm^2氮离子束注入的蛋白质突变频率大于其余两个剂量,而钴60伽玛辐射剂量间差异不大;诱变脂肪含量增加的材料占总材料份数的34.3%-40.0%,且8×10^16N^＋/cm^2氮离子束注入和200 Gy钴60伽玛辐射的脂肪突变频率分别大于其余两个剂量。[结论]选择适宜剂量的氮离子束注入和钴60伽玛辐射可以改善大豆农艺性状,增加产量,提高蛋白质和脂肪含量,因而氮离子束注入和钴60伽玛辐射是两种行之有效的大豆诱变育种方法。     

Protonated Ozone: Experimental Detection of O3H+ and Evaluation of the Proton Affinity of Ozone

The elusive protonated ozone ion (O(3)H(+)) has been long postulated as a reactive intermediate but never experimentally observed. This ion has been detected here in mass spectrometric experiments with the use of Fourier transform ion cyclotron resonance. In these experiments, ozone (O(3)) was protonated by strong acids-for example, H(3)(+), KrH(+), XeH(+), and CH(5)(+). The hitherto experimentally unknown proton affinity of O(3) was evaluated by a "bracketing" technique and determined to be 148 -/+ 3 kilocalories mole(-1) at 298 kelvin, in excellent agreement with a value determined in a recent theoretical study of the O(3)/O(3)H(+) system, which was 148 kilocalories mole(-1) at zero temperature ( approximately 149.5 kilocalories mole(-1) at 298 kelvin).     

植物激素及其金属配合物的生理活性研究

植物激素是调节和控制植物生长发育不可缺少的物质，其生理活性涉及到与植物体内金属离子的相互作用［１］。为了深入探讨植物激素与金属离子的相互作用及金属离子对其生理活性的影响。我们以四种植物激素为配体，首次合成了七种新配合物，并采用小麦芽鞘切段伸长法测定了四种配体及其配合物的生理活性，发现配合物的生理活性比配体的有显著提高，并分析了其作用机理。     

化肥减量配施不同有机肥对烤烟产质量的影响

为玉溪烟区科学施肥提供依据,通过田间试验研究了化肥减量配施烟草专用有机肥和生物有机肥对烤烟农艺性状、经济性状、外观质量、化学成分、感官质量及致香成分的影响。结果表明：化肥减量15%~45%配施两种有机肥均未对烟株整体农艺性状表现产生不利影响,且在化肥相同减量条件下烟草专用有机肥处理烤烟株高及节距均显著高于生物有机肥处理;各处理烟叶产值在47944.50~78820.50元/hm2之间,均价在21.83~26.78元/kg之间,上等烟比例在57.00%~68.10%之间,且均以化肥减量15%配施100kg烟草专用有机肥处理表现最佳。在烟叶品质方面,化肥减量15%~45%配施两种有机肥均可改善中部烟叶叶片结构、色度及外观质量综合得分;在化肥相同减量条件下,烟草专用有机肥处理中部烟叶外观质量综合得分、感官质量综合得分、化学成分及致香成分总量均优于生物有机肥处理,且均以化肥减量15%表现最优。综上所述,化肥减量15%配施100kg烟草专用有机肥有利于改善烤烟产量及烟叶品质。     

小麦抗赤霉病杂种的花培研究

利用MS培养基或N6培养基,添加适当的植物激素与有机成分,对非小偃血统的普通小麦抗赤霉病杂种材料进行组织培养,获得花粉植株。用花药作外植体进行离体培养,有愈伤组织形成,有些杂种材料花药诱导成愈伤组织的频率较高。因此,通过花药培养途经,以缩短杂种性状稳定的年限,加速小麦抗赤霉病高产品种的选育进程是可能的。