Chromosomal aberrations induced by C-12(6+) ions and Co-60 gamma-rays in mouse immature oocytes

The ovaries of Kun-Ming strain mice (3 weeks) were irradiated with different doses of C-12(6+) ion or Co-60 gamma-ray. Chromosomal aberrations were analyzed in metaphase II oocytes at 7 weeks after irradiation. The relative biological effectiveness (RBE) of C C-12(6+) ion was calculated with respect to Co-60 gamma-ray for the induction of chromosornal aberrations. The C-12(6+) ion and Co-60 gamma-ray dose-response relationships for chromosomal aberrations were plotted by linear quadratic models. The data showed that there was a dose-related increase in frequency of chromosomal aberrations in all the treated groups compared to controls. The RBE values for C-12(6+) ions relative to (CO)-C-60 gamma-rays were 2.49, 2.29, 1.57, 1.42 or 1.32 for the doses of 0.5, 1.0, 2.07 4.0 or 6.0 Gy, respectively. Moreover, a different distribution of the various types of aberrations has been found for C-12(6+) ion and Co-60 gamma-ray irradiations. The dose-response relationships for C-12(6+) ion and (CO)-C-60 gamma-ray exhibited positive correlations. The results from the present study may be helpful for assessing genetic damage following exposure of immature oocytes to ionizing radiation.

纳秒激光诱导C60分子碎裂中轻碎片离子C+n(n＜30)的产生机理研究

The time of flight mass spectrometric technique was used to determine the initial mean kinetic energy of small fragment ions C-n(+) (n <= 11) produced from C-60 excited by 532 nm nanosecond laser pulses. The measured kinetic energy shows little variation with the fragment mass and the laser fluence in a broad range. Based on the assumption that C-30(+) is produced predominantly by a single electron emission followed by successive C-2 evaporation from hot C-60 in the nanosecond laser field, the formation of small fragments is interpreted as the complete breakup of the unstable C-30(+) cage structure. The interpretation is consistent with the previously observed results.

Polymeric fullerene oxide films produced by decomposition of hexanitro[60]fullerene

A new poly(fullerene oxide) thin film material has been fabricated by thermal activation and electron bombardment on hexanitro[60]fullerene (HNF) film deposited on a An substrate, all under vacuum conditions. The reaction products in the polymerization process are analyzed by XPS, UPS, IR, TGA-MS and LDI-MS techniques. It is found that the main effect of thermal and radiation treatments is to induce cleavage of -NO bonds from HNF molecules resulted in the release of nitric oxide gas and the formation of fullerene-bound oxyradicals, C-60-C-6. Spectroscopic evidence strongly suggests that rearrangement of fullerenic nitro moieties into nitrito groups is involved in the HNF decomposition process prior to the generation of reactive oxyradical intermediates. Consequently, the intermolecular coupling reaction of these oxyradicals leads to carbon polymer networks containing oxygen-bridged fullerenes. The thermally generated polymeric thin film is stable up to 900 K. Electron bombardment is also effective in both the decomposition of -NO2 groups and the removal of -OH groups present in HNF films. UV irradiation at 365 nm alone is shown to be not as efficient for the polymer formation. (C) 2003 Elsevier Ltd. All rights reserved.

C-118 from fullerenols: Formation, structure and intermolecular nC(2) transfer reactions in mass spectrometry

In fast atom bombardment, two fullerenols C-60(OH)(x) (x=13-15) and C-60(OH)(x) (x-24-26) gave rise to a group of ions centered at C-118 with intervals of 24 mass units in the high mass region. In contrast, no such ions appeared in the mass spectra of pure C-60, C-70 and other fullerene derivatives such as C-60(C6H5)(10), under the same conditions. It is proposed that the pinacol rearrangement of C-60(OH)(2), resulting from partial rupture of the polyhydroxy molecules, produces C-59 with two carbon atoms bearing an unpaired electron, and that dimerization of this reactive intermediate is responsible for the formation of the predominant product C-118. An intermolecular nC(2) transfer process is used to explain the symmetrical abundance distribution of these product ions in the spectra of fullerenols.

Miscibility, crystallization, and morphology studies of thermosetting polyimide PMR-15/PEK-C blends

Miscibility, crystallization, and mechanical properties of blends of thermosetting polyimide PMR-15 and phenolphthalein poly(ether ketone) (PEK-C) were examined. With the exception of the 90/10 blend, which has two glass transition peaks, all the blends with PMR-15 less than 90 wt % are miscible in the amorphous state according to DMA results. Addition of PEK-C hindered significantly the crystallization of PMR-15, indicating that there must exist some kind of interaction between molecular chains of PMR-15 and those of PEK-C. The semi-IPN system of PMR-15/PEK-C blends exhibits good toughness. Two distinct microphases, interweaving at the phase boundaries, were found in the PMR-15/PEK-C 60/40 blend. The toughness effect of the blends is discussed in terms of the interface adhesion between the two distinct phases and the domain sizes of the phases. The relation between miscibility and toughness of the blends was investigated. (C) 1996 John Wiley & Sons, Inc.

C_(60)与某些有机小分子的气相离子-分子反应

气相C_(60)在化学电离质谱中分别与3种氯代甲烷和4种氯代乙烷的分子离子及其碎片离子发生气相离子-分子反应,观察到C_(60)的几十种气相加合离子(其中绝大多数为含氯原子的).通过对比分析认为,C_(60)的加合离子丰度并不与反应物氯代烷中相应碎片离子丰度成顺变关系,某些含自由基的碎片离子(或自由基)与C_(60)(或C~+-(60))表现出更强的反应活性,这体现了C_(60)作为烯烃的吸自由基特性.

Early development of Costaria costata (C. Agardh) Saunders and cultivation trials

Costaria costata (C. Agardh) Saunders is one of common kelps distributed in many coastal areas worldwide; however, in China, no reports have been made on cultivation of the genus. To investigate potential cultivation of the species in the northern part of China, trials on isolation and preservation of the gametophytes were conducted using C. costata from Korea; growth and development of the gametophytes were observed. We showed that at 10 +/- 1A degrees C, 60 mu mol m(-2)s(-1) and 12:12 h (L:D), freshly released zoospores settled down within 1 hour, and then developed into the primary cell during the following 2 days. After a vegetative growth phase lasting 6-8 days, female gametophytes became 3-4 times larger in diameter than that of the primary cell, but still remained at a unicellular stage, while male gametophytes divided into 4-10 cells with only a slight change in size. Fertilization occurred within 10 days after the zoospores were released from the sporangia, and the apical and basal tissues of the juvenile sporophyte divided and differentiated into the blade and stipe. Temperature and irradiance influenced gametophytic vegetative growth and developmental patterns. Generally, low irradiance (15 mu mol m(-2)s(-1) and 30 mu mol m(-2)s(-1)) was unfavorable to the induction of fertility, but it enhanced female gametophyte division. The optimal conditions for vegetative growth were 15A degrees C and 30 mu mol m(-2)s(-1). After transplantation of the juvenile seedlings and after eight months cultivation, the harvested mature blade reached 194 cm in length and 32.7 cm in width. Our study proves that it is feasible to implement propagation and large scale cultivation of C. costata in northern China.

Investigation Of Mode Ii Crack Growth Following A Very High Speed Impact

A recoverable plate impact testing technology has been developed for studying fracture mechanisms of mode II crack. With this technology, a single duration stress pulse with submicrosecond duration and high loading rates, up to 10(8) MPam(1/2)s(-1), can be produced. Dynamic failure tests of Hard-C 60# steel were carried out under asymmetrical impacting conditions with short stress-pulse loading. Experimental results show that the nucleation and growth of several microcracks ahead of the crack tip, and the interactions between them, induce unsteady crack growth. Failure mode transitions during crack growth, both from mode I crack to mode II and from brittle to ductile fracture, were observed. Based on experimental observations, a discontinuous crack growth model was established. Analysis of the crack growth mechanisms using our model shows that the shear crack extension is unsteady when the extending speed is between the Rayleigh wave speed c(R) and the shear wave speed c(S). However, when the crack advancing speed is beyond c(S), the crack grows at a steady intersonic speed approaching root 2c(S). It also shows that the transient mechanisms, such as nucleation, growth, interaction and coalescence among microcracks, make the main crack speed jump from subsonic to intersonic and the steady growth of all the subcracks causes the main crack to grow at a stable intersonic speed.

我国淡水养殖乌鳢的类立克次体感染

2001-2002年,湖北省某养殖场发生一种导致养殖乌鳢(Ophiocephalus argus C)大规模死亡的突发性传染病.该病发病率为60％-70％,发病死亡率高达100％.病鳢腹部膨大,内脏器官出现“粟粒”样结节,肾脏肿大成5-10个乳白色、灰白色“内瘤”状物或溃烂成“豆渣”样.光学显微镜观察发现细胞内出现嗜酸性或嗜碱性内含物,内脏器官出现肉芽肿炎症、细胞大范围的变性和死亡;电子显微镜观察显示细胞内包含物为质膜包绕的类立克次体(RLO).RLO圆形或椭圆形,直径0.5-1.5μm,具中心核区,胞质

碳纤维增强聚芳醚酮材料的研究

用氧化法（KClO_3 + H_2SO_4）对吉林碳素厂生产的碳纤维短丝（SCF）进行了表面处理，并采用预混、热压等工艺制备了 SCF 增强聚芳醚酮（PEK－C）复合材料（SCF／PEK－C）。PEK－C 是应化所开发的新型树脂。用 SCF 增强后弯曲模量可高达 10GPa。弯曲强度达 170 MPa，接近短纤维增强 PEEK（英国帝国化学公司产品）水平，是一类很有前途的热塑性结构材料。本工作用光电子能谱（ESCA）等方法对碳纤维表面的氧化程度和表面性能进行了分析，用扫描电子显微镜（SEM）等研究了材料的断面形貌和界面粘结。并根据材料的弯曲模量，弯曲强度，剪切强度及动态力学性能等的测试结果，分析和讨论了碳纤维表面氧化程度 ～ 复合材料界面粘结 ～ 材料力学性能的关系。结果证明，碳纤维经氧化后，表面含氧基团增加，吸附活性提高，由此导致复合材料界面粘结的改善和力学性能的大幅度提高。用氧化后纤维增强 PEK－C 材料的断面不再出现园孔，只有少量的拔出纤维，基体出现皱褶。变曲模量和强度的增强因子分别提高了 60％ 和 210％。

ELECTRONIC-STRUCTURES OF THE ALKALI-CONTAINING BUCKMINSTERFULLERENES (A-DELTA-C60) (A=LI,NA,K,RB,CS) AND THE HALOGEN-CONTAINING BUCKMINSTERFULLERENES (H-DELTA-C60) (H=F,CL,BR,I)

The geometrical parameters and electronic structures of C60, (A partial derivative C60) (A = Li, Na, K, Rb, Cs) and (H partial derivative C60) (H = F, Cl, Br, I) have been calculated by the EHMO/ASED (atom superposition and electron delocalization) method. When putting a central atom into the C60 cage, the frontier and subfrontier orbitals of (A partial derivative C60) (A = Li, Na, K, Rb, Cs) and (H partial derivative C60) (H = F, Cl) relative to those of C60 undergo little change and thus, from the viewpoint of charge transfer, A (A = Li, Na, K, Rb, Cs) and H (H = F, Cl) are simply electron donors and acceptors for the C60 cage resPeCtively. Br is an electron acceptor but it does influence the frontier and subfrontier MOs for the C60 cage, and although there is no charge transfer between I and the C60 cage, the frontier and subfrontier MOs for the C60 cage are obviously influenced by I. The stabilities DELTAE(X) (DELTAE(X) = (E(X) + E(C60)) - E(x partial derivative C60)) follow the sequence I < Br < None < Cl < F < Li < Na < K < Rb < Cs while the cage radii r follow the inverse sequence. The stability order and the cage radii order have been explained by means of the (exp-6-1) potential.

High negative ion production yield in 30 keV F2+ + adenine (C5H5N5) collisions

In collisions between slow F2+ ions (30 keV) and molecular targets, adenine, scattered particle production yields have been measured directly by simultaneous detection of neutrals, positive and negative ions. The relative cross-section for a negative ion formation channel was measured to be 1%. Despite a slight decrease compared to a larger target, the fullerene C-60, the measured negative ion formation cross section is still at least one order of magnitude larger than the yield in ion-atom interactions.

The properties and possible transformation path for C12B24N24

The structure and frequencies of C12B24N24 have been calculated by means of an ab initio method. By comparing the average bond energies with C-60, the calculated results predict that the cage C12B24N24 is a stable molecule. The calculated results indicate that the cage molecule C12B24N24 has a relative large HOMO-LUMO energy gap and a low rigidity The structures and stability of six possible isomers of C2B4N4 are used to suggest a possible transformation path from the pentagon CB2N2 to the C12B24N24 materials. (C) 2001 John Wiley & Sons, Inc.

Hybrid metal-base transistor with base of sulfonated polyaniline and fullerene emitter

We demonstrate hybrid vertical architecture transistors that operate like metal-base transistors, using n-type silicon as the collector, sulfonated polyaniline as the base, and C-60 fullerene as the emitter. Electrical measurements suggest that the sulfonated polyaniline base effectively screens the emitter from electric field variations occurring in the collector leading to the metal-base transistor behavior.

Characterization and electrocatalytic application of a fullerene/ionic-liquid composite

A fullerene/ionic-liquid composite was explored. Transmission Electron Microscopy (TEM) study showed that in the composite, C-60 mainly exists as nano-clusters, Raman spectrum proved that the composite formed only by physical Mix of C-60 and 1-Butyl-3-methyl-imidazolium hexafluorophosphate (BMIPF6), the combination did not change the chemical naturation of C-60. The electrochemical properties of the composite modified electrode, including the electrode reaction control function and the interfacial potential effect were studied.