加速器高频D电路Q值的计算与测量

介绍了回旋加速器高频单D型盒D电路Q值的计算与测量方法。重点对Q值的理论计算进行推导,并对计算原理进行说明。然后对计算结果和测量结果进行比较。得出的计算和测量结果基本吻合。误差产生的主要原因是计算过程中的近似和短路片接触电阻的取值,其中短路片接触电阻是一个重要因素,在设计腔体时应引起足够的重视。

大兴安岭樟子松林火历史及火烧对林分结构的影响(英文)

为准确评价林火在大兴安岭樟子松林中的地位和作用,在大兴安岭呼伦贝尔盟莫尔道嘎林区樟子松林内,利用火疤木解析的方法,确定了3块火疤木集中的样地历史林火发生的年代及每次林火的火焰高度(h);林火强度(I)通过经验公式计算;结合样地每木调查,推算了林火发生后样地林木胸径。研究表明,3块样地自1887～1976年间共发生10次林火,h为0.46～3.32m,I为48～3690kW/m,平均林火间隔期(tMFI)约为19.8a。在樟子松林内高强度的火烧对林分生长造成破坏,迫使林分重新开始更新和演替,中度与低强度火作为一个自然选择力,排除抗火性较樟子松差的树种、灌木和杂草,加速养分循环,使存活下来的樟子松获得更大的存活与发展空间。tMFI与I成反比,因此过分干扰林火发生必将增加发生大火的可能性。

Amperometric glucose biosensor based on single-walled carbon nanohorns

The biosensing application of single-walled carbon nanohorns (SWCNHs) was demonstrated through fabrication of an amperometric glucose biosensor. The biosensor was constructed by encapsulating glucose oxidase in the Nafion-SWCNHs composite film. The cyclic voltammograms for glucose oxidase immobilized on the composite film displayed a pair of well-defined and nearly symmetric redox peaks with a formal potential of -0.453V. The biosensor had good electrocatalytic activity toward oxidation of glucose.

Syntheses and crystalline structures of clusters Co-3(CO)(7)(mu(3)-S)(mu, eta(2)-SCNR2)

Through the reaction of Co-2(CO)(8) with four thiuram [R2NC(S)S](2), four new sulfur-capped trinuclear cobalt carbonyl clusters Co-3 (CO)(7) (mu(3)-S) (mu, eta(2)-S* C* NR2) ( I : R = Me; I : R = Et; II : R = i-Pr; IV : NR= -N [GRAPHICS] were prepared and characterized by elementary analysis, IR,H-1 NMR and MS spectroscopy. The crystal structure of the cluster Co-3(CO)(7)(mu(3)-S)[mu, eta(2)-S*C*N (i-Pr)(2)]( III) was determined by X-ray single crystal diffraction method. The crystal of m is monoclinic, belonging to space group P2(1)/n, and the cell parameters are as follows: a = 1, 145 2(2) nm, b = 1. 502 8(3) nm, c = 1, 214 4(2) nmj alpha = 90 degrees, beta = 92, 15(3)degrees, gamma = 90 degrees; V = 2. 088 5(7) nm(3) , Z = 4, F (000) = 1 096, D-c = 1. 747 mg . m(-3), mu = 2. 588 mm(-1), R=0. 040 7, R-w=0. 062 4, The structural analysis shows that cluster II has a pyrimidal Co3S framework and contains a heterocylic bridging bidentate ligand [mu, eta(2)-S* C* N (i-Pr)(2)] linked to the Co2 and Co3 atoms of the cluster by a cobalt-carbon and a cobalt-sulfur bond respectively.

Co_3(CO)_7(μ_3-S)(μ,η~2-SCNR_2)的合成和晶体结构

Co2 (CO) 8 与 4个二硫代双 (烷基硫代甲酰胺 )类前配体 [R2 NC(S) S]2 反应 ,得 4个含烷基硫代甲酰胺基的三核钴羰基硫簇合物 .通过元素分析、IR、 1H NMR和 MS等方法表征了它们的结构 ,用 X射线衍射法测定了其中一个簇合物 Co3 (CO) 7(μ3 - S) [μ,η2 - SCN(i- Pr) 2 ]( )的晶体结构 .晶体属单斜晶系 ,P2 1/n空间群 ,晶胞参数 a=1.1452 (2 ) nm,b=1.50 2 8(3) nm,c=1.2 144 (2 ) nm,α=90°,β =92 .15(3)°,γ =90°,V =2 .0 885(7) nm3 ,Z=4 ,F (0 0 0 ) =10 96 ,Dc=1.74 7mg· m-3 ,GOF(F2 ) =0 .835,μ=2 .588nm-1.最终因子 R[I>2 σ(I) ]=0 . 0 4 0 7,Rw=0 .0 6 2 4

微量元素锗化合物的生物活性

锗是周期表第Ⅳ主族的半金属元素,在地壳中的分布属于典型的稀散元素,土壤中平均约含0.2ppm,很多植物中都含有微量锗,其中许多名贵中药材和茶叶含比较丰富的锗化合物尽管迄今还不能确定锗是人体必须微量元素,但因许多中药的医疗保健作用被认为与其含有相对丰富的有机锗有关,因此,近二十年来锗化合物的生物活性日益受到人们的重视。锗和同族的其它元素类似,也容易生成有机化合物。1887年合成的四乙基锗是世界上合成的第一个

Diversity and spatial distribution of sediment ammonia-oxidizing crenarchaeota in response to estuarine and environmental gradients in the Changjiang Estuary and East China Sea

Ammonia-oxidizing archaea (AOA) have recently been found to be potentially important in nitrogen cycling in a variety of environments, such as terrestrial soils, wastewater treatment reactors, marine waters and sediments, and especially in estuaries, where high input of anthropogenic nitrogen is often experienced. The sedimentary AOA diversity, community structure and spatial distribution in the Changjiang Estuary and the adjacent East China Sea were studied. Multivariate statistical analysis indicated that the archaeal amoA genotype communities could be clustered according to sampling transects, and the station located in an estuarine mixing zone harboured a distinct AOA community. The distribution of AOA communities correlated significantly with the gradients of surface-water salinity and sediment sorting coefficient. The spatial distribution of putative soil-related AOA in certain sampling stations indicated a strong impact of the Changjiang freshwater discharge on the marine benthic microbial ecosystem. Besides freshwater, nutrients, organic matter and suspended particles, the Changjiang Diluted Water might also contribute to the transport of terrestrial archaea into the seawater and sediments along its flow path.

中国及相关海域褐虾总科系统分类学和动物地理学研究

褐虾总科包括褐虾科和镰虾科，是重要的底栖生物类群，而且很多褐虾种为常见的经济种，其中中国北方海域最常见的为日本褐虾Crangon hakodatei Rathbun, 1902，另外黄海褐虾Crangon uritai Kim & Hayashi, 1999在黄渤海也较为常见。在东海和南海，污泥疣褐虾Pontocaris pennata (Bate, 1888)和拉氏爱琴虾Aegaeon lacazei (Gourret, 1887)在底栖生物拖网时常可采到，有很大的经济价值。我国对褐虾总科的研究很少，亟需对我国海域的褐虾进行全面的系统分类学和地理分布研究。 本论文所依据的标本主要为中国科学院海洋研究所海洋生物标本馆馆藏的约1600号褐虾类标本，标本主要采自渤海、黄海、东海、南海四大海域，也有部分标本采自日本海、南极和北极等海域，并得到国外同行专家惠赠的褐虾类标本约100号，同时也检查了其它单位保藏的少量标本。 本论文主要采用传统的形态学方法进行分类学研究，共鉴定出褐虾科14属25种，其中1个新种，6个新记录种，镰虾科1属7种，其中2个新种，3个新记录种。参照历史文献与现在研究结果，中国海域的褐虾类至少有2科11属44种。 本文通过对约1700号标本的详细检查，总结了各个属和种的分类学特征和地理分布特点，对各属的分种均附有详细系统的检索表，对鉴定的32种褐虾均附有详细的背面整体图和侧面整体图以及附肢等的局部形态图，并对各种进行了中文名称的考订。 本研究是我国首次关于褐虾总科的系统分类学和动物地理学研究，研究结果将改变我国在褐虾总科研究报道方面的薄弱现状，并为此动物类群的多样性等研究提供重要的基础资料。研究结果澄清了分类学上存在争议的疑难种，发现了3个新种，报道了9个新记录种，阐明了我国褐虾总科的区系特点。

A new species and two new record species of genus Allokepon Markham, 1982 (Isopoda : Epicaridea : Bopyridae) from China

Descriptions of a new species and two new records of species of the genus Allokepon Markham, 1982 from Chinese waters are presented. The host species were portunid crabs. Allokepon hendersoni (Giard & Bonnier 1887) was found infesting Charybdis bimaculata (Miers), A. monodi (Bourdon, 1967) infesting Portunus pelagicus (L), Portunus trituberculatus ( Miers), and Thalamita sp. and A. longicauda n. sp. infesting Portunus pulchricristatus (Gorden). Three of the host species were recorded for the first time harboring isopod parasites, and the male of A. monodi is presented. Allokepon longicauda n. sp. is distinguished from the other four species found in China by the long slender uropods of females.

Production of a base population and its responses to F-1 selection in the bay scallop, Argopecten irradians irradians Lamarck (1819)

A base population of the bay scallop, Argopecten irradians irradians Lamarck, was produced by crossing two cultured bay scallop populations. After 1 year of rearing, the top 10% truncation selection of the top 10% (i=1.755) was carried out in the base population of about 1300 adults. A control parental group with a an identical number to the select parental group was randomly selected from the entire population before isolation of the select parental group. The result showed that, at the larval stage, the growth rate of larvae in the selected line was significantly higher than that of the control (P < 0.05), and that the genetic gain was 6.78%. Owing to the lower density of control at the spat stage, the mean shell length of the control line was larger than that of the select line at day 100. When the same density was adjusted between two lines in the grow-out stage (from day 100 to 160), the daily growth rate of the selected line was significantly higher than that of the control line (P < 0.05). Survival of the select line was significantly larger than that of the control line in the grow-out stage. In conclusion, the results obtained from this experiment indicate that selective breeding from a base population with a high genetic diversity established by mass spawning between different populations appears to be a promising method of genetic improvement in bay scallop, A. irradians irradians Lamarck.

Determination of free fatty acids in soil and bryophyte plants by precolumn derivatization via HPLC with fluorescence detection and tandem mass spectrometry (HPLC-MS/MS)

A sensitive method for the determination of 30 kinds of free fatty acids (FFAs, C-1-C-30) with 1-[2-(p-toluenesulfonate)-ethyl]-2-phenylimidazole-[4,5-f] 9,10-phenan- threne (TSPP) as labeling reagent and using high performance liquid chromatography with fluorescence detection and identification by online postcolumn mass spectrometry with atmospheric pressure chemical ionization (APCI) source in positive-ion mode (HPLC/MS/APCI) has been developed. TSPP could easily and quickly label FFAs in the presence of K2CO3 catalyst at 90 degrees C for 30 min in N,N-dimethylformamide (DMF) solvent, and maximal labeling yields close to 100% were observed with a 5-fold excess of molar reagent. Derivatives were stable enough to be efficiently analyzed by high performance liquid chromatography. TSPP was introduced into fatty acid molecules and effectively augmented MS ionization of fatty acid derivatives and led to regular MS and MS/MS information. The collision induced cleavage of protonated molecular ions formed specific fragment ions at m/z [MH](+)(molecular ion), m/z [M'+CH2CH2](+)(M' was molecular mass of the corresponding FFA) and m/z 295.0 (the, mass of protonated molecular core structure of TSPP). Fatty acid derivatives were separated on a reversed-phase Eclipse XDB-C-8 column (4.6 x 150 mm, 5 mu m, Agilent) with a good baseline resolution in combination with a gradient elution. Linear ranges of 30 FFAs are 2.441 x 10(-3) to 20 mu mol/L, detection limits are 3.24 similar to 36.97 fmol (injection volume 10 mu L, at a signal-to-noise ratio of 3, S/N 3:1). The mean interday precision ranged from 93.4 to 106.2% with the largest mean coefficients of variation (R.S.D.) < 7,5%. The mean intraday precision for all standards was < 6.4% of the expected concentration. Excellent linear responses were observed with correlation coefficients of > 0.9991. Good compositional data could be obtained from the analysis of extracted fatty acids from as little as 200 mg of bryophyte plant samples.Therefore, the facile TSPP derivatization coupled with HPLC/MS/APCI analysis allowed the development of a highly sensitive method for the quantitation of trace levels of short and long chain fatty acids from biological and natural environmental samples.