排序方式： 共有10条查询结果，搜索用时 46 毫秒
1
1.
We have measured P- and S-wave velocities on two amphibolite and two gneiss samples from the Kola superdeep borehole as a function of pressure (up to 600 MPa) and temperature (up to 600 °C). The velocity measurements include compressional (Vp) and shear wave velocities (Vs1, Vs2) propagating in three orthogonal directions which were in general not parallel to inherent rock symmetry axes or planes. The measurements are accompanied by 3D-velocities calculations based on lattice preferred orientation (LPO) obtained by TOF (Time Of Flight) neutron diffraction analysis which allows the investigation of bulk volumes up to several cubic centimetres due to the high penetration depth of neutrons. The LPO-based numerical velocity calculations give important information on the different contribution of the various rock-forming minerals to bulk elastic anisotropy and on the relations of seismic anisotropy, shear wave splitting, and shear wave polarization to the structural reference frame (foliation and lineation). Comparison with measured velocities obtained for the three propagation directions that were not in accordance with the structural frame of the rocks (foliation and lineation) demonstrate that for shear waves propagating through anisotropic rocks the vibration directions are as important as the propagation directions. The study demonstrates that proper measurement of shear wave splitting by means of two orthogonal polarized sending and receiving shear wave transducers is only possible when their propagation and polarization directions are parallel and normal to foliation and lineation, respectively. 相似文献
2.
TOF-SIMS在源岩单组分研究中的应用 总被引：1，自引：0，他引：1
应用飞行时间二次离子质谱 (TOF SIMS)对源岩单组分进行原位微分析 ,结果表明有机组分(1)二次离子峰集中分布在低质量数一端 ;(2 )无机离子峰强度普遍高于有机离子峰 ;(3)同类型相邻的有机离子峰之间相差一定单位的质量 (14,即CH2 ) ;(4 )不同有机组分峰强度最大的有机离子相同 ,但它们峰的相对强度差异非常明显 ,借助有机离子峰的相对强度可以反映有机组分的化学结构及其生烃性特征。 相似文献
3.
Fulvic acids of different origin, spray deposited on polished silicon after dissolution in high‐purity water without any additives, were analysed by time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) in combination with oblique 24...36 keV SF5+ ion bombardment. The observed, highly reproducible mass spectra cover more than five orders of magnitude in dynamic range, without background subtraction. Apart from lines due to atomic ions and low‐mass ion fragments, the mass spectra exhibit broad maxima between m/z 200...350, mainly due to a beat‐like superposition of lines at every single mass number, up to at least m/z 400. In the negative ion spectra the beats have a spacing of m/z 14, corresponding to a CH2‐unit. The high‐mass tails of the spectra extend well beyond m/z 5000, with similar slopes in the positive and the negative ion mass spectra. The negative spectra appear to be less affected by fragmentation products than the positive spectra. Fulvic acids (FAs) of different origin show distinctly different spectra, with mean masses ranging between m/z ≈ 450 and 580 (for a low‐mass cut‐off m/z 150). To further verify the ability of TOF‐SIMS to detect molecules and clusters with masses significantly above the maxima of the FA spectra, samples of glycyrrhizic acid (GA, as GA ammonium salt with molecular weight 840) were also analysed. Parent ions as well as multimers (GA)n were observed as positive and negative ions, up to n = 4 (m/z 3320). The results are compared with spectra recently obtained by other mass spectrometric techniques. 相似文献
4.
目的:通过对比单纯超声心动图和超声心动图联合64排CT心血管造影对肺动脉狭窄部位的诊断准确性,对肺动脉主干、左、右肺动脉内径、右心室流出道内径以及患儿肺血管发育情况的预测准确率,并通过相关性分析说明超声心动图和64排CT心血管造影两种方法对左右心室各指标测量结果的密切相关性,从而阐明联合应用两种方法在提高法洛四联症心血管成像诊断准确率中的重要意义。方法:分别采用超声心动图和超声心动图联合64排CT心血管造影诊断肺动脉狭窄部位以及评价患儿肺血管发育情况,并与手术后实际诊断结果比较;采用超声心动图和超声心动图联合64排CT心血管造影测量肺动脉主干、左、右肺动脉内径以及右心室流出道内径,并与手术后实际测得结果比较;相关性分析说明超声心动图和64排CT心血管造影两种方法对左右心室各指标测量结果的相关情况。结果:超声心动图联合64排CT心血管造影诊断肺动脉狭窄部位的准确率为91.5%,明显高于单纯超声心动图的准确率68.1%(P<0.05);联合诊断组所测得Me Goon指数、Nakata指数、肺动脉主干、左、右肺动脉内径以及右心室流出道内径与手术组实测结果间无明显统计学差异(P>0.05),而超声心动图与手术实测结果相比有明显统计学差异(P<0.05);超声心动图和64排CT心血管造影对左右心室各指标测量结果均呈现密切相关性(r>0.7,P<0.05)。结论:单纯超声心动图和64排CT心血管造影在诊断法洛四联症病变方面呈现密切相关性,但超声心动图联合64排CT心血管造影对法洛四联症(TOF)病变情况的诊断准确率明显高于单纯超声心动图,为临床上法洛四联症心血管成像提供了新的思路。 相似文献
5.
WANG Baojie PENG Hongni LIU Mei JIANG Keyong ZHANG Guofan WANG Lei 《中国海洋大学学报(英文版)》2013,12(3):477-483
The clotting protein (CP) plays important and diverse roles in crustaceans, such as coagulation and lipid transportation. A clotting protein was purified from the hemolymph of Chinese shrimp Fenneropenaeus chinensis (named as Fc-CP) with Q sepharose HP anion-exchange chromatography and phenyl sepharose HP hydrophobic interaction chromatography. Fc-CP was able to form stable clots in vitro in the presence of hemocyte lysate and Ca2+, suggesting that the clotting reaction is catalyzed by a Ca2+-dependent transglutaminase in shrimp hemocytes. The molecular mass of Fc-CP was 380 kDa under non-reducing conditions and 190 kDa under reducing conditions as was determined with SDS-PAGE. CP exists as disulfide-linked homodimers and oligomers. The N-terminal amino acid sequence of Fc-CP was identical to that of shrimps including Penaeus monodon, Farfantepenaeus paulensis and Litopenaeus vannamei; and similar to that of other decapods. The purified Fc-CP was digested with trypsin and verified on an ABI 4700 matrix-assisted laser desorption/ionization tandem time-of-flight (MALDI-TOF/TOF) mass spectrometry. Our results will aid to better understanding the coagulation mechanism of shrimp hemolymph. 相似文献
6.
L. S. Farenzena P. Iza R. Martinez F. A. Fernandez-Lima E. Seperuelo Duarte G. S. Faraudo C. R. Ponciano M. G. P. Homem A. Naves de Brito K. Wien E. F. da Silveira 《Earth, Moon, and Planets》2005,97(3-4):311-329
Experimental results on fast ion collision with icy surfaces having astrophysical interest are presented. 252Cf fission fragments projectiles were used to induce ejection of ionized material from H2O, CO2, CO, NH3, N2, O2 and Ar ices; the secondary ions were identified by time-of-flight mass spectrometry. It is observed that all the bombarded frozen gas targets emit cluster ions which have the structure XnR±, where X is the neutral ice molecule and R± is either an atomic or a molecular ion. The shape of the positive or negative ion mass spectra is characterized by a decreasing yield as the emitted ion mass increases and is generally described by the sum of two exponential functions. The positive ion water ice spectrum is dominated by the series (H2O)nH3O+ and the negative ion spectrum by the series (H2O)nOH− and (H2O)nO−. The positive ion CO2 ice spectrum is characterized by R+ = C+, O+, CO+, O2+ or CO2+ and the negative one by R− = CO3−. The dominant series for ammonia ice correspond to R+ = NH4+ and to R− = NH2−. The oxygen series are better described by (O3)nOm+ secondary ions where m = 1, 2 or 3. Two positive ion series exist for N2 ice: (N2)nN2+ and (N2)nN+. For argon positive secondary ions, only the (Ar)nAr+ series was observed. Most of the detected molecular ions were formed by one-step reactions. Ice temperature was varied from ∼20 K to complete sublimation. 相似文献
7.
首次采用飞行时间二次离子质谱在线微区分析技术,系统研究了不同成熟度镜状体的表现特征及解释方法.其结果对于全面掌握镜状体的属性,认识其生源及形成过程具有重要的理论与实际意义. 相似文献
8.
本研究利用阳离子交换和分子筛的方法成功分离鉴定出分子量为105kDa，以多聚体形式存在七鳃鳗凝集素。实验结果表明，首先运用阳离子交换色谱方法能够将七鳃鳗血清混合组分进行初步分离，结合凝集活性鉴定方法，鉴定凝集活性最强组分存在于第二峰中。其次；利用分子筛方法将具有凝集活性组分进一步分离，最终得到分子量为105kDa左右具有凝集活性组分。结合Native-PAGE和SDS-PAGE结果表明，凝集活性组分以三聚体形式存在。同时，飞行时间质谱方法鉴定结果为凝集素（gi:13094239）。最终，体外鉴定结果表明七鳃鳗凝集素对兔红细胞和山羊红细胞均具有较强的凝集活性。七鳃鳗凝集素的分离纯化对研究七鳃鳗先天免疫防御机制和可变淋巴受体介导的适应性免疫防御机制均具有重要意义。 相似文献
9.
In this paper, we present the final report of the data obtained from the Space Dust (SPADUS) instrument on the Earth-orbiting Advanced Research and Global Observation Satellite (ARGOS). The University of Chicago's SPADUS instrument on the US Air Force's Advanced Research and Global Observation Satellite has been operating in a nearly polar orbit, at an altitude of approximately 850 km, since soon after its launch on day 54, 1999 (23 February) until termination of the SPADUS operations on day 248, 2001 (5 September).The instrument consists of a polyvinylidene fluoride (PVDF) dust trajectory system, which includes two planar arrays of PVDF sensors (a total of 16 sensors per array) separated by 20.25 cm to provide time of flight (TOF) measurements. The trajectory system measures dust particle flux, mass distribution, velocity and trajectory. The instrument also includes the SPADUS Ancillary Diagnostic Sensor (ADS) subsystem, which measured energetic charged particles (electrons, protons, etc).The PVDF dust trajectory system detected a total of 368 dust impacts over the SPADUS live-time interval of 739 days, yielding an average particle flux of 0.50 impacts/day. Of these 368 impacts, 35 were D1-D2 type events—where particles impacted and penetrated a D1 sensor, then impacted a D2 rear array sensor—allowing for time-of-flight measurements. Of the 35 D1-D2 impacts on SPADUS, we identified 19 D1-D2 impacts yielding TOF values. Of these 19 events, 14 were ambiguous (either bound or interplanetary) and 5 were unambiguous interplanetary impacts. Examples of particle orbits for debris particles as well as D1-D2 impacts are detailed. We also describe transient particle streams detected by the SPADUS trajectory system, resulting from the passage of ARGOS through streams of debris particles in Earth orbit. One of the streams was shown to result from detection by SPADUS of the debris generated by the explosion of a Chinese booster rocket.The SPADUS flight data accumulated over the 30-month mission shows that PVDF-based dust instruments utilizing two planar arrays of PVDF dust sensors in a TOF arrangement—can provide useful measurements of particle velocity, mass distribution, flux, trajectory and particle orbital elements. 相似文献
10.
通过分析基于飞行时间(time of flight,TOF)的超宽带(ultra wide band,UWB)距离测量的特性,利用卡尔曼滤波及其变式处理原始TOF测距值,剔除TOF测距粗差并对距离观测值进行降噪处理以减小观测误差的影响;同时利用已知长度分析多路径效应和非视距环境等对TOF测距系统误差的影响规律。基于该实验数据的定位结果表明,在较好地改正TOF测距系统误差的情况下,UWB静态定位精度能达到10 cm以内,动态定位精度优于0.2m。 相似文献
1