碱驱对原油采收率的影响

在填砂模型上研究了三种类型的碱对沙特河拉伯萨法尼亚原油采收率的影响。使用的三种碱为NaOH、KOH和Na3PO4·12H2O。还研究了碱在各糖溶液中的影响。聚合物浓度为1000ppm。测定了碱溶液的三个物理性质，即：pH值、粘度和界面张力。结果表明使用NaOH溶液可取得最高的原油采收率，这是由于pH值高和油、水相之间界面张力低的原因。在将碱溶液的驱替效果与聚合物溶液中加碱的驱替效果进行比较后发现，通过聚合物溶液中加碱进行驱油，可获得萨法尼亚原油的最高采收率。     

高强度钢板在汽车车身上的应用及问题对策

主要介绍高强度钢板使用量增加背景、已开发或正在开发的种类、高强度钢板在汽车车身上的应用以及高强度钢板使用中存在的主要问题及其对策等。     

Acoustic microscopy and nonlinear effects in pressurized superfluid helium

The operation of an acoustic microscope having a resolution of 15 mm has been demonstrated. It uses as a coupling medium superfluid (4 )He colder than 0.9 K and pressurized to greater than 20 bar. The microscope has been used to image objects that show little or no contrast on a scanning electron microscope. In addition, the acoustic microscope has been used to study the properties of sound propagation in the coupling fluid. At low acoustic intensities, the coupling fluid has very low acoustic attenuation at the microscope's operating frequency (15.3 GHz), but near the focal point the acoustic intensity can be high enough that the helium behaves with extreme nonlinearity. In fact, this medium is capable of entering new regimes of nonlinear interaction. Plots of the received signal versus input power display a nearly complete source depletion at certain input power levels and a reconversion to the source frequency at higher power levels. Arguments that the process underlying this nonlinear behavior is harmonic generation are presented.     

Lever controls on specialised farm equipment: some control/response stereotypes

Linearly arranged banks of hydraulic control levers constitute common control layouts on many specialized pieces of equipment used in agriculture, especially in California. Such controls are used to control multi-function equipment with various types of articulating mechanisms performing both linear and rotary translations in order to effect pitch, roll and yaw movements; also other movements such as clamping and encircling. Stereotypes regarding the control of the motion of a cube with six degrees of freedom by a single control lever were assessed. Results generally were consistent with previous work except for the case of the up/down motion of the cube for which a strongly anomalous phenomenon was found. Stereotypes for the assignment of cube motions to sets of multiple control levers were found to be weak or non-existent.     

评估屋顶薄膜材料耐久性的新的实验室方法

引言人们对一种新一代屋顶薄膜材料耐久性测定方法的需求在迅速增长。所谓新一代薄膜材料是指热塑性、热固性、改性沥青薄膜。作为这些材料的使用者,必需了解在正常使用条件下这些产品能使用多久,产品安装在屋顶上会发生哪些变化?评估屋顶薄膜材料耐久性的现行实验室方法是采用人工气候装置,该装置     

Interaction of CETP inhibitory peptide and lipoprotein substrates in cholesteryl ester transfer assay: relationship between association properties and inhibitory activities

In a previous study, CETP inhibitory peptide (3 kDa) was isolated from hog plasma. The peptide, synthesized chemically according to the amino acid sequence of the 3-kDa peptide (designated P₂₈), showed CETP inhibitory activity both in vitro and in vivo [Cho et al. (1998) Biochim. Biophys. Acta 1391, 133–144]. We report herein further unique features of P₂₈ when it was associated with the cholesteryl ester (CE)-donor and-acceptor lipoproteins. Lipoprotein substrates with P₂₈ present in both HDL (as a CE-donor) and LDL (as a CE-acceptor) served as poor substrates, with CE-transfer activity decreased up to 60% compared to normal substrates without P₂₈. P₂₈ was found to be located in HDL fractions of hog plasma and showed the same electromobility as that visualized by PAGE on 7% polyacrylamide gel under nondenaturing conditions. Addition of apolipoprotein A-1 (apoA-1) or apoB antibody to a normal CE-transfer mixture did not alter CE-transfer activity. However, addition of apoA-1 or −B antibody to a CETP-inhibition mixture decreased the inhibitory activity of P₂₈ by ca. 20%. Western blot analysis revealed that P₂₈ was associated only with human and hog HDL among several lipoproteins purified from human, hog, and rabbit. CFTP-inhibition assays with various lipoprotein substrates revealed that P₂₈ exhibited substrate-specific inhibitory activity. The inhibitory activity of P₂₈ was highly dependent on the type of lipoprotein substrate (whether CE-donor or-acceptor); P₂₈ inhibited CE transfer from HDL to LDL, but it did not inhibit CE transfer from HDL to HDL.     

Synthesis of novel tri- and tetrasubstituted C<Subscript>18</Subscript> furan fatty esters

A methylene-interrupted C₁₈ keto-acetylenic fatty ester (methyl 12-oxo-9-octadecynoate) was obtained from methyl ricinoleate by bromination-dehydrobromination followed by oxidation. Reaction of methyl 12-oxo-9-octadecynoate with bis(benzonitrile) palladium(II) chloride, allyl bromide, or methyl-allyl bromide furnished methyl 8-[5-hexyl-3-allyl-furan-2-yl]-octanoate (1, 56%) or methyl 8-[5-hexyl-3-(2-methyl-allyl)-furan-2-yl]-octanoate (2, 55%). Reaction of methyl 12-oxo-11-chloro-or 11-fluoro-9-octadeyynoate (prepared from methyl santalbate-methyl 11-E-9-octadecynoate, found in sandalwood, Santalum album, seed oil) with bis(benzonitrile) palladium(II) chloride gave methyl 8-(4-fluoro-5-hexyl-furan-2-yl)-octanoate (3, 50%) or methyl 8-(4-fluoro-5-hexyl-furan-2-yl)-octanoate (4, 50%), respectively. And when methyl 12-oxo-11-chloro- or 11-fluoro-9-octadecynoate was treated with a mixture of bis(benzonitrile) palladium(II) chloride, allyl bromide, or methyl-allyl bromide, the reaction yielded tetrasubstituted C₁₈ furan derivatives, viz, methyl 8-(3-allyl-4-chloro-5-hexyl-furan-2-yl)-octanoate (5, 54%), methyl 8-[4-chloro-5-hexyl-3-(2-methyl-allyl)-furan-2-yl)-octanoate (6, 54%), methyl 8-(3-allyl-4-fluoro-5-hexyl-furan-2-yl]-octanoate (7, 10%), and methyl 8-[4-fluoro-5-hexyl-3-(2-methyl-allyl)-furan-2-yl]-octanoate (8, 10%). The presence of a fluorine atom in the furan derivatives 4, 7, and 8 was readily characterized by the appearance of doublets for carbon nuclei, which were coupled to the fluorine atom in the ¹³C NMR spectra. All furan fatty derivatives from this work were characterized by NMR spectroscopic and mass spectrometric analyses. The yields of compounds 7 and 8 were very low (10%) despite attempts to improve the procedure by increasing the amounts of the reactants and catalyst.     

Limitations of the lead oxide vidicon for dual-energy digital subtraction angiography

Dual-energy digital subtraction angiography (DSA) can be performed, with some modifications, using existing systems designed for conventional DSA work. However, the video camera generally found in such installations, the lead oxide vidicon, places significant limitations on the image quality of dual-energy DSA. If the video camera is operated in a 60 Hz, 266 line progressive scanning mode to maintain a nominal 30 subtraction images/s frame rate, the maximum available X-ray pulse width is limited to 5 ms. The resulting required increase in low-energy kVp reduces the dual-energy signal-to-noise ratio by approximately 40% for cardiac dual-energy DSA imaging. In addition, the performance of the video camera with respect to read-out lag is much more important for dual-energy DSA than conventional single-energy imaging. Measurements show that lag reduces the iodine contrast in dual-energy DSA by up to 20% when a 30 Hz vertical scan mode is used, and by up to 27% when a 60 Hz vertical scan mode is employed. Replacement of the lead oxide vidicon with a CCD camera removes these limitations.