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51.
固化疏浚泥作为填方材料的试验研究 总被引:2,自引:0,他引:2
港口、航道的建设和维护工程产生了大量的疏浚泥,如何处理这些疏浚泥已是国内外十分关注的问题.从资源的再生利用出发,提出利用固化材料固化疏浚泥作为填方材料的设想,并通过强度试验、溶出试验等一系列试验证实,固化疏浚泥作为填方材料在技术经济指标上完全可行. 相似文献
52.
Two methods for sampling and concentration of volatile organic compounds are reported. In the first method, traps coated with a very thick film (ca. 100 μm) of cross-linked silicone stationary phase are employed. Such thick films can be prepared with a modified dynamic coating procedure, which is briefly described. The low phase ratio traps can be utilized for enrichment of volatiles from gaseous as well as aqueous matrices. The second technique is based on chromatographic evaporation of a solvent in a capillary tube, where the process is sustained by a repeated sample injection and a cyclic flow reversal. In this way, large solvent volumes can be handled by a small volume system. Under optimal conditions, when using a solvent barrier, quantitative recovery is possible even for compounds of comparatively high volatility. Another important application of the technique is extraction of trace components from gases such as headspace samples, polluted air, etc. 相似文献
53.
Haim Gvirtzman Mordeckai Magaritz Eugenia Klein Arie Nadler 《Transport in Porous Media》1987,2(1):83-93
Cold stage Scanning Electron Microscopy (SEM) with a rapid cooling technique makes it possible to investigate the water phase within unsaturated porous media. It is thought that this technique preserves the main features of the micromorphology of the water menisci as it exists in the liquid phase in soils. Saddle-shaped elements, as well as pendular rings of water, were observed with concave and convex curvatures of the water-air interface. The hydraulic conductivity of an unsaturated soil may be inferred from SEM photographs. Observations of isolated water menisci indicate the existence of an immobile water domain. The surface geometry of the water menisci was analyzed quantitatively and surface tension and capillary pressure were determined. 相似文献
54.
Solubility of carbon dioxide in aqueous solutions of sodium chloride: Experimental results and correlation 总被引:2,自引:0,他引:2
The solubility of carbon dioxide in aqueous solutions of sodium chloride was measured in the temperature range from 40 to 160°C, up to 6 mol-kg salt solutions and total pressures up to 10 MPa. Pitzer's(1) equations as well as the Chen and Evans(2) model were used to correlate the new data. Results are reported and compared to literature data and correlations. 相似文献
55.
Marie‐France Llauro Julien Loiseau Fernande Boisson Frdric Delolme Catherine Ladavire J. Claverie 《Journal of polymer science. Part A, Polymer chemistry》2004,42(21):5439-5462
Low‐molecular‐weight poly(acrylic acid) (PAA) was synthesized by reversible addition fragmentation chain transfer polymerization with a trithiocarbonate as chain‐transfer agent (CTA). With a combination of NMR spectroscopy and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, the PAA end‐groups of the polymer were analyzed before and after neutralization by sodium hydroxide. The polymer prior to neutralization is made up of the expected trithiocarbonate chain‐ends and of the H‐terminated chains issued from a reaction of transfer to solvent. After neutralization, the trithiocarbonates are transformed into thiols, disulfides, thiolactones, and additional H‐terminated chains. By quantifying the different end‐groups, it was possible to demonstrate that fragmentation is the rate limiting step in the transfer reaction. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5439–5462, 2004 相似文献
56.
57.
研究了油/水界面电解的示差半微分循环伏安行为。在0.01mol/L LiCl(w)-0.01mol/L TBATCIPB(nb)体系“电位窗”比TBATPB(nb)向正方向扩展约50mV,残余电流基本消除,使“电位窗”内的平台向左右拓宽约50mV。算得界面电容约为16μF/cm~2。考察了琥珀酰胆碱离子在w/nb界面的传递伏安特性,结果与一般半微分循环伏安法相似。但峰形改善,检测限降低一个数量级(1×10~(-6)mol/L),相对标准偏差在5%以内,可用于定量测定琥珀酰胆碱。 相似文献
58.
A new, high performance liquid chromatography method has been developed for the separation of monovinyl- and divinyl-protochlorophyllides, using commercially available, C30 reverse phase column and isocratic elution. This method can be used both for analytical applications and preparative scale purification of monovinyl- and divinyl-protochlorophyllides using the same column where submilimolar concentrations of the crude protochlorophyllide extract can be separated in one run. The purity of the obtained protochlorophyllides was demonstrated by spectroscopic methods, as well by the formation of aggregates in toluene. 相似文献
59.
Brian H. Davison Nhuan P. Nghiem Gerald L. Richardson 《Applied biochemistry and biotechnology》2004,114(1-3):653-669
More than 25 sorbents were tested for uptake of succinic acid from aqueous solutions. The best resins were then tested for
successive loading and regeneration using hotwater. The key desired properties for an ideal sorbent are high capacity, complete
stable regenerability, and specificity for the product. The best resins have a stable capacity of about 0.06 g of succinic
acid/g of resin at moderate concentrations (1–5 g/L) of succinic acid. Several sorbents were tested more exhaustively for
uptake of succinic acid and for successive loading and regeneration using hot water. One resin, XUS 40285, has a good stable
isotherm capacity, prefers succinate over glucose, and has good capacities at both acidic and neutral pH. Succinic acid was
removed from simulated media containing salts, succinic acid, acetic acid, and sugar using a packed column of sorbent resin,
XUS 40285. The fermentation byproduct, acetate, was completely separated from succinate. A simple hot water regeneration successfully
concentrated succinate from 10 g/L (inlet) to 40–110 g/L in the effluent. If successful, this would lower separation costs
by reducing the need for chemicals for the initial purification step. Despie promising initial results of good capacity (0.06
g of succinic/g of sorbent), 70% recovery using hot water, and a recovered concentration of >100 g/L, this regeneration was
not stable over 10 cycles in the column. Alternative regeneration schemes using acid and base were examined. Two (XUS 40285
and XFS-40422) showed both good stable capacities for succinic acid over 10 cycles and >95% recovery in a batch operation
using a modified extraction procedure combining acid and hot water washes. These resins showed comparable results with actual
broth. 相似文献
60.
CunLiuZHOU YuQingZHOU ZhiYongWANG 《中国化学快报》2003,14(4):355-358
The chemoselective addition of aldehydes in aquoues medium was obtained under mild condition using improved Henry reaction. 相似文献