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991.
992.
993.
Keng-hong Tan 《Journal of chemical ecology》2000,26(3):697-704
The Asian house gecko, Hemidactylus frenatus, after being acclimatized to feeding on the melon fly, Bactrocera cucurbitae, consumed fewer numbers of 15-day-old (DO) and older male melon flies compared to sexually immature flies 10 DO and younger. The first male melon fly that performed mating did so on the 10th day after eclosion (DAE), but >80% of the males performed their first mating between 10 and 15 DAE. This confirmed that between 10 and 15 DAE most male melon flies are already sexually mature and producing sex pheromone. Synthetic 1,3-nonanediol, a component of male melon fly sex pheromone produced endogenously, when topically applied onto the thorax of housefly Musca domestica at ca. 80 or 320 ng/fly, reduced consumption by geckos compared with untreated flies in subsequent days after the first day in a four-day feeding test. Raspberry ketone (RK) is consumed and sequestered into the pheromonal gland and later released as a pheromonal component of male melon fly. Houseflies topically treated with 2.6 g RK/fly did not deter predation by geckos. However, houseflies treated with 5.1 g RK/fly caused geckos to consume fewer flies, especially on the third and fourth days during a four-day feeding test, compared with the period when they were offered untreated flies. 相似文献
994.
995.
铜铁试剂(CUP)—示波计时电位法直接测定天然水和饮用水中的铝含量。在0.5 mol/L(NH_4)_2SO_4-NH_3·H_2O(pH值=5.4)缓冲溶液中,加入铝后,铝—CUP配合物切口电位为-1.20V,切口深度在7.2×10~(-7)~3.2×10~(-5)mol/LAl范围内有线性关系,检测下限为5.8×10~(-7)mol/L。在2.0×10~(-5)mol/L时相对标准偏差为5.1(n=10)。应用该法测定了天然水和饮用水中铝含量,并同ICP/AES所获结果进行了对照。结果基本一致。 相似文献
996.
997.
This paper describes a fuzzy multiobjective optimization approach for determining the set‐points of the injection molding processing parameters to minimize the defects formed on the molded parts. The severities of the defects are represented by membership functions using the fuzzy set theory. The minimization of these membership functions, which is a multiobjective optimization problem, is transformed into a substitute problem. The preference function in the substitute problem is original and is proposed specifically for characterizing the quality requirements of the injection molding defects. The formulated optimization problem is solved with design of experiments, in which the process behavior is approximated empirically by a set of quadratic polynomials that can be easily optimized. Experimental results are presented to emphasis the workability of the proposed methodology. 相似文献
998.
PREPARATION OF PVA/CHITOSAN LIPASE MEMBRANE REACTOR AND ITS APPLICATION TO SYNTHESIS OF MONOGLYCERIDE 下载免费PDF全文
PVA/ Chitosan (CS) composite membrane was studied in this paper, which could be used for enzyme processing of fat and oils. The parameters such as concentration of lipase, pH, and cross-linking agent as well as metal ions, which influence the immobilization of lipase in membrane, were optimized. The immobilized lipase was 0.66 u/cm2 and the recovery of immobilized lipase activity was 24%. The membrane reactor could be used to synthesize monoglyceride (MG) with many batches. 相似文献
999.
A unsymmetrical and kink non-coplanar heterocyclic dicarboxylic acid monomer, 4-[4-(4-carboxy phenoxy)-naphthyl]-2-(4-carboxyphenyl)phthalazin-1-one
(3) was successfully synthesized with high purity and high yields. A series of novel polyamides containing phthalazinone were
prepared from the newly synthesized dicarboxylic acid with various aromatic diamines by means of the phosphorylation polycondensation
reaction. Molecular weights of the obtained polyamides were evaluated viscometrically, and the inherent viscosities (ηinh) measured were in the range 0.54–0.69 dL/g. These polyamides were amorphous and readily soluble in many organic solvents,
such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimetheylformamide, dimethyl sulfoxide, pyridine, and m-cresol etc., and they could easily be solution-cast into transparent,
flexible films with good mechanical properties, with tensile strength ranging from 63.9 to 81.6 MPa and elongation at break
from 7.2 to 11.4%. These polymers still kept good thermal stability with high-glass transition temperatures in the range of
283–338 °C, and the decomposition temperature in nitrogen for a 10% weight-loss temperatures in excess of 490 °C, and char
yield at 800 °C in nitrogen ranged from 56 to 63%. Furthermore, the polyamides films were essentially colorless; their cut-off
wavelengths were between 365 and 379 nm. 相似文献
1000.
汉代陶瓷艺术在我国漫长的陶瓷史上极具特色和个性张力,异彩纷呈,是中国陶瓷艺术继原始彩陶繁荣之后的又一个兴盛期.本文谨希望浅探在两汉陶瓷艺术背后所折射的其时代之文化内涵. 相似文献