共查询到20条相似文献，搜索用时 328 毫秒
1.
[目的]研究永浩浸种液对芝麻(Sesamum indicum)生物特性及产量的影响,为其在芝麻生产上的应用提供技术参考.[方法]试验设9个处理:对照(CK),为使用干种子播种；利用永浩浸种液分别浸种2、4、6、8 h；利用清水分别浸种2、4、6、8h.[结果]与对照相比,浸种液浸种能增加产量,且以浸种液浸种8h为最高.相同浸种时间下,浸种液浸种的处理产量均高于清水浸种的处理.浸种液浸种处理,初花期和盛花期的叶绿素含量与产量呈极显著正相关(r =0.788 7**、0.860 8**),初花期净光合速率和产量呈极显著正相关(r=0.888 8**).[结论]永浩浸种液处理芝麻以8h较好,清水浸种以6h较好. 相似文献
2.
金花茶含有丰富的黄酮类化合物。作为一类重要的天然产物,黄酮类化合物具有多种生物学功能,
如抗氧化、降血糖、抗癌、抗肿瘤等,其抗氧化作用最为突出,并构成其他功能的基础。为了实现金花茶中黄
酮类化合物的高效提取、分离及测定,开发金花茶黄酮类产品,对黄酮类化合物及金花茶黄酮类成分进行了分析,
介绍了黄酮类化合物的多种生物学功能,并就金花茶黄酮类化合物的提取方法（水提法、有机溶剂提取、超声
波辅助提取、酶解法）、分离方法（大孔树脂吸附法、色谱法、膜分离法）、测定方法（分光光度法、高效液
相色谱法、液相色谱与质谱联用法）进行综述研究。目前金花茶黄酮类化合物的提取方法主要是有机溶剂提取法,
其与超声波方法结合效果更佳;金花茶黄酮类化合物的分离大多采用大孔树脂吸附法及色谱法;金花茶黄酮类
化合物的测定以分光光度法为主,高效液相色谱法及液相色谱与质谱联用法具有较大应用潜力。 相似文献
3.
Liquid state structure has traditionally been characterized with the radial distribution functions between atoms. Although these functions are routinely available from x-ray diffraction and neutron scattering experiments or from computer simulations, they cannot be interpreted unambiguously to provide the spatial order in a molecular liquid. A direct approach to determining the spatial structure in the liquid state is demonstrated here. Three-dimensional maps representing the local atomic densities are presented for several water models. These spatial maps provide a picture of the short-range order in liquid water which reveals specific details of its local structure that are important in the understanding of its properties. 相似文献
4.
为了解水甲虫多样性与环境的关系,于2004—2006年每年6—10月在长白山北坡采集不同环境条件下水甲虫标本,共发现水甲虫8科38属70种。研究发现不同的环境,水甲虫的种类、数量、个体大小明显不同。通过多元回归分析发现:水甲虫Shannon-Wiener多样性指数与海拔（r=0.507）、底泥有机质含量（r=0.638）和全磷含量（r=0.668）成明显正相关,与水电导率（r=－0.470）、水深度（r=－0.461）和水pH值（r=－0.470）负相关显著;均匀度指数与底泥有机质含量（r=0.542）和全磷含量（r=0.489）正相关显著;物种数与海拔（r=0.590）、底泥有机质含量（r=0.593）和全磷含量（r=0.618）成正相关,与水深度（r=－0.636）、水电导率（r=－0.558）、水pH值（r=－0.535）成显著负相关。环境因子影响水甲虫的分布,但人类是最终决定因素,了解水甲虫多样性与环境的关系,有助于揭示生物-环境-人类三者之间的关系,为生态系统和生物多样性的修复和保护提供服务。 相似文献
5.
液体表面张力系数与温度和浓度的关系 总被引：6，自引：0，他引：6
为了进一步探讨影响液体表面张力系数的主要因素,通过微观分析,从热力学的角度讨论了液体表面张力系数与温度和浓度的关系,并通过试验进行了论证,得出了水及常用表面活性物质肥皂水的表面张力系数随着温度和浓度的增加是递减的,并和温度呈近似线性关系． 相似文献
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7.
针对现有技术的不足,发明实用新型专利即一种猪用具有节水功能的饮水系统（专利号：ZL201922058836.8）,通过回收、净水,达到节水功能,解决现有的自动化饮水系统设水资源浪费严重的问题,为探究不同阶段猪应用节水饮水系统的效果。选择3个具有代表性猪饲养阶段（体重15kg左右保育猪、体重 60kg左右育肥猪、体重120kg且怀孕54天左右的初产妊娠母猪）,每个阶段各10头,每组5头开展试验研究[1-2]。结果表明,各饲养阶段猪用水量存在明显差异;不同阶段猪在应用猪用具有节水功能的饮水系统后,均起到节水作用;妊娠猪应用节水饮水系统的节水效果最为突出,节水比例为31.88%。 相似文献
8.
采用正交试验设计,首次利用混合表面活性剂,研究了乳状液膜法对炼油厂氨氮液的处理效果及其影响因素。实验结果表明:以22 %硫酸为内相,4 %Span-80+2 %T152+煤油+11 %的液体石蜡为液膜组成,pH=11的废水为外相的处理体系,处理效果可达到99.8 %,并在实际应用中取得了满意的效果。 相似文献
9.
[目的]优化高产蛋白酶棒曲霉Asp-195v的发酵条件。[方法]利用正交设计方法研究培养基成分配比、含水量、初始pH值、培养时间、接种量和培养温度等发酵条件对棒曲霉Asp-195v产蛋白酶的影响。[结果]影响该菌株产酶的最主要因素是培养时间,其次是温度,其他4个因素对该菌株产酶影响较小。该菌株最适产酶条件为：培养基成分中麸皮和豆粕比例为7∶3（总量为10g）,含水量为90ml（250ml三角瓶）,pH值为7,培养时间为72h,接种量为1.5ml,培养温度为24℃,摇床转数为120r/min。棒曲霉Asp-195v对盐有一定耐受力,其中24%NaCl中的蛋白酶与空白样品相比仍有47.6%的活性。[结论]该菌株在豆酱生产中具有良好的应用价值。 相似文献
10.
为了降低耐寒赤桉试管前的生产成本，进行了培养基配制用自来水、山塘水、纯水代替蒸馏水，食用白糖代替蔗糖，培养基的不同形态，继代培养基二次利用和不同室内生根培养时间研究．结果表明，用自来水代替蒸馏水，试管苗的芽增殖倍数、生根率、发根量有所提高；以食用白糖替代蔗糖，对试管苗无影响；液体培养有利于试管苗的分化、生根和移栽成活；室内生根培养时间由常规的30d缩短为15d，不影响苗木的质量和移栽成活率．用自来水、食用白糖配制培养基，生根采取液体培养15d，比用蒸馏水、蔗糖配制培养基，生根采取固体培养30d，试管苗的直接生产成本可降低28％． 相似文献
11.
Formation of glasses from liquids and biopolymers 总被引：3，自引：0，他引：3
Angell CA 《Science (New York, N.Y.)》1995,267(5206):1924-1935
Glasses can be formed by many routes. In some cases, distinct polyamorphic forms are found. The normal mode of glass formation is cooling of a viscous liquid. Liquid behavior during cooling is classified between "strong" and "fragile," and the three canonical characteristics of relaxing liquids are correlated through the fragility. Strong liquids become fragile liquids on compression. In some cases, such conversions occur during cooling by a weak first-order transition. This behavior can be related to the polymorphism in a glass state through a recent simple modification of the van der Waals model for tetrahedrally bonded liquids. The sudden loss of some liquid degrees of freedom through such first-order transitions is suggestive of the polyamorphic transition between native and denatured hydrated proteins, which can be interpreted as single-chain glass-forming polymers plasticized by water and cross-linked by hydrogen bonds. The onset of a sharp change in ddT( is the Debye-Waller factor and T is temperature) in proteins, which is controversially indentified with the glass transition in liquids, is shown to be general for glass formers and observable in computer simulations of strong and fragile ionic liquids, where it proves to be close to the experimental glass transition temperature. The latter may originate in strong anharmonicity in modes ("bosons"), which permits the system to access multiple minima of its configuration space. These modes, the Kauzmann temperature T(K), and the fragility of the liquid, may thus be connected. 相似文献
12.
Endothelin: a novel peptide in the posterior pituitary system 总被引：21，自引：0，他引：21
T Yoshizawa O Shinmi A Giaid M Yanagisawa S J Gibson S Kimura Y Uchiyama J M Polak T Masaki I Kanazawa 《Science (New York, N.Y.)》1990,247(4941):462-464
Endothelin (ET), originally characterized as a 21-residue vasoconstrictor peptide from endothelial cells, is present in the porcine spinal cord and may act as a neuropeptide. Endothelin-like immunoreactivity has now been demonstrated by immunohistochemistry in the paraventricular and supraoptic nuclear neurons and their terminals in the posterior pituitary of the pig and the rat. The presence of ET in the porcine hypothalamus was confirmed by reversed-phase high-pressure liquid chromatography and radioimmunoassay. Moreover, in situ hybridization demonstrated ET messenger RNA in porcine paraventricular nuclear neurons. Endothelin-like immunoreactive products in the posterior pituitary of the rat were depleted by water deprivation, suggesting a release of ET under physiological conditions. These findings indicate that ET is synthesized in the posterior pituitary system and may be involved in neurosecretory functions. 相似文献
13.
甜玉米秸秆最佳青贮时期的研究 总被引：4，自引：0，他引：4
对甜玉米果穗采收后的茎秆含糖量、绿叶数量及含水量测定表明：果穗采收后天数与含糖量之间呈极显著正相关（r＝0．989），与绿叶数量呈极显著负相关（r＝－0．952），与含水量亦是极显著负相关（r＝－0.962）。果穗采收后第5～7天，茎秆含糖量达14％以上，绿叶数量和含水量均适合调制优质青贮饲料。 相似文献
14.
Water vapor that condenses on a metal surface at 10 degrees K forms a noncrystalline phase of estimated density 1.2 grams per cubic centimeter. X-ray diffraction data of high precision and resolution have been analyzed to yield oxygen atom pair correlation functions. The positional correlation in amorphous solid water extends over only a few molecular radii, and the radial distribution of nearneighbor oxygen atoms in amorphous solid water is qualitatively different from that found in the low-pressure ice modifications. Amorphous solid water is a useful material for liquid water models because it can be studied under conditions such that the effects of static disorder and thermal excitation can be separated. 相似文献
15.
Walba DM Korblova E Shao R Maclennan JE Link DR Glaser MA Clark NA 《Science (New York, N.Y.)》2000,288(5474):2181-2184
We describe the design and synthesis of a ferroelectric liquid crystal composed of racemic molecules. The ferroelectric polarization results from spontaneous polar symmetry breaking in a fluid smectic. The ferroelectric phase is also chiral, resulting in the formation of a mixture of macroscopic domains of either handedness at the isotropic-to-liquid crystal phase transition. This smectic liquid crystal is thus a fluid conglomerate. Detailed investigation of the electrooptic and polarization current behavior within individual domains in liquid crystal cells shows the thermodynamically stable structure to be a uniformly tilted smectic bow-phase (banana phase), with all layer pairs homochiral and ferroelectric (SmC(S)P(F)). 相似文献
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17.
Seismological studies indicate that the inner core of Earth is anisotropic for compressional waves (P waves), and has low shear wave (S wave) velocity, and high seismic attenuation. Using an effective medium theory for composite materials, we show that the presence of a volume fraction of 3 to 10% liquid in the form of oblate spheroidal inclusions aligned in the equatorial plane between iron crystals is sufficient to explain the aforementioned seismic phenomena. Variation of S-wave velocity between the polar axis and equatorial plane is more sensitive to the addition of liquid than that of P waves. The liquid could arise from the presence of dendrites or a mixture of elements other than iron that exist in liquid form under inner-core conditions. 相似文献
18.
通过对顶孢霉Ahy1菌株加工工艺的初步研究,筛选出了一级固体培养最适培养基为麦麸培养基,最佳培养时间为6 d;二级液体振荡培养的最适接种液为马铃薯-糖培养液,以120 r/min振荡培养(25±1)℃,3 d;通过13种培养介质培养顶孢霉菌的含孢量和活孢率检测,筛选出了三级产孢培养介质为低值陈米,初步获得孢子粉,孢子含量为5.8×1010孢子/g,含水量6%,活孢率93.5%. 相似文献
19.
灌水对河西绿洲冬小麦产量及光合生理指标的影响 总被引：1，自引：0，他引：1
在河西绿洲生态条件下,研究了不同灌水处理对冬小麦产量及相关指标的影响.在冬水灌量相等的基础上分别在拔节期(J)、抽穗期(H)和灌浆期(F)设等量不等次、等次不等量共5种灌水处理,灌水量分别为J1650m3/hm2(W1)J、1200 m3/hm2+H1050 m3/hm2(W2)J、1050 m3/hm2+H1050 m3/hm2+F1050 m3/hm2(W3)、J750m3/hm2+H750 m3/hm2+F750 m3/hm2(W4)J、1050 m3/hm2+H750 m3/hm2+F450 m3/hm2(W5).结果表明:各处理间单位面积籽粒产量、穗粒数、千粒质量、水分利用效率(WUE)、叶面积指数(LAI)、光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)和叶片相对含水量(RWC)均存在着显著或极显著的差异.籽粒产量以灌水量最多的W3处理最高,适量减少灌水量可以提高WUE.不同灌水处理下影响产量的主要因素是千粒质量和穗粒数.产量与开花期Pn呈显著正相关,但与各测定时期的Pn均值呈显著负相关.株高、生物产量、千粒质量、穗粒数等农艺指标与Pn呈阶段性相关.Pn、Tr、Gs和叶片RWC的相关性随生育时期的不同而变化. 相似文献
20.
建立了反相高效液相色谱法同时测定四数獐牙菜中的落干酸、獐牙菜苦苷、龙胆苦苷、芒果苷含量的方法。测定方法:在检测波长254 nm、柱温30℃、流速1 ml/min时,用ZORBAX SB-C18(250 mm×4.6 mm i.d.,5μm)柱,以甲醇和水(含0.04%H3PO4)在0～20min内由20%至35%线性梯度洗脱。试验结果:4种成分均达到基线分离,落干酸、獐牙菜苦苷、龙胆苦苷、芒果苷的线性范围分别为0.05～0.625μ(g r=0.999 9)、0.095～2.9μ(g r=0.999 8)、0.049～2.56μ(g r=0.999 7)、0.006～2.8μ(g r=0.999 9);回收率分别为101%(RSD=4.3%)、98.7%(RSD=3.3%)、99.5%(RSD=3.5%)、102%(RSD=1.0%)。结论:测定方法快速,结果准确、可靠。 相似文献