共查询到20条相似文献,搜索用时 15 毫秒
1.
传统化肥增效改性提升产品性能与功能 总被引:10,自引:9,他引:10
赵秉强 《植物营养与肥料学报》2016,22(1):1-7
【目的】当前,我国各类增效改性肥料年产量达到1300万吨(商品量),每年推广面积4亿多亩,年增产粮食110亿公斤,为农业增产、 农民增收和环境保护做出了重要贡献。推动传统化肥增效改性,是一项系统工程,需要国家从技术研究、 政策、 推广等领域给予支持。综合分析、 评述我国传统化肥增效改性的意义、 取得的研究成果与未来发展,为推动我国化肥提质增效,提升化肥产品性能与功能提供思路和策略。【方法】本文收集了我国有关传统化肥增效改性研究的主要文献,对目前改性增效肥料在我国的生产、 使用现状和研究取得的成果和观点进行系统分析、 归纳和综合评述,展望未来发展趋势,提出发展对策。【结果】传统氮肥因活性高、 损失途径多,磷肥施入土壤易被固定,加之我国单位面积化肥用量较高等,化肥利用率较低,对环境造成负面影响较大,化肥增效改性是提高肥料利用率的重要途径。目前对传统化肥进行增效改性的主要技术途径包括缓释法增效改性、 稳定法增效改性、 增效剂法增效改性以及有机物料与化学肥料复合(混)优化化肥养分高效利用,相应发展的增效改性产品包括缓释肥料、 稳定肥料、 增值肥料和有机无机复合(混)肥料。【结论】传统化肥增效改性是提升化肥产品性能与功能、 提高肥料利用率的重要途径,需要加强研究和政策支持。 相似文献
2.
Quintanilla-Guerrero F Duarte-Vázquez MA Tinoco R Gómez-Suárez M García-Almendárez BE Vazquez-Duhalt R Regalado C 《Journal of agricultural and food chemistry》2008,56(17):8058-8065
Peroxidase from turnip roots (TP) was isolated followed by modification with methoxypolyethylene glycol (MPEG). The catalytic activity of the modified TP (MTP) on ABTS increased 2.5 times after 80 min of reaction. MTP showed a KM similar value to that of TP, but a significantly greater kcat for ABTS oxidation, in aqueous buffer. Chemical modification produced an enhanced stability in organic solvents and increased thermal stability of about 4 times that of TP, in aqueous buffer at 70 degrees C. Circular dichroism showed that MPEG modification decreased TP alpha-helical structure from 26 to 16% and increased beta-turns from 26 to 34%, resulting in an enhanced conformational stability. The temperature at the midpoint of thermal denaturation (melting temperature) increased from 57 to 63 degrees C after modification. MTP was immobilized in alginate beads (IMTP) and tested for oxidative polymerization of concentrated phenolic synthetic solutions, achieving 17 effective contact cycles removing >65% phenols. IMTP may be useful for the development of an enzymatic process for wastewater effluent treatment. 相似文献
3.
聚乙烯包膜肥料控释膜层结构特征研究 总被引:1,自引:0,他引:1
4.
Fungicidal activity of Curcuma longa rhizome-derived materials against Botrytis cineria, Erysiphe graminis, Phytophthora infestans, Puccinia recondita, Pyricularia oryzae, and Rhizoctonia solani was tested using a whole plant method in vivo. It was compared with synthetic fungicides and four commercially available compounds derived from C. longa. The response varied with the tested plant pathogen. At 1000 mg/L, the hexane extract of C. longa showed fungicidal activities against E.graminis, P. infestans, and R. solani, and the ethyl acetate extract of C. longa showed fungicidal activities against B. cineria, P. infestans, Pu. recondita, and R. solani. Curcumin was isolated from the ethyl acetate fraction using chromatographic techniques and showed fungicidal activities against P. infestans, Pu. recondita, and R. solani with 100, 100, and 63% control values at 500 mg/L and 85, 76, and 45% control values at 250 mg/L, respectively. In the test with components derived from C. longa, turmerone exhibited weak activity against E. graminis, but no activity was observed from treatments with borneol, 1,8-cineole, sabinene, and turmerone. In comparison, potent fungicidal activity with chlorothalonil against P. infestans at 50 mg/L and dichlofluanid against B. cinerea at 50 mg/L was exhibited. These results may be an indication of at least one of the fungicidal actions of curcumin derived from C. longa. 相似文献
5.
为了提供一种姜黄素纳米颗粒的制备载体,该文以玉米醇溶蛋白水解物(zein hydrolyate,ZH)和大豆可溶性多糖(soluble soybean polysaccharides,SSPS)复合物(ZH-SSPS)为原料,通过反溶剂纳米沉淀法制备了一种水溶性姜黄素纳米颗粒(curcumin nanoparticles,Cur-Ps),并考查了SSPS与ZH在制备姜黄素纳米颗粒中的协同作用。研究结果表明,当ZH的质量浓度在2.5 mg/m L以下时,SPSS的存在会使姜黄素的水溶性有所提高。当ZH的质量浓度在2.5 mg/m L以上时,姜黄素在水中的溶解量可高达135μg/m L,SSPS的加入无法使姜黄素的水溶性进一步提升。在中性条件(p H值7.0)或低离子强度(50 mmol/L)下,ZH及ZH-SSPS分别制备的姜黄素纳米颗粒(Cur-Ps)都具有良好的胶体稳定性。但在酸性(p H值为4.5和2.0)或高离子强度(200 mmol/L)下,ZH-SSPS较单独的ZH制备的Cur-Ps具有更好的胶体稳定性。体外释放研究表明,ZH及ZH-SSPS分别制备的Cur-Ps都具有一定的缓释作用,但ZH-SSPS制备的Cur-Ps具有更好的缓释效果,6 h的累积释放率在80%以下。1,1-二苯基-2-苦基肼(1,1-Diphenyl-2-picrylhydrazyl,DPPH)游离基氧化稳定性试验表明,姜黄素经纳米包埋后其氧化稳定性得到了显著提高(P0.05)。此外,ZH-SSPS制备的Cur-Ps冻干粉呈现多孔的海绵状结构,其复溶率显著提高(P0.05),可达90%以上。因此,SSPS和ZH在制备Cur-Ps的过程中具有明显的协同作用。利用ZH-SSPS制备的Cur-Ps溶液,外观澄清透明,能够为功能性饮料的营养强化提供借鉴。 相似文献
6.
Luangtana-anan M Nunthanid J Limmatvapirat S 《Journal of agricultural and food chemistry》2010,58(24):12934-12940
The effects of molecular weight and concentration of plasticizer on physicochemical properties and stability of shellac films were investigated. Type of plasticizer was previously reported to have some effects on the stability of shellac films, and polyethylene glycol (PEG) was the plasticizer of choice for plasticizing shellac films. In this study, different molecular weights of PEG (200, 400 and 4000) were chosen at a concentration of 10% w/w of shellac films. Shellac in alcohol was prepared in a free film. The stability of shellac film was then performed at 75% RH, 40 °C for 3 months. The comparison was made between the film with and without plasticizer. Shellac films were then determined for acid value, insoluble solid, mechanical properties and water vapor permeability coefficient. It was reported that different molecular weights of PEG had some influence on physicochemical properties of the shellac films. Among different molecular weights of PEG, PEG 400 showed a suitable molecular weight that could protect the shellac chain at the carboxylic and hydroxyl groups. Therefore, the molecular weight of plasticizer played a crucial role for the protective ability at active sites. Further study was performed to investigate the effect of concentrations of PEG 400 on the stability. The results demonstrated that PEG 400 at a concentration of 10% (w/w) could prevent the polymerization process for only 4 months and a significant change of all parameters was then reported. However, a higher concentration, 20% (w/w) of PEG 400, could prolong the stability of shellac for 6 months of study. Therefore, the drawback of shellac as a natural polymer in pharmaceutical and food industries could be tackled by the appropriate size and concentration of plasticizer. 相似文献
7.
Volterra L. Musmeci L. Gucci P.M.B. Coccia A.M. Esposito S. 《Water, air, and soil pollution》1996,91(1-2):109-124
Effective minesoil recovery requires spoils to be converted to soils of similar quality to those previously existing on that site. The developing minesoil should thus acquire three critical capacities, namely the capacities to a) support plant production, b) degrade organic matter and c) remove contaminants from water. The degree of development of these capacities provides a useful measure of soil quality and thus of the success of a given soil recovery technique. At the Meirama lignite mine in Galicia (northwest Spain), the possibility of using cattle slurry instead of the inorganic fertilizers currently used is being investigated. The results of a number of experiments suggest that cattle slurry is more effective (in terms of the above three critical capacities) than inorganic fertilizer. In slurry-fertilized spoils, rapid increases are observed in vegetation cover, in the relative abundance of self-seeded native plant species, in soil microbial activity and in those physical and chemical properties which affect infiltration and the capacity to remove contaminants from percolating water. 相似文献
8.
Niu Y Wang X Chai S Chen Z An X Shen W 《Journal of agricultural and food chemistry》2012,60(7):1865-1870
The spectroscopic properties of liposomal curcumin in pH 7.0 sodium phosphate buffer were studied at various curcumin concentrations and temperatures. At 25 °C, liposomal curcumin exhibited much higher values than free curcumin in absorption maximum, fluorescence maximum, and fluorescence anisotropy. When curcumin concentration was increased from 2 to 20 μM, the values of fluorescence anisotropy of liposomal curcumin decreased gradually, consistent with the reduction of phase transition temperature of liposome. This observation revealed that liposomal curcumin can disrupt the packing of phospholipid bilayer and give a loose and disordered structure. On the other hand, as the temperature was increased from 25 to 80 °C, the relative intensity of maximum absorption of liposomal curcumin showed a more pronounced decrease above the phase transition temperature than lower temperatures, suggesting a weaker curcumin protection from the liquid crystalline phase of phospholipid bilayer than the rigid gel phase. However, it was observed that the fluorescence anisotropy of liposomal curcumin had higher values as the temperature increased. This phenomenon was explained as the result of location change of curcumin toward the core of phospholipid bilayer, although the structure of the phospholipid bilayer tended to be looser at higher temperatures. 相似文献
9.
Study on the supramolecular interaction of curcumin and beta-cyclodextrin by spectrophotometry and its analytical application 总被引:1,自引:0,他引:1
The supramolecular interaction of curcumin and beta-cyclodextrin (beta-CD) has been studied by spectrophotometry. The mechanism of the inclusion was studied and discussed based on the variations of pK(a), absorption intensity, and infrared spectrograms. The results show that beta-CD reacts with curcumin to form a 2:1 host-guest complex with an apparent formation constant of 5.53 x 10(5) mol(-2) x L2. Based on the enhancement of the absorbance of curcumin produced through complex formation, a spectrophotometric method for the determination of curcumin in bulk aqueous solution in the presence of beta-CD was developed. The linear relationship between the absorbance and curcumin concentration was obtained in the range of 0-15 microg/mL, with a correlation coefficient (r) of 0.9991. The detection limit was 0.076 microg/mL. The proposed method was used to determine the curcumin in curry and mustard with satisfactory results. 相似文献
10.
Masuda T Toi Y Bando H Maekawa T Takeda Y Yamaguchi H 《Journal of agricultural and food chemistry》2002,50(9):2524-2530
As a part of the research project on the elucidation of the chain-breaking antioxidant mechanism of natural phenolics against the oxidation of food components, curcumin, a main turmeric pigment, was investigated. A relatively high concentration of curcumin gave three dimers as radical termination products in addition to the coupling products with curcumin and the lipid hydroperoxide. The structural analysis of these dimers and quantitative analysis of their production rates revealed that radical-radical termination mainly occurred at the 2-position of curcumin. The contribution of the pathway for production of these dimers to the antioxidant mechanism of curcumin was estimated from the concentration-dependent data of the antioxidant activity and formation rates of these termination products. The A-A termination (dimer formation) was estimated to contribute at least about 40% of the entire antioxidant process against ethyl linoleate oxidation. 相似文献
11.
D C Siew C Heilmann A J Easteal R P Cooney 《Journal of agricultural and food chemistry》1999,47(8):3432-3440
The aim of this study is to determine the effects of plasticizer hydrogen bonding capability and chain length on the molecular structure of sodium caseinate (NaCAS), in NaCAS/glycerol and NaCAS/polyethylene glycol 400 (PEG) systems. Both solution and film phases were investigated. Glycerol and PEG reduced the viscosity of aqueous NaCAS, with the latter having a greater effect. This was explained in terms of protein/plasticizer aggregate size and changes to the conformation of the caseinate chain. In the film phase, glycerol caused more pronounced changes to the film tensile strength compared with PEG. However, the effect of glycerol on film water vapor permeability was smaller. These observations are attributed to the differences in plasticizer size and hydrogen bonding strength that controls the protein-plasticizer and protein-protein interactions in the films. Glass transition calculations from the tensile strength data indicate that the distribution of bonding interactions is more homogeneous in NaCAS/PEG films than in NaCAS/glycerol films. 相似文献
12.
为了进一步利用可再生资源植物油代替石油合成化学品,该研究使用豆油和甘油在230℃下合成了豆油单甘脂,将其作为合成聚酯的二元醇组分,与马来酸酐反应,并以异辛醇为封端剂控制分子量,经过酯化和缩合反应合成了豆油基聚酯增塑剂。采用红外光谱、核磁共振和凝胶渗透色谱对该豆油基聚酯产品的结构和分子量进行了表征;将其与聚氯乙烯热塑共混成型,使用转矩流变仪、扫描电镜、热重分析仪、动态热机械分析仪和万能拉力试验机对共混物的扭矩、相容性、热性能和力学性能进行了表征。研究发现:通过单甘脂与马来酸酐酯化缩合反应合成了分子量范围为3 000~3 500的聚酯产品,该聚酯产品与邻苯类增塑剂复配使用增塑聚氯乙烯,增塑聚氯乙烯在热塑过程中的扭矩从13.4 N·m降低到10.1 N·m;扫描电镜分析表明聚酯增塑剂较好地改善了聚氯乙烯和填料的相容性;增塑聚氯乙烯的热降解温度由254.7℃提高到255.6℃,玻璃化转变温度由55℃降低到42℃;拉伸强度由16.9 MPa降低到9.6 MPa,断裂伸长率由179.6%增加到269.3%,因此该产品可以作为聚氯乙烯的优良增塑剂使用。 相似文献
13.
毛管水头偏差率是确定毛管长度的主要技术指标。以正在运行的新疆棉田地下滴灌系统为试验对象,选取代表性毛管,实测正常灌溉过程中毛管首尾压力、流量和沿程土壤水分,研究地下滴灌毛管水头偏差率特性及其与土壤水分均匀度的关系。结果表明:在毛管设计工作水头为10 m条件下,测试毛管水头偏差率在0.58%~12.80%之间。同一管网中,不同毛管的水头偏差率各不相同且具有波动性,但同一支管位置处树状毛管与环状毛管之间的相对趋势稳定;在毛管设计工作水头为10 m条件下,支管入口压力对毛管水头偏差率的影响不显著(P0.05);毛管水头偏差率和毛管埋深层土壤水分均匀系数之间有强的负相关关系(P0.001),建立了水头偏差率和土壤水分均匀度之间的数学模型,经验证,85%毛管的绝对误差小于5%。研究可以为地下滴灌毛管长度设计与毛管工作状况评价提供参考。 相似文献
14.
乙二醇蓄冷库性能及其在黄冠梨保鲜上的应用 总被引:3,自引:3,他引:0
为解决果蔬贮藏保鲜设施运行成本高的问题,促进产地冷藏设施建设,研制了以乙二醇为载冷剂的蓄冷库,并对该库的性能、贮藏保鲜效果和运行成本进行了分析,探讨该冷库用于果品贮藏保鲜的可能性。研究发现乙二醇蓄冷库的平均温度为0.18~0.32℃,测温点间最大温差为0.8℃,好于对照冷藏库。结果说明乙二醇蓄冷库的温度稳定性和均匀性较好,有利于保障果品贮藏品质。乙二醇蓄冷库和对照冷藏库用于贮藏黄冠梨,贮藏效果差异不大。一个贮藏周期一间容量30t的乙二醇蓄冷库,用电量略高于对照冷藏库;但因实行峰谷电价,运行电费仅是对照冷库的75%。总体来说,与对照冷藏库相比,研制的乙二醇蓄冷库性能优良,保鲜效果理想,运行成本更低,是实施峰谷电价地区适宜的果品贮藏保鲜设施。 相似文献
15.
目的:初步建立猪前体脂肪细胞与肌卫星细胞体外联合培养的方法,探讨联合培养模式下两类细胞的基本生长特性。方法:利用差速贴壁法分别纯化前体脂肪细胞与肌卫星细胞,按1:10的浓度比接种混合培养,以单独两类细胞培养作对照;采用油红O染色、Desmin免疫组化染色鉴定;通过形态学观察、MTT比色绘制生长曲线研究细胞生长规律。结果:Desmin免疫组化染色观察肌细胞阳性率达97%以上,油红O染色计数诱导分化细胞比率大于60%;形态学观察发现,联合培养细胞接触汇合前形态呈梭形,接触后不规则重叠交织生长;充脂细胞呈现较晚,且数量稀少; HE染色可见多核细胞融合及肌管样结构;测定2~9d细胞生长曲线显示,联合细胞组增殖比率大于对照组,经历2~3d潜伏期、3~7d指数生长期后,并未与对照组同步进入平台期,而呈持续缓慢上升趋势。结论:初步实现了体外猪前体脂肪细胞与肌卫星细胞的直接联合培养,并由研究结果显示其与对照组生长特性存在差异。 相似文献
16.
为了去除生物油中的糠醛,该研究利用竹子为前躯体热解制得竹炭,选取糠醛为生物油模型化合物,在深入分析测试竹炭表面特性的基础上,研究竹炭对糠醛的静态吸附特性,并利用Langmuir和Freundlich等温吸附方程对试验数据进行拟合。结果表明以微孔为主的竹炭表面含有多种含氧官能团,如羟基、羧基等,同时还含有芳香族、脂肪族结构,这些表面官能团主要呈碱性;竹炭对糠醛具有较好的吸附脱除效果,25℃下,在糠醛浓度为10g/L,竹炭添加量为200g/L时,脱除率可达95%以上;其对糠醛的吸附主要依靠色散力作用;Freundlich等温吸附方程能更好地描述竹炭对糠醛的吸附特性。该研究有助于探索廉价的生物油除杂以适应糖发酵的新方法。 相似文献
17.
Pavlík M Vacek J Klejdus B Kuban V 《Journal of agricultural and food chemistry》2007,55(15):6147-6153
Influence of saccharose in the presence or absence of polyethylene glycol (PEG), methyl jasmonate, and an inactivated bacterial culture of Agrobacterium tumefaciens in cultivation medium on morphology of Hypericum perforatum L. and production of hypericin and hyperforin was studied under in vitro conditions. Production of hypericin and hyperforin was influenced by the presence of different concentrations of saccharose (10-30 g L(-1)) in cultivation medium. Addition of PEG (1.25-5 g L(-1)) in the presence of saccharose (10-30 g L(-1)) increased production of hypericin and hyperforin in the H. perforatum in vitro culture. Synthesis of hypericin and hyperforin was unchanged or reduced for most of the experimental plants at higher contents of PEG (10 and 15 g L(-1)). Concentrations of hypericin and hyperforin in the H. perforatum were on the order 100 and 103 microg g(-1) of dry plant material, respectively. Production of hypericin and hyperforin was stimulated either in the presence of a chemical elicitor (methyl jasmonate) or an inactivated bacterial culture of A. tumefaciens. Morphological changes induced by the abovementioned substances were observed and described in detail. The obtained results will be applied in experimental botany and in the technology of H. perforatum cultivation for pharmaceutical applications. 相似文献
18.
为提高抛物线形断面的水力特性,增加输水能力,该文提出了一种二分之五次(以下简称2.5次)方抛物线形渠道断面,推导其水力断面特性。将湿周用高斯超几何函数表示后,将水力最优断面的最优化模型转换为关于宽深比的一元方程,得到2.5次方抛物线形渠道水力最优断面的解析解,其最优宽深比为2.088 3。比较结果表明,2.5次方抛物线形断面较常规抛物线形断面具有更好的水力学特性。与平方、半立方抛物线形断面比较,在相同水深条件下,2.5次方抛物线形水力最优断面的过流能力更大。相反,在相同流量下,2.5次方抛物线形水力最优断面的过流面积、湿周、水深更小。2.5次方抛物线形水力最优断面的建造成本与其他2种断面相比是最小的。进一步地,为便于工程应用,基于高斯勒让德算法,提出2.5次方抛物线形断面的三点和四点格式近似湿周算法。结果表明,四点格式近似算法具有较高精度。研究可为明渠设计提供理论依据。 相似文献
19.
20.
L Castle H R Cloke J R Startin J Gilbert 《Journal of the Association of Official Analytical Chemists》1988,71(3):499-502
A method for the quantitative determination of monoethylene glycol (MEG) and diethylene glycol (DEG) in chocolate is described. The procedure involves dissolving the chocolate in hot water, defatting with hexane, removing sugars by precipitation, and analyzing as trimethylsilyl (TMS) ether derivatives by capillary gas chromatography. The use of butan-1,4-diol as an internal standard corrects for recovery, which is between 50 and 60%, to give a relative standard deviation of 10-11% for the determination of both glycols at the level of 50 mg/kg. The presence of MEG and DEG in chocolate is confirmed by full scanning gas chromatography/mass spectrometry of the TMS derivatives. 相似文献