包裹型缓释肥料生产技术实验研究

通过一系列的实验室研究和小型试验 ,选出了成本低、效果较好的包裹控释材料和粘结剂 ,提出了制造包裹型缓释肥料的生产工艺。对小试生产的包裹型缓释肥料进行缓释性评价 ,结果表明 :肥料的缓释性良好 ,工艺简便易行 ,生产成本低。     

Release rates of tetradecen-1-ol acetates from polymeric formulations in relation to temperature and air velocity

An apparatus was developed for investigating the release rates of pheromone formulations at temperatures and air velocities that correspond with those in the field. Polyurethane foam proved an excellent adsorbent for the recovery of tetradecen-1-ol acetates, allowing high air flows at low differential pressure and without breakthrough of these compounds. The experimental setup and procedures are described. The release rates of all formulations investigated were almost proportional to the square root of air velocity, and their logarithms were proportional to the reciprocal of temperature (K). When temperature is increased from 15°C to 25°C, the release rates increase by about 2-2.5 ×. Both relationships were combined into one equation that allows a reliable estimate to be made of the actual release rates of a formulation, under varying conditions, on the basis of its specific parameters and the relevant meteorological data.     

阿司匹林聚乳酸／SiO2微球的制备及其体外缓释研究

应用自制的聚乳酸／SiO2材料为药物载体通过溶剂挥发法制备了阿司匹林微球，并对该微球的粒径、包封率、载药量以及体外缓释性能进行了研究。微球电镜图片显示粒径大小分布在15μm左右，符合缓释制剂要求。体外缓释研究所得Higuchi方程为Q=0．3598＋0．03t^1/2，相关系数P=0．9961，该结果显示所得微球具有明显缓释作用。     

A vapor collection and thermal desorption method to measure semiochemical release rates from controlled release formulations

Chemicals (bp 270–490 °C/1 atm) evaporated from a controlled-release formulation dispenser were carried by an airflow to a collector packed with a polymeric adsorbent. After a set time, the chemicals were recovered by thermally desorbing them onto a gas-liquid chromatograpic column. They were then separated and quantified. The apparatus is described, and the requirements for its successful use are discussed. The soundness of the thermal desorption technique was confirmed by comparison with another technique: solvent elution from the collector. The advantages of the former technique are discussed.Mention of a commercial or proprietary product in this paper does not constitute an endorsement of that product by the USDA.     

Inhibitory Effect of Monoterpenes on Response of Pityogenes bidentatus to Aggregation Pheromone Released by Piezoelectric Sprayer for Precision Release of Semiochemicals

A piezoelectric sprayer for dispensing semiochemicals was developed and used for a field test of bark beetle semiochemicals. The sprayer consists of a geared pump that pushes a syringe slowly to dispense semiochemicals in solvents through a microtube to a glass micropipet fixed to a piezoelectric high-frequency vibrator. The frequency is adjusted via a function generator to about 120 kHz until the harmonic properties of the glass micropipet, drawn by an electrophysiological pipet puller, cause vibrations that atomize the solvent from the micropipet tip. The sprayer, syringe, pump, function generator, and power supply were hung on one arm of a rotating trap pair (traps 6 m apart) that was slowly rotated at 2 revolutions per hour (rph) to even out the position effects on trap catches. The aggregation pheromone components of Pityogenes bidentatus, grandisol and cis-verbenol, were released by standard tube dispensers in one trap and compared to the release of similar amounts by the sprayer in the other trap. No significant differences in catch were observed. No effect of the solvent hexane on aggregation could be observed. The trap pair also caught approximately equal numbers of bark beetles when the baits were identical. The release of (+)and (–)--pinene, (+)-3-carene, and terpinolene, monoterpenes of host Scotch pine, Pinus sylvestris, at increasing rates from 0.01 to 10 log-equivalents in decadic steps (each at 0.1–100 g/min) resulted in decreasing responses to aggregation pheromone (only 9% at highest rate). Inhibition by the individual monoterpenes tested at the 100 g/min rate was significant for (+)and (–)--pinene and terpinolene (12, 13, and 15% of control, respectively). The inhibition by the host Scotch pine monoterpenes may allow P. bidentatus to avoid resistant trees that release large amounts of toxic monoterpenes in their resin and instead colonize dying and diseased limbs or slash, the usual host substrate. The piezoelectric sprayer should prove generally useful to dispense precise amounts of semiochemicals in field and laboratory experiments.     

Apparatus and procedure for measuring release rates from formulations of lepidopteran semiochemicals

An apparatus was developed wherein a vacuum source was used to pull air across a controlled-release-formulation dispenser or a planchet containing a known quantity of a semiochemical and into a collector filled with a polymeric adsorbent. After a set time, the semiochemical was eluted with solvent and was quantified by gas-liquid chromatography (GLC). High percentages of known quantities of the lepidopteran semiochemicals (Z)-7-dodecen-l -ol acetate (Z7DDA), boiling point (bp) 275 ° C/1 atm, (Z)-9-tetradecen-1-ol formate (Z9TDF), bp 289 °C/1 atm, and (Z,Z)-3,13-octadecadien-1-ol acetate (ZZODDA), bp 490 °C/1 atm, were recovered. The semiochemicals did not oxidize and were recovered quantitatively from the adsorbent. The release rates of Z9TDF from a controlled-release dispenser were found to be directly proportional to the airflow rates. Release rate measurements on the Z9TDF dispensers were made for the purpose of estimating the method's precision. The method was shown to give internally consistent results by measurements on another Z9TDF formulation. The accuracy of the method is discussed.Mention of a commercial or proprietary product in this paper does not constitute an endorsement by the USDA.     

High-pressure fluidized bed coating utilizing supercritical carbon dioxide

Various particles with sizes between 100 and 200 μm were encapsulated with waxes commonly used in technical coating applications. For this, a homogeneous mixture of molten paraffin and supercritical carbon dioxide was prepared in an autoclave and injected into the high-pressure fluidized bed through a nozzle from the bottom. Due to the different conditions in the mixing autoclave and the fluidized bed, the paraffin precipitated in the vicinity of the nozzle and adhered to the solid particles. A complete, thin, uniform, and solvent-free coating was produced. The use of two paraffins with different alkane compositions resulted in dissimilar spreads on glass beads due to their different glass transition temperatures. A smaller pressure drop across the nozzle led to more uniform and even coatings. Glass beads, ceramic spheres, potassium chloride, and lactose showed similar coating results, whereas different morphologies were observed with a plastic material, characterized by a rougher surface and a lower surface energy. The high quality of the coating was confirmed by standard dissolution tests with coated potassium chloride crystals and lactose agglomerates.     

固载二氧化氯的释放特性及杀菌试验研究

主要研究了酸活化剂、填充剂、pH载体等因素对固载二氧化氯释放特性的影响，得到了不同情况下的释放峰值和峰值时间及几种常见菌种达到杀菌率100％所需固载二氧化氯释放剂量。     

缓释、控释肥料生产、使用前景展望

从我国氮、磷、钾肥高消费、低利用率的现状,阐述了为什么缓控释肥被列为国家中长期科学技术发展计划的优先主题之一。介绍了哪些肥料是缓释、控释肥及当前世界生产、消费量。据估计,2005年世界缓释、控释肥料产量及消费量不超过100万t/a,若包括用于大田作物,具有一定缓释性能的包膜、包裹、包囊肥料,即广义的缓释、控释肥料世界生产、消费量已达120万t/a。展望了缓控释肥生产使用前景,在世界范围内,缓控释肥生产与消费的制约条件是产品价格;就国内而言,农民对肥料要求速效、速溶、速散是推广缓释、控释肥的主要思想障碍。降低生产成本,转变农民对缓释肥的认识,才能推动我国缓控释肥高速发展。     

海藻酸微胶囊的制备及在药物控释中的研究进展

海藻酸具有相对温和的凝胶条件与良好的生物相容性 ,已广泛应用于药物缓释与生物医学工程。综述了海藻酸微胶囊的制作方法、增加海藻酸微囊的稳定性与控制物质扩散的主要方法及海藻酸凝胶在药物控释研究中的进展