尿素-壳聚糖微胶囊囊芯释放速率的研究

研究了操作条件对缓释型肥料——尿素-壳聚糖微胶囊囊芯释放速率的影响,并研究了微胶囊在中性(水)、弱酸、弱碱条件下的释放速率.实验表明,胶囊中囊芯的释放速率主要由芯壁比决定,囊壁的壳聚糖质量分数以3%为宜.     

Novel layered pesticide slow/controlled release materials——supramolecular structure and slow release property of glyphosate intercalated layered double hydroxides

Two different interlayer structured glyphosate(GLY) intercalated MgAI layered double hydroxides, as novel pesticide slow/controlled release materials, have been synthesized by co-precipitation method under various reaction pH values. The slow/controlled release properties have been tested in Na2CO3 aqueous solution. The release mechanism has been interpreted on the basis of the ion-exchange between the guest GLY anions in the lamellar host and CO3^2- in the release media, and the diffusion process of GLY anions in the interstice and interlayer of GLY intercalates, i.e.diffusion through the particles, is the rate-limiting step of GLY release process. The GLY intercalate assembled at lower pH, possessing higher interlayer gallery height and vertical monolayered arrangement of guest anions in the interlayer with larger packing density, exhibits better slow release property than that assembled at higher pH. The results reveal that the layered double hydroxides have potential application in the pesticide slow/controlled release area.     

半低挥发性核裂变产物在加热中从辐照后UO2中的释放

总结了从Ｃｈａｌｋ Ｒｉｖｅｒ实验室的１５４个实验中测得的半挥发性（Ｒｕ，Ｎｂ，Ｂａ，Ｓｂ，Ｔｃ）和低挥发性（Ｚｒ，Ｌａ，Ｃｅ，Ｅｕ，Ｐｒ，Ｎｄ，Ｐｍ和锕系元素Ｎｐ）裂变产物释放的数据。这些实验把二氧化铀燃料碎片在空气、不蒸气和惰性气氛中加热至４６５－２０８０℃。这些试样取自辐照近的燃料元件和燃料棒。     

中、小河流BOD—DO水质数学模型

本文提出一个适用于中、小河流,并考虑纵向分散作用和将生化需氧量分为碳化阶段和硝化阶段,以及底泥释放CBOD和NBOD与底泥耗氧的水质数学模型。经无锡市梁溪河实测资料验证,取得较为满意的成果。     

一种新的蛋白释放载体——水溶性壳聚糖纳米粒子

以三聚磷酸钠作为交联剂, 采用离子交联法制备了不同构成的水溶性壳聚糖纳米粒子(WSC NP). 以牛血清蛋白(BSA)为模型药物, 所制得的空载及载药WSC NP粒径、Zeta电位分别在35~190 nm和35~42 mV之间. 红外光谱证实了纳米粒子中水溶性壳聚糖的氨基与TPP的磷酸基团发生了交联反应. 考察了WSC NP蛋白药物释放的一些影响因素. BSA浓度的增加(0.05~1 mg /mL)提高了WSC的载药量但同时降低了负载率; 聚乙二醇的添加加速了WSC载体中BSA的释放; WSC的脱乙酰度(72.6%~90%)及分子量(3.5~15.8 kDa)的增加在一定程度上提高了负载率而降低了释放率. 结果表明, 水溶性壳聚糖是一种极具应用潜力的蛋白药物释放载体.     

Influences of the degradation of swamp and alpine meadows on CO2 emission during growing season on the Qinghai-Tibet Plateau

CO2 emission fluxes of two types of ecosystem, swamp meadow and alpine meadow, in the Fenghuo- shan region of the Qinghai-Tibet Plateau were studied by the static chamber-portable infrared chro- matographic method. The results showed that there was large difference in the CO2 emission fluxes between the two ecosystems and in the same ecosystem of different degradation degrees. CO2 emis- sion flux of the swamp meadow gradually decreased with increasing degradation degree, while that of the alpine meadow gradually increased with increasing degradation degree except in May. The CO2 emission flux of undegraded swamp meadow was 65.1%―80.3% higher than that of undegraded alpine meadow; and the CO2 emission flux of moderately degraded swamp meadow was 22.1%―67.5% higher than that of alpine meadow; but the CO2 emission flux of severely degraded alpine meadow was 14.3%―29.5% higher than that of swamp meadow. The soil moisture content and temperature in the upper 5 cm soil layer and above-ground biomass were significantly correlated with the CO2 emission fluxes and regarded as the main environment factors to control the CO2 emission.     

铁核结构对马脾铁蛋白释放铁动力学的影响

铁蛋白的主要生理功能是储存机体中过剩的铁及释放已储存的铁给需铁的细胞生物。此外，铁蛋白还能表达吸氢活性及从物理电极上接受电子等的新的生理功能。本文选用不同铁核结构为探针研究马脾铁蛋白（HSF）释放铁的动力学规律．为今后深入探讨铁蛋白的新生理功能提供有价值的理论研究依据。     

生物反应器填埋场中重金属固定和释放规律实验研究

通过实验柱模拟生物反应器填埋场的完全厌氧状态与氧气入侵状态,用以研究填埋场完全厌氧稳定化过程及氧气介入的情况下重金属的固定与释放规律。结果表明,Cd、Mn、Ni、Pb和Zn,在厌氧降解完全结束时其滞留率分别达到70.2%、83.9%、90.6%、70%和95.7%。氧气的入侵不会增加Pb和Cd的活性,却促进了Mn、Ni和Zn的释放,但相对于固定总量来说,释放量不大。因此,生活垃圾对于重金属有很大的固定容量,且环境变化的冲击对填埋场重金属固定的影响较小。     

一种数据库连接池的动态控制策略

分析了传统数据库连接池的不足，提出了一种能根据连接请求数来动态地改变连接池内连接数目的策略。 该策略的核心延迟释放算法能有效地控制每个连接的释放时机，使连接池既能在常规条件下满足正常的连接需 求，又能应对大量的突发需求，而且该策略还能有效地节约系统资源和通信资源。测试结果显示，在有大量突发连 接需求的环境中，使用该策略的连接池表现出了优于传统连接池的性能。     

以聚合物／硅藻土为控释材料的阿维菌素颗粒剂的制备及其性能研究

以聚合物/硅藻土复合材料为缓释剂,阿维菌素(Avermectin)为模型药物,采用转动包衣法制备了阿维菌素控释颗粒剂,应用红外光谱及扫描电镜分别对颗粒剂及复合控释材料的表面结构进行了表征,同时,利用体外释放实验测定了控释颗粒剂的释药特性,并用其进行了防治胡椒根结线虫的田间药效试验.结果表明:复合控释材料较单一硅藻土的表面结构致密,粒间堆积紧凑,孔隙量少,且与有效成分阿维菌素之间无化学键合,为物理包膜吸附作用.控释颗粒剂释药机理不属化学反应型释放,初步确定为Super Case Ⅱ型传递机理.该颗粒剂对胡椒根结线虫具有较好的防治效果,用量为75 kg·hm -2时,药后60 d,防效能保持在95%以上.