水性聚氨酯结构与微相分离的研究

合成了一系列水性聚氯酯，并用红外光谱、差示扫描量热仪对乳液胶膜进行表征，考察了软段组成、DMPA含量及。(-NCO)：n(-OH)比值对产物微相分离的影响。实验结果表明：聚醚型产物的微相分离程度高于聚酯型产物。提高DMPA用量，软段Tg移向低温区，说明体系的做相分离程度加大。随着n(-NCO)：n(-OH)比值的增大，软段Tg也移向低温区，软硬段的微相分离程度增大.     

高效液相色谱法测定止痛养胃软胶囊中延胡索乙素的含量

测定止痛胃软胶囊中延索乙素的含量,可用高效液相色谱法。选用甲醇—磷酸缓冲溶液(40∶60)为流动相,测定波长280nm。结果:延胡索乙素浓度在0.02140～1.37mg/mL范围内,与峰面积线性关系良好,y=(8.390×106)x+7.505×103(r=0.9997)。结论:该法操作简便、快捷、特异性强,可用于控制止痛养胃软胶囊的质量。     

BIOFUMIGANT COMPOUNDS RELEASED BY FIELD PENNYCRESS (<Emphasis Type="Italic">Thlaspi arvense</Emphasis>) SEEDMEAL

Defatted field pennycress (Thlaspi arvense L.) seedmeal was found to completely inhibit seedling germination/emergence when added to a sandy loam soil containing wheat (Triticum aestivum L.) and arugula [Eruca vesicaria (L.) Cav. subsp. sativa (Mill.) Thell.] seeds at levels of 1.0% w/w or higher. Covering the pots with Petri dishes containing the soil-seedmeal mixture decreased germination of both species at the lowest application rate (0.5% w/w), suggesting that the some of the phytotoxins were volatile. CH₂Cl₂, MeOH, and water extracts of the wetted seedmeal were bioassayed against wheat and sicklepod (Senna obtusifolia (L.) H. S. Irwin & Barneby) radicle elongation. Only the CH₂Cl₂ extract was strongly inhibitory to both species. Fractionation of the CH₂Cl₂ extract yielded two major phytotoxins, identified by gas chromatography–mass spectrometry and NMR as 2-propen-1-yl (allyl) isothiocyanate (AITC) and allyl thiocyanate (ATC), which constituted 80.9 and 18.8%, respectively, of the active fraction. When seeds of wheat, arugula and sicklepod were exposed to volatilized AITC and ATC, germination of all three species was completely inhibited by both compounds at concentrations of 5 ppm or less. In field studies, where seedmeal was applied at 0.50, 1.25, and 2.50 kg/m² and tarped with black plastic mulch, all of the treatments significantly reduced dry weight of bioassay plants compared to the tarped control, with the highest seedmeal rate decreasing dry matter to less than 10% of the control 30 d after seedmeal application. Field pennycress seedmeal appears to offer excellent potential as a biofumigant for high-value horticultural crops for both conventional and organic growers.Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable.     

基于PLS快速剪枝法的RBF神经网络软测量模型建模方法和应用

提出一种从RBF神经网络隐含层的输出信息出发，通过PLS快速剪枝法，一次性剪去多余节点，生成最优规模的数学解析模型的方法。并用该方法建立了某化工企业精对苯二甲酸(PTA)晶体平均粒径的软测量模型，针对实际对象进行仿真研究，结果表明，该方法计算速度快，建立的模型精度高，适合实际工程应用的需求。     

碘和硫增感剂在卤化银颗粒表面的分布

碘和硫增感剂在卤化银颗粒表面的分布＊李金培＊＊王素娥（中国科学院感光化学研究所，北京１００１０１）关键词碘化银，硫增感，软硬酸碱原理碘在卤化银微晶中的含量和分布对感光度的影响引起乳剂配方设计者的广泛注意和重视．颗粒中的碘引起其内部结构和表面结构的改变...     

Regional mass flux balancing for controlling gentle soil remediation operations

Extraction of heavy metals by accumulating plants is a method which is currently in development for the "gentle" remediation of contaminated agricultural soils (phytoremediation, see [2]). Areal contaminant mass flux balances are basic criteria for the design of such remediations and their control. A framework for the integration of contaminant balances relating the field scale of remediation with the regional scale of soil monitoring networks is provided by the recently developed method PROTERRA [3]. The objective of the study presented in this paper was to test the suitability of PROTERRA for planning and monitoring gentle soil remediations. For this purpose we applied the PROTERRA method to the contaminated agricultural land in and around Dornach, Switzerland, to assess copper flux balances.The calculations showed that atmospheric deposition and the application of pesticides and manure are important pathways for the inputs of copper. The copper export with a special maize cultivar accumulating heavy metals would be about three times higher than the average metal export with crops. A moderate increase of sewage sludge application would lead to a substantial increase of the copper input. Decisions to remediate the soil should take the uncertainty of mass flux balances both on field scale as well as on regional scale into account. Therefore, an important need of further development of the PROTERRA method is the integration of uncertainty analysis on both scales.     

基于微结构指标响应曲面法的固化盐渍土力学特性分析

固化土力学强度指标与固化土结构变化的关系是盐渍土特性研究中的重要问题。选取颗粒粒度分维D_(ps)、颗粒定向分维D_(di)、等效直径D_e为试验因素,利用响应曲面法进行试验。响应曲面模型可以对固化土的力学性能指标进行分析和预测,利用该模型研究石灰固化盐渍土的力学强度指标与最优微结构参数之间的关系,并进行了验证。结果表明,固化土微结构最优指标是粒度分维D_(ps)为0.8、颗粒定向分维D_(di)为0.93、等效直径D_e为1.75时,固化土无侧限抗压强度q达到1.636 MPa,与实测值仅相差0.038 MPa;黏聚力c为456.7 k Pa,与实测值完全一致;内摩擦角为39.6°,与实测值仅相差0.2°。该模型为探讨各类固化盐渍土物理化学指标、各掺加料比例及固化土微结构之间相互关系提供了借鉴和依据。     

含水量对渠道保温板保温耐久性的影响及保温板厚度设计

北方渠道大多使用保温板防止混凝土衬砌受冻胀破坏。在计算保温板厚度时为了降低成本,容易忽略保温板使用过程中受各种因素的影响导致保温效果变差的情况,使混凝土衬砌达不到设计使用年限便提前被破坏。内蒙古河套灌区试验结果表明,由于受酸雨、冻融作用、含水量等因素的影响,保温板保温效果平均每年降低0.9℃,其中受含水量变化的影响最大。经试验测得:聚苯乙烯保温板(EPS)含水量每增加1%,会导致导热系数增大5%。基于多层材料串联热阻叠加原理和热阻等效原理,对保温板厚度计算公式进行完善,并提出相应的铺设方法和施工技术要求。该设计对保温板在季节性冻土区的推广应用具有一定参考价值。     

陕北无定河流域土壤侵蚀与植被覆盖和降雨关系研究

基于2000—2014年陕北无定河流域日降水、DEM、土壤类型、MODIS NDVI等数据,利用修正通用土壤流失方程(RUSLE)估算了流域土壤侵蚀情况,定量分析了植被覆盖和降雨在土壤侵蚀中的作用,结果表明:(1)无定河流域土壤侵蚀以微度侵蚀为主,平均占流域面积的88.35%,各土壤侵蚀等级面积比例随等级的升高而降低。2000—2014年微度侵蚀面积比例为下降趋势,轻度及以上等级面积比例均为上升趋势。(2)不考虑降雨因子影响时,无定河流域仍以微度侵蚀为主,且为增加趋势,而其他土壤侵蚀等级均为下降趋势。不考虑植被覆盖因子时,流域土壤侵蚀与模型计算结果的变化趋势基本一致。(3)植被覆盖对土壤侵蚀面积比例和变化速率的贡献率分别为13.67%和24.55%,而降雨作用达到86.33%和75.44%,表明降雨是流域土壤侵蚀的主要动力和控制因子,降雨变化主导着流域土壤侵蚀变化过程。     

粤北某市"土法炼砷"土壤中化学砷污染的研究

粤北某市“土法炼砷”造成的砷污染,严重破坏了当地生态环境,而且砷还会进入河流或地下水,严重威胁了当地及北江下游的饮用水安全和生态安全。本文对“土法炼砷”遗址现场进行调查取样,并对砷污染的特点进行了分析。