磁处理对原油结蜡影响的机理分析

分析了磁处理对原油结蜡的影响因素,用石油胶体分散体系理论分析了原油结蜡过程,应用胶体化学中的"DLVO理论"解释了磁处理对原油结蜡的影响.分析认为,磁场通过对蜡晶分子间色散力的影响作用,致使蜡晶胶粒之间的范德华引力势能增大,从而促进了原油中蜡晶胶粒的聚结,这就是磁处理对原油凝胶结构产生影响从而降粘的基本原因.     

渭河中游全新世晚期古洪水沉积物特征

通过野外实地调查,在渭河中游咸阳市南寺村一级阶地的全新世黄土-古土壤剖面,发现了含有波状水平层理的古洪水滞流沉积层,对所采集的全新世地层样品进行了粒度、磁化率、烧失量、CaCO3和石英颗粒微结构表面特征分析,表明古洪水滞流沉积物（SWD）平均粒径小,磁化率值低,CaCO₃含量高,石英颗粒表面“V”形坑和三角痕明显等特征,与风成黄土和古土壤差别显著,判定为典型的古洪水滞流沉积物。通过OSL（光释光）测年及地层学对比,确定古洪水SWD记录了渭河中游3 200~2 800 aBP发生的一组3次古洪水事件,正处于全新世大暖期向晚期转变的过渡时期,气候不稳定,降水变率大,引发了连续的特大洪水事件。此研究成果对于揭示区域水文变化对全球气候变化的响应规律具有重要科学意义。     

航空静电喷雾与非静电喷雾沉积效果的比较

利用直升机R44和固定翼飞机Y5B挂载自主研制的航空静电喷雾系统设备进行机场和野外航空静电喷雾与非静电喷雾的比较试验.结果表明:静电喷雾存地面和空中靶标表面、树冠中上部叶片正面的沉积效果明显优于非静电喷雾:雾粒细小、分布均匀、沉积密度提高1倍以上,最高达1.75倍;直升机静电喷雾在叶片背面的沉积率为非静电喷雾的2.15倍,是常规航空喷雾的3.31倍.Y5B静电喷雾在叶片背面的沉积率为非静电喷雾的2.38倍,是常规航空喷雾的3.44倍.     

埋置一端固定的弹性地基梁解决"桥头跳车"的设想与分析

针对公路路堤与桥台差异沉降问题,提出了在桥梁台背中埋置一端固定在桥台中的弹性地基梁的设想,并运用局部弹性地基梁模型初步论述了这种地基梁的作用机理及其设计思想,为研究解决公路工程的最大"顽疾"--"桥头跳车"提供了一种新的思路和方法.     

鲁中地区风成沉积与湖泊沉积粒径参数量化分析

对鲁中地区风尘堆积剖面和湖泊沉积进行了系统的野外考察,以平阴龙桥黄土剖面和东平湖为例,并进行了粒度参数分析。研究表明,中位数(Median)、众数(Mode)、最小值(Minimum)、最大值(Maximum)、百分位数变量值(Percentile values)之间具有差异。同时,对平阴龙桥黄土剖面和东平湖样品进行了Mann-Whitney U检验,Mann-Whitney U为8 678,检验统计量Z=-1.270,其相伴概率P=0.020<0.05,可以看出两者粒径之间有显著性差异。最后,对两者粒径均值进行了T检验,F统计量的值为34.757,其相伴概率P=0.032<0.05,粒径的方差不相等。t统计量的值为-3.597,自由度df=150.77,其相伴概率为P=0.029<0.05,同样表明两者粒径之间具有明显差异,并且分析了其环境意义。     

土石混合崩积体坡面细沟跌坑发育试验研究

为了探究土石混合崩积体坡面细沟跌坑发育情况,采用室内放水冲刷试验,通过设置4个流量(2,4,8,12 L/min)和4种砾石含量的土石混合崩积物(砾石质量比例0,10%,30%,50%),研究不同条件下细沟跌坑的发育特征。结果表明:在不同冲刷时段,跌坑数量变化为3～17个,跌坑平均深度为1.10～5.93 cm,细沟纵断面形态系数为2.97～19.97。各跌坑参数随冲刷时间的延长总体呈增大趋势,部分坡面在5 min或7.5 min时出现最大值;跌坑参数随流量的增加总体呈先增大后减小趋势,8 L/min流量条件下出现最大值,而随着砾石含量增加总体呈增大趋势;流量对跌坑发育的影响大于砾石含量。各跌坑参数与流速、阻力系数及曼宁粗度系数密切相关,径流剪切力是描述跌坑发育的最适合水动力学指标,可用线性函数表达。     

Finite dose diffusion studies: II. Effect of concentration and pH on NAA penetration through isolated tomato fruit cuticles

The effects of NAA [2‐(1‐naphthyl)acetic acid] concentration and pH on penetration of NAA from aqueous droplets (5 µl) through isolated tomato (Lycopersicon esculentum) fruit cuticles were studied using a finite dose diffusion system. Penetration time‐courses were characterized by a lag phase, which generally extended beyond the time of droplet drying. Initially penetration rates increased, reached a maximum penetration rate, remained constant for several hours, and then decreased with time. Penetration approached a plateau within 120 h after droplet application. Increasing NAA concentration in the donor droplet increased NAA penetration in both the presence and absence of the citric acid buffer (20 mM , pH 3.2). Maximum rates of penetration and the total amount of NAA that penetrated at 120 h were both linearly related to the initial concentration of the donor droplet (ranging from 0.001 to 0.1 mM NAA). The apparent first‐order rate constants for the concentration dependence of NAA penetration rates were greater with buffer than without (0.94 × 10⁻⁸ vs 0.50 × 10⁻⁸ m s⁻¹, respectively). While pH of the receiver solution (pH 6.2 vs 2.2) did not affect penetration, decreasing donor pH from 6.2 to 2.2 increased NAA penetration at 120 h. © 2000 Society of Chemical Industry     

Deposit structure and efficacy of pesticide application. 1: Interactions between deposit size,toxicant concentration and deposit number

Application of pesticides through a hydraulic nozzle produces deposits on a plant surface which have a spatial structure with elements of deposit size, number per area, and toxin per deposit. To investigate the relative contributions of these elements to the interaction of deposit structure and toxicant efficacy, we used a stochastic cellular automaton model of diamondback moth feeding on Bacillus thuringiensis (Bt)-treated cabbage – the Pesticide Dose Simulator (PDS) model. Data were analyzed using a specialized response surface approach called a mixture design. The advantage of this design was that it integrated the effects of deposit size, number per area and toxin per deposit on toxicant efficacy. Results from PDS simulations led to the following conclusions: (1) Deposit structure plays a major role in toxin efficacy. (2) Small deposits are not always the most efficacious. (3) Uniform coverage is not the best deposit structure if one is forced to limit application rates and field persistence. (4) Since uniform deposit structures allow an insect to live longer, uniform deposit structures should result in more insects acquiring sub-lethal doses. This may result in an interaction between ‘uniform coverage’ and the development of pesticide resistance in insect populations. (5) Percentage mortality and the level of crop protection are not necessarily correlated. Overall, these results help reconcile laboratory observations that small droplets are more efficacious with field observations that application of small droplets (eg from spinning disk sprayers) does not necessarily increase field efficacy. © 1999 Society of Chemical Industry     

存款保险制度的研究

我国存款保险制度已于2015年5月1日正式出台,它的存在对我国这样一个经济转轨的经济体而言是否有利大于弊的功效,这需要结合中国特色社会主义的特殊国情,借鉴国际经验和实例,对我国建立存款保险制度的利弊作出分析。     

Factors influencing the association between active ingredient and adjuvant in the leaf deposit of adjuvant-containing suspoemulsion formulations

BACKGROUND: For an oil adjuvant to enhance uptake of a particulate active ingredient (AI), it is hypothesised that closer association between the two should result in higher uptake. Accordingly, factors important for the spray deposit size on grapevine leaves have been investigated for a series of model suspoemulsion formulations containing colloidal crystalline AI or fluorescent pigment particles and an emulsion of an oil adjuvant with different degrees of wetting and different spray volumes. RESULTS: Low spray volumes (<100 L ha(-1)) produced small deposits with high particle-adjuvant association. Complementary uptake studies showed increased uptake with decreasing deposit size, in agreement with the above hypothesis. Higher spray volumes produced larger deposits that consisted of annuli formed by pinning of the contact line by particles. Low surfactant concentrations favoured particles in the annulus and adjuvant separated in the centre. Intermediate surfactant concentrations produced annuli containing both particles and adjuvant, while with high surfactant concentrations the deposits were large with few annuli.CONCLUSIONS: Small deposits result in high AI-adjuvant association. With larger deposits, annulus structures allow for enhanced AI-adjuvant association (5-20 times greater). The formation of annuli appears to be important in enhancing the biodelivery of particulate AIs in adjuvant-containing suspoemulsion formulations at intermediate spray volumes.