N,N—乙基苄基苯胺合成研究

以苯胺为原料,先用乙醇作烷基化试剂合成Ｎ－乙基苯胺,研究了反应的影响因素,烷基化反应在２２０℃,物料配比为１：２,反应时间３０小时,其主要产品收率可达９０％以上,纯度可达９７．３％,进而再用苄氯作为苄基化试剂合成Ｎ,Ｎ－乙基苄基苯胺,奠基反应的影响因素,苄基化反应在６０－８０℃,物料配比为１：１,反应时间１５小时能获得最佳反应结果,主产品收率可达９０％以上,纯度可达９９％,是迄今较理想的合成路线     

常压催化合成N—乙基—N—羟乙基苯胺

介绍了Ｎ－乙基苯胺和环氧乙烷常压催化合成Ｎ－乙基Ｎ－羟乙基苯胺新工艺,确定工艺条件为：反应温度１２０￣１３０℃,反应时间６￣８ｈ,摩尔比１：１．２,催化剂用量２％￣５％。     

N—甲基—N—羟乙基苯胺制备

以Ｎ－甲基苯胺和环氧乙烷为原料，采用气相非均相法合成了Ｎ－甲基－Ｎ－羟乙基苯胺。在反应温度１２０－１４０℃，反应压力０．４－０．６ＭＰａ，催化剂 ０．３％－０．４％的条件下，得到了较好的产品质量和收率。     

苄基三乙基氯化铵相转移催化合成N,N-二己基邻乙基苯胺的研究

采用苄基三乙基氯化铵为相转移催化剂，以邻乙基苯胺为原料、１－溴己烷为烷基化试剂，常压下合成了Ｎ，Ｎ－二己基邻乙基苯胺，并研究了反应物摩尔比、催化剂用量、反应时间对目的产物产率的影响，确定了实验设计范围内的最佳工艺条件。目标化合物的结构经ＩＲ和１ＨＮＭＲ谱图解析确认。     

相转移催化合成N,N—二乙基苯胺的研究

使用苄基三甲基氯化铵作相转移催化可在常压下由苯胺和溴乙烷合成Ｎ，Ｎ－二乙基苯胺。研究了多种反应因素对目的产物产率的影响，提出了常上催化合成目的产物的最佳工艺条件。     

四乙基溴化铵相转移催化合成N，N－二乙基苯胺的研究

在常压下以四乙基溴化铵作相转移催化剂合成制得Ｎ，Ｎ 二乙基苯胺，研究了各反应因素对目的产物产率的影响，其优化工艺条件为：在５０ｍｌ５０％的氢氧化钠溶液中，苯胺和溴乙烷的摩尔比为１∶２，四乙基溴化铵用量为０２５ｇ，６０℃下常压反应７ｈ，产品产率为８１５％。     

N—氰乙基—N—乙酰氧乙基苯胺合成研究

本文以Ｎ－氰乙基苯胺为原料，经常压Ｎ－烷化，Ｎ－酰化反应制取了Ｎ－氰乙基－Ｎ－乙酰氧乙基苯胺，并通过工业试生产，总收率达９３．３％。     

四乙基溴化铵相转移催化合成N，N－二乙基苯胺的研究

在常压下以四乙基溴化铵作相转移催化剂合成制得Ｎ，Ｎ二乙基苯胺，研究了各反应因素对目的产物产率的影响，其优化工艺条件为：在５０ｍｌ５０％的氢氧化钠溶液中，苯胺和溴乙烷的摩尔比为１∶２，四乙基溴化铵用量为０２５ｇ，６０℃下常压反应７ｈ，产品产率为８１５％。     

间乙酰胺基—N—乙基—N—苄基苯胺合成工艺研究

研究了由间苯二胺经单氨基酰化，氯化苄苄基化及溴乙烷乙基化合成间乙酰胺基－Ｎ－乙基－Ｎ－苄基苯胺的工艺，总收率达７１．２４％。     

N—乙基N—苄基苯胺的制备

介绍了Ｎ－乙基Ｎ－苄基苯胺的制备方法，研究了反应温度、物料配比、催化剂等对反应的影响。     

Effect of the timing and rate of nitrogen fertilization on the growth and recovery of fertilizer nitrogen within the potato (Solanum tuberosum L.) crop

The effect of the timing of N fertilizer application on the uptake and partitioning of N within the crop and the yield of tubers has been studied in two experiments. In 1985 either none, 8 or 12 g N m^–2 was applied and in 1986 none, 12 or 18 g N m^–2. Fertilizer N was applied either at planting, around the time of tuber initiation or half at planting and the remainder in four foliar sprays of urea during tuber bulking.¹⁵N-labelled fertilizer was applied to measure the recovery of fertilizer N in the crops.There was an apparent pre-emergence loss of nitrate from the soil when N was applied at planting in 1986, thereby reducing the efficiency of fertilizer use. Applying the N at tuber initiation delayed and reduced the accumulation of N in the canopy compared with crops receiving all their fertilizer at planting. Foliar sprays of urea slightly increased both tuber yields and tuber N contents when compared to a single application at planting. The proportion of the fertilizer N recovered in the crop was little affected by the rate of N application, but a greater proportion of foliar-applied N was recovered than N broadcast at planting, due partly to pre-emergence losses of nitrate in 1986. It is suggested that late applications of N was foliar sprays can be of benefit to crops with a long growing season and reduce environmental losses of N.     

Simulating the fate of subsurface-banded urea

Compared to surface broadcasting of nitrogen (N), subsurface-banding increases crop yield and N removal, reducing the N amount available for loss into the environment. Subsurface banding results in two-dimensional (2-D) N movement and high localized N concentrations that reduce N transformation rates. A physically-based, field-scale model was developed and tested for its ability to simulate the fate of subsurface-banded N. The 1-D moisture sub-model simulates moisture redistribution, evapotranspiration, and percolation using the Richards equation. Using the convective-dispersive equation, the 2-D N sub-model uniquely simulates the fate of urea, ammonium, and nitrate by accounting for urea particle dissolution rate and substrate concentration effects. Over 325 d, the model displayed robustness with respect to selection of grid sizes and exhibited mathematical accuracy. Analyses highlighted the importance of incorporating substrate concentration effects on N transformations; disregarding substrate concentration effects could result in overestimation of crop N removal and N movement in the soil. Analyses also indicated the importance of including molecular diffusion in simulating the fate of subsurface-banded N. While evapotranspiration, crop N removal, and residual applied inorganic-N estimates appeared realistic, measured and simulated moisture and applied-N amounts and distributions differed greatly. Errors in measurements of moisture and N and uncertainty in parameter estimation likely increased the difference in simulated versus measured values. The model was highly sensitive to soil pH and Freundlich distribution coefficient. Additional model evaluation with field data, though required, could not be performed due to lack of data describing distribution of soil N resulting from subsurface-banding.     

N-乙基哌嗪合成方法的改进

以哌嗪水溶液与溴乙烷反应合成N乙基哌嗪,并以共沸蒸馏方法分离N乙基哌嗪及副产物N,N′二乙基哌嗪。合成方法具有新颖、简便、收率及纯度高的特点,适合于工业生产。     

Adapting the potentially mineralizable N concept for the prediction of fertilizer N requirements

Quantification of N dynamics in the ecosystem has taken on major significance in today's society, for economic and environmental reasons. A major fraction of the available N in soils is derived from the mineralization of organic matter. For decades, scientists have attempted to quantify the rate at which soils mineralize N, but the complexity of the N cycle has made this a major task. Further, agronomists have long sought soil test methods that are practical, yet will provide accurate means of predicting the amounts and rates of release of N from soils. Such tests would allow us to make more precise fertilization decisions. This paper discusses the potentially mineralizable N concept, first promoted by Stanford and colleagues [61, 62, 64], and suggests how it may be incorporated into deterministic models, such as CERES and LEACHM, so as to provide more accurate estimates of N mineralization under field conditions. We also suggest how the potentially mineralizable N concept may be coupled to quick, routine laboratory methods of determining available soil N, such as the hot 2M KCl extracted NH₄-N method recently developed by Gianello and Bremner [35], and used together with deterministic N models, such as CERES, for predicting probable fertilizer N requirements.     

四甲基肼的合成研究

研究了四甲基肼的合成方法,先以水合肼和甲酰胺为起始原料发生醛基化反应得到二醛基肼,然后再与硫酸二甲酯发生甲基化反应得到二甲基二醛基肼,最后经锂铝氢还原,以15%的总收率得到目标产物四甲基肼。同时,对合成工艺进行了优化研究,反应收率较之文献有较大程度的提高。     

炭黑并用对NR／ENR共混胶力学性能及减震性能的影响

对比N660研究了N330／N660、N660／N990炭黑填充体系对天然橡胶（NR）／环氧化天然橡胶（ENR）共混胶力学性能、压缩疲劳生热性能及减震性能的影响,并采用橡胶加工分析仪（RPA）对其加工性能进行了分析。结果表明：N660／N330和N660／N990两种填充体系硫化胶的力学性能,基本上是单用一种炭黑所得硫化胶力学性能的加权平均;不同粒径炭黑并用均能使共混胶的贮能模量E′下降,并且有利于拓宽NR／ENR减震材料的减震范围;不同粒径炭黑并用有利于改善NR／ENR共混胶料的加工性能。     

Nitrogen mineralization from sheep faeces can be predicted from the apparent digestibility of the feed

It is difficult to predict plant availability of N in faeces because most faecal N is bound in organic form. In this study the influence of diet and faeces composition on mineralization of sheep faeces in soil were investigated. Net mineralization of C and N from 16 different samples of sheep faeces originating from sheep fed different known diets was studied after incubation in a sandy soil. After 4 weeks net mineralization of N ranged from –41 to 9% of faeces N and after 12 weeks –28 to 43% was net mineralized. Mineralization was related to different feed and faeces characteristics (apparent digestibility, NDF, ADF, crude fibre, lignin, C/N ratio and N concentration) by regression analysis. The two single factors showing the highest correlation with N mineralization after 12 weeks were the log transformed N concentration of faeces and the C/N ratio (r=0.84 and r=–0.87). The N concentration and C/N of faeces were closely related to apparent digestibility of the feed (r=0.88 and r=–0.93), and apparent digestibility was the feed characteristic showing the highest correlation with faeces N mineralization after 12 weeks (r=0.81). The estimate of faeces N mineralization was not improved when chemical characteristics of the feed were combined in a multiple linear regression analysis. Mineralization of sheep faeces C showed the highest correlation with NDF of the feed (r=–0.89) and N concentration of faeces (r=0.88). The study showed that it is difficult to make reliable predictions of the mineralization of sheep faeces N in soil based on chemical analyses of the feed. However, when using a biological measure of the feed quality (apparent digestibility) a robust prediction of faeces N mineralization was possible.     

Validation of the DNDC-Rice model to discover problems in evaluating the nitrogen balance at a paddy-field scale for single-cropping of rice

The DNDC (DeNitrification–DeComposition)-Rice model is one of the most advanced process-based models for estimating greenhouse gas emissions from paddy fields, and can be used to simulate the N balance of a paddy field. In this study, we validated DNDC-Rice using field observation data, including N balance data, and revealed problems when using the model to evaluate a paddy field’s N balance. Using a modified process submodel for fixation of ammonium (NH₄ ⁺) ions by clay, DNDC-Rice simulated the dry weight of roots, stems, and grains well, but overestimated leaf dry weight. The normalized root-mean-square errors (nRMSEs) for the root, stem, grain, and leaf dry weights were 13, 16, 7, and 60 %, respectively. DNDC-Rice also overestimated the leaf area index (LAI) and leaf N content, with nRMSEs of 125 and 37 %, respectively. The overestimation of leaf dry weight and LAI resulted from overestimation of N uptake by rice and of N allocation to leaves. The high N uptake might have been caused by a high available soil N content. At harvesting, the simulated N balance (=N input ? N output) was ?38.8 kg N ha^?1, which was much lower than the N balance determined by observations and from relevant literature (12.8 kg N ha^?1). The underestimation of the N balance resulted mostly from the model’s inability to calculate dry N deposition and N fixation as inputs and from overestimation of grain N uptake as outputs.     

氮化硅浆料的胶体特性研究

本文研究了Si3N4浆料的胶体特性,结果表明:Si3N4悬浮粒子的等电点(isoelectric point,简称IEP)在pH=4.2处.分散介质的离子强度影响Si3N4粒子的Zeta电位.分散剂的引入有效地提高Si3N4粒子的Zeta电位,并引起IEP的位移.粉体经不同工艺的预处理后IEP均发生不同程度的位移.X光电子能谱(XPS)分析表面组成发现其IEP的位移与Si3N4粉体表面的氧化程度有关.同时,对Si3N4浆料在不同条件下的分散性进行了考察,表明其分散性与胶体特性具有很好的一致性.     

多级串联等体积全混流反应器与平推流反应器等效性研究——以二级可逆反应为例

在多级串联全混流反应器中,在等温等容条件下给出了二级可逆反应第Ⅳ级反应器的出口浓度表达式.讨论了在相同操作条件下,达到平推流反应器的转化率所需要的等体积串联全混流反应器的级数Ⅳ;主要考察了正反应速率常数k1、平衡常数K、反应物初始浓度之比M、停留时间τ等因素对N的影响,得出了N与正反应速率常数k1、相平衡常数K以及停留...