苯乙酸溶解度测定及提取工艺研究

为了提取6-氨基青霉烷酸(6-APA)、7-ADCA生产过程中产生的副产物苯乙酸,采用物理法测定了苯乙酸在水、水-乙醇、水-丙酮中的溶解度及其在水中的溶解速率,由此确定了水法多次提取的工艺方案。结果表明,在提取温度(60±2)℃,时间10~15 m in,水用量1 500 mL,提取次数3~4次时,苯乙酸收率为90.8%,纯度为99.3%。该法污染少、成本低,所得PAA产品质量好。     

新型疏水沉淀二氧化硅的制备

以沉淀二氧化硅的半成品为原料,用DMC(二甲基聚环硅氧烷)进行表面改性,得到疏水度为29.9%的疏水二氧化硅产品。实验研究了DMC用量、改性时间、体系酸度、异丙醇的加入量及表面活性剂的添加等因素对改性效果的影响。结果表明,异丙醇和表面活性剂(Tween-20)的加入及酸性介质对提高产品改性效果影响显著;改性后样品的DBP、比表面积以及孔隙度均下降,说明改性后产品结构排布更加紧密,部分微孔被堵塞封闭。该方法具有工艺简单、成本较低、无有害腐蚀气体产生等优点。     

通用循环水冷却器延时关闭控制联动电路设计

目前许多大型仪器的循环冷却水系统，都没有提供相应的自动化延时关闭装置，给工作带来不便。经过分析，将主机供电系统与循环冷却水供电系统进行关联，设计了联动电路，实现了正常关机，循环冷却水系统自动延时20min后关闭。既节约了工作时间，又提高了工作效率。     

飞灰快速水化团聚颗粒的热态磨耗研究

利用热态磨耗实验台研究快速水化团聚颗粒在流化床中热态条件下的磨耗特征.研究表明,飞灰团聚用水量、添加剂用量和流化速度是影响飞灰团聚颗粒磨耗速率大小的关键因素.随着流化速度的降低和添加剂用量的提高,团聚颗粒的磨耗速率降低.飞灰团聚用水量在40%左右时,团聚颗粒磨耗速率最低.亦即在上述条件下团聚颗粒在流化床中停留时间相对较长,进而飞灰碳降低的幅度和自由氧化钙的利用率可能较大.     

环保型水处理药剂的合成与性能研究

本文首先分别合成了聚天冬氨酸和丙烯酸-丙烯酸酯共聚物，并对其性能进行评定，然后以聚天冬氨酸为主体，通过与聚丙烯酸类阻垢分散剂和磷系阻垢缓蚀剂的复配，开发出一种低磷、可部分生物降解的新型阻垢缓蚀剂，并对其性能进行了综合评定，表明该药剂具有优良的阻垢缓蚀性能，适合用在高温、高硬度、高浓缩倍数的循环冷却水系统。     

The effect of grazing intensity and the presence of a forage legume on nitrogen dynamics in Brachiaria pastures in the Atlantic forest region of the south of Bahia, Brazil

It has been shown that with careful grazing management and addition of Pand K, but not N, fertilisers Brachiaria pastures are ableto maintain sustainable live weight gains over many years. However, standardon-farm practice, which generally involves high stocking rates, leads after afew years to pasture decline due mainly to N deficiency for grass regrowth. Togenerate an understanding of the mechanism of pasture decline and possiblemanagement options to mitigate this process, a study was performed in theAtlantic forest region of the south of Bahia state to study the N dynamics inpastures of Brachiaria humidicola subject to threedifferent stocking rates of beef cattle, with and without the presence of theforage legume Desmodium ovalifolium. Despite the fact thatthe C:N ratio of the deposited litter was high (60 to 70) the rate ofdecomposition was very rapid (k –0.07 gg^–1 day^–1) and annual rates of Nturnover through the litter pathway were between 105 and 170 kg Nha^–1 year^–1. In the grass-onlypasturesas stocking rate increased from 2 to 3 head ha^–1, N recycledinthe litter decreased by 11%, but a further increase to 4 headha^–1 decreased N recycling by 30% suggesting thatbeyonda certain critical level higher grazing stocking rates would lead to pasturedecline if there was no N addition. High stocking rates decreased theproportionof the legume in the sward, but at all rates the concentration of N in both thegreen and dead grass in the forage on offer and in the litter was higher in themixed sward. The presence of the legume caused a decrease in the C:N ratio ofthe microbial biomass while both soil N mineralisation and nitrificationincreased. This increased rate of turnover of the microbial biomass and thecontribution of N₂ fixation to the legume resulted in largeincreasesin the N recycled via litter deposition ranging from 42 to 155 kg Nha^–1 year^–1.     

掺铈镧氧化锆触媒材料的研制

以锆、铈、镧的无机盐为原料 ,采用共沉淀法制备了含CeO2 -La2 O3的ZrO2 复合氧化物触媒材料。通过改变铈化合物和镧化合物的添加量及焙烧温度来考察其对比表面积和主晶相的影响。利用XRD、BET、DTA等分析手段对合成的复合氧化物的部分性质和主要晶相进行检测分析 ,结果表明加入氨水作沉淀剂及铈化合物和镧化合物添加量一定时可得到以四方相为主的ZrO2 晶相 ,比表面积较大 ;通过碳—氢转化率的测定 ,碳氢转化率在 60 0℃可达到 80 % ,表明具有一定的触媒性能     

Surface Composition of Myrmecophilic Plants: Cuticular Wax and Glandular Trichomes on Leaves of <Emphasis Type="Italic">Macaranga tanarius</Emphasis>

Primary plant surfaces, covered with cuticles consisting of cutin and waxes, are important substrates for interaction with insects. The composition of leaf surfaces of the myrmecophilic plant Macaranga tanarius was studied. The prenylated flavanone nymphaeol-C was identified in surface extracts and was localized exclusively in glandular trichomes on the abaxial leaf side. The epidermal pavement cells surrounding these trichomes were covered with a smooth film of epicuticular wax from which few small wax crystals protruded. The epicuticular wax amounted to approximately 8 μg cm⁻², corresponding to 85% of the wax load on the adaxial as well as the abaxial leaf sides. The epicuticular wax mixtures from both leaf surfaces contained more than 70% primary alcohols, 14% fatty acids, 2% aldehydes, and traces of alkyl acetates, with chain lengths ranging from C₂₀ to C₃₈. In contrast, the intracuticular wax layer was largely dominated by triterpenoid alcohols α-amyrin, β-amyrin, and lupeol. Consequently, these characteristic compounds are not available for direct contact with insects on the plant surface.     

催化-分离脱氢膜反应器的透氢性能研究

1 前言在化学化工领域中利用膜材料的选择性渗透和催化作用来改善反应性能正越来越受到人们的重视。与传统的颗粒状催化剂-固定床反应器体系相比较,膜催化反应器在质量传递、热量传递和活化反应物方面有较大的差异。例如,用传统的固定床反应器由于受热力