Phytoplankton and cloudiness in the Southern Ocean

The effect of ocean biological productivity on marine clouds is explored over a large phytoplankton bloom in the Southern Ocean with the use of remotely sensed data. Cloud droplet number concentration over the bloom was twice what it was away from the bloom, and cloud effective radius was reduced by 30%. The resulting change in the short-wave radiative flux at the top of the atmosphere was -15 watts per square meter, comparable to the aerosol indirect effect over highly polluted regions. This observed impact of phytoplankton on clouds is attributed to changes in the size distribution and chemical composition of cloud condensation nuclei. We propose that secondary organic aerosol, formed from the oxidation of phytoplankton-produced isoprene, can affect chemical composition of marine cloud condensation nuclei and influence cloud droplet number. Model simulations support this hypothesis, indicating that 100% of the observed changes in cloud properties can be attributed to the isoprene secondary organic aerosol.     

Aerosols, cloud microphysics, and fractional cloudiness

Increases in aerosol concentrations over the oceans may increase the amount of low-level cloudiness through a reduction in drizzle-a process that regulates the liquid-water content and the energetics of shallow marine clouds. The resulting increase in the global albedo would be in addition to the increase due to enhancement in reflectivity associated with a decrease in droplet size and would contribute to a cooling of the earth's surface.     

Nutmeg dispersal by tropical birds

Frugivorous birds preferentially remove fruits from Panamanian Virola trees where the ratio of edible aril to indigestible seed is high. A negative correlation between the proportion of the crop removed and mean seed size explains 59 percent of the variance in removal, suggesting that birds minimize ingestion of useless bulk.     

管式燃油加热炉除尘器的研制

管式燃油加热炉的吹灰作业,会造成严重的环境污染,有必要研制环境友好型管式燃油加热炉除尘器。需要解决的技术难题有3个:一是在不改变加热炉结构、不影响加热炉效率的情况下,除去烟气中98%的烟尘;二是烟尘由油滴、沥青、炭黑及杂质组成,容重小,1μm以下粒径的细小颗粒占90%,易飞扬、易粘连,不易捕集;三是吹灰时由于烟尘量急剧增大,瞬间排尘浓度较高,除尘器应具备良好的负荷适用性。基于烟气产物相关数据的计算,提出了除尘器的技术要求,计算了关键部分的设计参数,设计了清灰结构形式和控制方式,实现了从吹灰到除尘全过程的自动控制,其模块组设计理念使得整套装置可以根据烟气总处理量和场地大小对设备模块进行有机组合。研制样机在睢宁输油站安装投用,性能良好,收到了预期效果。     

利用Excel处理热带作物机械噪声检测数据

噪声是评价热带作物机械质量的一项重要技术指标，在检测中是必不可少的，但其计算十分繁琐。本文简单介绍了利用Excel处理噪声检测数据的方法。     

Pt取代的LaCoO3催化氧化碳烟的研究

用柠檬酸法制备了不同量Pt取代的钙钛矿LaCo1-xPtxO3(x=0.02,0.04,0.06,0.08,0.1),以热重法测试了催化剂样品对碳烟的催化活性,并采用程序升温还原法(Hydrogen temperature-programmed reduction,H2-TPR)和X-射线衍射仪(X-ray Diffraction,XRD)对催化剂进行了表征.结果表明,催化剂LaCo0.96Pt0.04O3显示了最高的活性,起燃温度为493 ℃;XRD特征峰的衍射角向低角度偏移,表示Pt进入了钙钛矿结构;Pt取代量增加,催化剂的TPR还原峰向低温方向移动,还原峰的强度也发生了变化.     

Fe0还原土壤中对硝基甲苯的实验研究

采用零价铁(ZVI,Fe<'0>)还原技术.修复被对硝基甲苯(PNT)污染的土壤,研究不同反应条件对还原效果的影响及随时间推移产物的变化,并对反应机理进行了初步探讨.结果表明,常温常压下,Fe0可有效地将土壤中对硝基甲苯还原为苯胺化合物,反应过程中先生成对甲基亚硝基苯,最终生成对甲基苯胺.土壤含水量达到饱和时能显著提高PNT的还原率,土壤初始酸碱度控制在中性偏酸性有利于还原反应的进行,体系温度上升到25～35℃还原效果较好,当Fe0加入量小于25 mg·g-1时增加Fe0用量能有效增大还原率.当2 g土壤中PNT的初始浓度约为2.5×10-6mol·g-1,Fe0加入量是25 mg·g-1,土壤水含量75%,土壤初始pH值6.8时,于25℃下反应5 h后PNT的还原率可达95%以上.     

Space, stars, c60, and soot

Although carbon has been subjected to far more study than all other elements put together, the buckminsterfullerene hollow-cage structure, recently proposed to account for the exceptional stability of the C(60) cluster, has shed a totally new and revealing light on several important aspects of carbon's chemical and physical properties that were quite unsuspected and others that were not previously well understood. Most significant is the discovery that C(60) appears to form spontaneously, and this has particularly important implications for particle formation in combustion and in space as well as for the chemistry of polyaromatic compounds. The intriguing revelation that 12 pentagonal "defects" convert a planar hexagonal array of any size into a quasi-icosahedral cage explains why some intrinsically planar materials form quasi-crystalline particles, as appears to occur in the case of soot. Although the novel structural proposal has still to be unequivocally confirmed, this article pays particular attention to the way in which it provides convincing explanations of puzzling observations in several fields, so lending credence to the structure proposed for C(60).     

还原铁粉去除地下水中硝酸盐氮的研究

地下水中硝酸盐氮的污染问题变得日益突出,为此以100～200目的铁粉为还原剂,采用静态试验方法研究了不同pH值、硝酸盐氮初始浓度、溶解氧、铁粉表面预处理及铁与硝酸盐氮的质量比等因素对硝酸盐氮去除率的影响。结果表明,溶液的初始pH值对硝酸盐氮的去除影响很大,pH>4时,铁粉几乎不与水中硝酸盐氮进行反应;铁粉经过表面处理后在同一时刻内对硝酸盐氮的去除率提高1倍多;铁与硝酸盐氮的最佳质量比为200∶1;溶解氧对硝酸盐氮的去除没有太大影响;反应产物主要是氨氮。     

Vibratory communication through living plants by a tropical wandering spider

Female Cupiennius salei pheromone on banana and Agave plants elicits patterned oscillations by the male. Resulting pulse trains of vibrations through the leaf average 76 hertz. The brief vibratory response by the otherwise immobile female hidden up to at least 1 meter away on another leaf guides the male across the plant to her location. Reciprocal signaling continues in the presence of random noise that masks the male's airborne sounds.     

Reduction of a larval herring population by jellyfish predator

The scyphomedusa Aurelia aurita consumes large amounts of yolk-sac herring larvae in Kiel Fjord. The decline of the larval herring population in late spring coincides with a major population growth of the jellyfish. The size of the larval herring population seems to be more significantly affected by the size of the predator stock than by the size of the parental herring stock.     

Reduction of ferricytochrome c by some free radical agents

Fast pulse radiolysis and kinetic spectroscopy were used to rapidly generate a variety of free radicals in situ and study their reactions with ferricytochrome c in the time range 10(-6) to 1 second. The radicals included t-butanol, which is inert to ferricytochrome c; malate, lactate, and ethanol, which react with it relatively slowly but are completely utilized in reducing it to ferrocytochrome c; and hydrated electrons and hydrogen atoms, which react with it very rapidly but yield ferrocytochrome c only in part, showing intramolecular consecutive reactions and further attack on the ferrocytochrome c protein. From a detailed comparison between malate and hydrogen atoms it is argued that malate reacts directly and selectively with a specific part of the ferricytochrome c surface while hydrogen atoms react with other parts of the protein too, yielding radicals which in part transfer intramolecularly to yield ferrocytochrome c.     

利用多菌种固态发酵降解玉米秸秆

以玉米秸秆和麦麸为原料,利用具有降解纤维素和半纤维素能力的黑曲霉、地衣芽孢杆菌、酵母、植物乳酸杆菌4种菌混合发酵,降低原材料的纤维素含量,提高玉米秸秆的饲料营养价值。由单因素试验确定各种菌接种时间、发酵时间、无机水含量、温度;由正交试验确定秸秆和麦麸的最佳比例。结果表明:发酵温度37℃、发酵时间6 d、秸秆与麦麸比例为2∶1、水的添加量50 mL,粗纤维降解率为26.68%。采用4种菌分批发酵,即先用黑曲霉和芽孢杆菌发酵72 h后,再添加酵母和乳酸杆菌继续发酵,粗纤维下降率为27.95%,蛋白质含量为24.67%。     

壳聚糖对啤酒中嘌呤的吸附性能

以不同浓度的壳聚糖加入啤酒中,吸附以高氯酸水解出的嘌呤碱基,用高效液相色谱法(HPLC)测定吸附前后4种嘌呤碱基量,结果显示:壳聚糖可以有效吸附啤酒中的嘌呤碱基,降低啤酒中的嘌呤含量。     

Reduction of intestinal carcinogen absorption by carcinogen-specific secretory immunity

A secretory immune response to the carcinogen 2-acetylaminofluorene (AAF) was elicited in rabbits by directly immunizing the small intestine with an AAF-cholera toxin conjugate. High-titer, high-affinity secretory immunoglobulin A (IgA) antibody to AAF was secreted into the intestinal lumen in response to this immunogen. Immune secretions reduced the transepithelial absorption of a 125I-labeled derivative of AAF by more than half. This reduction of absorption by hapten-specific IgA suggests that oral vaccines against carcinogens and toxicants could be developed for humans.