CO2气调防治储粮害虫试验研究

利用自行设计的试验装置,充入CO2气体使储粮害虫(谷蠹与米象)窒息死亡,以达到杀灭粮食害虫的目的.试验分为两个部分,一是在实验室里进行,试验温度分别在15～18℃和23～28℃;试验的CO2气体浓度分别控制在25%、30%、35%、40%、45%、50%、55%和60%左右;试验时间分别为24、48、72、96、120、168 h.通过多次试验,找出了实验室试验的最佳参数:温度为(25±3)℃;CO2气体浓度为25%～35%;谷蠹杀虫保持时间为72 h以上;米象杀虫保持时间为48 h.二是在实验仓进行试验,将传感器通过管道分别布置在仓的各个部位,并每隔12～24 h,测取温、湿度等.实验仓的试验验证了实验室的试验结果,但杀虫的持续时间为10 d以上,研究成果为实仓应用CO2气调防治储粮害虫提供了可靠的依据.     

超临界CO2萃取大蒜精油及油树脂的研究

研究了大蒜精油及油树脂的超临界CO₂提取工艺，探讨了粒度，萃取及分离的温度、压力和时间对各萃取率的影响，建立了萃取温度、压力与各萃取率的数学模型。确定了超临界CO₂同时提取大蒜精油及油树脂的优化工艺条件。     

超临界CO2喷雾干燥制备乙基纤维素微粒的实验研究

为了扩大喷雾干燥技术在生物物料微粒制备方面的应用，在自行设计的实验台上，以超临界CO₂为干燥介质进行了乙基纤维素微粒的制备。研究了喷嘴出口直径、气液比、溶液浓度、温度、压力对微粒粒径及其粒径分布的影响。实验结果表明：改变工艺参数，可在较大范围内调控微粒大小，所制微粒平均粒径为1.07～9.84 μm；气液出口为8 mm的喷嘴所得微粒粒径比4 mm的要小且分布变窄、粒度均匀；气液比对微粒粒径的影响存在一个粒径最大值；高浓度溶液所得微粒粒径比低浓度溶液大，粒径分布略有变宽；随温度升高，微粒粒径增大，高温时所得微粒的粒径分布比低温时宽；随压力增加，微粒粒径减小，高压时所得微粒的粒径分布比低压时略有变窄。     

超临界CO2萃取辣椒红色素的研究初探

简介了超临界CO₂流体的基本特性及国外将该流体应用于萃取分离技术的概况。报道了作者应用超临界CO₂从红辣椒中萃取红色素的研究情况。试验表明,色素和辣味素可以全部萃取出来,并可获得基本分离。     

超临界CO2提取分离银杏叶药用成分的工艺研究

该文从理论与实践两方面着手，研究探讨超临界CO₂提取分离银杏叶药用成分的适用性和可操作性，提出溶剂浸提与超临界流体萃取相结合的生产工艺，既可降低生产成本，保证产品质量，又可大幅度削减设备造价，为超临界流体萃取技术的实际应用创造条件。     

超声强化超临界CO2萃取人参皂苷的研究

为了探讨超声波对超临界CO₂萃取(SCE)的影响，考察了在不同萃取温度、萃取压力、萃取时间和流体流量下，有、无超声时超临界CO₂萃取人参皂苷的萃取率。试验结果发现，超声强化超临界CO₂萃取(USCE)的合适萃取温度比没加超声(SCE)时的低10℃；在各自合适的萃取压力下，USCE的皂苷萃取率是SCE的1.64倍；CO₂流体的流量大更有利于USCE。在SCE中，超声的加入能明显提高产物的萃取率和生产效率，降低生产能耗和节     

用超临界CO2脱除绿茶浓缩液中咖啡碱的工艺研究

对绿茶浓缩液中咖啡碱的超临界CO₂萃取工艺进行了研究，通过4因素正交试验探讨了浓缩液的浓度、操作压强、操作温度、萃取时间对咖啡碱脱除率的影响。结果表明，超临界CO₂萃取技术可以有效地脱除绿茶浓缩液中大部分的咖啡碱，在此基础上完成了用超临界CO₂脱除绿茶浓缩液中咖啡碱的连续作业试验，从而获得了加工脱咖啡碱绿茶浓缩液或速溶绿茶的新工艺。     

乙醇溶剂与超临界CO2相结合提取高纯度卵黄磷脂的研究

采用乙醇溶剂首先提取蛋黄粉中的卵黄油，然后用超临界CO₂萃取方法脱除卵黄油中的中性脂肪，获得高纯度的卵黄磷脂。考察了工艺参数对提取效果的影响。试验表明：在乙醇溶剂提取卵黄油阶段，乙醇浓度是影响卵黄油提取率的最主要因素，温度是影响卵黄磷脂提取率的最主要因素；在超临界CO₂萃取阶段，磷脂的溶解度随萃取温度的升高而降低，中性脂质在55℃时溶解度最大。采用此工艺，卵黄磷脂得率为17.66%，纯度94.41%，且不含胆固醇。     

超临界CO2流体萃取杏仁油工艺研究

该研究以单因素试验和正交试验相结合的方法对苦杏仁脂肪油的超临界CO₂萃取工艺进行了研究。确定了超临界CO₂萃取杏仁油的最佳工艺为：萃取压力35 MPa、萃取温度50℃、CO₂流量24 L/ｈ、粒径60目、萃取时间2 h。各因素影响杏仁的得率的顺序为：粒径>时间>萃取压力>CO₂流量>萃取温度。最佳工艺验证试验的杏仁油的得率为52.98％。本研究的结果为下一步综合、无毒、高效地开发利用苦杏仁奠定了基础。     

高密度CO2处理对E. coli细胞膜渗透性的影响

以E. coli菌悬液为研究对象,通过测定高密度CO₂处理(DPCD)后E. coli上清液中蛋白质、核酸、Mg2+、K+离子和丙二醛的含量,辅助透射电镜观察,研究DPCD 对E. coli细胞膜渗透性的影响。在7MPa、37℃条件下,E. coli经高密度CO₂处理10min后,99%以上的E. coli失活,同时研究发现蛋白质、核酸及Mg2+、K+离子等胞内物质均发生了不同程度的泄漏,丙二醛含量增加,E. coli胞内物质密度降低。密度CO₂处理造成E. coli细胞膜渗透性的增加,这也是导致E. coli死亡的原因之一。     

A new technique to measure soil CO2 efflux at constant CO2 concentration

A new principle for measuring soil CO₂ efflux at constant ambient concentration is introduced. The measuring principle relies on the continuous absorption of CO₂ within the system to achieve a constant CO₂ concentration inside the soil chamber at ambient level, thus balancing the amount of CO₂ entering the soil chamber by diffusion from the soil. We report results that show reliable soil CO₂ efflux measurements with the new system. The novel measuring principle does not disturb the natural gradient of CO₂ within the soil, while allowing for continuous capture of the CO₂ released from the soil. It therefore holds great potential for application in simultaneous measurements of soil CO₂ efflux and its δ¹³C, since both variables show sensitivity to a distortion of the soil CO₂ profile commonly found in conventional chamber techniques.     

Relationship between soil CO2 concentrations and forest-floor CO2 effluxes

To better understand the biotic and abiotic factors that control soil CO₂ efflux, we compared seasonal and diurnal variations in simultaneously measured forest-floor CO₂ effluxes and soil CO₂ concentration profiles in a 54-year-old Douglas fir forest on the east coast of Vancouver Island. We used small solid-state infrared CO₂ sensors for long-term continuous real-time measurement of CO₂ concentrations at different depths, and measured half-hourly soil CO₂ effluxes with an automated non-steady-state chamber. We describe a simple steady-state method to measure CO₂ diffusivity in undisturbed soil cores. The method accounts for the CO₂ production in the soil and uses an analytical solution to the diffusion equation. The diffusivity was related to air-filled porosity by a power law function, which was independent of soil depth. CO₂ concentration at all depths increased with increase in soil temperature, likely due to a rise in CO₂ production, and with increase in soil water content due to decreased diffusivity or increased CO₂ production or both. It also increased with soil depth reaching almost 10 mmol mol⁻¹ at the 50-cm depth. Annually, soil CO₂ efflux was best described by an exponential function of soil temperature at the 5-cm depth, with the reference efflux at 10 °C (F₁₀) of 2.6 μmol m⁻² s⁻¹ and the Q₁₀ of 3.7. No evidence of displacement of CO₂-rich soil air with rain was observed.Effluxes calculated from soil CO₂ concentration gradients near the surface closely agreed with the measured effluxes. Calculations indicated that more than 75% of the soil CO₂ efflux originated in the top 20 cm soil. Calculated CO₂ production varied with soil temperature, soil water content and season, and when scaled to 10 °C also showed some diurnal variation. Soil CO₂ efflux and concentrations as well as soil temperature at the 5-cm depth varied in phase. Changes in CO₂ storage in the 0–50 cm soil layer were an order of magnitude smaller than measured effluxes. Soil CO₂ efflux was proportional to CO₂ concentration at the 50-cm depth with the slope determined by soil water content, which was consistent with a simple steady-state analytical model of diffusive transport of CO₂ in the soil. The latter proved successful in calculating effluxes during 2004.     

几种主要CO2施肥肥源性能的比较与评价

在空闲拱棚和黄瓜日光温室内，分别研究了化学反应法(H₂SO₄+NH₄HCO₃）、煤球燃烧法和颗粒CO₂气肥3种肥源的性能，并与液体CO₂进行成本比较，结果表明：化学反应法产气迅速，设备折旧成本较低；煤球燃烧法产气速度中等，原料成本最低；颗粒CO₂气肥产气速度较慢且不易调控，原料成本最高。考虑化学反应产物的再利用因素，化学反应法、煤球燃烧法和液体CO₂ 3种肥源总成本接近，但从生态、节能、成本和效果等方面综合评价，煤球燃烧法原料丰富、成本低廉，较符合我国目前的设施、经济、资源和技术条件。     

Elevated CO2 stimulates N2O emissions in permanent grassland

To evaluate climate forcing under increasing atmospheric CO₂ concentrations, feedback effects on greenhouse gases such as nitrous oxide (N₂O) with a high global warming potential should be taken into account. This requires long-term N₂O flux measurements because responses to elevated CO₂ may vary throughout annual courses. Here, we present an almost 9 year long continuous N₂O flux data set from a free air carbon dioxide enrichment (FACE) study on an old, N-limited temperate grassland. Prior to the FACE start, N₂O emissions were not different between plots that were later under ambient (A) and elevated (E) CO₂ treatments, respectively. However, over the entire experimental period (May 1998–December 2006), N₂O emissions more than doubled under elevated CO₂ (0.90 vs. 2.07 kg N₂O-N ha⁻¹ y⁻¹ under A and E, respectively). The strongest stimulation occurred during vegetative growth periods in the summer when soil mineral N concentrations were low. This was surprising because based on literature we had expected the highest stimulation of N₂O emissions due to elevated CO₂ when mineral N concentrations were above background values (e.g. shortly after N application in spring). N₂O emissions under elevated CO₂ were moderately stimulated during late autumn–winter, including freeze–thaw cycles which occurred in the 8th winter of the experiment. Averaged over the entire experiment, the additional N₂O emissions caused by elevated CO₂ equaled 4738 kg CO₂-equivalents ha⁻¹, corresponding to more than half a ton (546 kg) of CO₂ ha⁻¹ which has to be sequestered annually to balance the CO₂-induced N₂O emissions. Without a concomitant increase in C sequestration under rising atmospheric CO₂ concentrations, temperate grasslands may be converted into greenhouse gas sources by a positive feedback on N₂O emissions. Our results underline the need to include continuous N₂O flux measurements in ecosystem-scale CO₂ enrichment experiments.     

作物—CO2环境模拟装置及评价

利用作物—ＣＯ₂环境模拟装置,探讨未来大气ＣＯ₂浓度倍增与作物生长关系的实验研究,已在各国取得不同程度的进展。该文简要综述了近年来国外有关的实验装置概况和发展动向,概述了三种类型装置（封闭式气室、开顶式气室、开放式系统）的结构、性能、特色及其应用,并作出了综合评价。     

夹带剂对超临界CO2萃取结晶穿心莲内酯的影响

以穿心莲内酯粗品和高纯品(纯度分别为30%和95%)为原料，采用超临界CO₂萃取结晶法，考察了乙醇、丙酮、异丙醇与乙酸乙酯四种夹带剂对超临界CO₂萃取结晶穿心莲内酯的结晶率、纯度、晶型和形貌等的作用规律。结果：因乙酸乙酯分离纯化综合效果较好，且既能与前处理工序中选择的浸提溶剂相统一，减少采用多种溶剂存在的污染，又能保持晶体优良晶型和结晶品质，所以优先选择了乙酸乙酯为夹带剂。     

Elevated CO2 does not favor a fungal decomposition pathway

We examined the effect of prolonged elevated CO₂ on the concentration of fungal- and bacterial-derived compounds by quantifying the soil contents of the amino sugars glucosamine, galactosamine and muramic acid. Soil samples were collected from three different terrestrial ecosystems (grassland, an aspen forest and a soybean/corn agroecosystem) that were exposed to elevated CO₂ under FACE conditions for 3-10 years. Amino sugars were extracted from bulk soil and analyzed by gas chromatography. Elevated CO₂ did not affect the size or composition of the amino sugar pool in any of the systems. However, high rates of fertilizer N applications decreased the amount of fungal-derived residues in the grassland system. We suggest that these results are caused by a decrease in saprophytic fungi following high N additions. Furthermore, our findings imply that the contribution of saprophytic fungi and bacteria to SOM in the studied ecosystems is largely unaffected by elevated CO₂.     

Long term CO2 enrichment stimulates N-mineralisation and enzyme activities in calcareous grassland

Elevated concentration of atmospheric carbon dioxide will affect carbon cycling in terrestrial ecosystems. Possible effects include increased carbon input into the soil through the rhizosphere, altered nutrient concentrations of plant litter and altered soil moisture. Consequently, the ongoing rise in atmospheric carbon dioxide might indirectly influence soil biota, decomposition and nutrient transformations.N-mineralisation and activities of the enzymes invertase, xylanase, urease, protease, arylsulfatase, and alkaline phosphatase were investigated in spring and summer in calcareous grassland, which had been exposed to ambient and elevated CO₂ concentrations (365 and 600 μl l⁻¹) for six growing seasons.In spring, N-mineralisation increased significantly by 30% at elevated CO₂, while there was no significant difference between treatments in summer (+3%). The response of soil enzymes to CO₂ enrichment was also more pronounced in spring, when alkaline phosphatase and urease activities were increased most strongly by 32 and 21%. In summer, differences of activities between CO₂ treatments were greatest in the case of urease and protease (+21 and +17% at elevated CO₂).The stimulation of N-mineralisation and enzyme activities at elevated CO₂ was probably caused by higher soil moisture and/or increased root biomass. We conclude that elevated CO₂ will enhance below-ground C- and N-cycling in grasslands.