不同摇青工艺对乌龙茶品质的影响

为了研究不同摇青次数对乌龙茶品质的影响,在春、夏、秋3个季节,对同一批次的鲜叶分别进行不同摇青次数处理(2次、4次、6次),并以凉青为对照,然后按照乌龙茶传统加工工艺制得成品茶.经GC-MC检测,结果表明,3个季节中的6次摇青处理均在香气组分数量和香精油总量上高于其他处理,其规律为6次＞4次＞2次.感官审评结果亦表明,6次摇青处理制得的乌龙茶感官品质优于其他对照组,其中秋茶6次摇青品质最好.     

An unusual occurrence of probable Pleistocene corestone within a Cretaceous dioritic enclave,Peninsular Ranges,California

We here document an unusual occurrence of probable Pleistocene corestone within an ∼ 5 m by ∼ 5 m dioritic enclave contained within a Cretaceous tonalitic pluton, Santa Margarita Ecological Reserve, SW California. The enclave lies within ∼ 3.5 km of the seismically active ∼ 1.5–2 Ma Elsinore fault zone, and may have been subjected to ∼ 70–90 ground shaking events since ∼ 22,000–18,000 years ago. The studied corestone is elliptical with major axis measuring ∼ 55 cm and minor axis ∼ 26 cm in length. It is surrounded by a discontinuous ∼ 7 cm thick rind that breaks apart under slightly greater finger pressure than does the surrounding saprolite. In order to assess changes in the physical and chemical properties of the corestone, rind, and saprolite we collected along an ∼ 66.5 cm long traverse 4 samples from the corestone, 1 from the rind, and 5 from the saprolite for bulk and grain density, porosity, and major and trace element analyses. Textural and clay mineral data, along with the redistribution of elemental mass, indicate that the weathering of biotite, and to much lesser degrees apatite and the An-rich cores of plagioclase, played critical roles in the production of saprolite especially in a narrow ∼ 20 cm wide zone adjacent to the rind of the corestone. Within this zone bulk densities reach their minimum values, while porosities and positive volume strains reach their maximums. In addition, the maximum loss of K, Fe, Mn, and Ca mass occurred just inside this region, and is paralleled by the highest CIA values and highest additions of Si and Rb mass. In contrast, the masses of Na and Sr are progressively increased and decreased, respectively along the entire sampling traverse while the loss of Mg, Ti, and P mass is episodic with the greatest losses occurring within the narrow zone adjacent to the rind and at the end of the traverse. The above observations indicate that the conversion of biotite to expandable mixed-layered clay minerals, aided by the alteration of the An-rich cores of plagioclase, produced sufficient stress on grain boundaries that a weakening or loss of intercrystalline cohesion occurred. However, unlike the well documented isovolumetric development of saprolite in other areas, at the study site saprolitization was accompanied by a volume expansion. We speculate that repeated ground shaking in response to earthquakes generated in the nearby Elsinore fault zone may be responsible for this difference. Important byproducts of ground shaking would include additional weakening or loss of intercrystalline cohesion, and the production and enhancement of new and older fluid pathways respectively. The fact that the most intensely altered material at the study site lies adjacent to the boundary between the rind and saprolite, suggests that this interface acted to guide fluid flow around the corestone and rind and into the adjacent saprolite where elemental mass was redistributed down various paths leading to the underlying water table. Most of the leached elemental mass was removed from the area of the sampling traverse, but small increases in Si, Rb, and Na mass suggest redistribution of these elements from elevated areas outside the area sampled during this study. The result of the above complex set of processes is a variably porous and chemically altered saprolitic enclave that is still undergoing modification as it adjusts to the vicissitudes of the paralithic environment and continuing ground shaking during earthquakes generated along the Elsinore fault.     

偏心式林果振动采收机的研制与试验

为提高林果采收效率,降低采收成本,针对中国果园矮化密植模式下机械化作业条件差的特点,设计了偏心式林果振动采收机。该机安装在电控履带车上,通过偏心块旋转产生的离心力激振树干实现林果振动采收。建立了偏心式振动采收动力学模型,得出了采收机—果树系统稳态响应振幅表达式并分析了主要影响因素。利用该采收机对核桃(新新2号)进行了采收试验,结果表明:激振频率对树干全振幅和果实采净率具有显著性影响(P=0.05),树干全振幅和果实采净率随激振频率的增大而增大,激振频率20Hz时达到最大值,分别为8.83mm和92.6%;落果和树干夹持处均未见破坏性损伤,但激振频率越大,夹持处痕迹越明显,建议控制激振频率于19～20Hz,平均采净率约达到89.5%～92.6%,而且果实和树干没有破坏性损伤。该研究为实际生产提供指导。     

不同晒青、摇青程度对花香绿茶成茶品质的影响

【研究目的】通过在夏、秋茶季对不同品种、不同晒青程度、不同摇青程度进行三因素二水平正交组合试验，比较不同组合成茶样品感官审评及香气组分，提出综合利用夏秋茶提质增效最优工艺参数；【方法】采用正交组合对比试验；【结果】结果表明：A2B2C1组合成茶品质最佳，送测感官审评得分最高（为95.7分），所测香气组分多达41种，突显兰花香气，持久悠长，滋味鲜醇回甘，与香气成分的含量及种类数量成正比。【结论】以川小叶种为原料，经日光晒青(轻晒青，控制晒青过程鲜减重率9%~11%）、摇青（轻摇青，控制晒青后鲜叶减重率20%~23%）为综合利用夏秋茶提质增效生产花香绿茶最优加工工艺参数，所制茶产品相比于相同级别原料所制炒青绿茶，干茶增效5~10元/斤，促进茶地产值亩增800~1200元，具较强的市场竞争力。     

考虑三维地震动作用下振动台试验隔震层简化

基于等效原则、相似理论，考虑三维地震动作用下振动台试验中原型结构隔震层的简化，并对模型结构隔震层进行系统研究。针对不同高宽比隔震结构，提出完全等效简化方法和部分等效简化方法，包括隔震垫等效、模型支座参数及坐标确定、相似关系确定等。利用不同高宽比隔震结构振动台试验，结合有限元数值模拟，进行方法验证。理论推导与数值模拟证明简化方法具有良好的准确性，且在误差允许范围内，简化后的隔震层所获得的加速度、速度、位移等动力特性与简化前相同，可以用于振动台试验模型设计。     

四轮转向汽车最优转向控制研究

特高压输电塔线体系具有跨越档距大、塔体高的特点，进行地震模拟振动台试验测试时，现有结构试验方法难以完成.本文以特高压交流单回路输电线路工程为背景，设计制作了三塔两线体系缩尺模型，文中详细阐述了振动台试验的模型设计工作，其中包括试验材料的选取、动力相似关系的确定、模型的制作以及试验方案设计等方面.针对由强几何非线性的导、地线与弹性输电铁塔这两种不同形式的结构所组成的耦联体系提出了动力参数分离式模型设计方法，解决了塔线体系按统一比例无法满足振动台台面尺寸要求的问题.理论分析和实测对比验证了该模型较好地满足了振动台试验要求，该方法使得通过振动台试验研究特高压输电塔线体系的地震反应得以实现.