无定河粗泥沙产沙量的变化及其原因

 为了解决黄河治理中迫切需要解决的粗泥沙来源和数量问题,依据大量实测资料,运用统计方法对无定河粗泥沙产沙量进行研究。结果表明:无定河流域d>0.05 mm粗泥沙产沙量呈现出减少趋势,这种减少与年降水量、年沙尘暴频率的减少和水土保持面积的增大有一定的因果关系;估算出最大30d降雨量和年沙尘暴频率的变化对d>0.05mm粗泥沙产沙量变化的贡献率分别为66.5%和33.5%,即沙尘暴特征的变化对粗泥沙产沙量变化的贡献率相当于暴雨特征的变化贡献率的1/2。建立了粗泥沙年产沙量与最大30d降雨量、年沙尘暴频率和水土保持措施面积之间的回归方程,表明粗泥沙年产沙量随最大30d降雨量、年沙尘暴频率的减小而减小,随水土保持面积的增大而减小。因此,20世纪50年代以来暴雨的减弱、沙尘暴的减弱和水土保持措施面积的增大是无定河流域粗泥沙产沙量减少的原因。     

水旱轮作对土壤微生物群落构建过程的影响机制

为探究稻田生态系统微生物学机制,采集水旱轮作稻田土壤,并以相同土壤母质下长期淹水的藕田土壤以及旱作的果树土壤为对照,研究了稻田生态系统细菌群落结构以及基于零模型的群落构建机制。结果表明:旱作和水旱轮作两个生态系统,由于频繁耕作以及施肥管理等农业措施形成特定的生态位格局,确定性过程主导群落构建。旱作生态系统下确定性过程占78.6%,随机性过程占10.7%;相对于旱作,由于水旱轮作的淹水条件,土壤肥力积累,水体连通性较好等特性导致内部环境变化缓和,其随机性过程(39.3%)影响增加,确定性过程(50.0%)下降;同理,长期淹水的水生生态系统中随机性群落构建(50.0%)成为主导过程。群落构建影响细菌群落结构和功能,因此随机性生态过程的增强进一步增加了细菌多样性以及物种生态网络的交互度和稳定性,增强了微生物抵抗外部环境扰动的能力,该过程有助于维持农田生态系统功能的稳定性和可持续性。     

臭氧/紫外-活性炭工艺去除水源水中莠去津的效能研究

为了考察高级氧化技术对水中莠去津处理效果,分别通过臭氧(O3)氧化与活性炭组合工艺、紫外(UV)消毒与活性炭组合工艺、臭氧-紫外与活性炭组合工艺这3种处理方法对松花江哈尔滨段江水中的莠去津处理效果进行试验.试验结果表明,莠去津去除效果O3/UV-活性炭工艺＞UV-活性炭工艺＞O3-活性炭工艺,且与活性炭联用技术都比单独工艺效果要好,经O3/UV-活性炭工艺处理后出水中莠去津的平均浓度为0.033 μg/L.     

高级氧化法处理腈纶厂废水的研究进展

介绍了腈纶厂废水的主要来源和危害,并综述了几种高级氧化法在处理腈纶废水、丙烯腈废水中的研究进展,同时分析了高级氧化法处理腈纶厂废水的作用机理、优势和存在的问题,并对其应用前景提出了展望。     

Subtotal ostectomy of dorsal spinous processes performed in nine standing horses

OBJECTIVE: To describe and evaluate subtotal ostectomy of dorsal spinous processes (DSP) performed in standing horses. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Nine adult horses. METHODS: The diseased portions of the DSP were removed with the horses standing and sedated after infiltrating a local anesthetic agent around the affected DSP. Medical records of affected horses were reviewed to determine history, findings of physical and radiographic examination, surgical technique, postoperative complications, and outcome. RESULTS: Five horses had subtotal ostectomy of DSP because of osteomyelitis, and 4 because of impingement and/or fracture of DSP. Affected portions of DSP were removed safely and effectively, with no apparent discomfort to the horses; hemorrhage was minimal. CONCLUSIONS: Subtotal ostectomy of DSP can be performed safely in standing, conscious horses and the risks associated with general anesthesia are eliminated. Hemorrhage is minimal compared to that which occurs when the procedure is performed with horses anesthetized and in lateral recumbency. CLINICAL RELEVANCE: Access and visibility are better when subtotal ostectomy of the DSP is performed with the horse standing rather than anesthetized and in lateral recumbency. Performing subtotal ostectomy of diseased DSP with the horse standing avoids the expense and risks of general anesthesia.     

红天麻箭麻发育进程中天麻素和多糖含量的变化规律研究

[目的]研究红天麻箭麻在不同发育阶段的天麻素和天麻多糖含量的相关性规律,确定其品质特征,为红天麻GAP质量控制提供科学依据。[方法]在川天麻主产区采集传统主流红天麻品系箭麻块茎样品,在原产地室内采用原位动态沙藏法贮藏箭麻;在采样后沙藏10、80、95、175和220 d分别采集天麻块茎样品,采用高效液相色谱法和苯酚-硫酸比色法分别测定天麻素含量和天麻多糖含量,并运用SPSS17.0版统计软件分析在红天麻箭麻不同发育阶段进程中天麻素和天麻多糖含量的相关性规律。[结果]川产红天麻箭麻块茎的天麻素和天麻多糖的平均含量分别为0.36%和8.17%;随着天麻沙藏休眠期-萌动期-抽茎开花-果实成熟至腐烂发育阶段进程增加,红天麻箭麻块茎的天麻素和天麻多糖含量下降,且呈极显著的负相关(P<0.001),其回归方程分别为:天麻素y1=-2E-08x3-1E-06x2-0.0001x+0.365(R2=0.996),天麻多糖y2=-5E-07x3-1E-06x2-0.008x+8.267(R2=0.996)。[结论]红天麻箭麻品质较优良,其块茎沙藏发育进程和品质下降密切相关,开花后空心和腐烂的红天麻块茎不宜作药用和制药原料。     

农村一体化生活污水处理设备评析与研究

农村生活污水污染问题现已成为一个不可忽视的问题,迫切需要解决。一体化污水处理设备具有投资低、能耗少、处理效率高、占地面积小、管理方便等一系列优势,适合在农村地区推广。针对农村生活污水的水质水量特征,介绍了一体化污水处理设备在农村地区推广的优越性,并分析对比了国内一体化污水处理设备常采用的主体工艺,为农村地区采用一体化生活污水处理设备提供了技术经济参考。     

面向过程挖掘的C4．5在营销决策支持系统中的应用

产品营销过程中,企业需从目标市场中判断高、中、低档产品,哪类更适合其市场需求,以此可使在复杂的市场环境下及时调整产品结构,适应市场需求变化。本文采用数据挖掘C4．5算法,将原有的硒数据经处理后,导入到数据仓库中形成结构化数据,采用过程挖掘的方法对挖掘结果进行分析和评估,充分发挥决策支持系统的辅助决策作用。     

Characteristics of the Light Response in Seedlings and Saplings of Two Mid-Successional Species,Ash and Kalopanax,During the Early Stage of Regeneration in a Mature Forest

Abstract

Growth characteristics of ash (Fraxinus mandshuricavar. japonicd)and kalopanax (Kalopanax pictus), two mid-succcs-sional species, were monitored in relation to seasonal light in a deciduous broadleaf forest. During the growing, relative light intensity of the gap was 4 to 6 times higher than that under the closed canopy. Seedlings could be found on the mixed hardwood forest floor where relative light intensity was around greater than 7% of full sunlight. When saplings gap openings which had relative light intensities above 20%, they quickly developed lateral branches and increased their foliage volume. The light-photosynthesis curve of seedlings of both species showed a curve typical of the “shade leaf” type even though they grew under sunlight. In contrast, saplings of both species showed the “sun leaf” type of light-photosynthesis curve. This seedling to sapling shift from shade to sun adaptation was also found in other foliage characteristics. This study shows that species can efficiently adjust their leaf and branch characteristics to changing light environments from shade to openings in a forest.