浅谈大扩孔桩施工技术

本文详尽地叙述了大扩孔桩在基础施工中应采取的施工技术。     

杂多县防灾基地“四配套“建设效益的调查

杂多县自1990年实施防灾基地"四配套"建设以来,截止2000年底共建成定居点、围栏草场、牲畜暖棚、人工种草"四配套"建设户2600户,占全县牧户总数的45%,经对定居点、暖棚、围栏、人工种草以及全县畜牧业生产指标的调查与对比分析,其效益显著.     

Purple nutsedge tuber sprouting

Purple nutsedge ( Cyperus rotundus L.) tubers remain viable for several years and serve as its principal means of survival. The maintenance of high moisture content is essential to tuber survival. Apical dominance influences bud dormancy within a tuber and in a chain of tubers, and dormancy increases with tuber age. Several growth inhibitors were identified in tubers, but their role in tuber dormancy has not been established. Moisture levels in soil must increase to a critical level before sprouting occurs, but excess soil moisture deters sprouting. Oxygen may be a limiting factor for tuber sprouting in waterlogged soils. Although light is not a requirement for sprouting, it has promoted sprouting. Temperature regulates sprouting; no sprouting occured below 10°C and above 45°C. Optimum sprouting occurred between 25 and 35°C when provided with constant temperatures. However, daily alternating temperatures greatly stimulated sprouting. A daily short duration (0.5 h) of high temperature increased sprouting to nearly 100%, whereas less than 50% sprouting occurred without the daily high temperature pulse. Bud break occurred readily for most tubers at 20°C and in nearly 100% of the tubers with a single 0.5 h exposure to a high temperature (35°C) pulse. However, most buds did not elongate if the tuber remained at 20°C. Bud elongation occurred at higher temperatures, and daily alternating temperatures stimulated shoot elongation up to eightfold greater than at the respective mean constant temperatures. Daily soil temperature fluctuation may be a major signal for purple nutsedge emergence, such as when the plant canopy is removed, or when soils are solarized. Future research is needed to determine tuber sprouting for different ecotypes, and on the role of the rhizome chain. Systems to manipulate sprouting may provide new strategies for purple nutsedge management.     

小麦白粉病菌闭囊壳萌发及其对三唑酮敏感基线的建立

在没有甾醇脱甲基抑制剂 (DMI)类药剂用药历史的湖北利川山区麦田采集小麦白粉病菌闭囊壳 ,带回室内萌发 ,从每样本单孢子堆中分离得到61个野生菌株。采用叶段法测得每个菌株的EC₅₀,建立起小麦白粉病菌对三唑酮的相对敏感基线EC₅₀=(0.1090±0.0048)μg/ml。     

地理专家系统的知识表示与知识库组织

本文介绍了地理专家系统的知识表示和知识库组织的基本原理和方法，并以水土保持专家系统为例，阐述了水土保持专家知识的分类分级方法，以及在水土保持专家系统中知识表示的基本规划和知识库中专家知识的组织方式。在知识获取机构中，系统提供了以辅助编辑手段为主，自然语言理解为辅的人机交互界面，从而简化了专家知识的录入过程，提高了系统的工作效率。     

Percutaneous balloon pericardiotomy as a treatment for recurrent pericardial effusion in 6 dogs

Percutaneous balloon pericardiotomy (PBP) has been performed in people and in a small number of dogs as a treatment for recurrent pericardial effusion with tamponade (PET). We performed this technique on 6 dogs with recurrent PET (5 with heart base tumors and 1 with no identifiable mass). Under general anesthesia and fluoroscopic guidance, a balloon-dilating catheter (diameters 14-20 mm) was introduced percutaneously at the 5th intercostal space through a sheath-introducing catheter, positioned across the parietal pericardium, and inflated 3 times. No dog experienced serious complications. The procedure was considered successful in 4 of 6 dogs. One dog is still alive without recurrence of PET 1 year after the procedure. Three dogs died of unrelated disease without recurrence of PET 5. 19, and 32 months after the procedure. The procedure was not beneficial in 1 dog that was euthanized 9 weeks later because of recurrence of pleural and abdominal effusion thought to be secondary to PET. One dog may have temporarily benefited but developed symptomatic PET 6 months after PBP. PBP appears to be a safe, economical, and potentially effective palliative treatment for recurrent PET and is a reasonable, less invasive alternative to surgery for dogs with recurrent PET, especially effusions caused by heart base tumors and possibly idiopathic pericardial effusion. Premature closure of the stoma is a potential cause for long-term failure and was thought to have been responsible for the recurrence of clinical signs in 2 dogs.     

日本矮紫薇花芽形态分化的研究

日本矮紫薇花芽由中上部侧枝和主枝顶芽发育而成,花芽分化从4月末开始至5月末结束,历时30d,包括花序分化和小花分化两个过程,分为形态分化前、开始分化期、花序原基分化期、花蕾分化期、小花花萼分化期、花瓣分化期、雄蕊分化期、雌蕊分化期8个时期,花序和小花分化的顺序分别是离心和向心的.花芽分化与春梢生长有一定的相关性.     

城市生态环境与城市园林绿化

从城市化给城市带来的一系列环境问题以及城市园林绿化建设的重要性出发,分析建立“城市生态绿化新优良种示范基地”的意义及综合效益.     

多年生黑麦草高频再生体系的建立及优化

从外植体预处理方式、基本培养基、激素浓度等方面着手,对多年生黑麦草愈伤组织诱导、继代、不定芽分化及再生过程中的影响因素进行了研究,提高了再生频率。结果如下：切取胚端半粒种子,经75%乙醇处理1min,0.1%HgCl处理15min,在经无菌水清洗4～6次后接种方式较好;愈伤组织诱导培养基以MS＋2,4—D 8.0 mg/L（或另添加甘露醇25 g/L）为佳;愈伤组织接种于MS＋2,4—D 8.0mg/L＋甘露醇25 g/L上进行1～2次继代后于NB＋6—BA2.0 mg/L上进行分化;不定芽转接至MS＋6—BA2.0 mg/L上进行扩繁或于1/2MS＋NAA0.5mg/L＋IAA0.5mg/L上进行生根。