1000 resultados para 05-Yak-01
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用梯度浓度的微囊藻毒素(6.7μg/L、26.7μg/L、66.7μg/L、166.7μg/L、333.8μg/L、1 335.2μg/L)和人工培养的有毒铜绿微囊藻(Microcystis aeruginosa7806)对澳洲水泡螺(Bulinus australinanus)分别进行急性和亚慢性毒性暴露,观察对螺的毒性效应.急性毒性实验结果表明,澳洲水泡螺对微囊藻毒素有很强的耐受力,试验期间(5 d)未发现螺中毒死亡情况,甚至当微囊藻毒素高达1 335.2μg/L时,仍无死亡.亚慢性口服毒性实验结果发
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研究了稀土元素Ce4+对铜绿微囊藻生长效应及其被铜绿微囊藻富集的动力学过程。结果表明:当Ce4+的添加浓度小于0.2mg/L时,对铜绿微囊藻的生长有促进作用,当Ce4+的添加浓度大于0.2mg/L时铜绿微囊藻的生长受到抑制。Ce4+在铜绿微囊藻中富集的动力学过程可用二级吸附动力学模型表征。
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研究了不同浓度甲基苯丙胺在不同pH值条件下对铜绿微囊藻的生长效应及其动力学过程,并用色谱法对其作用机理进行了初步探讨.结果表明,在pH8.0,甲基苯丙胺浓度为0.2,2.0,20.0mg/L时,对微囊藻生长分别表现出促进、部分抑制和完全抑制效应;而在pH6.0时,3个浓度的甲基苯丙胺对微囊藻生长均表现出抑制效应,且随浓度的增大抑制效应增强.色谱分析结果表明,低浓度(0.2mg/L)的甲基苯丙胺促进了微囊藻的生长代谢,而高浓度(20.0mg/L)的甲基苯丙胺则损伤微囊藻细胞,抑制其生长代谢.
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太阳光/多孔TiO2膜体系对水中微囊藻毒素(MC-RR)具有较好的去除效果,反应可用准一级反应动力学描述。TiO2膜的镀膜次数对催化效果有重要影响,溶液的pH值对反应也有一定的影响,偏酸性条件对MC-RR的降解有利。在该体系中MC-RR主要通过光催化氧化作用被去除。
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本实验对在不同Zn2+浓度条件下培养的固氮鱼腥藻(Anabaena azoticaLey)的生长、光合放氧速率和叶绿素荧光参数Fv/Fm进行了测定.结果表明,当Zn2+浓度为1.0μmol/L时,其比生长速率(Specific growth rate)最大,光合放氧速率和Fv/Fm值最高.当Zn2+浓度大于等于5.0μmol/L时会抑制A.azotica Ley的生长和光合作用.对在0μmol/L和5.0μmol/L Zn2+浓度下生长的藻细胞藻胆体-类囊体膜复合物吸收光谱的比较和对与5.0μmol/L
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The existing methods for the discrimination of varieties of commodity corn seed are unable to process batch data and speed up identification, and very time consuming and costly. The present paper developed a new approach to the fast discrimination of varieties of commodity corn by means of near infrared spectral data. Firstly, the experiment obtained spectral data of 37 varieties of commodity corn seed with the Fourier transform near infrared spectrometer in the wavenurnber range from 4 000 to 12 000 cm (1). Secondly, the original data were pretreated using statistics method of normalization in order to eliminate noise and improve the efficiency of models. Thirdly, a new way based on sample standard deviation was used to select the characteristic spectral regions, and it can search very different wavenumbers among all wavenumbers and reduce the amount of data in part. Fourthly, principal component analysis (PCA) was used to compress spectral data into several variables, and the cumulate reliabilities of the first ten components were more than 99.98%. Finally, according to the first ten components, recognition models were established based on BPR. For every 25 samples in each variety, 15 samples were randomly selected as the training set. The remaining 10 samples of the same variety were used as the first testing set, and all the 900 samples of the other varieties were used as the second testing set. Calculation results showed that the average correctness recognition rate of the 37 varieties of corn seed was 94.3%. Testing results indicate that the discrimination method had higher precision than the discrimination of various kinds of commodity corn seed. In short, it is feasible to discriminate various varieties of commodity corn seed based on near infrared spectroscopy and BPR.
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介绍了采用MSC1210单片机,结合CPLD和DDS设计的一个电源测控模块,它通过RS-485总线实现与上位机的通信,来控制电源的开关、调节和状态获取等。实践表明,该模块具有较高的可靠性、实时性和适应性。
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通过分析人工智能中的A和A*启发式搜索,提出了通过PVM工具包,设计和实现A和A*启发式搜索的并行计算模型。在启发搜索过程中同时进行评估函数计算,使计算的速度加快。解决了在搜索解空间庞大,评估函数计算复杂的情况下,使用单计算机计算速度慢的问题。该文实现了基于PVM的启发式搜索过程,该模型可应用于一般性启发式搜索问题的并行计算模型。
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将PROFIBUS现场总线技术成功应用于重离子加速器高频发射机控制系统中,达到了在强电磁干扰环境下系统稳定运行的要求。应用PLC控制设备和STEP7软件编程,采用分布式I/O模式,降低了系统调试和布线难度,缩短了开发周期,并为控制系统扩展提供灵活性。
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除虫菊酯是新型植物源农药,由于其具有杀虫谱广,杀虫活性高,对哺乳动物毒性低等优点而被广泛地应用于室内卫生昆虫防治。拟除虫菊酯是人工合成的除虫菊酯的结构类似物。由于人们在使用过程中不可避免地会接触除虫菊酯类药物,对其进行毒理学研究显得尤为重要。本论文以雄性Sprague-Dawley大鼠为材料,研究了除虫菊酯、氯氰菊酯、增效醚(PBO)和迷迭香对大鼠大脑突触体ATP酶活性的影响。采用Percoll梯度离心法分离出大脑突触体,通过测定ATP酶催化ATP产生的无机磷量测定ATP酶的活性。结果:总ATP酶和Mg2+-ATP酶在10 μM除虫菊酯作用下的活性分别为80.3%和45.9%,当除虫菊酯浓度上升到100 μM时,活性分别下降到5.4%和6.2%;总ATP酶在100 μM氯氰菊酯作用下活性为80.7%,氯氰菊酯浓度上升到1000 μM时,活性下降到2.3%;在3000 μM PBO作用下,总ATP酶活性为79.9%,相同浓度的迷迭香能使总ATP酶活性下降到66.8%;当有3倍浓度PBO存在时,10 μM除虫菊酯降低总ATP酶活性至37.8%,100 μM氯氰菊酯降低总ATP酶活性到28.5%;有3倍浓度迷迭香存在时,10 μM除虫菊酯降低总ATP酶活性到72.9%,100 μM氯氰菊酯降低总ATP酶活性至43.0%。结论:除虫菊酯和氯氰菊酯在适当浓度下都能显著抑制总ATP酶和Mg2+-ATP酶的活性。除虫菊酯的抑制作用比氯氰菊酯显著,除虫菊酯类药物对Mg2+-ATP酶活性抑制比对总ATP酶活性的抑制显著。增效剂PBO能有效增强除虫菊酯和氯氰菊酯对突触体ATP酶活性的抑制作用。在极高浓度下,PBO单独也能部分抑制ATP酶的活性。迷迭香本身只在极高浓度下才对ATP酶起部分抑制作用,但是能轻微增强除虫菊酯和氯氰菊酯的抑制活性,这可能与其延迟除虫菊酯和氯氰菊酯被氧化有关。本研究结果表明,除虫菊酯只在浓度 > 1 μM时才会对ATP酶起显著的抑制作用(p < 0.05),但是前人研究表明除虫菊酯在0.01 μM下即能有效改变昆虫钠离子通道动力学,可见,除虫菊酯类药物在0.01-1 μM浓度下既能有效杀灭害虫,又对人畜安全,这一结论可用于指导除虫菊酯类药物的使用。此外,本研究还测定了云菊5%除虫菊酯乳油对东亚飞蝗四龄和五龄若虫的室内药效实验,结果表明除虫菊酯能有效杀灭东亚飞蝗,适用于东亚飞蝗防治。
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一直以来同位素地球化学在气源对比研究中发挥着重要作用,天然气组分碳、氢稳定同位素已经用于判别天然气的烃源岩、源岩热演化程度和成藏过程,稀有气体同位素也已经广泛运用于天然气的来源判别。近年来,又发展了诸如流体包裹体气源对比方法,利用苯、甲苯、二甲苯、甲基环己烷等轻烃单体碳同位素气源对比方法,天然气组分的详细解剖与气源直接对比方法和气源动态综合对比方法等,这些方法促进了天然气气源对比的深入研究。比较系统地介绍了气源对比方法上的发展、创新和今后发展的一些趋势。
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Parker, R. & Urquhart, C. (2007). Lessons learned in an information skills training programme for a mental health Trust. Health Information and Libraries Journal, 24(1), 58-61.
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202 hojas : ilustraciones, fotografías a color.
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Ballineaspig, anglicised Bishopstown, consists of two townlands which are Ballineaspigmore and Ballineaspigbeg. Taken together, both townlands occupy an area identifiable in modern day terms as lying approximately between the old Glasheen National School on the east side and what was, until recently, the University Farm Curraheen Road on the west. A townland is the smallest administrative land division in Ireland. Historians and other scholars are as yet inconclusive about the origins of these divisions. They are certainly as old as the seventeenth century. The townland with which this booklet is concerned is known as Ballineaspigmore. It extends west from the new Regional Hospital at Wilton and includes modern housing estates such as Uam-Var, Benvoirlich and Firgrove. The simplest translation of the townland name is the large land division of the bishop. To clarify a popular misconception, Bishopstown does not derive its name from the fact that in the early eighteenth century a bishop of Cork built his country residence there. The name is much older and can be found in sources dating back to the sixteenth century.
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The technological role of handheld devices is fundamentally changing. Portable computers were traditionally application specific. They were designed and optimised to deliver a specific task. However, it is now commonly acknowledged that future handheld devices need to be multi-functional and need to be capable of executing a range of high-performance applications. This thesis has coined the term pervasive handheld computing systems to refer to this type of mobile device. Portable computers are faced with a number of constraints in trying to meet these objectives. They are physically constrained by their size, their computational power, their memory resources, their power usage, and their networking ability. These constraints challenge pervasive handheld computing systems in achieving their multi-functional and high-performance requirements. This thesis proposes a two-pronged methodology to enable pervasive handheld computing systems meet their future objectives. The methodology is a fusion of two independent and yet complementary concepts. The first step utilises reconfigurable technology to enhance the physical hardware resources within the environment of a handheld device. This approach recognises that reconfigurable computing has the potential to dynamically increase the system functionality and versatility of a handheld device without major loss in performance. The second step of the methodology incorporates agent-based middleware protocols to support handheld devices to effectively manage and utilise these reconfigurable hardware resources within their environment. The thesis asserts the combined characteristics of reconfigurable computing and agent technology can meet the objectives of pervasive handheld computing systems.