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Search Results: 1 - 10 of 278544 matches for " 张正一 "
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黄河口水域微量重金属表观络合容量研究
孙铭,,
华东政法大学学报 , 1987,
Abstract: 本文采用物理涂汞膜电极阳极溶出伏安法络合滴定技术结合ip-Ea*特性曲线的研究,完成了黄河口水域两个站位的微量重金属(Cu、Pb、Cd)的表观络合容量测定.结果表明,黄河口水样中微量重金属的表观络合容量大小顺序为:Cu>Cd>Pb,近岸水样比远岸水样的表观络合容量高.同时还对紫外线照射对有机配位体的破坏效应及电解池壁的吸附效应进行了研究,并利用ip-Ea*特性曲线探讨了海水中微量重金属在电极上还原的机理.
支持向量回归增量学习
凡?,冯爱民?,林?
计算机科学 , 2014, DOI: 10.11896/j.issn.1002-137X.2014.06.032
Abstract: 针对支持向量回归因时空复杂度较高而无法处理大规模数据的问题,提出了一个新颖的增量学习模型——l增量υ支持向量回归(lincrementalυsupportvectorregression,lisvr)。该模型针对支持向量丢失所产生的不利影响,通过不断对支持向量样本加权并及时淘汰非支持向量,降低了时空复杂度。从理论上证明了算法可收敛到全局最优解。结合人工数据集、uci数据集和机场噪声的实际问题对该算法做了相应测试,结果验证了算法的有效性。
嗜热链霉菌过氧化氢酶的纯化及性质研究
,严自,树政
微生物学报 , 1990,
Abstract: 嗜热链霉菌(Thermostreptostreptomyces sp.)T485的除去菌体的培养液,经硫酸铵盐析,Sepha- dex G—100、DEAE—Sephadex A-50及羟基磷灰石等柱层析,得到了凝胶电泳均-的过氧化氧酶,纯化了954倍,得率为7%。用浓度梯度PAGE测定分子量为152000,SDS—PAGE测定亚基分子量为57000,凝胶薄层等电点聚焦测定等电点为4.25。过氧化氢酶的反应最适温度为60℃,最适pH为7.0;对H2O2的K为50 mmol·L-1,Vmas值为6.0 mmol·min-1·mg-1。Nall3和Hg2+对酶活力有强烈抑制作用.Ca2+对酶活力有激活作用。测定了波长200—500nm的吸收光谱,在405nm处有明显的吸收峰。根据受NaN3,抑制和吸收光谱性质,推测它为含血红素酶。此外还测定了过氧化氢酶的氨基酸组成。
海水中微量元素分配在粘土矿物上的一种新的化学模型
孙铭,,刘莲生
华东政法大学学报 , 1984,
Abstract: 本文研究了海水中微量元素与粘土矿物的相互作用并提出一个化学模型,即低铅浓度下以阳离子交换作用为主,高铅浓度下以表面沉淀作用为主.两种作用分别用粘土矿物和铅相互作用的pH效应和温度效应加以验证.应用描述气-固吸附的Toth方程于我们的试验体系,从而建立了适用于液固体系的等温方程式,理论曲线与试验结果较为一致.
圆柱腔内微波等离子体激励的研究
廖斌,,安同,朱守
华东师范大学学报(自然科学版) , 2005,
Abstract: 根据谐振腔理论,证明圆柱反应腔内的主模为TM01p模,并在圆柱坐标下采用FD-TD数值方法求解圆柱形反应腔中的场分布情况,改善和提高微波等离子体反应装置的激励性能.等离子体实际分布与场分布的预测结果基本吻合.
ATM网络中面向ABR服务的一种流量控制机制
张孝林,吴介,,飒兵
电子学报 , 2002,
Abstract: 在ATM网络有效和稳定的运行过程中,拥塞控制起着重要的作用.对此,本文提出一种方法来设计基于速率的流量控制机制以便调节ABR服务并有效地控制网络拥塞.目标是在多个竞争用户间公平分配可用链路带宽、维持瓶颈结点的队列长度在希望值.该机制基于最小节拍(DR)控制并具有非常简单的结构.仿真结果表明,该控制机制是公平的并且具有快速收敛、无振荡和高链路带宽利用率的优点.
云芝多糖对运动训练大鼠脑组织抗氧化能力和atpase活性的影响
习雪峰,王单,,
食品科学 , 2012,
Abstract: ?目的:探讨云芝多糖对力竭运动大鼠脑组织的部分抗氧化酶活性和na+,k+-atp酶(na+,k+-atpase),ca2+,mg2+-atp酶(ca2+,mg2+-atpase)活性影响。方法:选取成年雄性sd大鼠24只。将大鼠随机分为3组:安静对照组8只,运动对照组8只,运动加药组8只,进行为期8周的大强度耐力跑台训练。测定大鼠脑组织部分抗氧化酶和na+,k+-atpase,ca2+,mg2+-atpase活性的变化。结果:与安静对照组相比,运动对照组脑组织中超氧化物歧化酶(sod)、过氧化氢酶(cat)、谷胱甘肽过氧化物酶(gsh-px)、总抗氧化能力(t-aoc)、na+,k+-atpase、ca2+,mg2+-atpase活性和血糖含量显著下降(p<0.01或p<0.05),mda生成显著增多(p<0.05);云芝多糖提高了力竭运动大鼠脑组织sod、cat、gsh-px、t-aoc、na+,k+-atpase、ca2+,mg2+-atpase活性和血糖含量(p<0.01或p<0.05),减少mda生成(p<0.05)。结论:云芝多糖可以提高力竭运动大鼠脑组织中抗氧化酶活性和na+,k+-atpase和ca2+,mg2+-atpase的活性,这对于维持运动中能量的供应和抗氧化能力,从而提高大鼠的运动能力具有重要意义。
木材表面组装PEI/纳米ZrO2/FAS复合薄膜及其性能
,于海鹏,
- , 2017, DOI: 10.13360/j.issn.2096-1359.2017.03.014
Abstract: 以大青杨木材为研究对象,为提高其抗润湿和耐老化性能,采用层层自组装技术,将聚乙烯亚胺(PEI)和纳米ZrO2交替吸附在木材表面,然后用全氟癸基三甲氧基硅烷(FAS)对组装后的木材进行修饰,在木材表面形成复合的功能薄膜。结果表明,在组装过程中,纳米ZrO2的单斜晶系晶体结构没有发生转变。(PEI/ZrO2)i膜层能均匀地负载在木材表面,随着层数的增加,膜层变得更加致密。接触角测试结果发现,与未处理材相比,组装后的木材试样经过FAS修饰后均具有较稳定的疏水效果,初始接触角最高可达148°。加速老化试验结果表明,未处理材的颜色变化ΔE*可达35.36,而处理后木材的ΔE*明显减小,降幅达到66.4%。因此,利用层层自组装技术,在木材表面吸附了(PEI/ZrO2)i/FAS膜层,可使木材具有良好的抗润湿及耐老化效果。
Wood is widely used in construction and furniture fields as a sustainable and natural polymer material. However, some drawbacks such as hygroscopic swelling and aging discoloration have limited its applications. It is necessary to improve the anti-wettability and aging resistance performance for the Populus ussuriensis wood during the utilization. In this study, the polyethyleneimine(PEI)and nano-zirconium dioxide(ZrO2)were alternately adsorbed on wood surface via layer-by-layer assemble method. Then, the assembled wood samples were treated with low-surface-energy 1H, 1H, 2H, 2H-Perfluorodecyltrimethoxysilane(FAS), which formed composite(PEI/ZrO2)i/FAS coatings on wood surface. The results of XRD curves indicated that, compared with the untreated wood, the monoclinic crystal structure of ZrO2 emerged from the assembled wood samples. The diffraction peak intensity of ZrO2 on wood surface enhanced obviously with the increase of assembled layer number, and the crystal structure remained unchanged. Field emission scanning electron microscope(FE-SEM)images showed that(PEI/ZrO2)icoatings were well-distributed and consecutive on wood surface, and became denser with the increase of layer number. The results of water contact angle measurements demonstrated that the untreated wood was hydrophilic, however, the wood samples with(PEI/ZrO2)i/FAS coatings retained stable hydrophobic effect. The original contact angle reached 148°, and the changes were not obvious afterwards. Then, wood samples alternately exposed under the UV irradiation and wet environment for artificial accelerated aging test. When the irradiation time reached 600 h, the total color change(ΔE*)of the untreated wood was calculated to be 35.36. Owing to the good ultraviolet absorption and reflection performance of ZrO2, ΔE* of the treated wood samples significantly decreased with the increase of assembled layer number. For the(PEI/ZrO2)20/FAS wood sample, ΔE* was 11.87, which was decreased by 66.4% compared with that of the untreated wood. Therefore,(PEI/ZrO2)i/FAS coatings were equably coated on wood surface through the layer-by-layer assemble method, and the assembled wood samples were possessed of great anti-wettability and aging
三维片上网络故障及拥塞感知的容错路由器设计
欧阳,,梁华国,
电子学报 , 2013, DOI: 10.3969/j.issn.0372-2112.2013.05.013
Abstract: 三维片上网络中路由器的输入端口和交叉开关出现故障,将严重影响整个网络的性能,因此文章提出了一种故障及拥塞感知的容错路由器.通过增加一个冗余的输入端口和旁路总线,不仅能实现对输入端口和交叉开关容错的目的,而且还能在没有端口故障的情况下使用冗余端口有效地解决拥塞问题.实验表明此容错机制能够使得网络在故障路由器多、拥塞严重的情况下,仍然保持良好的性能.
中国绿色公路建设与评估技术
Construction and assessment technology of green road in China

,王朝辉,,王帅,曾伟
- , 2018,
Abstract: 为了解决中国绿色公路建设中目前存在的建设理念不统一、评估体系不完善等问题,通过系统梳理中国绿色公路理念发展历程,明确绿色公路建设基本思想,进而确定绿色公路基本概念;全面调查了中国80余条和国外部分道路以绿色、景观、生态、节能、低碳为主题的绿色公路建设概况,总结分析了现阶段国内外绿色公路的建设特点,提出中国典型区域绿色公路建设的建议;基于绿色公路建设关键技术指标,提出现阶段绿色公路评估技术要求;从绿色理念、生态保护、资源节约、节能低碳、安全智慧、服务提升、品质建设7个方面,构建了包括7类一级指标、22个二级指标和58项评估内容的绿色公路评估体系,明确了不同地域自然环境及建设状况下的绿色公路可不参评指标,确定了绿色公路相应评估指标权重及评估分值计算方法,并运用该评估指标体系对中国某绿色公路进行了评估。结果表明:绿色公路评估体系可涵盖待评估公路的评价指标,具有较强的科学性和适用性;参评的绿色公路总分为64.06,在资源节约与服务提升等方面略有不足;绿色公路评估体系对中国绿色公路的发展建设具有指导意义,可为中国绿色公路的可持续发展提供借鉴。
In order to solve the problems in the process of China??s green road construction, such as inconsistent construction concepts and incomplete evaluation systems. The development of the green road concept in China systematically was reviewed. The basic idea of green??road construction, integrates the green??road concept was clarified, and the construction of green roads with the theme of green, landscape, ecology, energy savings, and low carbon for more than 80 green roads in China were investigated, as well as green roads abroad. A summary and analysis of the characteristics of green road in China were presented. Then, suggestions for green road construction in special areas were put forward. Based on the crucial technical indicators of green road construction, the technical requirements for evaluating a green road under at present stage were put forward. The evaluation indices system of green roads was set up from 7 aspects, such as green concept, ecological protection, resource conservation, energy??saving and low??carbon, safety and intelligence, service improvement, and quality construction. This evaluation indices system included 7 types of primary assessments 22 secondary indicators and 58 assessments. In this research, the green road non??evaluation indicators under different regional natural environments and construction conditions were defined, and the corresponding weights of the evaluation indicators and the green road evaluation score calculation method were determined. Meanwhile, the evaluation indices system was applied to evaluate a green road in China. The results show that the green road evaluation indices system can completely cover the indicators involved in the highway to be evaluated and has a strong scientific basis and applicability. The total score of the green road is ??64.06?? points, the green road falls short in resource conservation and service improvement. The green road evaluation indices system provides guidance for construction of China??s green road, and can provide reference for the sustainable development of China??s green highways. 6 tabs, 26
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