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Search Results: 1 - 10 of 58341 matches for " 阳辉 "
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潇河表层沉积物中氮素分布特征及其污染评价

人民黄河 , 2014,
Abstract: ?为了研究河道表层沉积物中氮素分布特征,以潇河为研究区,选取7个采样点,研究表层沉积物中两种形态的氮素——氨氮和硝酸盐氮,测定分析其含量、分布特征及成因,并探究其与有机质之间的关系。其中氨氮用kcl浸提-靛酚蓝比色法测定,硝酸盐氮用酚二磺酸比色法测定,沉积物中有机质的测定用重铬酸钾法。在测定结果的基础上,采用单项指标标准指数法对沉积物中氮的污染程度进行评价。结果表明:①潇河表层沉积物中氮素总量表现为中下游段高于中上游段的特征。就两个河流段而言,同时呈逐渐下降的趋势。氮素总量受到上覆水体氮营养盐水平、溶解氧含量及沉积物的氧化还原电位、沉积物中有机质的降解影响。氨氮含量大于硝酸盐氮,二者平均值之比为1.38∶1,表明潇河沉积物还原程度较低。②利用线性回归分析可知,沉积物中硝酸盐氮和有机质含量呈显著正相关。③潇河沉积物中总氮的含量较高,一半以上采样点的标准指数超过1,说明潇河沉积物环境质量受氮的污染相对严重。
基于Zedboard的WLI图像缩放算法的硬件设计
Hardware Design of WLI Image-Zooming Algorithm Based on Zedboard
 [PDF]

许世, 董航,
Computer Science and Application (CSA) , 2015, DOI: 10.12677/CSA.2015.56025
Abstract:
本文选择了一种新颖的图像缩放算法进行FPGA硬件实现。该算法基于奇偶分解的思想,具有复杂度低、硬件需求小和缩放效果良好等突出优点。首先利用MATLAB对该算法进行了功能验证,然后用缩放耗时、PSNR、边缘模糊等级和脉冲噪声等指标评估基于该算法图像处理效果。与传统时域算法作对比,对比结果表明该算法在处理效果和运算速度上的优异性。基于Zedboard开发板,运用Vivado HLS高级综合工具将算法的C程序综合成硬件IP,并搭建了包含ARM处理器和VGA等模块的软硬协同验证系统。实验验证了图像缩放算法硬件设计的正确性和实用性。
A novel zoom algorithm is researched and further realized by a FPGA board. The algorithm is of low complexity, low hardware requirements, and wonderful zoom result thanks to even-odd de-composition method. First, function of the algorithm was verified by MATLAB. Second, zoom results of pictures were evaluated using PSNR, time consuming, edge fuzzy grade, and impulse noise. Compared to the conventional algorithm in the time domain, the even-odd decomposition method has advantages on zoom quality and computational efficiency. Based on Zedboard, we wrote C program of WLI image zoom algorithm and used high level synthesis tool Vivado HLS to generate the IP from the program. Then, a software and hardware co-verification system was constructed including modules such as ARM processor, VGA controller. Finally, hardware design of the zoom algorithm using even-odd decomposition method was proved correct by experiments.
稀土Yb对Mg-Zn-Zr镁合金组织及性能的影响
Effect of Ytterbium on the Microstructure and Mechanical Properties of the Mg-Zn-Zr Magnesium Alloys
 [PDF]

, 徐洪
Material Sciences (MS) , 2016, DOI: 10.12677/MS.2016.61009
Abstract:
采用Ta坩埚熔炼法制备Mg-Zn-Zr-Yb镁合金,利用光学显微镜(OM)、扫描电镜(SEM/EDS)和维氏显微硬度仪等分析手段探究了稀土Yb含量对Mg-4%Zn-0.5%Zr-xYb (x = 0, 0.6, 1.2, 2.4, 4.0)镁合金的显微组织及性能的影响。结果表明:合金中添加Yb元素,可以细化晶粒,当Yb含量为2.4 wt.%时,晶粒显著细化,晶粒大小也更为均匀。此外,能谱成分分析发现,稀土Yb在Mg基体中固溶度很小,主要分布在共晶组织中。固溶时效处理后,合金的硬度均有上升。不含Yb元素的镁合金,达到时效峰值的时间为10 h;添加Yb元素后,时效峰值时间缩短至3 h。且添加2.4 wt.% Yb时,时效峰硬度值增加最为明显。
Five Mg-Zn-Zr-xYb (x = 0, 0.6, 1.2, 2.4, 4.0) magnesium alloys were prepared by using a special melting method that the pure elements were sealed in tantalum crucibles and melted in a furnace with the temperature program-controlled. The effect of the ytterbium addition in the alloys on their microsructures and mechanical properties was investigated by using the optical microscope and scanning electron microscope with energy dispersive spectrometer. The experimental results indicated that the grain refinement of the alloys is attained after the addition of ytterbium. Ytter-bium is also useful for the purification of grain boundary. The best grain refining effect was achieved in the alloy with the Yb addition of 2.4 wt.%. The EDS analysis suggested that the ytterbium content in the magnesium matrix is negligibly little. The added ytterbium is present almost wholy in the eutectic mixture. After the solution treatment and aging treatment, the hardness of the magnesium alloys increased. The 125?C aging time for the magnesium alloys without ytterbium to reach the hardness peak is 10 h while those of the Yb-added magnesium alloys are shortened to be about 3 h. The alloy containing 2.4 wt.% Yb has the highest aging hardness peak.
浅析衍生金融工具的会计确认和计量

财会月刊 , 2005,
Abstract:   衍生金融工具,由于其交易的杠杆性,成为游离于传统财务报表之外的巨大潜在风险源,并对传统的历史成本会计体系提出挑战。针对这一问题,IASC和美国FASB对衍生金融工具采用公允价值会计。我国尚未制定衍生金融工具会计准则。鉴于我国的实际情况,建议对衍生金融工具交易实行表内历史成本计量、表外披露公允价值及其他相关信息的会计处理。  【关键词】衍生金融工具会计历史成本公允价值  自1972年美国推出首张外汇期货合约以来,衍生金融工具迅速发展,对全球金融市场产生了日益重大的影响。随着我国改革开放的日益深入,金融市场国际化、银行企业化、资金商品化、利率自由化将得以实现,衍生金融工具的发展也将成为必然的趋势。本文就衍生金融工具的国际会计的确认和计量以及我国对策做以下探讨。  一、衍生金融工具的含义及其特点  1.衍生金融工具的含义。基本金融工具是指现金以及表明特定权利和义务关系且涉及资产负债表左右两方若干项目的可流通契约凭证。
新农村建设应推广太阳能住房
,廖秋
工业建筑 , 2010, DOI: 10.13204/j.gyjz201012031
Abstract: 阐述了新农村建设中农房利用太阳能的必要性,介绍了太阳能工作的原理及应用,指出目前太阳能推广面临的问题及提出解决的方法。
对自同步混沌密码的分割攻击方法
金晨,
电子学报 , 2006,
Abstract: 本文分析了自同步混沌密码的信息泄漏规律,并据此提出了对自同步混沌密码的分割攻击方法.由于能够利用所有时刻的已知明文进行攻击,因而自同步混沌密码比同步混沌密码的抗分割攻击能力更弱.本文以HongZhou等提出的自同步混沌密码为例,完成了对密钥规模为64比特且以混沌映射的65次迭代为自同步映射的自同步密码的分割攻击.利用1万个已知明文,在主频为2.5GHz的Pentium-4PC上,攻击的平均时间为25小时22分,成功率为0.86.
以冰为模板制备超轻多孔氧化锆块材
,贺军
材料研究学报 , 2009,
Abstract: ?以冰为模板,经真空冷冻干燥过程制备轻质zro2多孔材料和水玻璃为粘结剂的超轻多孔zro2块材,研究了其微观结构、形成机理和隔热耐火性能.结果表明,冰是一种理想的制作多孔材料的模板,可同时获得多种尺度的孔结构,还可获得多孔和层状两种结构复合的微观结构.zro2多孔材料的微观结构为奇特的周期性层状结构.添加水玻璃作为粘结剂,制备出多孔和层状两种微结构复合的zro2多孔块材,在400℃煅烧6h后仍良好地保持原有的微观结构,孔隙率达87%,表观密度仅为0.50g??cm-3,?超轻且机械强度有较大提高,在1300℃丁烷气火焰灼烧下表现出较好的隔热耐火性能.
青兰浸膏片处方及制备工艺研究
,
中国中医药信息杂志 , 2007,
Abstract: 目的优选青兰浸膏片处方及制粒压片工艺条件。方法采用l9(34)正交试验设计,以颗粒粒度、片芯硬度、脆碎度、崩解度为考察指标,对青兰浸膏片处方及制粒压片工艺条件进行优选。结果最佳工艺为青兰浸膏粉与淀粉、糊精的比例(kg)为25∶4∶1,用青兰浸膏混和粉0.25倍(kg)95%乙醇湿润搅拌8min制软材。结论用优选出的工艺参数制得的片剂综合评分最好,工艺科学合理。
宗族的现代国家改造与村庄治理――以南部G市郊区“横村”社区治理经验为例
,刘炳
南京农业大学学报(社会科学版) , 2017,
Abstract: 宗族是中国乡村传统社会最为重要的组织基础,在中国村庄治理中一直扮演着十分重要的角色。近现代以来,国家权力在乡村社会得以全面渗透,并对传统的宗族进行了现代化改造,但由于区域环境的差异以及偶然性因素的叠加,却造成了宗族参与村庄治理的不同症候。总结宗族型村落治理的现实经验以及宗族与国家关系的演变,可以概括出宗族参与现代村庄治理的一个类型学谱系:宗族在现代国家改造过程中,国家治理的组织体系与意识形态嵌入村落传统治理结构的不同程度,是产生宗族型村落不同治理后果的重要原因。依据国家与宗族在治理结构上的“组织互嵌度”与“意识形态耦合度”,可以将现代宗族型村落概括为“博弈型宗族”“对抗型宗族”“边缘型宗族”“治理型宗族”。其中“治理型宗族”是宗族接受现代国家改造的一个理想类型。横村的社区治理经验说明了“治理型宗族”的产生过程及其对村庄治理的积极意义,也阐释了传统治理资源对于现代乡村社会重建的可能价值。
Clan is the most important organizational foundation in Chinese traditional rural society, which has been playing a very important role in the village governance of China. In modern times, the state power has fully penetrated into the rural community and modernized the traditional clan. However, differences in the regional environment and superposition of contingency factors result in different problems of claninvolved village governance. By summarizing the practical experience of clan-type village governance and the evolution of relations between clan and country, we can get a typology pedigree, which is in the transformation process of the modern state, the combination of different degrees between organizational and ideological system of governance and traditional village governance structure is an important reason for the appearance of different governance consequences. Based on the ‘mutual insertion of organizations’ and ‘coupling of ideology’ on the governance structure of clan and country, modern clan villages can be summed up as‘Game-Type Clan’, ‘Confrontation-Type Clan’, ‘Borderline Clan’ and ‘Governance Model Clan’, of which the ‘Governance Model Clan’ is an ideal type of modernized clan. The management experience of Village Heng demonstrates the production process of ‘Governance Model Clan’ and its positive significance for village governance. At the same time it also shows that traditional governance resources have potential value for the reconstruction of modern rural society
Research on Database Security Model
数据库安全模型的研究

张剡,,柏文
计算机科学 , 2004,
Abstract: 在现有安全模型的基础上提出了NDMAC模型。该模型对主客体进行了明确的定义和分类。并采用最细客体枉度为属性和元组级的方案。该模型提出了隶属完整性规则、实体完整性规则和推理完整型规则。并给出了六种操作的处理策略。此外模型引入了同步约束、互斥约束和推理约束,并通过引入特权机制增强该模型的灵活性。
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