13 resultados para 13368-049
em Chinese Academy of Sciences Institutional Repositories Grid Portal
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Estimation of the far-field centre is carried out in beam auto-alignment. In this paper, the features of the far-field of a square beam are presented. Based on these features, a phase-only matched filter is designed, and the algorithm of centre estimation is developed. Using the simulated images with different kinds of noise and the 40 test images that are taken in sequence, the accuracy of this algorithm is estimated. Results show that the error is no more than one pixel for simulated noise images with a 99% probability, and the stability is restricted within one pixel for test images. Using the improved algorithm, the consumed time is reduced to 0.049 s.
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稀土离子掺杂的氧氟玻璃是一种新型上转换发光材料。制备了Tm^3/Yb^3+单掺、共掺的摩尔分数为n(SiO2)-0.30,n(PbF2)-0.50,n=(Al2O3)=0.15,n(AlF3)=(0.049-x),n(TmF3)=y,n(YbF3)=x(x=0,0.001,0.010,0.015,0.020,y=0,0.001)系统氧氟玻璃,研究了其上转换发光特性、分析了其上转换发光机理。研究发现,在970nm抽运光源激发下,Tm^3+单掺时没有可见光上转换发射;而加入Yb^3+后产生了强的蓝光(452n
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本发明是一种单模高功率垂直腔面发射激光器,属半导体光电子领域。其特征在于,包括P型电极(1),P型Si衬底(2),金属键合层(3),P型分布布拉格反射镜(DBR)(4),氧化限制层(5),有源区(6),N型DBR(7),SiO2掩膜(8),聚酰亚胺或苯并环丁烯(BCB)(9),N电极(10),光子晶体(11),出光窗口(12)。在该结构的垂直腔面发射激光器中引入光子晶体,可增大氧化孔径,提高单模输出功率,同时采用键合技术将传统VCSEL外延片转移到Si衬底上和采用底部出光的设计,便于拉近VCSEL外延片有源区与Si衬底的距离,改善器件热学特性,进一步提高单模输出功率。
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以黄土高原从北向南不同地区典型土壤类型为对象,采用Bremner淹水培养法,研究铵态氮肥对黄土高原典型土壤氮素的激发效应。结果表明,在测定NH4+-N的激发效应时,只有考虑粘土矿物对有机氮矿化产物或者添加NH4+-N的固定,才可获得可靠结果。在培养20 d和60 d时,NH4+-N对不同土类氮素激发效应存在极显著和显著的影响(P≤0.01和<0.05);培养40 d时,尽管不同土类氮素激发效应也存在很大差异,但统计检验不显著。从整体评价,NH4+-N对土垫旱耕人为土和黄土正常新成土表现出正的激发效应,而对干润砂质新成土表现出负的激发效应,对简育干润均腐土在培养20 d和40 d时无激发效应,而在培养60 d时,表现出显著的负激发效应。结果还看出,在培养40 d和60 d时,NH4+-N对农田土壤表现出负激发效应,对林地和裸地土壤表现出正激发效应,而草地土壤在培养40 d时为正激发效应;培养20 d和60 d时无激发效应。添加有机物料在培养20 d和40 d时对激发效应的影响不显著(P=0.0872和0.1641),培养时间延长至60 d时影响显著(P=0.049)。添加紫花苜蓿(Medicago sati-v...
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本文对贵金属电极和钴卟啉膜电极进行了动力学研究,并根据实验数据提出了SO_2在不同电极材料上的反应机理。一、各种电极材料催化性能的比较用循环伏安法得出SO_2在Pt、Au、Pd电极上的氧化在不同电位区有不同的机理。一种是在低电位区SO_2分子的直接放电,另一种是在高电位区表面吸附氧的化学氧化。在贵金属Ir、Ru、Rh电极上,So_2的氧化只有一种途径,即只能通过电极表面吸附氧的化学氧的化学氧化。根据SO_2在贵金属电极上氧化的峰电位得出SO_2在这些电极上的活性次序如下:Au > Ir > Pd,Ru > Pt > Rh SO_2在钴卟啉膜电极上氧化也只有一种途径,但和Ir、Ru、Rh电极不同,不是通过吸附氧的化学氧化,而是SO_2分子的直接放电。二、氧化机理1、SO_2在Au电极上电化学氧化机理 对SO_2在Au电极上电化学过程进行研究,用稳态极化曲线法测得在较负电位区Tafel线性区的斜率为0.049, 可说明SO_2分子第二个电子的脱除为控制步骤;用计时-电流法、计时-电位法求得SO_2在Au电极上电化学氧化的动力学参数R_6~o为10~(-11)数量级。测量不同电位下交流阻抗的频谱,得到两个明显的半园,表明电极过程包括了中间吸附物的形成。根据实验数据推导SO_2在Au电极上可能的电化学氧化机理如下:H_2SO_3 → H_2SO_3ads H_2(SO_3)_(ads) - e → H_2SO_3~+ H_2SO_3~+ +H_2O → HSO_3+H_3O~+ HSO_3 - e → HSO_3~+ HSO_3~+ + 2H_2O → H_2SO_4+H_3O~+ 2. So_2在Ru电极上的氧化机理在贵金属Ru电极上,SO_2通过吸附氧氧化,提出如下如能的反应机理:Ru + H_2O → Ru(OH)_(ads) + H~+ + e Ru(OH)_(ads) + H_2O → RuO_(ads) + H_3O~+ + e RuO_(ads) + SO_2 + H_2O → Ru + H_2SO_4用稳态法测得Tafel斜率为0.055,限制步骤可能为吸附氧氧化SO_2分子。3、SO_2 在Copp/Pt上的氧化机理在非金属钴卟啉膜电极上,SO_2氧化为SO_2分子的直接放电。稳态测量法得到极化曲线的Tafel斜率为0.107 (α=0.54)。表明SO_2分子的第一电子的脱除为控制步骤;计时-电位法表明SO_2在钴卟啉电极上氧化有个前置的化学反应p在不同电位下测量交流阻抗频谱也为两个半园,表明有中间吸附物形成。根据实验数据推导SO_2氧化的可能机理如下:H_2SO_3 → H_2SO_(3_(ads)) H_2SO_(3_(ads)) <-> H~+ + HSO_(3_(ads))~- HSO_(3_(ads))~- - e → HSO_3 HSO_3 - e → HSO_3~+ HSO_3~+ 2H_2O → H_2SO_4 + H_3O~+
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土地利用是人类根据土地质量特性来开发利用土地,创造财富,满足人类生产和生活的需要,同时改善环境,满足人类生存需要的过程。土地利用总体规划是对未来各类用地在空间上、时间上作出总体的协调的预先安排,不仅受到一定历史背景的制约,同时也受影响于当前的社会经济发展情况。但是,国内传统的土地利用总体规划往往从狭窄的技术经济观点出发,对远期的生态环境问题、社会问题缺少考虑,将新的用地尽量安排在最便捷、最经济的地方。 由于土地利用总体规划对环境影响具有长期性、复杂性、综合性、有时还有不可逆转性等特点,迫切需要在编制土地利用总体规划时对规划区与土地利用有关的环境影响进行科学研究,把环境保护纳入土地利用活动的计划、决策和规划实施中,促进土地资源持续、协调的利用。为更好地进行土地利用总体规划环境影响评价必须首先建立相应的评价指标体系,而目前国内关于该项研究的理论和实践的相关报道都较少。 本论文在综述国内外土地利用总体规划环境影响评价的理论与实践的基础上,在国内第一批开展了相关领域的案例研究,采用理论研究和案例分析相结合的研究方法对土地利用总体规划环境影响评价方法和指标体系进行了研究,对邛崃市土地利用总体规划进行了环境影响评价,其研究的主要内容和论点如下: (1)第一次根据FAO 确定的五大原则,引入了生态用地的概念并按照价值模型构建了以土地资源可持续利用为目标的县级土地利用总体规划环境影响评价的指标体系。以生产性、稳定性、保护性、经济活力、社会可接受性五个方面作为指标层来度量土地利用总体规划的环境影响,并选取了土地利用率、土地整理率、水面指数、生态用地面积比例、耕地转化率、建设用地产值指数、公众满意度等21 个元指标作为具体的评价指标。该指标体系强调了规划方案的公众参与,便于充分吸收公众的意见和建议;并且评价指标获取容易,实用性较强。 (2)在土地利用总体规划环境影响评价方法上进行了有益的探索和尝试,由于土地利用总体规划环境影响评价的主要对象是几个拟定的规划方案,所以采用综合评分法(包括特尔斐法和层次分析法)和公众参与相结合的评价方法。应用上述指标体系和评价方法对邛崃市土地利用总体规划的三个方案进行了评价筛选,高方案最终得分为92.049;中方案最终得分为91.028;而低方案最终得分为95.541,为最优方案。 (3)开展了对土地利用总体规划替代方案和公众参与机制的研究,对公众参与的方式、程序及主要内容从理论和实践两方面进行了有益的尝试,收到了良好的效果。 (4)对邛崃市土地利用总体规划进行了环境影响评价,根据邛崃市的具体情况,对规划实施后可能造成的环境正、负面影响进行了分析和预测,提出了预防或者减轻不良环境影响的对策和措施。 Land use is a process, which is to develop land according to its mass property. Bycreating the wealth and improving the environment, it can meet the need of production,life and human survival. Land use planning, as a planning form to guide land use, issubject to the historical background, and influenced by development of economic andsociety. The land use planning in the past, from narrow economic technology view,lacking of concerning ecologic environmentand social problem, arranged new land in the most convenient and economic place. Because of complexity, comprehensive and sometimes irreversible characteristicsof environmental impact caused by land use planning which has been implemented, it isneed to carry on scientific research on environmental impact related to land use as theland use planning is forming, to bring environmental protection within the plan, policymaking and implementing of land use activity, promoting the sustainment, harmonious use of land resource. This paper, taking the readjustment of land use planning in Qionglai as an example,assessed its environmental impact of land use planning. The main contents and results arepresented as follows: (1) On the basis of the five criterions of AFO, for the first time propose county classoverall planning of land uses SEA index by inducting ecological land use andestablishing the Value factor system, according to Productivity criterion,Stabilitycriterion,Sheltered criterion,Economic livingness criterion,Social acceptabilitycriterion,the environmental impact of land use system was assessed by using Valuemodel. Through identifying the factors of environmental impact of land use planning, thepaper established the factor system of SEA of land use planning. From the land usefactors, 21 factors was chosen to assess the environmental impact degree of land useplanning, such as, index of land use degree, the rate of land collating, index of watersurface, the rate of ecological use land, cultivated land conversion ratio, forest landconversion ratio, public satisfaction degree and so on. These indexes make a point thatpublic participation of plan project fully absorb public idea and propose and the index easily get, better utility. (2) Attempt useful assessment method system of SEA of land use planning. In viewof there are no or almost no inevitable contact among the factors of SEA of land useplanning,we use AHP (Analytic Hierarchy Process) as the main assess method . Thereare three plans are compared in this paper apply the foregoing index and assessmentmethod. The high plan finally score is 92.049,while the middle plan is 91.028. The lowplan score is 95.541,is the best one,as the selected plan. (3) Carry on the research of the alternative scheme of overall planing of land useand public participation,to the fashion ,procedure and object matter carry out helpfulattempt from theory to practice,the results is good. (4)Took place SEA of Qionglai County overall planing of land use,according to thecircumstance of Qionglai,we analyze and forecast the positive and negative affect afterthe plan implement,and put forward the countermeasure and means to prevent or abatebad environmental impact.
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通过引进包含tune调制的传输矩阵,模拟计算了由四极铁电源纹波所引起的tune调制对HIR-FL-CSRm动力学孔径的影响。模拟计算中,对HIRFL-CSRm实际(lattice)跟踪1.0×106圈。从结果可以看出,动力学孔径随调制振幅的增大迅速减小,大体呈线性变化;动力学孔径随调制tune值的变化在研究范围内也有变化,变化的范围在0.049~0.089m之间。
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Reaction of [Ph(4)P]2WS4 With NiCl2 in methanol solution in the presence of NaOCH3 leads to the formation of [Ph(4)P](2) [S2W(mu-S)(2)Ni(S-2)] (I) A Similar reaction between (NH4)(2)WS4 and NiCl2 under O-2 atmosphere in the presence of Ph(4)PCl or (n)Bu(4)NCl affords [Ph(4)P](2)([(S-2)W(O)(mu-S)(2)]Ni-2] (IIa) and [(n)Bu(4)N](2)([(S-2)W(O)(mu-S)(2)]Ni-2} (IIb) Under argon the same reaction gives [Ph(4)P](2)[Ni(WS4)(2)] (IIIa) and [(n)Bu(4)N](2)[Ni(WS4)(2)] (IIIb). [Ph(4)P](2)[Ni(WOS3)(2)] (IV) and [Ph(4)P](2)[Ni(WO2S2)(2)] (V) can be prepared from the reaction of [Ph(4)P]2WOS3 and [Ph(4)P]2WO2S2 with NiCl2. Treatment of (NH4)(2)WS4 with CuCl in the presence of PPh(3) in boiling pyridine produces W(mu-S)(4)Cu-2(PPh(3))(3) (VI), which can further react with excess PPh(3) to give W(mu-S)(4)Cu-2(PPh(3))(4) . py (VII). Complex I crystallizes in the space group P2(1)/n with the cell parameters: a = 20.049(4), b = 17.010(4), c = 14.311(7) Angstrom; beta = 110.24(3)degrees and Z = 4; R = 0.058 for 4267 independent reflections. The structural study confirms that complex I contains two terminal sulfide ligands, two bridging sulfide ligands, a side-on disulfide ligand, and a planar central W(mu-S)(2)Ni four membered ring. Complex VII crystallizes in the space group C2/c with the cell parameters: a = 26.436(8), b = 20.542(6), c = 19.095(8) Angstrom; beta = 125.00(3)degrees and Z = 4; R = 0.080 for 3802 independent reflections. The structural study reveals a perfect linear arrangement of the three metal atoms Cu-W-Cu.
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合成了三茚基稀土配合物(η~5-C_9H_7)_3Ln·OC_4H_8(Ln=Nd、Gd、Er),经元素分析、红外光谱、水解产物核磁共振谱及质谱表征,并测得了(η~5-C_9H_7)_3Nd·OC_4H_8(1)及(η~5-C_9H_7)_3Gd·OC_4H_8(2)的晶体结构。(1)、(2)均属六方晶系,P6_3空间群,Z=2。(1)的晶体学参数为a=b=1.1843(3)nm,c=1.0304(4)nm,V=1.25165(87)nm~3,D_c=1.49g·cm~(-3),最后一致性因子R=0.049;(2)的晶体学参数a=b=1.1805(2)nm,c=1.0236(2)nm,V=1.23536(56)nm~3,D_c=1.54 g·cm~(-3),R=0.023。平均Nd-C=0.2812nm,Gd-C=0.2795nm;Nd-O=0.2557(21)nm,Gd—O=0.2459(13)nm。配合物中四氢呋喃的四个碳原子处于完全无序状态。
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The complexes named in the title (eta-5-C9H7)3Ln.OC4H8 (Ln = Nd, Gd, Er) were synthesized by the reaction of anhydrous lanthanide trichlorides with indenyl potassium and cyclooctadienyl potassium (1:2:1 molar ratio) in THF. The complexes were characterized by elemental analysis, infrared and H-1-NMR spectroscopy, and mass spectrometry. In addition, the crystal structures of (eta-5-C9H7)3Nd.OC4H8 (1) and (eta-5-C9H7)3Gd.OC4H8 (2) were determined by an X-ray diffraction study. Complexes 1 and 2 belong to hexagonal space group P6(3) with unit cell parameters a = b = 11.843(3), c = 10.304(4) angstrom, V = 1251.7(9) angstrom-3, D(c) = 1.49 g.cm-3, Z = 2 for 1, and a = b = 11.805(2), c = 10.236(2) angstrom, V = 1235.4(6) angstrom-3 D(c) = 1.54 g.cm-3, Z = 2 for 2. The structures were solved by Patterson and Fourier techniques and refined by least-squares to final discrepancy indices of R = 0.049, R(w) = 0.053 using 925 independent reflections with I greater-than-or-equal-to 3-sigma(I) for 1, and R = 0.023, R(w) = 0.025 using 1327 independent reflections with I greater-than-or-equal-to 3-sigma(I) for 2. Coordination numbers for Nd3+ and Gd3+ are 10; the average bond lengths Nd-O and Gd-O are 2.557(21) and 2.459(13) angstrom, respectively. The structural studies showed the complexes to have 3-fold symmetry, but the THF molecule has no such symmetry; consequently the arrangement of carbon atoms in the THF molecule are disordered.
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本文以人类活动影响下的典型海湾-胶州湾为研究对象,在对典型柱状沉积物精确定年的基础上,剖析了胶州湾百年来沉积环境演变的过程,通过对沉积物中氮、磷、重金属以及生态环境的综合分析,提取了其受人类活动影响的信息指标,获得了一系列新的结果和认识。主要结论如下: 1. 研究揭示了近百年来胶州湾沉积速率具有区域与年际变化明显这一显著特点。通常,湾内的沉积速率较高,而湾口沉积速率变化很大,湾外沉积速率明显低于湾内和湾口;且随着年代的增加,胶州湾的沉积速率呈上升趋势,如1984年左右,B3站位的沉积速率高达1.17 cm/a,而之前仅为0.30 cm/a左右,主要是由于这一时期环胶州湾工农业迅速发展导致人为排入的物质的量增加的结果,但从2000年以来由于沿岸环境治理和污控措施的加强,这种境况已经有所改善,沉积速率有减小趋势。 2. 阐明了胶州湾沉积物氮、磷的生物地球化学特征及生态环境意义,沉积物中可交换态磷、铝磷、铁磷与有机磷在一定程度上表征了磷的生物可利用性部分,而铝磷、铁磷与闭蓄态磷可用于反映沉积物受污染的程度,沉积物中的有机氮(强氧化剂浸取态氮)作为其优势存在形态,可潜在参与水体氮的循环,参与的量与沉积物粒度密切相关,沉积物中的氮可粗略反映水体的生物量。研究显示,无机磷是胶州湾沉积物中磷的主要赋存形态,在湾内、湾口和湾外,分别占到沉积物总磷的44.57% ~ 94.41%(B3)、44.83 % ~ 95.54 % (D4)和55.09% ~ 95.20 % (D7),铝磷、铁磷与闭蓄态磷与污染程度关系密切,可以作为沉积环境污染程度的指示因子。可交换态磷、铝磷、铁磷与有机磷等四种形态磷与浮游植物的数量和水体中磷酸盐的含量呈正相关,是胶州湾潜在的生物可利用磷。强氧化剂浸取态(SOEF-N,主要为有机氮)是沉积物可转化氮的优势形态,其含量分别为0.070 mg/g(B3)、0.069 mg/g(D4)和0.049 mg/g(D7),且随沉积物的粒度变细,其含量越高。沉积物中不同形态氮与水体中的硝酸盐、浮游植物数量和叶绿素a呈正相关,可粗略反映水体的生物量。 3. 通过系统研究胶州湾沉积物中重金属的地球化学特征,阐明了人为活动对其沉积环境的影响,提出了胶州湾沉积环境演变的“三段论”论点。胶州湾沉积物重金属的富集因子和地质累积指数的研究显示胶州湾沉积物的Cd、Pb和Cu是受人类活动影响较为严重的三种元素,并且重金属在沉积层序的分布特征说明重金属的污染在20世纪70、80年代开始加重,但在本世纪初,这种状况已经得到较大改善。胶州湾的环境演变过程可分为三个阶段,即1980年以前,1980年至2000年左右和2000年后。第一个阶段可以看作是胶州湾环境演变的一个背景值,该段时期内明显的特征是相对较低的沉积速率,较轻的重金属污染和富营养化状况;第二阶段是青岛地区工农业迅猛发展的阶段,加上治污措施和环境保护措施较少,这段时期胶州湾的环境一度恶化,是人类活动影响最为明显的一个阶段;第三个阶段是胶州湾环境质量不断改善的一个阶段,由于各项治污措施的实施,到本世纪初,胶州湾的环境质量较20世纪的最后20年里有了较大的改善。
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Temporal and spatial variability in the kinetic parameters of uptake of nitrate (NO3-), ammonium (NH4+), urea, and glycine was measured during dinoflagellate blooms in Changjiang River estuary and East China Sea coast, 2005. Karenia mikimotoi was the dominant species in the early stage of the blooms and was succeeded by Prorocentrum donghaiense. The uptake of nitrogen (N) was determined using N-15 tracer techniques. The results of comparison kinetic parameters with ambient nutrients confirmed that different N forms were preferentially taken up during different stages of the bloom. NO3- (V-max 0.044 h(-1); K-s 60.8 mu M-N) was an important N source before it was depleted. NH4+ (V-max 0.049 h(-1); K-s 2.15 mu M-N) was generally the preferred N. Between the 2 organic N sources, urea was more preferred when K. mikimotoi dominated the bloom (V-max 0.020 h(-1); K-s 1.35 mu M-N) and glycine, considered as a dominant amino acid, was more preferred when P. donghaiense dominated the bloom (V-max 0.025 h(-1); K-s 1.76 mu M-N). The change of N uptake preference by the bloom-forming algae was also related to the variation in ambient N concentrations. Published by Elsevier B.V.