964 resultados para 12-P-0708-1
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以香溪河附石藻类密度、藻类叶绿素a浓度、Shannon Wiener多样性指数及生态系统初级生产力随河流级别的变化为例探索该河流的连续统特征 .结果表明 ,附石藻类密度、藻类叶绿素a浓度和Shan non Wiener多样性指数总体上都有随着河流级别增加而增加的趋势 ,但在 1~ 3级河段之间这种趋势并不明显 ,甚至出现了逆转 .河流初级生产力也有随河流级别增加而增加的趋势 ,并在第 4级河流达到最大 ,随后有所下降 .在全水系范围内河流初级生产力 (P)与群落呼吸 (R)比值P/R均大于 1,说明香溪河
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The present study aimed to evaluate the effect of dietary linolenic acid (LNA)linoleic acid (LA) ratio on growth performance, hepatic fatty acid profile and intermediary metabolism of juvenile yellow catfish Pelteobagrus fulvidraco. Six isonitrogenous and isolipidic diets were formulated to contain incremental levels of LNA from 0 to 5% at the expense of corn oil (rich in LA), resulting in six dietary treatments with LNA to LA ratios ranging from 0.35 to 14.64. The experiment continued for 7 weeks. Best growth and feed intake were obtained in the fish fed the diets containing the LNA/LA ratios of 1.17 and 2.12 (P<0.05). In contrast, feed conversion ratio was the lowest for fish fed the diets containing the LNA/LA ratios of 1.17 and 2.12 (P<0.05). Dietary LNA to LA ratios significantly influenced viscerosomatic index and hepatosomatic index (P<0.05), but not condition factor (P>0.05). Body composition was also significantly influenced by dietary LNA to LA ratios (P<0.05). Generally, liver FA compositions reflected dietary FA profiles. Declining LA and increasing LNA contents in liver were observed with the increasing dietary LNA/LA ratios (P<0.05). Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) increased with the increasing LNA to LA ratios, suggesting that yellow catfish could elongate and desaturate C18 polyunsaturated fatty acids into highly unsaturated fatty acids. As a consequence, the n-6 fatty acids (FA) declined, and total n-3 FA and n-3/n-6 ratios increased with the dietary ratios of LNA/LA (P<0.05). Dietary LNA to LA ratios significantly influenced several enzymatic activities involved in liver intermediary metabolism (P<0.05), such as lipoprotein lipase, hepatic lipase, pyruvate kinase, succinate dehydrogenase, malic dehydrogenase and lactate dehydrogenase, suggesting that dietary LNA/LA ratios had significant effects on nutrient metabolism in the liver. To our knowledge this is the first demonstration of the effects of dietary LNA to LA ratios on the enzymatic activities of liver in fish, which provides information on diet quality and utilization, and can also be used as an indicator of the nutritional status of this fish. (C) 2009 Elsevier B.V. All rights reserved.
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A fluorescence immunoassay for human IgG (Ag) was developed using a pH-sensitive polymer prepared by thermal initiation or redox initiation polymerization as a carrier. In the competitive immunoassay, appropriate quantity of Ag was immobilized on the polymer and the standard Ag (or sample) solution, and a constant amount of fluorescein isothiocyanate labeled goat anti-human IgG antibody (Ab-FITC) was added. Immobilized Ag and the standard (or sample) Ag competed for binding to the Ab-FITC in 37 C in homogeneous format. After changing the pH to separate the polymer-immune complex precipitate, it was re-dissolved and determined by fluorescence method. The results showed that the immobilization efficiency, immunological reaction activities of immobilized Au and phase transition pH range were improved as Ag was immobilized by thermal initiation instead of redox initiation polymerization. Under optimum conditions, the calibration graphs for the Ag in both methods, thermal initiation and redox initiation, were linear over the concentration range of 0.0-1000 ng mL(-1), with detection limits 8 (thermal initiation) and 12 ng mL(1) (redox initiation), respectively. Moreover, some pH-sensitive polymer prepared only in organic solvent or under high temperature could also be used as an immunoreaction carrier by thermal initiation polymerization. Thermal initiation polymerization was a better immobilization mode. (C) 2004 Elsevier B.V. All rights reserved.
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本发明是一种双面键合长波长垂直腔面发射激光器(VCSEL)及其制作方法。所述激光器包括N电极(1),N型GaAs衬底(2),N型GaAs/AlGaAs材料系的下分布布拉格反射镜(DBR)(3),InP基应变量子阱有源区(4),GaAs/AlGaAs材料系的上DBR(5),其中上DBR(5),由P型DBR(6)和本征DBR(7)组成,SiO2掩膜(8),P电极(9),出光窗口(10)。所述结构和所述方法改进了传统长波长VCSEL的DBR材料折射率差较小,热导、电导差的缺点,不仅可实现很好的电流限制,而且降低材料的吸收损耗、生长的难度和免去二次外延工艺步骤。
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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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High-dose ion implantation of phosphorus into 4H-SiC (0001) has been investigated with three different ion fluxes ranging from 1.0 to 4.0 x 10(12) P(+)cm(-2.)s(-1) and keeping the implantation dose constant at 2.0 x 10(15) P(+)cm(-2). The implantations are performed at room temperature and subsequently annealed at 1500 degrees C. Photoluminescence and Raman scattering are employed to investigate the implantation-induced damages and the residual defects after annealing. The electrical properties of the implanted layer are evaluated by Hall effect measurements on the sample with a van der Pauw configuration. Based on these results, it is revealed that the damages and defects in implanted layers can be greatly reduced by decreasing the ion flux. Considering room temperature implantation and a relatively low annealing temperature of 1500 degrees C, a reasonably low sheet resistance of 106 Omega/square is obtained at ion flux of 1.0 x 10(12) P(+)cm(-2.)s(-1) with a donor concentration of 4.4 x 10(19)cm(-3).
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试验研究了不同施肥处理对小麦产量及肥料、水分利用率的影响。结果表明:氮磷配施对产量的贡献率最高,产量达5 099.8 kg/hm2,增产率达21.5%,较氮、磷肥单施产量分别增产14.0%和18.4%,具有正交互效应;单施有机肥较NM、PM、NPM增产率分别达到6.63%、4.12%、11.3%。化肥配施可显著提高旱地小麦的肥料利用率和水分利用效率,氮磷有机肥配施肥料氮、磷肥的利用率分别较氮、磷肥单施提高1.71和12.55个百分点;氮磷配施可同时提高氮肥、磷肥肥效,此时氮贡献率为15.53%,磷贡献率达12.26%,且水分利用率提高了24.1%,耗水系数降低了17.57%。
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微全分析系统(μ-TAS),即芯片实验室,在过去的十几年中发展迅速,通过微加工技术将芯片片基蚀刻成各种微米结构的微通道网络或点阵结构,再将其表面进行化学改性,使其表面生成羟基、氨基或醛基等生化活性的官能团,用于固定化酶,蛋白质,抗原抗体或无机催化剂,也可以修饰电极或色谱等,还是构建自组装的基础,其片基表面的氨基是重要的反应基团,能使成千上万个与生命相关的信息集成在一块厘米见方的芯片上,进行生命科学和医学中的各种生物化学反应,为此本论文主要就以下方面开展研究工作: 1 研究了用灵敏度较高9-蒽醛检测不同氨基硅氧烷在玻璃或石英片基表面的组装过程,氨丙基三乙氧基硅烷和氨丙基二乙氧基甲基硅烷随时间增长生成多层网状结构,而氨丙基二甲基乙氧基硅烷和氨丙基二甲基甲氧基硅烷则生成饱和单层膜。 2 研究了溶液中的可控自组装方法,通过在片基表面交替进行二醛和二胺的缩聚反应,生成共轭芳香亚胺聚合物;或交替进行二酐和二胺的交替组装,制备应用于各种电子器件的p-堆积、有序和取向多层膜,利用紫外可见光谱监测单体的组装过程,谱线形状随着单体的交替变化而变化,所得组装膜热稳定性很好。 3 提供了利用组装双官能团化合物或甲基丙烯酸缩水甘油酯的ATRP反应在300 ℃键合玻璃或石英片基的方法,剪切强度在15 kg/cm2以上,键合层清晰透明,厚度在30-60 nm,不会阻塞微流体的内部管道。 4 在氨基化片基表面组装2-甲酰吡啶、6-甲酰基-2,2’-联吡啶和6-甲酰基-2,2’: 6’,2”-三联吡啶及相应的钌络合物。
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制备了具有keggin结构及其过渡金属离子取代的杂多化合物PW_11, PW_(11)Mn, PW_(11)Co和具有Dawson结构及其过渡金属取代的杂多化合物P_2W_(18), P_2W_(17), P_2W_(17)M_n, P_2W_(17)Co,并表征了它们的热差热重、红外、X射线衍射等性质。热分析结果表明,杂多酸和杂多酸盐的脱水行为不同,杂多酸的脱水分三个阶段,依次脱出结晶水,结合水和结构水。杂多酸盐保有结晶水和少量的结构水,结构水的脱除在热差曲线上产生一个放热峰。这个峰也是热差曲线上的第一个放热峰。它可作为杂多化合物热稳定性的一个判据。据此,Dawson结构的杂多化合物的热稳定性比kggin结构的好。P_2W_(18)、PW_(12)比相应的缺位的P_2W_(17), PW_(11)的热稳定性好。过渡金属取代不能改善热稳定性。杂多化合物的红外光谱表明,keggin结构区别于Dawson结构的是Dawson结构的杂多化合物要多一个P-P振动吸收峰(约1010cm~(-1))缺位杂多化合物的P=0键会产生劈裂,这是它区别于非缺位杂多化合的一个明显特征。根据这些特征,可以初步鉴定杂多化合物对以上杂多化合物及PW_(12)共八种催化剂催化的H_2O_2分解行为进行了考察,keggin结构杂多化合物的催化活性比Dawson结构的好,缺位杂化合物比不缺位杂多化合物的催化活性要好得多,催化活性是由整个杂多阴离子决定的。以上八种杂多化合物催化的苯乙烯H_2O_2氧化反应实验结果表明,其催化活性基本上与H_2O_2分解反应中表现出的催化活性一致,易氧化的Mn~(2+)取代的杂多化合物PW_(11)Mn,P_2W_(17)Mn的催化活性很差。Na_2HPW_(12)O_(40)催化的H_2O_2分解反应动力学结果表明,反应开始有一个反期、催化剂、H_2O_2反应级数均为零。之后,反应线性加速,反应速度与催化剂浓度成线性关系,其表现活化能求得的为E_=161KJ/mol。Na_2HPW_(12)O_(40)催化的苯乙烯氧化反应动力学结果表明,反应明显地分为两个阶段。前阶段为诱导期,反应速度较慢,苯乙烯转化率不高。反阶段为反应加速,催化剂的反应级数是1,与苯乙烯的浓度无关。E_=15.9KJ/mol。合成并分离得到了PW_(12), H_2O和相转移剂作用生成的过氧化物,碘量法滴定结果知每分子过氧化合物含三个活性氧。在红外区域的951cm~(-1)处有一特征振动吸收峰,在紫外范围350mm处有一特征电子吸收峰。这种过氧化合物中的活性氧具有很高的活性,常温下就能与苯乙烯迅速反应。根据两者反应的特点,设计了反应过程,结合实际现象和结果提出了反应机理,反应前期的速度控制步骤反应在水相中进行。反阶段的速度控制步骤反应在有机相中进行。推导了反应动力学方程。验证了动力学推导结果与实验结果的一致性。得到了令人满意的结果。
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近年来,高功率1319 nm波长全固态激光器成为激光领域的研究热点之一,它可以广泛应用于光纤通信、激光医疗、频率转换、激光武器等领域.本实验室采用独特的双棒串接热补偿技术,通过对Nd:YAG激光晶体主振荡波长1064 nm及次振荡波长的抑制,实现了最高输出功率为1261 W的1319 nm波长激光输出,光光转换效率为21.7%.
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采用直接键合的方法成功实现了n-GaAs和p-GaN晶片的高质量键合.扫描电子显微镜观测结果表明,键合界面没有空洞.键合前后光致发光谱测试表明,键合工艺对材料质量影响不大.室温下界面的电流-电压特性表明,键合得到的n-GaAs/p-GaN异质结为肖特基二极管并且理想因子为1.08.n-GaAs和p-GaN材料直接键合的成功对于集成GaAs和GaN材料制备光电集成器件有重要意义.
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研究了Al0.1-Ga0.9N/GaN异质结p-i-n结构可见盲紫外探测器的制备与性能,P区采用Al组分含量为0.1的AlGaN外延材料形成窗口层,使340-365nm波段的紫外光可以直接透过P区到达i区并被吸收,有效提高了这个波段的响应率与量子效率,并且研究了不同P区AlGaN外延层厚度对探测器性能的影响,制备了两种不同P区厚度(0.1μm和0.15μm)的器件,测试结果表明,P区的厚度对200-340nm波段光吸收的量子效率影响较大,而i区的晶体质量的提高可以有效提高340-365nm波段光吸收的量子效率,并且当P区AlGaN厚度为0.15μm时,器件的峰值响应率达到0.214A/W,在考虑表面反射时外量子效率高达85.6%,接近理论极限,并且在零偏压时暗电流密度为3.16nA/cm^2,表明器件具有非常高的信噪比。
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制作了一种低成本硅基1.55μm可调谐共振腔增强型探测器.首次获得硅基长波长可调谐共振腔探测器的窄带响应,共振峰量子效率达44%,峰值半高宽为12.5nm,调谐范围14.5nm,并且获得1.8GHz的高频响应.本制作工艺不复杂,成本低,有望用于工业生产.
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用金属有机化学气相淀积技术在蓝宝石衬底上成功外延了高P组分的GaN_(1-x)P_x 三元合金。俄歇电子能谱深度剖面结果表明在GaN_(1-x)P_x 中P的掺入量最高达到20%且分布均匀;X射线光电子能谱价态分析证实了外延层中Ga-P键的存在。对不同P组分的GaN_(1-x)P_x 样品进行了低温光致发光(PL)测试,与来自GaN衬底的带边发射相比,随三元合金中P组分的变化,GaN_(1-x)P_x 的PL峰呈现出了不同程度的红移。在GaN_(1-x)P_x 的PL谱中没有观测到有关GaP的发射峰,表明该合金材料没有发生相分离。
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于2010-11-23批量导入