953 resultados para S. X. y P.
Resumo:
The morphological defects and uniformity of 4H-SiC epilayers grown by hot wall CVD at 1500 degrees C on off-oriented (0001) Si faces are characterized by atomic force microscope, Nomarski optical microscopy, and Micro-Raman spectroscopy. Typical morphological defects including triangular defects, wavy steps, round pits, and groove defects are observed in mirror-like SiC epilayers. The preparation of the substrate surface is necessary for the growth of high-quality 4H-SiC epitaxial layers with low-surface defect density under optimized growth conditions. (c) 2006 Elsevier Ltd. All rights reserved.
Resumo:
We have investigated the hydride vapor-phase epitaxy growth of (10 (1) over bar(3) over bar)-oriented GaN thick films on patterned sapphire substrates (PSSs) (10 (1) over bar0). From characterization by atomic force microscopy, scanning electron microscopy, double-crystal X-ray diffraction, and photoluminescence (PL), it is determined that the crystalline and optical qualities of (10 (1) over bar(3) over bar) GaN epilayers grown on the cylindrical PSS are better than those on the flat sapphire. However, two main crystalline orientations (10 (1) over bar(3) over bar) and (11 (2) over bar2) dominate the GaN epilayers grown on the pyramidal PSS, demonstrating poor quality. After etching in the mixed acids, these (10 (1) over bar(3) over bar) GaN films are dotted with oblique pyramids, concurrently lining along the < 30 (3) over bar2 > direction, indicative of a typical N-polarity characteristic. Defect-related optical transitions of the (10 (1) over bar(3) over bar) GaN epilayers are identified and detailedly discussed in virtue of the temperature-dependent PL. In particular, an anomalous blueshift-redshift transition appears with an increase in temperature for the broad blue luminescence due to the thermal activation of the shallow level.
Resumo:
利用中国科学院长武农田生态试验站的长期田间试验(1984年2~007年),研究了小麦产量,耕层有机碳变化,评价了土壤管理和气候因素对土壤有机碳(Soil organic C,SOC)变化的影响。研究涉及6个处理:休闲地(F);不施肥(CK);有机肥(M);氮肥(N);氮、磷肥(NP)和氮、磷、有机肥(NPM)处理。结果表明,施肥可以显著提高作物产量和SOC积累,CK、M、N、NPNPM处理平均产量依次为1.5、2.6、2.0、3.3、4.0 t/hm2,2007年F、CK、M、N、NPNPM处理0—20 cm土层SOC积累量依次为-1.09、0.76、8.59、1.02、3.42和9.5 t/hm2。作物产量与SOC含量呈显著的正相关关系(r=0.80),有机碳输入量与SOC含量相关性更好(r=0.97),外源有机碳的输入也是提高SOC的重要措施。施肥措施对作物固碳和SOC影响存在显著(P<0.05)差异。土壤固碳速率(Y)与SOC输入量(X)符合线性方程Y=0.231X-0.0813(r=0.98)。施肥可以提高黄土高原半干旱地区土壤生产力和SOC的积累,且无机肥和有机肥配施效果最佳。
Resumo:
目前,国内外对于铕和铽等稀土配合物的可见区发光和应用都有大量研究,但对具有近红外发光(800-1700 nm)性能的稀土配合物的研究还处于起步阶段。由于稀土的近红外发光在光纤通讯、激光系统及诊断学等方面应用具有特殊的优点,越来越引起人们的兴趣和重视。 稀土近红外发光配合物的致命弱点是其光、热和化学稳定性较差,从而限制了其在很多领域的实际应用。而溶胶-凝胶材料和介孔材料具有良好的光、热和化学稳定性,能改善客体分子的结构环境和化学微环境,从而能有效提高客体分子的发光性能。因此,本论文将具有优良近红外发光性能的稀土配合物分别与上述两种基质复合,从实验和理论研究稀土近红外发光杂化材料的性能和应用价值,制备出具有良好稳定性的高效稀土近红外发光杂化材料,以期为光纤通讯、激光等领域提供潜在的候选材料。围绕这一宗旨,开展了如下工作: 通过原位技术分别得到了掺杂和嫁接[Ln(dbm)3phen]化合物(Ln = Er, Nd, Yb)的杂化凝胶材料,Ln-D-P gel和Xerogel-Ln。通过对其近红外发光性能的研究,表明材料中配体能很好的保护稀土离子,并将能量有效的传递给稀土离子。采用Judd-Ofelt理论对所得部分材料进行了光谱分析,基于实验数据和理论分析表明其具有潜在的光放大和激光应用价值。 选择了两种含全氟化烷基链的β-二酮配体Hhfth和Htfnb,通过功能化的phen-Si配体,将三元配合物[Ln(hfth)3phen] (Ln = Er, Nd, Yb, Sm)和[Pr(tfnb)3phen]成功共价嫁接到介孔MCM-41和SBA-15杂化材料中,得到的衍生材料Ln(hfth)3phen–MCM-41、Pr(tfnb)3phen–MCM-41和Ln(hfth)3phen–SBA-15、Pr(tfnb)3phen–SBA-15都保持了高度有序的介孔p6mm结构,并展现出稀土离子特征的近红外发射。所得稀土配合物功能化的材料的发射光谱能完全覆盖对光通讯极具应用价值的1300-1600nm区域。 通过对Er(dbm)3phen–M41(X, Y) (X = 1~14, Y = 3, 6, 12, 18, 24 h)材料系统的比较研究,选择了X = 12, Y = 6作为合成目标材料的优化参数,通过功能化的phen-Si配体将[Ln(dbm)3phen]配合物共价嫁接于有序介孔MCM-41和SBA-15中(Ln = Er, Nd, Yb),所得两类材料Ln(dbm)3phenM41和Ln(dbm)3phenS15都保持了很好的介孔有序性,并具有良好的近红外发光性能。通过对Ln(dbm)3phenM41和Ln(dbm)3phenS15两类材料发光行为的比较,以及两类材料中稀土离子的含量及孔结构的分析,推出以SBA-15为载体得到的材料在相对发光强度和荧光寿命上,均比以MCM-41为载体的材料有所提高。 通过对8-羟基喹啉配体进行改性,合成了具有双功能的配体Q-Si,继而合成了共价嫁接8-羟基喹啉衍生物的介孔杂化材料Q–SBA-15,其形貌均一,并具有高度有序的介孔p6mm结构。通过配体交换反应,得到了嫁接稀土喹啉配合物的具有近红外发光性能的介孔杂化材料LnQ3–SBA-15 (Ln = Er, Nd, Yb),其仍然保持高度有序的介孔结构,且外形呈现与母体材料Q–SBA-15相似的弯曲圆柱状。激发配体的吸收,LnQ3–SBA-15材料都分别展现出相应稀土离子特征的近红外发射,并详细分析和讨论了所得介孔杂化材料的近红外发光性能。
Resumo:
贮氢合金是镍一金属氢化物电池的核心材料,其综合性能的改善是提高镍一金属氢化物电池性能的关键。本研究以探索镍一金属氢化物电池新型负极材料为目的,以非ABS贮氢合金为研究对象,采用X线衍射、Rietveld分析、恒电流充/放电、P-C-T曲线及线性微极化等方法,从基础和潜在应用等方面详细研究了非ABS合金的结构与电化学性能。对La-Ni体系中非ABS二元合金的结构和电化学性能的研究表明,LaNi_(228)具有最优异的高倍率充电性能;La_2Ni_7合金电极的高倍率放电性能最佳;La_7Ni_3在低温条件下表现出较好的放电性能。然而,所有得到的La-Ni合金电极容量远低于其理论容量。因此,必须通过进一步研究,如元素取代、热处理、表面处理等来提高其电化学容量。对RENi_3(RE=La,Ce,Pr,Nd,Sm,Gd,Th,Dy,Ho,Er,Y)研究表明:YNi_3合金因其具有最大的晶胞体积,最小的密度,而表现出最好的高倍率充/放电性能及低温放电性能,但其高温放电性能需要进一步提高,以满足实际应用的要求。用Al、Mn、Ti、Fe、Sn、Si、Cr、M。、Cu和Co十种元素取代Ni进行了大量的配方筛选工作。得到了大量的实验数据,并发现LaNi_(3.7)Al_(0.3)合金电极电化学放电容量最高,达290.8mAh/g;LaNi_(3.7)Mo_(0.3)合金电极的高倍率放电性能最好,在以4200mA/g的电流密度下进行放电时,其放电容量仍达到145.8mA/g;而I镍一金属氢化物电池新型负极材料研究镍一金属氢化物电池新型负极材料的研究Al的取代会使合金电极性能对温度不敏感。以我们的实验为基础,进一步进行合金配方的微调,具有可能开发出具有实用价值的贮氢合金的潜力。在Ar保护下用真空电弧炉熔炼合成了四种Lal一xMg:(NICoAI)3.6体系贮氢合金,制成姐卜Ni电池负极,通过恒电流充/放电方法研究了其电化学性能。结果表明:Lal一xMg:(NiCoAI)3.6体系金属氢化物电极较容易活化,室温下具有优异的高倍率放电性能,在以4200mA/g电流放电时,La卜汉gxNICoAI)36合金电极的放电容量是ABS合金电极的3倍,达152hah/g,显示出良好的动力学特性。R,入1兮Ni(R:raree田劝,Ca,Y)型合金因能吸引/释放1.8一1.87%质量的HZ而被认为是种很有希望的贮氢合金。但其吸/放氢平台过高,循环寿命短。如何提高Rh厦g剑19循环稳定性是这类合金能否成功商业化的关键。研究发现,Co能够显著提高ABS合金电极的循环寿命,但其价格太贵。人们发现Al在提高电极寿命方面与C。有类似的作用,但Al元素的添加因其在碱性电解质的作用下在电极表面易生成致密的氧化膜而不利于氢的扩散,进而对高倍率放电性能不利。入物在提高电极表面活性,改善其高倍率放电性方面作用明显。本工作在前面的基础上用Al和MO联合取代Ni,以期待同时改善La一Mg一Ni一Co合金的循环稳定性和高倍率放电性能。详细研究了La07Mg03Ni切一(A105Mo05)xxo,0.2,0.4,0.6,0.8)系列贮氢合金的晶体结构和电化学性能。X线衍射及Rietveld分析发现:所有La07Mg03Ni4D一xA105Mo05)x金均为包含PuNi3结构的六方LaZMgNig相、CaCus构的LaNis相及L匆Ni7,LaN儿和LaNi杂相的多相结构。合金中La(La,Mg)剑19相及LaNis的晶格参数及晶胞体积均随合金中Al和Mo含量的增加而增大。用电化学方法测得的RC一T曲线显示:Al和'fo部分取代Ni降低了氢的平台压力。随合金中Al和Mo含量的增加,电极的电化学容量从329.7(x0)、徽橇毓孺鑫盆一11瀚加至365.物A吨(=0.6)后又降低到351.3毗吨(x0.8)。当以1200m刀g的电流密度进行放电时,其I{RD从62.0%沁0)增加到82.1%沁0.8)。线性微极化结果显示:Al和Mo的添加增大了合金表面的交换电流密度,因而也改善了合金电极的高倍率放电性能。另外,Al和M。取代合金中的Ni增大了氢在电极合金中的扩散系数(D),改善了La07Mgo3Ni4。一xAlo5M。。5)xXo,0.2,0.4,0.6,0.8)合金电极的低温放电性能(LTD)。
Resumo:
由于科学的发展和社会的需要、探索新的半导体材料、开辟稀土化合物的新用途成了重大的研究课题。众所周知,Ⅲ_a-Ⅴ_a族化合物是已被广泛应用的重要半导体材料。而对于Ⅲ_b-Ⅴ_a族化合物是否是半导体还在探索中。人们对Ⅲ_b-Ⅴ_a族化合物的磁学光学、电学性质及热电性质做了大量的研究。但是,对其是否是半导体未能得出一致的结论。Sclar等人总结了求Ⅲ-Ⅴ族化合物带宽度的公式,预言稀土单氮族化合物是半导体;Yim等人测量了稀土磷化物的吸收光谱,由此证实了其半导体性;Hasegawa用Apw法计算了GdX (x = N、PAsSb)的能带,计算得出GdP能带重迭,故他认为LnP金属性材料;(Ln=稀土元素)。Guntherodt测量了GdP体介电常数与波长关系,由此得出GdP高载流了浓度材料,他由此解释了GdP阻率低的现象,但对其是否是半导体未做结论。大量的研究已证实了LnN是半导体,而对LnP未能得出一致结论。本文以La、Nd、Sm、Y为代表研究了稀土磷化物的光学性质、电学性质和热电性质。由实验结果证实了稀土磷化物是N型半导体。稀土磷化物多晶粉末是用元素合成法制备的。合成LnP最佳条件为:温度:950 ℃-1000 ℃;时间:10 ~ 36小时;真空度:3 * 10~(-5)笔。对制备后的LnP了X-ray衍射分析,确定了LnP氯化钠结构。其中,YP有ASTM卡,我们参照其衍射图计算了它的晶面间距值,得出其晶格常数为a = 5.652A,计算的d_(nkL)值与实验值符合很好。通过实验证实了合成的LnP单一化合物。在实验中测量了LnP膜的吸收光谱并将其与GaAs吸收光谱做了比较,证实了稀土磷化物是直接跃迁型材料。同时也求出了LnP禁带宽度值。其中,NdPLaPYP禁带宽度值是首次得到,文献中未见有报导。从La到Y随着晶格常数变小,禁带宽度值亦减小,该实验结果与Sclar用经验式计算的结果是一致的。在实验中还利用热探针、霍尔系数和热电菌率系数测量了LnP导电类型,结果表明它们是N型半导体。用四探针测量了它们的电阻率为~10~(-3)ncm。并研究了它们的电阻与温度关系,发现LnP有半导体的重要特征-电阻的负湿度系数。同时,从电阻与温度关系求出了LnP激活能、该值较小,说明LnP存在浅施主能级,我们分析是由于磷缺位在LnP成正电中心而引入的。所测量的LnP热电功率系数为近百μv/℃。也以热电功率系数与温度的关系求得了LnP激活能,这与从电阻与湿度关系所得的激活能值是相符的。这证实了我们对LnP在浅施主能级所做的判断。本文还对上述试验结果做了简要分析讨论。提出了LnP能带图。我们认为:稀土磷化物是直接跃迁型的N型半导体。
Resumo:
The objectives were to investigate the effect of cryoprotectants on the hatching rate of red seabream embryos. Heart-beat embryos were immersed in: five permeable cryoprotectants, dimethyl sulfoxide (DMSO), glycerol (Gly), methanol (MeOH), 1,2-propylene glycol (PG), and ethylene glycol (EG). in concentrations of 5-30% for 10, 30, or 60 min; and two non-permeable cryoprotectants: polyvinylpyrrolidone (PVP), and sucrose (in concentrations of 5-20% for 10 or 30 min). The embryos were then washed and incubated in filtered seawater until hatching occurred. The hatching rate of the embryos treated with permeable cryoprotectants decreased (P < 0.05) with increased concentration and duration of exposure. In addition, PG was the least toxic permeable cryoprotectant, followed by DMSO and EG, whereas Gly and MeOH were the most toxic. At a concentration of 15% and 30 min exposure, the hatching rate of the embryos immersed in PG was 93.3 +/- 7.0% (mean +/- S.D.), however. in DMSO. EG, Gly. and MeOH, it was 82.7 +/- 10.4, 22.0 +/- 5.7, 0.0 +/- 0.0, and 0.0 +/- 0.0%, respectively. Hatching rate of embryos treated with PVP decreased (P < 0.05) with the increase of concentration and exposure time, whereas for embryos treated with sucrose, there was no significant decrease in comparison with the control at the concentrations used. (C) 2008 Elsevier Inc. All rights reserved.
Resumo:
进化生物学得益于近代分子生物学和当代基因组学的发展,已经脱 离了自达尔文时代起博物学式的观察和思辨性的研究状态。很多古老而又 经典的问题,因为在一些年轻的进化系统中的研究,绽放出其背后深刻的 机制。在本工作中,我们通过在模式物种果蝇和珍稀动物黑麂中的研究, 揭示了有关遗传的基本单位-- 基因是如何起源和消亡的,以及这些重要过 程背后的规律。 决定人类雄性的Y 染色体起源于一亿六千万年前X 染色体的同源 染色体。但现今Y 染色体上的基因数目仅仅是X 染色体的百分之一左 右。如此巨大的数目差异,是由于Y 染色体和X 染色体之间重组抑制以 后,大量的Y 染色体基因发生退化消亡所致。 由于哺乳动物的Y 染色体 大都非常古老,Y 退化的过程和机制一直以来无法得以深入研究。 在本工 作的前半部分,我们首次在中国特有的珍稀鹿科动物黑麂中报道鉴定了一 对行为和模式类似人类性染色体的常染色体。这对“新性染色体”(neosex) 仅仅起源于50 万年以内,由于雄性特异的染色体倒位,致使数以千计 的基因像Y 染色体连锁的基因那样,无法与其等位基因重组。对23 个新 Y 染色(neo-Y)体连锁的基因25kb 的蛋白编码区和它们35kb 的非编码区的 序列分析发现,与其他可重组区域相比,这些基因的遗传多态性显著降 低,并积累了改变氨基酸的有害突变。我们还首次用体内表达试验证明Y 染色体的基因在其顺式调控区域也发生了退化。这些积累在启动子或者非 翻译区域(UTR)的有害突变,将扰乱Y 染色体上基因的正常表达,并进一 步促进退化过程和剂量补偿效应以单个基因(gene-by-gene)的模式进化。 本论文的另外一部分工作主要研究了果蝇中新基因起源的总体模式 问题。对遗传新元件如何起源的兴趣,最早可以追溯到达尔文。近年来通 过对“年轻基因”的案例研究,我们已经知道通过基因重复,逆转座,水 平迁移和从头起源等机制可以产生新基因。但这些机制在全基因组水平对 新基因起源的贡献各自如何,以及以非编码区从头起源合成一个新的基因 是否普遍等重要问题一直未得到解答。我们利用比较基因组的手段,在6个果蝇全基因组中,通过12017 个黑腹果蝇基因序列,鉴定刻画了超过 300 个起源于不同时间点的新基因。我们对这些新基因的序列,结构和表 达模式的分析发现,串联重复在产生年轻的新基因过程中占了主导地位 (超过80%)。但是最后固定在群体内,有功能的新基因主要(44.1%)是散在 重复的形式。我们惊奇地发现非编码区从头起源的基因在新基因的起源过 程中也扮演了重要角色,产生了超过10%的有功能的新基因,并且大部分 都进化出了睾丸特异的表达模式。有大约30%的新基因通过招募其他基因 的编码区或者重复元件,形成了新的嵌合结构,暗示它们可能获得了新的 功能。最后,我们估计在果蝇中,每百万年将产生5 至11 个有功能的新 基因。
Electronic structure and magnetic coupling properties of Gd-doped AlN: first-principles calculations
Resumo:
In this work, the electronic structure and magnetic coupling properties of Gd doped AlN have been investigated using first-principles method. We found that in the AlN:Gd system, due to the s-f coupling allowed by the symmetry, the exchange splitting of the conduction band is much larger than that of the valence band, which makes the electron-mediated ferromagnetism possible in this material. This property is also confirmed by the energy differences between anti-ferromagnetic and ferromagnetic phase for Al14Gd2N16 with different concentrations of electrons (holes), as well as by the calculated exchange constants. The result indicates that Gd-doped AlN is a promising candidate for the applications in future spintronic devices.
Resumo:
分别用稀盐酸、王水以及(NH_4)_2S液处理p-GaN表面,通过测试样品表面OlsX线光电子能谱(XPS),比较了这些溶液去除p-GaN表面氧化层的能力;在经不同溶液处理后的样品表面,以相同的条件制作Ni/Au电极,并测试其与p-GaN的比接触电阻,结果表明经稀盐酸处理后的样品表面,由于其氧含量较高,不能与Ni/Au形成良好的欧姆接触,而经王水和(NH_4)_2S液处理后的p-GaN表面,能与Ni/Au形成良好的欧姆接触;最后,通过比较样品表面的Ga/N原子浓度比,探讨了王水处理p-GaN表面能够形成良好欧姆接触的原因.
Resumo:
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掺入量最高达到20%且分布均匀;X线光电子能谱价态分析证实了外延层中Ga-P的存在。对不同P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发射峰,表明该合金材料没有发生相分离。
Resumo:
简要报告气态源分子束外延实验结果。材料是GaAs(100)衬底上外延的晶格匹配的In_y(Ga_(1-x)Al_x)_(1-y)P(x=0~1,y=0.5),InGaP/InAlP量子阱;在InP(100)衬底上外延的InP,晶格匹配的InGaAsInAlAs及InP/InGaAsInP/InAsP多量子阱,InGaAs/InAlAs HEMT等,外延实验是用国产第一台化学束外延(CBE)系统做的。
Resumo:
The Fermi-level pinning (FLP) at the metal/high-k interface and its dependence on the electron state density of the metal gate are investigated. It is found that the FLP is largely determined by the distortion of the vacuum level of the metal which is quantitatively ruled by the electron state density of the metal. The physical origin of the vacuum level distortion of the metal is attributed to an image charge of the interface charge in the metal. Such results indicate that the effective work function of the metal/high-k stack is also governed by the electron state density of the metal.
Resumo:
小麦加工品质改良已成为我国小麦育种的主要目标之一。特别是我国加入WTO以后,对小麦产品的质量提出了更高的要求,小麦品质改良的任务将更加艰巨和重要,小麦胚乳蛋白是影响小麦加工品质性状的重要因素。因此,深入了解小麦胚乳蛋白对加工品质性状的影响及其分子基础,为品质改良提供理论依据和科学指导,对加速我国小麦品质育种和优质小麦生产具有重要意义。本研究选用在麦谷蛋白5个基因位点(Glu-A1、Glu-B1、Glu-D1、Glu-B3和Glu-D3)上均含不同等位基因的小麦品种99G45和京771及Pm97034和京771杂交F9代共164个麦谷蛋白纯合系,及228个中国推广普通小麦品种和高代育成品系为试材,研究了麦谷蛋白Glu-1和Glu-3位点基因等位变异对籽粒蛋白、湿面筋含量、Zeleny沉降值和SDS降值间的关系;本研究还利用小麦A、B和D基因组中低分子量麦谷蛋白亚基(LMW-GS基因特异引物,通过PCR方法克隆了1个Glu-A3位点和3个Glu-B3位点LMW-GS因片段,在此基础上分析了不同等位基因对品质造成差异的分子基础;另外,本研究对中国近年推广的部分品种和育成的高代品系资源的多样性进行了分析。现将主要研究结果简述如下: 1. 对来自三个麦区的148份材料的醇溶蛋白组成进行了分析,结果表明,各麦区醇溶蛋白模式具有较大差异。在ω区,A7、B、E、F、G、J、PQ、SU仅存在于西南秋播麦区;A3、M、N、R、W和X存在于黄淮特种麦区;K仅存在于北方冬麦区;A6是北方冬麦区出现频率最高的带型模式,而西南秋播麦区中D出现的频率最高。ω-区的E、H和M几种模式是以前国内外未曾报道的。且初步确定,这些模式对品质性状具有正效应。至于γ区,A、B、D、E和F在各区均有出现,其中B和E在各区出现的频率都很高,在26.1-39.6%之间。相反,H 仅出现在黄淮特种麦区,J仅限于西南秋播麦区。对于β-区醇溶蛋白,B型模式在所有区中都相当高,而模式A仅存在于第三区.对于α-区,模式A在Ⅲ区而模式D在Ⅱ区出现的频率很高。1BL.1RS位系在中国小麦品种中出现频率高达41.2%,在I, II和Ⅲ麦区的出现频率分别为 45.5、43.5和35.2%。各生态区模式的差异可能是品种适应不同生态条件和人为选择的结果,但这有待进一步证明。由于醇溶蛋白位点(Gli-1)与LMW-GS点(Glu-3)紧密连锁,本结果可为下面确定普通小麦LMW-GS位基因变异所用。 2. 利用Gli-1与Glu-3的紧密连锁,以228个小麦品种/系为材料,首次对中国小麦品种麦谷蛋白亚基的6个位点进行综合分析,研究小麦籽粒蛋白与品质性状间的关系,结果表明6个高分子量(HMW)和低分子量(LMW)麦谷蛋白位点对蛋白质含量的效应大小为,Glu-D1>Glu-B3>Glu-A1=Glu-B1> Glu-A3=Glu-D3;对GMP量的效应大小为, Glu-A3>Glu-B3>Glu-D1> Glu-B1>Glu-A1>Glu-D3;对湿面筋含量的效应大小为, Glu-B1>Glu-B3= Glu-D3>Glu-A3>Glu-A1>Glu-D1;对Zeleny沉降值的效应大小为, Glu-A1> Glu-B3>Glu-D3>Glu-D1>Glu-B1>Glu-A3;对SDS降值的效应大小为, Glu-B3>Glu-A1=Glu-D1=Glu-A3>Glu-D3>Glu-B1。对蛋白含量而言,各位点的最佳组合方式为1、17+18、5+10、Glu-A3e、Glu-B3g、Glu-D3b;对湿面筋含量而言,各位点的最佳组合方式为1、6+8、5+10、Glu-A3d、Glu-B3c、Glu-D3b;对Zeleny沉降值而言,各位点的最佳组合方式为N、17+18、5+10、Glu-A3d、Glu-B3d、Glu-D3b;对SDS降值而言,各位点的最佳组合方式为1、7+8、2.2+12、Glu-A3b、Glu-B3g、Glu-D3b。另外,分析了稀有亚基对5+12与2.2+12与品质性状的关系,认为5+12对品质有负效应,2.2+12对品质有正效应。在品质育种时,应对优异组合或优异亚基加以利用。 3. 首次利用重组自交系(RILs为材料,研究麦谷蛋白亚基表达量与品质性状的关系,通过对重组自交系中各HMW-GS达量的分析,认为,就单个亚基的表达量而言,7亚基最高;其次为2亚基、5亚基、12亚基和10亚基;亚基9和1的表达量最小;N亚基不表达。对成对出现的亚基对而言,x和y型亚基的总表达量2+12>5+10>7+9>17+18。就单个亚基与品质性状的关系而言,仅有10亚基的表达量与蛋白含量的相关性达5%的显著水平,2亚基的表达量与湿面筋含量呈负相关,显著水平也达5%,其余单个亚基对品质性状均无显著影响;就x/y型亚基的比例来看,2/12和5/10对湿面筋含量都有显著的负效应;对某一位点等位基因控制的亚基表达总量来看,2+12对SDS降值有显著负效应。另外,本研究得出:2+12的亚基对的负效应主要体现在2亚基上,且在同一位点上,x亚基的表达量大于y型。所以推导稀有亚基组合2+10很可能也是劣质亚基。 4. 以 Glu-A1、Glu-B1、Glu-D1、Glu-B3和Glu-D3作为5个因素对99G45/京771和Pm97034/京771杂交后代的蛋白质含量和SDS降值进行多因素方差分析。结果表明,Glu-A1和Glu-D3对蛋白含量的加性效应达5%显著水平;Glu-D1 * Glu-D3对蛋白质含量的互作效应也达5%显著水平;其余位点的加性和互作效应对蛋白质含量的影响均不显著。对SDS 沉降值而言,Glu-D1的加性效应最大,贡献率为4.2 % ,达1 %显著水平,其次是Glu-B1位点,贡献率为3.3% ,达5%显著水平。其余位点对SDS 沉降值的加性和互作效应均未达5%显著水平。总体而言, 各位点对蛋白含量的效应大小为Glu-D3 > Glu-A1 > Glu-D1>Glu-B1>Glu-B3;对SDS降值的效应大小为Glu-D1>Glu-B1> Glu-D3>Glu-A1> Glu-B3。Glu-D1和Glu-D3位点上等位基因变异对蛋白含量有显著或极显著影响,含Glu-D1d和Glu-D3 GD、Glu-D3 JD基因的株系分别比含Glu-D1a和Glu-D3 PD基因的株系有较高的蛋白含量;在该遗传背景下,麦谷蛋白各基因位点对蛋白含量的效应大小依次排列为:Glu-A1位点1>N;Glu-B1位点7+9>17+18>14+15;Glu-D1位点5+10>2+12;Glu-B3位点GB>JB>PB;Glu-D3位点GB>JB>PB。对SDS降值的效应大小依次排列为:Glu-A1位点1>N;Glu-B1位点7+9=17+18>14+15;Glu-D1位点5+10>2+12;Glu-B3位点GB>JB>PB;Glu-D3位点GB>JB>PB。所以,对蛋白含量和SDS降值均较好的组合为1,7+9,5+10,GB,GD。 5. 因为GB和PB对品质的效应有显著差异,选取LMW-GS点特异扩增引物对京771、99G45和Pm97034的Glu-B3位点进行扩增,结果得到三个不一样的扩增片段(Genebank号为DQ539657-DQ539659),得到的基因片段与Genebank中已报道的同类序列高度同源。通过克隆片段组成的分析,发现对Pm97034的序列较京771和99G45段少一个7氨基酸的重复单元,这可能是它较另外两个片段对面筋强度影响小的主要原因;另外,在99G45的序列中,124位处出现L(亮氨酸)代替P脯氨酸),158位处出现了T(苏氨酸)代换M(蛋氨酸),这可能是99G45Glu-B3位点序列对SDS降值的效应显著优于Pm97034的原因。 6.通过对RILs位点同普通小麦品种(系)各位点与品质关系的比较,发现对SDS降值的效应,各位点在不同研究材料中是不同的,普通小麦中:Glu-B3>Glu-A1=Glu-D1=Glu-A3>Glu-D3>Glu-B1,RILs:Glu-D1>Glu-B1> Glu-D3>Glu-A1> Glu-B3。利用重组自交系材料(完全排除了1BL/1RS位干扰)所得到的结果与Gupta and MacRitchie (1994)所得结论一致。进一步证实了1BL/1RS位对小麦品质的重要影响。对蛋白含量而言,普通小麦品种(系)中,Glu-D1>Glu-B3>Glu-A1=Glu-B1> Glu-A3=Glu-D3,RILs,Glu-D3 > Glu-A1 > Glu-D1>Glu-B1>Glu-B3,和对SDS降值的效应一样,推断在非1BL/1RS位的情况下,各位点对其效应应为Glu-D3 > Glu-A1 > Glu-D1>Glu-B1>Glu-B3。 对同一位点的等位基因而言,普通小麦和重组自交系中Glu-A1和Glu-D1上的等位基因对品质性状的贡献是一致的,但Glu-B1上的等位基因对SDS降值的贡献发生了变化,普通小麦中17+18>7+9,RILs7+9>17+18,这可能也是1BL/1RS成的。 Baking quality improved is one of the main object of wheat bread in China. The overall objective of the present studies was to increase the understanding about protein quality in wheat, i.e. to make it possible to improve the production of wheat with desired quality for different end-uses. With the analysis of gluten protein in RILs, 99G45/Jing 771 and Pm97034/Jing, and 228 wheat cultivars or lines in China, the correlations between glutenin compositions and protein content, glutenin macropolymer(GMP), wet gluten content, Zeleny sedimentation value and SDS sedimentation value contentand breadmaking quality were studied. Also a rapid and efficient detection method of geneticpolymorphism at Glu-B3 loci in wheat was established using polymerase chain reaction(PCR).The results obtained were as follows: 1. Cultivated Chinese wheat germplasm has been a valuable genetic resource in international plant breeding. Patterns of gliadin among cultivated Chinese accessions are unknown, despite the proven value and potential novelty. The objective of this work was to analyse the diversity within improved Chinese wheat germplasm. The electrophoretic banding patterns of gliadin in common wheat cultivars and advanced lines were determined by acid-polyacrylamide gel electrophoresis. For 148 leading commercial cultivars and promising advanced lines used in our study, 48 patterns were identified, 29 corresponding to ω-gliadin, 9 to γ-gliadin, 5 to β-gliadin and 5 to α-gliadin. The most frequent patterns were A6 in ω; B in γ; B in β and A in the region of α. 116 band types appeared in the148 samples: 94 accessions had unique gliadin types, and 22 gliadin types while not unique were found in 54 accessions. The gliadin patterns of Chinese wheat cultivars and lines greatly differed from the patterns of wheat lines from other countries. Three patterns, E, J, H, M, N and O in the ω-zone had not previously been reported. Three wheat zonesthe Northern Winter Wheat Region, the Yellow and Huai Valley River valleys Winter Wheat Region and the Southwestern Winter Wheat Region,in China showed different frequencies in their gliadin patterns. This information can be used to monitor genetic diversity with Chinese wheat germplasm. 2. To analyse the relationship between the loci and characteristics quality, we utilized the 228 cultivars/lines. The results showed that : For protein content, Glu-D1 >Glu-B3>Glu-A1=Glu-B1>Glu-A3=Glu-D3. For GMP content, Glu-A3>Glu-B3 >Glu-D1>Glu-B1>Glu-A1>Glu-D3. For wet gluten content, Glu-B1>Glu-B3= Glu-D3>Glu-A3>Glu-A1>Glu-D1. For Zeleny sedimentation value, Glu-A1>Glu-B3> Glu-D3>Glu-D1>Glu-B1>Glu-A3, For SDS sedimentation value, Glu-B3>Glu-A1= Glu-D1= lu-A3>Glu-D3>Glu-B1。For protein content, the best combination of 6 loci is (1,17+18,5+10,Glu-A3e, Glu-B3g,Glu-D3b). For wet gluten content, the best combination of 6 loci is (1,6+8,5+10,Glu-A3d,Glu-B3c,Glu-D3b). For Zeleny sedimentation value, the best combination of 6 loci is (N,17+18,5+10,Glu-A3d, Glu-B3d, Glu-D3b). For SDS sedimentation value, the best combination of 6 loci is(7+8,2.2+12,Glu-A3b, Glu-B3g,Glu-D3b)。Additional, we analysed the relationship between the subunits 5+12 and 2.2+12, think that 5+12 was negative for quality, 2.2+12 is postive for quality. It should be effective utilized. 3. It’s the first time to utilize RILs to study the relationship between subunits expression quantity and characteristics quality. The results showed that: For single subunit, the expression quantity of 7 is the highest. Then the 2, 5, 12 and 10. The expression of subunit 9 and 1 is the lowest. Subunit N is not expressed. For subunits, the expression quantity of x type and y type are 2+12>5+10>7+9>17+18. The significant relation of 5% only showed between the expression quantity of subunit 10 and protein content. The relationship between expression quantity of others and characteristic quality was not significant. For x type/ytype, 2/12 and 5/10 is negative relation insignificant level. For the subunit(s) in a loci, Only 2+12 effect SDS sedimentation value negative in significant level. 4. With RILs 99G45/Jing 771 and Pm97034/Jing 771, we found that: The effective of Glu-A1, Glu-D3 and Glu-D1 * Glu-D3 for protein content is significant at 5% level. The effect of other loci for protein wre not significant. For SDS sedimentation value, the effect of Glu-D1is the highest, which contribution is 4.2 % .Then the Glu-B1, contribution is 3.3%. The effect of other loci for SDS sedimentationvalue were not significant. In total, for protein content: Glu-D3 > Glu-A1 > Glu-D1>Glu-B1>Glu-B3; for SDS sedimentationvalue: Glu-D1>Glu-B1> Glu-D3>Glu-A1>Glu-B3. The effect of alleles in Glu-D1 and Glu-D3 loci are significant at 1% or 5%. In Glu-A1, 1>N; Glu-B1, 7+9>17+18>14+15; Glu-D, 5+10>2+12; Glu-B3, GB>JB>PB; Glu-D3, GB>JB>PB. For SDS sedimentation, Glu-A1, 1>N; Glu-B1, 7+9=17+18>14+15; Glu-D1, 5+10>2+12; Glu-B3, GB>JB>PB; Glu-D3, GB>JB>PB. The best combinations for SDS sedimentation value is 1,7+9,5+10,GB,GD. 5. Because of the difference of GB and PB for SDS sedimentation value, we selected the specific primer for LMW-GS loci to amplified the Glu-B3 of Jing771, 99G45and Pm97034. We got 3 amplify fragment (Gene Bank accession number are DQ539657-DQ539659). We found that the fragment of Pm97034 were deleted a repetitive 7 amino acid domain, which is perhaps the reason effect the gluten strength. Furthermore, in the position 124 of sequence 99G45, L has been replaced with P. Position 158, T replaced M, which may be the reason why the Glu-B3 locus of 99G45 is prefer to Pm97034 when refer to SDS sedimentation value. 6. Comparing the results of RILs and common wheat, we found that perhaps just the1BL/1RS made the difference of loci in different accession.