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1.
本文利用密度泛函理论,研究了L-半胱氨酸及L-胱氨酸在CdTe上的吸附特征. 优化之后分别得到了四种稳定的吸附构型,计算了它们的吸附能、电荷密度、前沿分子轨道以及紫外可见吸收光谱等. 研究发现:L-半胱氨酸在CdTe上的吸附能较大、紫外可见光吸收较强,说明L-半胱氨酸在CdTe上的吸附较稳定,容易产生分子荧光,而L-半胱氨酸转化为L-胱氨酸之后,吸附稳定性降低、紫外可见光吸收强度减弱. 该研究为L-半胱氨酸配体合成的CdTe QDs荧光材料用于生物体内H2O2和葡萄糖的检测提供了理论支撑.  相似文献   

2.
利用电化学现场表面增强拉曼光谱技术研究了在粗糙化金电极和银电极表面吸附的L-蛋氨酸自组装单分子膜结构随电位改变的特征.实验结果表明:在外加电位0--0.6V范围内,L-蛋氨酸主要是通过硫原子和去质子化羧基2个吸附位点与银电极表面产生相互作用的;而在金电极表面表现为分子中的氨基、去质子化羧基和硫原子3个吸附位点随电位负移而改变的特征;另外,对于金电极表面吸附的L-蛋氨酸单分子膜而言,还伴随着吸附物分子由于分子内旋转等而引致的分子构型的转变.  相似文献   

3.
通过不同电位下,SERS光谱各谱峰相对强度的变化以及分子力学对青蒿素结构的计算和分子图形模拟对青蒿素在银表面上的吸附状态进行研究。  相似文献   

4.
新的分子组装技术:自组装成膜及其应用   总被引:1,自引:0,他引:1  
通过化学吸附可实现有机分子在固体表面上的自动有序排列,形成的自组装膜的稳定性和有序性优于LB膜,成膜技术简便,在非线性光学,微电子学,分子器件,传感器件,分子生物学及表面修饰等方面具有广泛应用价值。  相似文献   

5.
L-半胱氨酸(L-Cys)自组装单分子膜(SAM)已在化学传感器及生物传感器研究领域得到了广泛应用.但是,L-Cys SAM容易通过静电吸附或分子间氢键形成二聚体,而降低表面功能基团的活性,进而对生物传感器的性能产生不利影响.首先在不同pH条件下,将L-Cys自组装在金电极表面,用循环伏安法、交流阻抗法和偏振模式傅里叶变换红外反射吸收光谱法对L-Cys SAM进行表征.结果表明,在pH 3.0的醋酸盐缓冲溶液中于金表面上制备L-Cys SAM可以较为有效的抑制二聚体的形成,为蛋白质的固定化提供了理想的界面,为进一步制备免疫传感器、酶传感器等生物传感器提供了技术支持.  相似文献   

6.
利用自组装方法将DNA分子吸附于Si基底表面, 并通过原子力显微镜(AFM)观察不同质量浓度的DNA溶液在Si基底表面进行自组装后的结构: 当DNA溶液的质量浓度较低时, Si基底表面会吸附单个、 拉伸、 环状的分子; 当DNA溶液的质量浓度为60~160 ng/μL时, 在Si基底表面会形成网状结构; 当DNA溶液的质量浓度超过200 ng/μL时, 仅形成DNA薄膜. 实验结果表明, 可以利用该方法制作基于Si材料的DNA分子器件.  相似文献   

7.
自组装单分子膜的缺陷及修饰研究现状   总被引:1,自引:0,他引:1  
综述了自组装单分子膜的结构及组装方法,缺陷产生的机理、表征方法,以及对自组装单分子膜缺陷的修饰方法.自组装单分子膜可分为单层膜和多层膜.单层膜主要指以共价键和离子键为驱动力形成的,多层膜的组装方法主要是分子沉积(MD)技术和基于化学吸附的自组装单分子膜技术.自组装膜的缺陷对其具有的特殊性能有影响,分子的倒伏造成了膜的缺陷,其影响因素很多,其中基片表面的化学组成与化学性质和成膜分子自身性质起决定作用;优化成膜反应条件,可有效地控制膜的增长.  相似文献   

8.
Au(111)表面磺酸甜菜碱自组装单层膜的分子模拟   总被引:1,自引:0,他引:1  
旨在探索磺酸甜菜碱型材料阻抗蛋白质吸附的微观机理,以更好地指导新型无生物污染材料的设计和开发.采用分子力学和分子动力学方法,对磺酸甜菜碱在Au(111)表面的分子自组装结构和性能进行研究.研究结果表明,磺酸甜菜碱在Au(111)表面可形成7×7的稳定结构,真空模拟中分子平均倾斜角为23,°水溶剂化模拟中则为25°,两性离子端基偶极方向趋于平行;水和磺酸甜菜碱的两性离子基团相互作用而吸附于表面上,形成一层牢固的水膜,从而有效地阻止蛋白质吸附到材料表面上.  相似文献   

9.
以探寻氢在碳基材料上适宜的存储条件为目的,在温度区间113~293 K、压力范围0~13MPa测定氢在活性炭LY-1上的平衡吸附数据,应用格子理论导出的通用吸附等温方程,通过吸附平衡态的能量分析、等温方程的线性标绘以及10-4-3吸附势函数的迭代求解,确定氢分子在吸附表面的最大密度、受到的壁面吸附势以及氢分子间作用能.研究结果表明:氢分子在吸附空间以压缩气体的状态聚集,温度和表面遮盖率对氢分子吸附行为的影响明显;温度升高将使氢分子问作用能受压力和表面遮盖率变化的影响加剧;较高的表面遮盖率也使吸附氢分子间作用能随温度、压力以更高的速率变化;改善材料结构和降低储存系统温度可提高碳基材料的储氢性能.  相似文献   

10.
热镀锌板上γ-APT硅烷自组装膜的制备及相容性   总被引:1,自引:0,他引:1  
采用交流阻抗谱和接触角的方法研究了γ-APT硅烷的单分子自组装膜在热镀锌钢板表面的成膜过程,以及γ-APT硅烷自组装膜和γ-GPT硅烷的相容性.实验成功制备硅烷单分子自组装膜.组装开始时硅烷分子水解生成硅醇键的一端快速吸附在锌的表面并形成了Si—O—Zn键,硅烷分子之间的硅醇键随即脱水形成Si—O—Si键,从而自组装成为有序、规律排布的单分子自组装膜,组装10 h后膜的完整性最好,随后形成连续性较差的混杂膜.经过10 h组装后的γ-APT硅烷自组装膜与γ-GPT硅烷具有良好的相容性.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

15.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

19.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

20.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

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