一种Mortar型旋转Q1元方法

提出了一种mortar型旋转Q1元方法,相应的mortar条件仅依赖于子区域边界上的自由度;并得到了较优的误差估计.     

Probe-Integrated Label-Free Electrochemical Immunosensor Based on Binary Nanocarbon Composites for Detection of CA19-9

Convenient and sensitive detection of tumor biomarkers is crucial for the early diagnosis and treatment of cancer. Herein, we present a probe-integrated and label-free electrochemical immunosensor based on binary nanocarbon composites and surface-immobilized methylene blue (MB) redox probes for detection of carbohydrate antigen 199 (CA19-9), which is closely associated with gastric malignancies. Nanocarbon composites consisting of electrochemically reduced graphene oxides and carbon nanotubes (ErGO-CNT) are electrodeposited onto an indium tin oxide (ITO) electrode surface to form a 3D nanocomposite film, which could provide high surface area to immobilize abundant MB probes, facilitate the electron transfer of MB, and therefore, improve sensitivity. Polydopamine (PDA) served as a bifunctional linker is able to immobilize anti-CA19-9 antibodies and stabilize the inner probe, conferring the sensing interface with specific recognition capacity. Electrochemical detection of CA19-9 is achieved based on the decrease of the redox signal of MB after specific binding of CA19-9 with a wide linear range of 0.1 mU/mL to 100 U/mL and a limit of detection (LOD) of 0.54 nU/mL (S/N = 3). The constructed electrochemical immunosensor has good selectivity, repeatability, reproducibility, and stability. Furthermore, determination of CA19-9 in human serum samples is also realized.     

A Molecular Electron Density Theory Study of the [3+2] Cycloaddition Reaction of an Azomethine Ylide with an Electrophilic Ethylene Linked to Triazole and Ferrocene Units

The [3+2] cycloaddition (32CA) reaction of an azomethine ylide (AY) with an electrophilic ethylene linked to triazole and ferrocene units has been studied within the Molecular Electron Density Theory (MEDT) at the ωB97X-D/6-311G(d,p) level. The topology of the electron localization function (ELF) of this AY allows classifying it as a pseudo(mono)radical species characterized by the presence of two monosynaptic basins, integrating a total of 0.76 e, at the C1 carbon. While the ferrocene ethylene has a strong electrophilic character, the AY is a supernucleophile, suggesting that the corresponding 32CA reaction has a high polar character and a low activation energy. The most favorable ortho/endo reaction path presents an activation enthalpy of 8.7 kcal·mol⁻¹, with the 32CA reaction being exergonic by −42.1 kcal·mol⁻¹. This reaction presents a total endo stereoselectivity and a total ortho regioselectivity. Analysis of the global electron density transfer (GEDT) at the most favorable TS-on (0.23 e) accounts for the high polar character of this 32CA reaction, classified as forward electron density flux (FEDF). The formation of two intermolecular hydrogen bonds between the two interacting frameworks at the most favorable TS-on accounts for the unexpected ortho regioselectivity experimentally observed.     

海藻酸钙-活性炭纤维固定化生物小球的强化除苯性能

在传统海藻酸钙固定化过程中加入活性炭纤维作为改性载体,以苯系物(BTEX)降解菌为对象,制备了海藻酸钙-活性炭纤维固定化生物小球(MB),并研究了MB微观结构及强化除苯性能.结果表明:所制备的MB直径为2～4,mm,其表面通透、孔道致密,孔径均一(约为200,μm),并可多次重复应用.MB强化除苯过程主要是吸附和生物降解共同作用的结果,且去除速率呈现由快速到慢速两个阶段,均符合一级动力学规律.微生物接种量为6.89,mg/mL(包埋载体溶液)时,MB结构稳定性最好,强化除苯效果最佳.不同接种量条件下,苯生物降解的平均半衰期为64 h,高于游离态BTEX降解菌.     

一种电子商务税收征管系统模型的研究

探讨了网上交易的过程,给出了一个基于SET协议和CA认证的税收征管方案．     

基于ECDSA的校园CA设计

利用校园网络可以实现校园内信息与资源的共享和网上交易，由于电子信息本身可更改，且交易时无需面对面进行，这使得假冒身份、抵赖所发送的电子信息成为可能，基于椭圆曲线数字签名算法(ECDSA)有着密钥长度小、计算负载少、节省带宽等特性，提出了一种校园CA设计，为校园网络的进一步应用，提供了安全通信机制。     

浅谈美国《化学文摘》（CA）的发展与变化

介绍了CA的特点,论述了CA的结构体系,探讨了CA检索方式的发展与变化。     

Intrinsic surface binding energy shifts in Yb metal

We report on the four-peak structure observed in the region of 4f photoemission in Yb metal, using synchrotron radiation in the energy range 70–200 eV. We conclude, contrary to previous reports, that the doublet associated with surface emissions results from an intrinsic surface shift on clean regions of the surface. We also demonstrate that the observed structure is consistent with earlier XPS measurements, and we set an upper limit on the width of the bulk peaks.     

颜料对聚合物水泥砂浆性能的影响

向聚合物水泥砂浆中掺入氧化铁颜料制备彩色聚合物水泥砂浆,研究了不同颜料及其掺量的变化对聚合物水泥砂浆力学性能、工作性能和粘结强度的影响,并借助扫描电镜(SEM)表征了彩色聚合物水泥砂浆的微观组织形貌。结果表明：颜料会一定程度降低聚合物砂浆的抗折、抗压强度,且颜料掺量为5%时,对聚合物砂浆的抗折、抗压强度影响显著,随着颜料掺量的逐渐增加,聚合物砂浆的抗折、抗压强度呈现先增加后平缓的趋势;聚合物砂浆的流动度和粘结强度随颜料掺量的增加而减小;SEM测试结果表明颜料一方面会包裹水泥颗粒,阻碍水泥水化,降低彩色聚合物砂浆的抗折、抗压强度,但另一方面颜料能有效填充聚合物砂浆空隙,改善密实度,提高聚合物砂浆的抗折、抗压强度。     

Photochemistry of β, γ-unsaturated ketones-V: The direct irradiation of some γ-phenyl β, γ-enones

The photochemistry of some members of the two series of γ-phenyl substituted acyclic β, γ-unsaturated ketones 1 and 2 upon direct irradiation with γ 310nm has been investigated, viz 1c–1h and 2b+2c.The alkyl substituted (E)-5-phenyl-4-penten-2-ones 1c–1h yield the corresponding 1,3-acyl shift products and (Z)-isomers, and 1g and 1h in addition two decarbonylated products. 2b only yields the (Z)-isomer and some benzaldehyde, but 2c yields the 1,3-acyl shift product, the ODPM product, three hydrocarbons formed by disproportionation of the allyl radical, and some benzaldehyde. The β-phenyl β, γ-UK 3a proved to be photostable. The 1,3-acyl shift products of 1c–1h result mainly from the singlet excited state in a cage radical process. The exclusive formation of the (E)-configuration of the 1,3-acyl shift product is explained in terms of conformational preference of the intermediate allyl radical. It is proposed that the formation of the (Z)-isomer proceeds from ¹T(π -π^*) which is populated according to

. Evidence is presented which supports the proposed mechanism.The β,γ-UK 2b containing a benzoyl moiety leads to a higher degree of (E)-(Z) isomerization than the corresponding 1d which has an acetyl moiety.The triplet energies of (E)- and (Z)-1h are 56 and ca 70 kcal/mol respectively.