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991.
The electronic properties of graphene nanoribbons (GNRs) with heteroatom (boron or nitrogen) substitutional doping at different sites are investigated by performing first-principles calculations based on density functional theory. The calculated results show that boron substitutional doping changes the conducting characteristics of GNRs to half-metallic. In contrast, nitrogen substitutional doping results in retention of the half-metallic characteristics of GNRs. It is predicted that the theoretical results may be valuable to the design of GNR-based spintronics devices. 相似文献
992.
993.
This paper studies Menon–Sury’s identity in a general case, i.e., the Menon–Sury’s identity involving Dirichlet characters in residually finite Dedekind domains. By using the filtration of the ring \({\mathfrak {D}}/{\mathfrak {n}}\) and its unit group \(U({\mathfrak {D}}/{\mathfrak {n}})\), we explicitly compute the following two summations:
$$\begin{aligned} \sum _{\begin{array}{c} a\in U({\mathfrak {D}}/{\mathfrak {n}}) \\ b_1, \ldots , b_r\in {\mathfrak {D}}/{\mathfrak {n}} \end{array}} N(\langle a-1,b_1, b_2, \ldots , b_r \rangle +{\mathfrak {n}})\chi (a) \end{aligned}$$and
$$\begin{aligned} \sum _{\begin{array}{c} a_{1},\ldots , a_{s}\in U({\mathfrak {D}}/{\mathfrak {n}}) \\ b_1, \ldots , b_r\in {\mathfrak {D}}/{\mathfrak {n}} \end{array}} N(\langle a_{1}-1,\ldots , a_{s}-1,b_1, b_2, \ldots , b_r \rangle +{\mathfrak {n}})\chi _{1}(a_1) \cdots \chi _{s}(a_s), \end{aligned}$$where \({\mathfrak {D}}\) is a residually finite Dedekind domain and \({\mathfrak {n}}\) is a nonzero ideal of \({\mathfrak {D}}\), \(N({\mathfrak {n}})\) is the cardinality of quotient ring \({\mathfrak {D}}/{\mathfrak {n}}\), \(\chi _{i}~(1\le i\le s)\) are Dirichlet characters mod \({\mathfrak {n}}\) with conductor \({\mathfrak {d}}_i\).
相似文献994.
ADSORPTION OF TANNIN FROM AQUEOUS SOLUTION ONTO MACROPOROUS CROSSLINKED POLY(N-VINYL-ACETAMIDE) VIA HYDROGEN BONDING 总被引:3,自引:0,他引:3
XU Mancai WANG Cairong XU Mingcheng SHI Zuoqing ZHANG Shang LI Haitao SHI Rongfu FAN Yunge HE Binglin 《Chinese Journal of Reactive Polymers》2000,(1)
I INTRODUCTIONTannin is existed widely in the roots, stems and fruits of many plants 111. Tannin is stronglyastringent and puckery due to the hydrogen bonding between the phenolic hydroxyl groups intarmin and abide groups in Protein al. A series of PYOb\m won\d be abed if t~ is nOIremoved from the products made from plants. For example, the injection site of the patientwould be red and swollen if tannin had not been removed from the injection made from plantssuch as red-rooted sajvia; … 相似文献
995.
Ricardo Baggio Bruce Foxman Maria Teresa Garland Mireille Perec Wen Shang 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):e505-e506
The title compound, [Cu(O2CCH=CHCH3)2(C5H5N)2(H2O)], crystallizes as a monomer, with the copper ion in a pentacoordinated square‐pyramidal environment, bisected by a twofold axis passing through the metal atom and the apex. The molecules organise in chains connected by hydrogen bonds running along the unique b axis. 相似文献
996.
Ming Li Maoyu Shang Hugues F. Duval W. Robert Scheidt 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(10):1206-1207
The precise structure of the title compound, [Fe2O(C44H24Br4N4)2]·2CH2Cl2, is reported. The Fe—N distances are non‐equivalent in pairs because of the asymmetric peripheral substitution; the values are 2.098 Å to the brominated rings and 2.041 Å to the other two rings. The Fe—O bond distance is 1.7583 (4) Å. The molecule has required twofold symmetry so that there is one unique porphyrin macrocycle and one Fe—O bond length in contrast to a previous report on the same species. 相似文献
997.
对TEAMS和eXpress两款主流测试性建模与分析软件所采用的测试性框图模型——多信号模型和混合诊断模型,从产品结构单元表示、端口表示、功能(信号)表示、故障模式表示、测试表示等多个方面进行了深入比较研究,并对二者进行了综合评价。在此基础上,综合两者特性提出了一种新的测试性框图模型改进方案——端信号模型。通过将组元端口所通过信息流直接视作信号、引入结点、扩充信号映射定义、允许定义多值测试等多种设置,端信号模型方案能够支持基于电路网表创建模型和更为精确化的故障-测试关联性描述。 相似文献
998.
We studied the exponential stabilization problem of a compounded system composed of a flow equation and an Euler–Bernoulli beam, which is equivalent to a cantilever Euler–Bernoulli beam with a delay controller. We designed a dynamic feedback controller that stabilizes exponentially the system provided that the eigenvalues of the free system are not the zeros of controller. In this paper we described the design detail of the dynamic feedback controller and proved its stabilization property. 相似文献
999.
基于国际热核聚变实验反应堆磁约束聚变-裂变混合能源系统次临界包层的物理-热工设计结果,提出了聚变-裂变混合堆次临界包层燃料区结构设计方案,包括纵骨支撑结构、燃料区结构和锆包壳结构。运用Pro/e建模软件建立了次临界包层燃料区结构模型,并利用ANSYS-workbench mechanical有限元分析软件对纵骨式支撑结构开展了初步力学分析,得到了燃料部件和纵骨式多层支撑结构的最大Tresca应力值、应力分布云图和总变形量,其中最大应力为87.04 MPa,最大变形量为0.17mm。按照第3强度理论校核,计算结果表明纵骨式次临界包层结构各部件能够满足强度要求。 相似文献
1000.
Youjin Zhang Zhenyu Xu Xiaobin Yin Zhiyong Fang Wei Zhu Hongmei He 《Crystal Research and Technology》2010,45(11):1183-1188
EuCO3OH microspheres have been successfully prepared using a facile hydrothermal approach, by using urea as the precipitant without the assistance of any surfactants or templates. Several experimental parameters were examined, such as the reaction temperature, the reaction time, and the molar ratios of the starting reagents. The Eu2O3 microspheres have been prepared by thermal conversion of EuCO3OH microspheres at 800 °C in air for 6 h. The as‐obtained products were characterized by X‐ray diffraction, scanning electron microscopy, X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, thermogravimetry–differential thermal analysis and photoluminescence. The possible growth process for the EuCO3OH microspheres was discussed. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献