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81.
Ryan McCulloch 《代数通讯》2017,45(3):983-991
This paper provides the first steps in classifying the finite solvable groups having Property A, which is a property involving abelian normal subgroups. We see that this classification is reduced to classifying the solvableChermak–Delgado simple groups, which the author defines. The notion of “Chermak–Delgado simple,” or “CD-simple” for short, is a generalization of simple groups through the Chermak–Delgado lattice. The author completes a classification of Chermak–Delgado simple groups under certain restrictions on the primes involved in the group order. 相似文献
82.
Dr. Bob C. Schroeder Dr. Zhe Li Michael A. Brady Dr. Gregório Couto Faria Dr. Raja Shahid Ashraf Dr. Christopher J. Takacs John S. Cowart Dr. Duc T. Duong Kar Ho Chiu Ching‐Hong Tan Dr. João T. Cabral Prof. Alberto Salleo Prof. Michael L. Chabinyc Prof. James R. Durrant Prof. Iain McCulloch 《Angewandte Chemie (International ed. in English)》2014,53(47):12870-12875
Cost‐effective, solution‐processable organic photovoltaics (OPV) present an interesting alternative to inorganic silicon‐based solar cells. However, one of the major remaining challenges of OPV devices is their lack of long‐term operational stability, especially at elevated temperatures. The synthesis of a fullerene dumbbell and its use as an additive in the active layer of a PCDTBT:PCBM‐based OPV device is reported. The addition of only 20 % of this novel fullerene not only leads to improved device efficiencies, but more importantly also to a dramatic increase in morphological stability under simulated operating conditions. Dynamic secondary ion mass spectrometry (DSIMS) and TEM are used, amongst other techniques, to elucidate the origins of the improved morphological stability. 相似文献
83.
McCulloch RD Robb DB Blades MW 《Rapid communications in mass spectrometry : RCM》2008,22(22):3549-3554
This technical note describes in detail the fabrication, operation and characterization of a pneumatically driven dopant introduction device, with a solvent reservoir capacity of 300 mL. Dopant flow rates and stability for this device are governed by the simple regulation of gas pressure rather than the progression of a stepper motor and syringe diameter, as is the case for typical infusion pumps. The device has the potential to provide days or even weeks of continuous, uninterrupted dopant flow at rates commonly adopted for atmospheric pressure photoionization (APPI) experiments without the need to replenish the dopant supply. Although not a refined instrumental design, this device was developed as an alternative cost-effective means of introducing stable dopant flow to an APPI source. The device was designed such that all components would be commercially available and easily procurable from common scientific part vendors. Figures and suggested part numbers are provided to allow those interested to fabricate similar devices to suit their individual experimental needs. Device characterization was performed while monitoring such factors as flow rate calibration, overall flow stability and reproducibility. In addition, a standard mixture of three polycyclic aromatic hydrocarbons was employed as a model sample for a typical reversed-phase liquid chromatography/atmospheric pressure photoionization mass spectrometry (LC/APPI-MS) application in order to demonstrate device performance. 相似文献
84.
An alignable fluorene thienothiophene copolymer with deep-blue electroluminescent emission at 410 nm
Gather MC Heeney M Zhang W Whitehead KS Bradley DD McCulloch I Campbell AJ 《Chemical communications (Cambridge, England)》2008,(9):1079-1081
An alignable, liquid-crystalline fluorene fused-ring thienothiophene copolymer has been synthesized with electroluminescence peaking at 410 nm for deep blue, polarised emission in polymer light-emitting diodes, light-emitting transistors and photonic structures. 相似文献
85.
Heeney M Zhang W Crouch DJ Chabinyc ML Gordeyev S Hamilton R Higgins SJ McCulloch I Skabara PJ Sparrowe D Tierney S 《Chemical communications (Cambridge, England)》2007,(47):5061-5063
The synthesis of regioregular poly(3-hexyl)selenophene is reported, and its optical and electrical properties are compared to those of regioregular poly(3-hexyl)thiophene. 相似文献
86.
Allison W. McCulloch Patricia L. Marshall Jessica T. DeCuir‐Gunby Ticola S. Caldwell 《School science and mathematics》2013,113(8):380-389
Mathematics autobiographies have the potential to help teachers reflect on their identities as mathematics learners and to understand their role in the development of their students' mathematics identities. This paper reports on a professional development project for K‐2 teachers (n = 41), in which participants were asked to write mathematics autobiographies. Using an adaptation of an existing framework for characterizing teachers' mathematics stories, we describe the consistencies among the participants' experiences as mathematics learners and the events that are identified as being the impetus for a transition from a negative to a positive attitude toward mathematics. Implications for both teachers and teacher educators are presented. 相似文献
87.
DR Matravers 《Contemporary Physics》2013,54(3):251-254
The history of absolute measurements of gravity is mentioned and the reasons for making absolute measurements are indicated. The principles and main advantages and difficulties of the main method—reversible pendulum, free fall, symmetrical free motion—are discussed and examples of each method are described. Problems of comparison of different determinations and of estimating systematic errors are considered. 相似文献
88.
Ho V Boudouris BW McCulloch BL Shuttle CG Burkhardt M Chabinyc ML Segalman RA 《Journal of the American Chemical Society》2011,133(24):9270-9273
Conjugated rod-coil diblock copolymers self-assemble due to a balance of liquid crystalline (rod-rod) and enthalpic (rod-coil) interactions. Previous work has shown that while classical block copolymers self-assemble into a wide variety of nanostructures, when rod-rod interactions dominate self-assembly in rod-coil block copolymers, lamellar structures are preferred. Here, it is demonstrated that other, potentially more useful, nanostructures can be formed when these two interactions are more closely balanced. In particular, hexagonally packed polylactide (PLA) cylinders embedded in a semiconducting poly(3-alkylthiophene) (P3AT) matrix can be formed. This microstructure has been long-sought as it provides an opportunity to incorporate additional functionalities into a majority phase nanostructured conjugated polymer, for example in organic photovoltaic applications. Previous efforts to generate this phase in polythiophene-based block copolymers have failed due to the high driving force for P3AT crystallization. Here, we demonstrate that careful design of the P3AT moiety allows for a balance between crystallization and microphase separation due to chemical dissimilarity between copolymer blocks. In addition to hexagonally packed cylinders, P3AT-PLA block copolymers form nanostructures with long-range order at all block copolymer compositions. Importantly, the conjugated moiety of the P3AT-PLA block copolymers retains the crystalline packing structure and characteristic high time-of-flight charge transport of the homopolymer polythiophene (μ(h) ~10(-4) cm(2) V(-1) s(-1)) in the confined geometry of the block copolymer domains. 相似文献
89.
Zhang X Richter LJ DeLongchamp DM Kline RJ Hammond MR McCulloch I Heeney M Ashraf RS Smith JN Anthopoulos TD Schroeder B Geerts YH Fischer DA Toney MF 《Journal of the American Chemical Society》2011,133(38):15073-15084
We describe a series of highly soluble diketo pyrrolo-pyrrole (DPP)-bithiophene copolymers exhibiting field effect hole mobilities up to 0.74 cm(2) V(-1) s(-1), with a common synthetic motif of bulky 2-octyldodecyl side groups on the conjugated backbone. Spectroscopy, diffraction, and microscopy measurements reveal a transition in molecular packing behavior from a preferentially edge-on orientation of the conjugated plane to a preferentially face-on orientation as the attachment density of the side chains increases. Thermal annealing generally reduces both the face-on population and the misoriented edge-on domains. The highest hole mobilities of this series were obtained from edge-on molecular packing and in-plane liquid-crystalline texture, but films with a bimodal orientation distribution and no discernible in-plane texture exhibited surprisingly comparable mobilities. The high hole mobility may therefore arise from the molecular packing feature common to the entire polymer series: backbones that are strictly oriented parallel to the substrate plane and coplanar with other backbones in the same layer. 相似文献
90.
Ohkita H Cook S Astuti Y Duffy W Heeney M Tierney S McCulloch I Bradley DD Durrant JR 《Chemical communications (Cambridge, England)》2006,(37):3939-3941
Efficient triplet formation is observed for films of high ionisation potential polythiophenes blended with a fullerene derivative, and assigned to formation via geminate charge recombination of bound radical ion pair states. 相似文献