Taming Charge Transport in Semiconducting Polymers with Branched Alkyl Side Chains

The solid‐state packing and polymer orientation relative to the substrate are key properties to control in order to achieve high charge carrier mobilities in organic field effect transistors (OFET). Intuitively, shorter side chains are expected to yield higher charge carrier mobilities because of a denser solid state packing motif and a higher ratio of charge transport moieties. However our findings suggest that the polymer chain orientation plays a crucial role in high‐performing diketopyrrolopyrrole‐based polymers. By synthesizing a series of DPP‐based polymers with different branched alkyl side chain lengths, it is shown that the polymer orientation depends on the branched alkyl chain lengths and that the highest carrier mobilities are obtained only if the polymer adopts a mixed face‐on/edge‐on orientation, which allows the formation of 3D carrier channels in an otherwise edge‐on‐oriented polymer chain network. Time‐of‐flight measurements performed on the various polymer films support this hypothesis by showing higher out‐of‐plane carrier mobilities for the partially face‐on‐oriented polymers. Additionally, a favorable morphology is mimicked by blending a face‐on polymer into an exclusively edge‐on oriented polymer, resulting in higher charge carrier mobilities and opening up a new avenue for the fabrication of high performing OFET devices.     

Book reviews

A Fourth Way? Privatization, Property and the Emergence of New Market Economies. Gregory S. Alexander & Grazyna Skapska (Eds). London, Routledge, 1994, xxiii + 336 pp., ISBN 0415906970 (HB), 0415906989 (PB)

From Public Housing to the Social Market. Rental Policy Strategies in Comparative Perspective. Jim Kemeny. London and New York, Routledge, 1995, 194 pp., £40.00

European Housing Finance. Single Market or Mosaic?. Will Bartlett & Glen Bramley (Eds). Oxford, The Alden Press, School for Advanced Urban Studies (SAUS) publication 12 (Bristol) 1994, 282 pp., £19.95, paperback, ISBN 1 873575 63 7

Housing, Financial Markets and the Wider Economy. David Miles. Chichester, John Wiley & Sons, 1994, 228 pp., £35.00

Women in the Housing Service. Marion Brion. London, Routledge, 1994, ISBN 0 415 08094 £45.00 Hardback

Slippery Customers: Estate Agents, The Public and Regulation. Michael Clarke, David Smith & Michael McConville. London, Blackstone Press, 1994, 295 pp., £19.95     

Comparative B‐mode and Doppler renal ultrasonography with histopathological findings in dogs positive for canine visceral leishmaniasis

Morphological parameters and renal flow were assessed and measured in six clinically healthy dogs with negative serological and parasitological examinations for canine visceral leishmaniasis (CVL) and six dogs with CVL‐positive serological and parasitological tests and asymptomatic condition of the disease. Kidney length and diameter were measured and compared with the aorta/kidney ratio. Alterations in flow were measured using the flow velocity (cm/s) and resistance index (RI). Renal function was assessed by serum biochemical examination (urea, creatine, total proteins, albumin, and globulin) and urinalysis. CVL‐positive animals presented heterogeneous kidney echotexture, reduced vascular flow, hypoperfusion, lesser visualization of the arcuate arteries, high RI values (1.06 ± 0.28 for the right kidney and 1.10 ± 0.30 for the left kidney), reduced diastolic flow, and high systolic peak. They also presented positive creatine/RI correlation and between the renal artery vascular flow and kidney diameter. Histopathological analysis of CVL‐positive animals was compatible and confirmed hemodynamic changes observed by Doppler ultrasound. The findings in the present study showed that Doppler ultrasonography is a valid method to assess and detect alterations in flow in renal pathological processes with kidney vascular damage, as in the case of leishmaniasis, and can help in the diagnosis of animals with this infection. Microsc. Res. Tech. 79:637–645, 2016. © 2016 Wiley Periodicals, Inc.     

Making a Bang

‘Design is a performance and a process, a form of seeking, a journey where the caravan expands and contracts.’ Guest-editor Bob Sheil describes the extraordinary make-up and approach of the studio of the accomplished maker Thomas Heatherwick. With Ron Packman , he also describes how this translates into physical form in the making of the sculpture The B of Big Bang. Copyright © 2005 John Wiley & Sons, Ltd.     

Review of A new psychotherapy for traditional men.

Reviews the book, A new psychotherapy for traditional men by Gary R. Brooks (see record 1998-06013-000). Gary Brooks spent 6 years writing this book in which he presents a therapeutic model for working with "traditional men." The text's quality—reflected in its organization, structure, and content—demonstrates the success of this very thorough labor. The therapy discussed is a gender-aware model, oriented and very empathetic to the needs and special perspective of contemporary males. Brooks makes the reader aware of the dilemma facing traditional man. Brooks's compassionate and sensitive presentation makes the pain and distress of the traditional man very real and palpable for the reader. The men for whom the model is targeted are those individuals who are closely attached to the traditional definition of manhood; they are emotionally stoic, prefer action to reflection, are shame-bound by any sense of incompetence or hint of failure, and do not ask for help. Brooks is very complete, comprehensive, and convinced about his gender-sensitive therapy for traditional men. His comprehensive intervention is intriguing. The compassionate and compelling manner in which he presents his total model is provocative. It challenges readers to consider or at least reexamine many of their concepts and attitudes regarding men, the process of therapy, and their behaviors as therapists. Brooks's many clinical insights should prove useful to therapists of all experiential levels. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Guest editorial

This issue contains papers presented at the 7th International Conference on Electrical and Related Properties of Organic Solids (ERPOS-7). It is a companion issue to Vol. 6. No. 5/6 which contained the bulk of the papers. Unfortunately, not all of the papers could be published in one special issue. © 1997 John Wiley & Sons, Ltd.     

纵波-转换横波联合反演技术在页岩气藏勘探中的应用

近几年的页岩油气开发实践表明,页岩非均质性及水平井段的方位对页岩气单井产量、采收率及页岩气开采的经济性影响较大,而页岩非均质性主要受到天然微裂缝的影响。因此,开展页岩内天然微裂缝研究,寻找页岩储层“甜点”等是成功部署高产气井、提高页岩气开采经济效益的必然选择。基于美国阿巴拉契亚盆地Marcellus页岩区的3C/3D高分辨率地震资料,利用快/慢速转换横波（PSV-1/PSV-2）反射时间厚度差法,对Marcellus地层的天然微裂缝发育带进行了探测。应用纵-转换横波（PP-PS）联合反演技术,结合联合反演密度、纵横波速度比（v_P/v_S）等组合属性参数,对天然微裂缝的开闭性及张性天然微裂缝孔隙空间的含气性分别进行了识别和检测,并利用实钻井资料对地球物理方法预测的页岩储层“甜点”（含气张性微裂缝）进行验证,取得较好效果。实际应用表明,纵-横波联合反演技术对于张性天然微裂缝的识别及含气性检测具有突出优势,能有效降低钻探风险。     

Collapse of <Emphasis Type="Italic">ρ</Emphasis><Subscript><Emphasis Type="Italic">xx</Emphasis></Subscript> Ringlike Structures in 2DEGs Under Tilted Magnetic Fields

In the quantum Hall regime, the longitudinal resistivity ρ _xx plotted as a density–magnetic-field (n _2D –B) diagram displays ringlike structures due to the crossings of two sets of spin split Landau levels from different subbands [see, e.g., Zhang et al., in Phys. Rev. Lett. 95:216801, 2005. For tilted magnetic fields, some of these ringlike structures “shrink” as the tilt angle is increased and fully collapse at θ _c ≈6°. Here we theoretically investigate the topology of these structures via a non-interacting model for the 2DEG. We account for the inter Landau-level coupling induced by the tilted magnetic field via perturbation theory. This coupling results in anticrossings of Landau levels with parallel spins. With the new energy spectrum, we calculate the corresponding n _2D –B diagram of the density of states (DOS) near the Fermi level. We argue that the DOS displays the same topology as ρ _xx in the n _2D –B diagram. For the ring with filling factor ν=4, we find that the anticrossings make it shrink for increasing tilt angles and collapse at a large enough angle. Using effective parameters to fit the θ=0° data, we find a collapsing angle θ _c ≈3.6°. Despite this factor-of-two discrepancy with the experimental data, our model captures the essential mechanism underlying the ring collapse.