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TRANSIMIDIZATION IN THERMOPLASTIC POLYIMIDES

Chinese Journal of Polymer Science 1999年第2期17卷 171-184页

作者： Yoan Kim Doyun Kim frank w.harris Stephen Z.D.Cheng Maurice Morton Institute and Department of Polymer Science The University of Akron Akron Ohio 44325-3909 USAMaurice Morton Institute and Department of Polymer Science The University of Akron Akron Ohio 44325-3909 USAMaurice Morton Institute and Department of Polymer Science The University of Akron Akron Ohio 44325-3909 USAMaurice Morton Institute and Department of Polymer Science The University of Akron Akron Ohio 44325-3909 USA

In order to improve the processibility in thermoplastic polyimides, a new method, termed the'reactive plasticizer' approach, has been proposed. This method uses a small amount (5～15 mol%) of a lessactivated, weak nucleophilic diamine co-monomer as a 'reactive plasticizer' to obtain copolyimide resinswhich possess relatively low viscosity at low temperatures and can be readily processed through the autoclavecycle at low pressures. During a high temperature treatment, the reactive plasticizers join the reaction to formhigh molecular weight copolyimides, and the preferred material properties are thus achieved. The mosteffective reactive plasticizer is aromatic heterocyclic diamines, such as 2, 6-diaminopyridine diamine (DAP),and the transimidization involved with a reactive plasticizer has been proposed to play a major role for thesuccess of this approach. In order to understand the transimidization mechanism, three steps have been takenin this research: first, a copolyimide system of 50% of DAP and 50% 1, 4 -bis [4-aminophenoxy] benzenediamine (DODA) with 100% of 2, 2'-bis[4-(3, 4-dicarboxyphenoxy)phenyl] propane dianhydride (Ultem^(R)DA) is prepared. Second, several specifically designed polyimide mixture systems were used, and they consistof two homopolyimides: one is Ultem^(R) DA-DODA, and the other is Ultem^(R) DA-DAP. The third step is toinvestigate two mixture systems in which Ultem^(R) DA-DODA is mixed with DAP monomer solution andUltem^(R) DA-DAP is mixed with DODA monomer solution. For all systems, with increasing degree oftransimidization upon heat-treatment, the chain structures of the mixtures and their thermal and dynamicmechanical transition behaviors are investigated via one-dimensional and two-dimensional nuclear magneticresonance, differential scanning calorimetry, and dynamic mechanical analysis experiments. Experimentalresults indicate that in the mixture of two homopolyimides, transimidization takes place much moreefficiently in solution than in th

关键词： Transmidization Thermoplastic polyimides

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wHAT ARE THE DIFFERENCES OF POLYMER SURFACE RELAXATION FROM THE BULK?

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Chinese Journal of Polymer Science 2011年第1期29卷 81-86页

作者： Ian Mann Ryan M.Van Horn Jason J.Ge Matthew J.Graham frank w.harris Stephen Z.D.Cheng College of Polymer Science and Polymer Engineering Department of Polymer Sciencethe University of Akron

The polymer surface relaxation in thin films has been a long debating issue. we report a new method on studying surface relaxation behaviors of polymer thin films on a solid substrate. This method involved utilizing a rubbed polyimide surface with a pretilting angle in a liquid crystalline cell. Due to the surface alignment, the liquid crystals were aligned along the rubbing direction. During heating the liquid crystalline cell, we continuously monitored the change of orientation of the liquid crystals. It is understood that at a temperature where the orientation of liquid crystal is lost, the surface relaxation on the glass substrate takes place to lose the polyimide surface orientation. It was found that the relaxation temperature at which the liquid crystals lose their orientation depends on the film thickness of the polyimide. A quantitative linear relationship between the relaxation temperature and reciprocal of the film thickness can be observed. Furthermore, different topologies of the rubbed and relaxed thin films were amplified using the polyethylene decoration method and observed using atomic force microscopy.

关键词： Surface relaxation Liquid crystal orientation Polyethylene decoration.

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PHASE STRUCTURES AND TRANSITION BEHAVIORS OF A TRIPHENYLENE DISCOTIC LIQUID CRYSTAL

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Chinese Journal of Polymer Science 2007年第1期25卷 57-71页

作者： Kwang-Un Jeong Alexander J.Jing Bart Mansdorf Matthew J.Graham frank w.harris 程正迪 Maurice Morton Institute and Department of Polymer Science The University of AkronAkronOhio 44325-3909USA

The phase behaviors and structures of a triphenylene-derived discotic liquid crystal （LC） hexa-n-octoxyl- triphenylene （C8HET） were studied using the combined techniques of differential scanning calorimetry （DSC）, wide angle X-ray diffraction （wAXD）, selected area electron diffraction （SAED） and polarized light microscopy （PLM）. Onedimensional （1D） powder wAXD results at different temperatures coupled with DSC and PLM observations revealed that the C8HET compound possessed an LC phase and three different crystalline （K3, K2 and K1） phases below the isotropic （I） melt. The I←→ LC phase transition was thermodynamically reversible and independent of the heating and cooling rates. The development and experimental observation of the three crystalline phases relied on different thermal histories. Among the three crystalline phases in CSHET, the K3 phase is the most stable phase, while the K2 and K1 phases are metastable. Note that the K1 phase only formed via a quenching process. Oh the basis of structure sensitive diffraction experiments such as 2D wAXD of oriented samples and SAED of single crystals, detailed structures and molecular packings of these four ordered phases were identified. The LC phase exhibited a hexagonal columnar phase with 2D lattice dimensions ofa = b = 2.38 nm and γ= 120°. All the three crystalline phases possess monoclinic unit cells, yet the y angle is not 90° in the cases of the K2 and the K3 phases, while in the case of the K1 phase the a angle is not 90°.

关键词： Triphenylene discotic liquid crystal Metastability Crystal structure Columnar phase Phase transitions.

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微米级含近晶相液晶的高分子胶囊合成

微米级含近晶相液晶的高分子胶囊合成

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2010年两岸三地高分子液晶态与超分子有序结构学术研讨会（暨第十一次全国高分子液晶态与超分子有序结构学术论文报告会）

作者：屠迎锋 frank w.harris 程正迪苏州市工业园区仁爱路苏州大学材化部 The Maurice Morton Institute and Department of Polymer Science The University of Akron

受柔性显示迅猛发展的影响,近晶相液晶显示最近得到了广泛的研究。虽然近晶相液晶显示相对于向列相液晶显示具有反应时间慢的缺点,但却具有反差好,设备简单,能耗极低,双稳定性等优点,因此特别适合于户外显示。要达到彩色显示的要求,需... 详细信息

受柔性显示迅猛发展的影响,近晶相液晶显示最近得到了广泛的研究。虽然近晶相液晶显示相对于向列相液晶显示具有反应时间慢的缺点,但却具有反差好,设备简单,能耗极低,双稳定性等优点,因此特别适合于户外显示。要达到彩色显示的要求,需要合成近晶相液晶的高分子胶囊,将近晶相小分子液晶封装于1～10微米大小均匀的高分子胶囊中。

关键词：高分子胶囊液晶封装近晶相液晶乳液聚合

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The Fourier space restricted Hartree-Fock method for the electronic structure calculation of linear poly(tetrafluoroethylene)

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Science China Chemistry 2014年第10期57卷 1355-1362页

作者： FRIPIAT Joseph G. harris frank E. Laboratoire de Chimie Théorique Unité de chimie physique théorique et structurale University of NamurRue de Bruxelles Department of Physics University of Utah Quantum Theory Project University of Florida

Building on the pioneering work of Jean-Marie Andre and working in the laboratory he founded, the authors have developed a code called FT-1D to make Hartree-Fock electronic structure computations for stereoregular polymers using Ewald-type con- vergence acceleration methods. That code also takes full advantage of all line-group symmetries to calculate only the minimal set of two-electron integrals and to optimize the computation of the Fock matrix. The present communication reports a bench- mark study of the FT-1D code using polytetrafluoroethylene （PTFE） as a test case. Our results not only confirm the algorith- mic correctness of the code through agreement with other studies where they are applicable, but also show that the use of con- vergence acceleration enables accurate results to be obtained in situations where other widely-used codes （e.g., PLH and Crys- tal） fail. It is also found that full attention to the line-group symmetry of the PTFE polymer leads to an increase of between one and two orders of magnitude in the speed of computation. The new code can therefore be viewed as extending the range of electronic-structure computations for stereoregular polymers beyond the present scope of the successful and valuable code Crystal.

关键词： poly(tetrafluoroethylene) band structure Fourier-space Hartree-Fock lattice sum Ewaid

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Characterization of novel Brown midrib 6 mutations affecting lignin biosynthesis in sorghum

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Journal of Integrative Plant Biology 2016年第2期58卷 136-149页

作者： Erin D. Scully Tammy Gries Deanna L. Funnell-harris Zhanguo Xin frank A. Kovacs wilfred Vermerris Scott E. Sattler Grain Forage and Bioenergy Research Unit USDA-ARS Lincoln NE 68583 USA Department of Agronomy and Horticulture University of Nebraska-Lincoln Lincoln NE 68583 USA Department of Plant Pathology University of Nebraska-Lincoln Lincoln NE 68583 USA Plant Stress and Germplasm Development Unit USDA-ARS Lubbock TX 79414 USA Department of Chemistry University of Nebraska-Kearney Kearney NE 68849 USA Department of Microbiology & Cell Science and UF Genetics Institute University of Florida Gainesville FL 32610 USA

The presence of lignin reduces the quality of lignocellulosic biomass for forage materials and feedstock for biofuels. In C4 grasses, the brown midrib phenotype has been linked to mutations to genes in the monolignol biosynthesis pathway. For example, the Bmr6 gene in sorghum （Sorghum bicolor） has been previously shown to encode cinnamyl alcohol dehydrogenase （CAD）, which catalyzes the final step of the monolignol biosynthesis pathway. Mutations in this gene have been shown to reduce the abundance of lignin, enhance digestibility, and improve saccharification efficiencies and ethanol yields. Nine sorghum lines harboring five different bmr6 alleles were identified in an EMS-mutagenized TILLING population. DNA sequencing of Bmr6 revealed that the majority of the mutations impacted evolutionarily conserved amino acids while three-dimensional structural modeling predicted that all of these alleles interfered with the enzyme＇s ability to bind with its NAPPH cofactor. All of the new alleles reduced in vitro CAD activity levels and enhanced glucose yields following saccharification. Further, many of these lines were associated with higher reductions in acid detergent lignin compared to lines harboring the previously characterized bmr6-ref allele. These bmr6 lines represent new breeding tools for manipulating biomass composition to enhance forage and feedstock quality.

关键词： Cinnamyl alcohol dehydrogenase (CAD) EMS mutagenesis biofuels C4 grass forage

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Simultaneous Erb's and Klumpke's palsy: Case report

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world Journal of Clinical Cases 2015年第12期3卷 984-987页

作者： Ashley Dawson Eliana Vasquez David Garrett Jr frank S harris Ibrahim M El Nihum Samantha Dayawansa Jason H Huang Soren Singel Faculty of Medicine Texas A and M University Department of Neurosurgery Baylor Scott and White Health Care

Mapping nerve deficits during a physical exam after trauma to the upper extremity can help determine not only if the brachial plexus was injured but also which nerve roots were involved. A 28-year-old male presented with simultaneous signs and symptoms of Erb's(C5) and Klumpke's(C8, T1) palsy, with sparing of the C6 and C7 roots. The patient presented several months ago to his local emergency room with shortness of breath, which was determined to be caused by left diaphragmatic paralysis through clinical and radiographical evidence. However, the etiology of the current nerve dysfunction in the upper extremity remained unknown. with persistent questioning and establishing the patient's trust in the caregivers, it was revealed that the patient had attempted suicidal hanging. we describe the clinical features and the likely mechanism of injury leading to this previously unreported combination of brachial plexus injuries. The unique injuries to this patient's brachial plexus can be explained by the sequence of events during the attempted suicidal hanging. The upper brachial plexus was injured during the initial moments where the neck was excessively stretched and the lower brachial plexus was injured due to the patient reaching up and holding himself by his arm for an extended period of time.

关键词： Erb’s palsy Klumpke’s palsy Hanging injury

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The Jesuits II: Cultures, Sciences, and the Arts, 1540–1773

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2006年

作者： John w. O'Malley Gauvin Alexander Bailey Steven J. harris T. frank Kennedy (eds.)

ISBN: (纸本)0802038611

Recent years have seen scholars in a wide range of disciplines re-evaluate the history of the Society of Jesus. In 1997, a group of scholars convened a major international conference to discuss the world of the Jesuits between 1540 and 1773 (the year of its suppression by papal edict). This meeting led to the creation of the first volume in this series, The Jesuits, which examined the worldwide Jesuit undertaking in such fields as music, art, architecture, devotional writing, mathematics, physics, astronomy, natural history, public performance, and education, with special attention to the Jesuits''interaction with non-European *** second volume, following a second conference in 2002, continues in a similar path as its predecessor, complementing the regional coverage with contributions on the Flemish and Iberian provinces, on the missions in Japan, and in post-Suppression Russia and the United States. The performing arts, like theatre and music, are broadly treated, and, in addition to continued attention to painting and architecture, the volume contains essays on a range of objets d''art, including statuary, reliquaries, and alter pieces - as well as on gardens, mechanical clocks, and related automata. Other themes include finances, natural theology, censorship within the Jesuit order, and the Society''s relationship to *** most important, the volume gives particular attention to the eighteenth century, the''age of disasters''for the Jesuits - the negative papal ruling on Chinese Rites, the destruction the of Paraguay Reductions, and the suppressions of the order that began in Portugal and that culminated in the general Suppression of 1773. with contributions from distinguished scholars from a dozen different countries, The Jesuits, II continues in the illustrious tradition of its predecessor to make an important contribution to religious memory.

关键词： Jesuits

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Arthroscopic Treatment of Acetabular Cartilage Lesions in Cam-Type Hip Impingement with Membrane Induced Chondrogenesis versus Microfracturing

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Journal of Sports Science 2016年第1期4卷 9-17页

作者： Goeminne Sofie Jan frank August Department of Orthopaedic Surgery University of Leuven Leuven 3000 Belgium Department of Orthopaedic Surgery Jan Yperman Hospital Ypres 8900 Belgium

we report on a consecutive series of patients with cam type FAI （femoro-acetabular impingement） with acetabular cartilage rim lesions larger than 150 mm2 that were treated with an arthroscopic AMIC （Autologous Matrix Induced Chondrogenesis） procedure and compared these patients to a matched cohort of patients who underwent an arthroscopic microfractufing. The AMIC group consisted 16 patients with a mean age of 34. Mean follow up is 38 months. Sixteen age and sex controlled patients who underwent an arthroscopic microfractufing of a similar size cartilage lesion were used as a comparative study group with a mean follow up of 41 months. No complications and no adverse reactions were seen, and all patients would have the same surgery again. we report 2 failures in the AMIC group with conversion to THR （Total Hip Replacement） at 8 and 36 months, respectively. In the microfracturing group, there were 3 conversions to THR after 12, 14 and 24 months. The HHS （harris Hip Score） was 96.5 in the AMIC group and 93.5 in the microfracturing group. Patients had significantly less symptomatic synovitis postoperatively in the AMIC group and more athletes could resume their activities to the pre-injury level in this group. In conclusion, AMIC offers promising results in the treatment of cartilage lesions in patients with cam-type FAI.

关键词： FAI cartilage lesions hip arthroscopy AMIC.

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现代工程建设管理

现代工程建设管理

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1995年

作者：（英）F·哈里斯（frank harris）（英）R·麦卡费（Ronald McCaffer）吴之明等译

书名原文:Modern construction management:本书全面介绍了工程建设中从现场管理到上层管理所涉及的各种问题,并反映这个领域近期发展的新成果。

关键词：建筑工程施工管理工程管理

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