Successive melting and crystallization of poly(3-hexylthiophene) in the melt-memory domain versus isotropic melt domain

Journal of Materials Science - We studied the influence of self-nuclei of poly(3-hexylthiophene), present at different temperatures in the melt-memory domain, and thermal polymer degradation during...     

Chemically Tuned p‐ and n‐Type WSe2 Monolayers with High Carrier Mobility for Advanced Electronics

Monolayers of transition metal dichalcogenides (TMDCs) have attracted a great interest for post‐silicon electronics and photonics due to their high carrier mobility, tunable bandgap, and atom‐thick 2D structure. With the analogy to conventional silicon electronics, establishing a method to convert TMDC to p‐ and n‐type semiconductors is essential for various device applications, such as complementary metal‐oxide‐semiconductor (CMOS) circuits and photovoltaics. Here, a successful control of the electrical polarity of monolayer WSe₂ is demonstrated by chemical doping. Two different molecules, 4‐nitrobenzenediazonium tetrafluoroborate and diethylenetriamine, are utilized to convert ambipolar WSe₂ field‐effect transistors (FETs) to p‐ and n‐type, respectively. Moreover, the chemically doped WSe₂ show increased effective carrier mobilities of 82 and 25 cm² V^?1s^?1 for holes and electrons, respectively, which are much higher than those of the pristine WSe₂. The doping effects are studied by photoluminescence, Raman, X‐ray photoelectron spectroscopy, and density functional theory. Chemically tuned WSe₂ FETs are integrated into CMOS inverters, exhibiting extremely low power consumption ( ≈ 0.17 nW). Furthermore, a p‐n junction within single WSe₂ grain is realized via spatially controlled chemical doping. The chemical doping method for controlling the transport properties of WSe₂ will contribute to the development of TMDC‐based advanced electronics.     

A CPW-fed wearable antenna at ISM band for biomedical and WBAN applications

Wireless Networks - In this paper, a Mercedes-Benz logo antenna with a metal plate located at an optimized distance from the proposed antenna is introduced as a wearable antenna to operate in the...     

Can energy optimization lead to economic and environmental waste in LPWAN architectures?

As low-power wide-area network (LPWAN) end devices (EDs) are deployed in massive scale, their economic and environmental costs of operation are becoming too significant to ignore and too difficult to estimate. While LPWAN architectures and protocols are designed to primarily save energy, this study shows that energy saving does not necessarily lead to lower cost or environmental footprint of the network. Accordingly, a theoretical framework is proposed to estimate the operational expenditure (OpEx) and environmental footprint of LPWAN EDs. An extended constrained optimization model is provided for the ED link assignment to gateways (GWs) based on heterogeneous ED configurations and hardware specifications. Based on the models, a simulation framework is developed which demonstrates that OpEx, energy consumption, and environmental footprint can be in conflict with each other as constrained optimization objectives. We demonstrate different ways to achieve compromises in each dimension for overall improved network performance.     

Inverse Kinematics Based Human Mimicking System using Skeletal Tracking Technology

Humanoid robots needs to have human-like motions and appearance in order to be well-accepted by humans. Mimicking is a fast and user-friendly way to teach them human-like motions. However, direct assignment of observed human motions to robot’s joints is not possible due to their physical differences. This paper presents a real-time inverse kinematics based human mimicking system to map human upper limbs motions to robot’s joints safely and smoothly. It considers both main definitions of motion similarity, between end-effector motions and between angular configurations. Microsoft Kinect sensor is used for natural perceiving of human motions. Additional constraints are proposed and solved in the projected null space of the Jacobian matrix. They consider not only the workspace and the valid motion ranges of the robot’s joints to avoid self-collisions, but also the similarity between the end-effector motions and the angular configurations to bring highly human-like motions to the robot. Performance of the proposed human mimicking system is quantitatively and qualitatively assessed and compared with the state-of-the-art methods in a human-robot interaction task using Nao humanoid robot. The results confirm applicability and ability of the proposed human mimicking system to properly mimic various human motions.     

The crossover of strain from school principals to teachers and vice versa.

The study investigated crossover of stress and strain in the workplace on a sample of 47 school principals and 183 teachers in Israeli elementary schools. The main goal of this study was to examine whether the crossover effect found among couples in the family also exists in the workplace. A 2nd aim of the study as to unravel the mechanisms that account for the crossover process. Using structural equation modeling, the authors found a significant crossover of job-induced tension but not of burnout from principals to teachers and vice versa. Being undermined by their principals elevated teachers' burnout and job-induced tension. This is the 1st study to demonstrate crossover of strain in the workplace and to discuss the implications of contagious job-induced tension in work environments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

制革固体废弃物的吸附特性

分别研究了含铬废革屑和含单宁废革屑对染料和金属离子的吸附特性.结果表明：含铬废革屑对酸性染料和直接染料具有较强的吸附能力,而对碱性染料的吸附能力较弱;含单宁废革屑对Au3+、U6+、Th4+及Hg2+具有较强的吸附能力.含铬废革屑对染料的吸附平衡符合Langmuir方程;含单宁废革屑对Cu2+、U6+、Pb2+和Hg2+的吸附平衡符合Freundlich方程,而对Au3+及Th4+的吸附平衡符合Langmuir方程,因此含单宁废革屑对不同的金属离子可能具有不同的吸附机理.含铬废革屑对染料的吸附动力学以及含单宁废革屑对金属离子的吸附动力学均符合拟二级速度方程.含铬废革屑固定床对染料具有良好的吸附特性,固定床易再生和重复使用.含单宁废革屑固定床对Au3+的吸附量很大,但不易再生;而吸附其他金属离子后则容易再生,而且其吸附性能变化不大.     

塔里木油田酸压返排液重复利用研究

为确定组成复杂、浮油和高价金属离子含量高、酸性强的塔里木油田酸压返排液处理后能否顺利地配制压裂液,通过对返排液水质分析,提出了一套"过滤-化学沉淀-絮凝沉降-压裂液配制"的处理工艺。大量的浮油影响压裂液的溶胀及交联,滤布过滤可去除浮油与块状杂质组成的黏稠物;高价金属离子阻碍稠化剂分子的伸展,影响压裂液的携砂性能,碳酸钠可直接沉淀金属离子并中和残酸;简单处理之后需絮凝剂进一步絮凝处理,除去返排液中的小颗粒杂质。将处理后的水调节至中性或弱酸性直接配制成压裂液使用,可杜绝环境污染,缓解油田水资源匮乏问题。沉淀剂质量浓度为145g/L、絮凝剂质量浓度为1 000mg/L时,返排液中悬浮颗粒杂质的去除率达98%,水质平均粒径2.36μm。利用处理后的酸压返排液配制的压裂液挑挂性能良好,其流变性能和黏弹性能与清水直接配制的压裂液相差不大,均满足SY/T 6376-2008《压裂液通用技术条件》常规压裂液性能标准,适用于塔里木油田超深井高温高剪切要求。研究表明,酸压返排液重复利用配制压裂液的工艺是可行的。     

Multifaceted Analysis of IL-23A- and/or EBI3-Including Cytokines Produced by Psoriatic Keratinocytes

Interleukin (IL) 23 (p19/p40) plays a critical role in the pathogenesis of psoriasis and is upregulated in psoriasis skin lesions. In clinical practice, anti-IL-23Ap19 antibodies are highly effective against psoriasis. IL-39 (p19/ Epstein-Barr virus-induced (EBI) 3), a newly discovered cytokine in 2015, shares the p19 subunit with IL-23. Anti-IL-23Ap19 antibodies may bind to IL-39; also, the cytokine may contribute to the pathogenesis of psoriasis. To investigate IL23Ap19- and/or EBI3-including cytokines in psoriatic keratinocytes, we analyzed IL-23Ap19 and EBI3 expressions in psoriasis skin lesions, using immunohistochemistry and normal human epidermal keratinocytes (NHEKs) stimulated with inflammatory cytokines, using quantitative real-time polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and liquid chromatography-electrospray tandem mass spectrometry (LC-Ms/Ms). Immunohistochemical analysis showed that IL-23Ap19 and EBI3 expressions were upregulated in the psoriasis skin lesions. In vitro, these expressions were synergistically induced by the triple combination of tumor necrosis factor (TNF)-α, IL-17A, and interferon (IFN)-γ, and suppressed by dexamethasone, vitamin D3, and acitretin. In ELISA and LC-Ms/Ms analyses, keratinocyte-derived IL-23Ap19 and EBI3, but not heterodimeric forms, were detected with humanized anti-IL-23Ap19 monoclonal antibodies, tildrakizumab, and anti-EBI3 antibodies, respectively. Psoriatic keratinocytes may express IL-23Ap19 and EBI3 proteins in a monomer or homopolymer, such as homodimer or homotrimer.