The theory of instantaneous power in three-phase four-wire systems: a comprehensive approach

This paper describes a holistic approach to the theory of instantaneous power in three-phase four-wire systems, focusing on the original theory created in 1983 and a modified theory presented in 1994. The two theories are perfectly identical if no zero-sequence voltage is included in a three-phase three-wire system. However, they are different in the instantaneous active and reactive power in each phase if a zero-sequence voltage and current are included in a three-phase four-wire system. Theory and computer simulations in this paper lead to the following conclusions: an active filter without energy storage components can fully compensate for the neutral current even in a three-phase four-wire system including a zero-sequence voltage and current, when a proposed control strategy based on the original theory is applied. However, the active filter cannot compensate for the neutral current fully, when an already-proposed control strategy based on the modified theory is applied</p

What Motivates Software Piracy in China: Q-Methodology Perspective

This study explores why Chinese consumers use pirated software programs and how they think about their illegal use, relying on Q methodology. We developed 32 Q statements that outline reasons for using pirated software and surveyed 30 respondents from public officials, and software companies employees to students, professors, researchers, and the public. We developed four Q factors to describe four types of response to the use of pirated software. One group addresses a normative legal response, the second makes an economic utility argument, the third calls for punishing violators, and the fourth claims that they find themselves facing an uncomfortable dilemma in having to choose between the cheapness of illegal software and its illegality. Chinese respondents believe that government intervention can reduce the extent of illegal use (normative legal) and that intellectual property should be protected (economic utility). Furthermore, they acknowledged that the illegal use of software is a socio-structural problem across all social groups rather than a problem of a specific demographic group, such as a group of teenagers. Future research is required to explore not only whether or not perceptions regarding the use of illegal software vary from country to country but also how Confucian culture and norms are related to attitudes about the widespread use of counterfeit products in Asian countries

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A 24-Week, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Efficacy, Safety and Tolerability of the Rivastigmine Patch in Japanese Patients with Alzheimer's Disease

Background: As of 2010, the rivastigmine patch was licensed for the treatment of Alzheimer’s disease (AD) in 64 countries. Methods: This 24-week, multicenter, randomized, double-blind, placebo-controlled study evaluated the efficacy, safety and tolerability of the 5-cm2 (9-mg loading dose; 4.6 mg/24 h delivery rate) and 10-cm2 (18-mg loading dose; 9.5 mg/24 h delivery rate) rivastigmine patch in Japanese patients with AD. Results: In the primary analysis population (intent-to-treat last observation carried forward) at week 24, delayed deterioration was seen with the 10-cm2 patch versus placebo on the Japanese version of the Alzheimer’s Disease Assessment Scale-cognitive subscale (ADAS-J cog; p = 0.005) and the Japanese version of the Clinician’s Interview-Based Impression of Change plus Caregiver Input (CIBIC plus-J; p = 0.067). Participants receiving the rivastigmine patch showed numerically less decline versus placebo at week 24 on the CIBIC plus-J, although this did not reach statistical significance. Statistical significance for the CIBIC plus-J was met following adjustment for body weight and baseline Mini-Mental State Examination score as dynamic allocation factors (p = 0.042) and on the Disability Assessment for Dementia (DAD; p = 0.024) and Mental Function Impairment (MENFIS; p = 0.016) subscales. Serious adverse events were rare and were consistent with the known safety profile of the rivastigmine patch. Conclusion: The rivastigmine patch has a favorable efficacy and tolerability profile in Japanese patients with AD

Synthesis of fluorinated analogues of a practical polymer TQ for improved open-circuit voltages in polymer solar cells

In an attempt to further lower the HOMO of a cost-effective polymer poly(2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-dyl-alt-thiophene-2,5-diyl) (TQ) by adding F atoms onto the existing quinoxaline acceptor within the polymer backbone, we have synthesized two structurally identical fluorinated analogues of TQ (TQ-F (single F) and TQ-FF (double F)), except for the number of F atoms. The effects of inclusion of F atoms on the optical property, nature of charge transport, and molecular organization are thoroughly investigated. The resulting two fluorinated polymers show a decrease in both the HOMO and the LUMO energy levels relative to non-fluorinated TQ. Moreover, the fluorination of the polymer backbone has lowered the HOMOs more than the LUMOs, slightly widening the energy bandgaps as the number of F atoms increases. Thus, use of these polymers in bulk-heterojunction (BHJ) solar cells, in all cases, leads large VOC values. The power conversion efficiency (PCE) of the optimized PSCs based on TQ-F reaches 4.41%. In addition, it is interesting to note that, despite TQ-FF having the PCE that is lower than TQ-F, an unprecedentedly high VOC of 1.00 V is achieved, which is nearly equaled the highest VOC values ever reported for polymers.close4

Replacing the metal oxide layer with a polymer surface modifier for high-performance inverted polymer solar cells

Replacing ZnO with PEIE, both as a surface modifier for the low work function electrode and as an electron selective layer, enhances the performance and air stability of inverted polymer solar cells by improving electron transport, wettability between the active layer and the cathode, and maximizing light absorption within the active layer without light interference.close3

In vitro and in vivo assessments of an optimal polyblend composition of polycaprolactone/gelatin nanofibrous scaffolds for Achilles tendon tissue engineering

In this study, we manufactured various ratios of polycaprolactone (PCL)/gelatin (GE) highly aligned electrospun nanofibrous scaffolds (ENs) to investigate the effects of polymer ratio on tenogenic differentiation activity. For biological assessments, the cell proliferation rate was optimal in the PCL/GE (9:1) group. Interestingly, however, the tenogenic differentiation rate was best for the PCL/GE (7:3) group. From our outcomes, we established that a poly-blending mix of PCL/GE (7:3) is a promising ratio for tenogenic differentiation. Thus, our findings may provide for an effective mesh to promote tenogenic differentiation of ENs in future tendon tissue engineering applications.This work was supported by the Bio & Medical Technology Development Program of the National Research Foundation (NRF) & funded by the Korean government (MSIP&MOHW) (No. 2017M3A9E4048170)

Symmetry-breaking in patch formation on triangular gold nanoparticles by asymmetric polymer grafting

Synthesizing patchy particles with predictive control over patch size, shape, placement and number has been highly sought-after for nanoparticle assembly research, but is fraught with challenges. Here we show that polymers can be designed to selectively adsorb onto nanoparticle surfaces already partially coated by other chains to drive the formation of patchy nanoparticles with broken symmetry. In our model system of triangular gold nanoparticles and polystyrene-b-polyacrylic acid patch, single- and double-patch nanoparticles are produced at high yield. These asymmetric single-patch nanoparticles are shown to assemble into self-limited patch‒patch connected bowties exhibiting intriguing plasmonic properties. To unveil the mechanism of symmetry- breaking patch formation, we develop a theory that accurately predicts our experimental observations at all scales—from patch patterning on nano- particles, to the size/shape of the patches, to the particle assemblies driven by patch‒patch interactions. Both the experimental strategy and theoretical prediction extend to nanoparticles of other shapes such as octahedra and bipyramids. Our work provides an approach to leverage polymer interactions with nanoscale curved surfaces for asymmetric grafting in nanomaterials engineering.Synthesis and self-assembly experiments for this work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under Award DE- SC0020723 (A.K. and Q.C.). Experiments were carried out in part in the Materials Research Laboratory Central Research Facilities, University of Illinois. Theory and simulation for this work was supported by the Department of the Navy, Office of Naval Research under ONR award number N00014-18-1-2497 (T.V. and S.C.G). This research utilized computational resources and services supported by Advanced Research Computing at the University of Michigan, Ann Arbor, and provided by the Extreme Science and Engineering Discovery Envir- onment (XSEDE), which is supported by National Science Foundation Grant ACI-1053575, XSEDE Award DMR 140129 (T.V. and S.C.G.). LSPR of this work was performed by P.B. at the Center for Nanoscale Mate- rials, a U.S. Department of Energy Office of Science User Facility, and was supported by the U.S. DOE, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. D.M. and P.B. acknowledge partial support from the Center for Dynamics and Control of Materials: an NSF Materials Research Science and Engineering Center (NSF MRSEC) under Cooperative Agreement DMR-1720595 and the Welch Founda- tion (F-1848).Center for Dynamics and Control of Material

Synergistic surface modification for high-efficiency perovskite nanocrystal light-emitting diodes: divalent metal ion doping and halide-based ligand passivation

Surface defects of metal halide perovskite nanocrystals (PNCs) substantially compromise the optoelectronic performances of the materials and devices via undesired charge recombination. However, those defects, mainly the vacancies, are structurally entangled with each other in the PNC lattice, necessitating a delicately designed strategy for effective passivation. Here, a synergistic metal ion doping and surface ligand exchange strategy is proposed to passivate the surface defects of CsPbBr3 PNCs with various divalent metal (e.g., Cd2+, Zn2+, and Hg2+) acetate salts and didodecyldimethylammonium (DDA+) via one-step post-treatment. The addition of metal acetate salts to PNCs is demonstrated to suppress the defect formation energy effectively via the ab initio calculations. The developed PNCs not only have near-unity photoluminescence quantum yield and excellent stability but also show luminance of 1175 cd m−2, current efficiency of 65.48 cd A−1, external quantum efficiency of 20.79%, wavelength of 514 nm in optimized PNC light-emitting diodes with Cd2+ passivator and DDA ligand. The “organic–inorganic” hybrid engineering approach is completely general and can be straightforwardly applied to any combination of quaternary ammonium ligands and source of metal, which will be useful in PNC-based optoelectronic devices such as solar cells, photodetectors, and transistors

Highly efficient plasmonic organic optoelectronic devices based on a conducting polymer electrode incorporated with silver nanoparticles

Highly efficient ITO-free polymeric electronic devices were successfully demonstrated by replacement of the ITO electrode with a solution-processed PEDOT:PSS electrode containing Ag nanoparticles (NPs). Polymer solar cells (PSCs) and light emitting diodes (PLEDs) were fabricated based on poly(5,6-bis(octyloxy)-4-(thiophen-2-yl)benzo[c][1,2,5]thiadiazole) (PTBT):PC61BM and Super Yellow as a photoactive layer, respectively. The surface plasmon resonance (SPR) effect and improved electrical conductivity by the Ag NPs clearly contributed to increments in light absorption/emission in the active layer as well as the conductivity of the PEDOT:PSS electrode in PSCs and PLEDs. The ITO-free bulk heterojunction PSCs showed a 1% absolute enhancement in the power conversion efficiency (3.27 to 4.31%), and the power efficiency of the PLEDs was improved by 124% (3.75 to 8.4 lm W-1) compared to the reference devices without Ag NPs. The solution-processable conducting polymer, PEDOT:PSS with Ag NPs, can be a promising electrode for large area and flexible optoelectronic devices with a low-cost fabrication process.close11