A Facet‐Specific Quantum Dot Passivation Strategy for Colloid Management and Efficient Infrared Photovoltaics

Colloidal nanocrystals combine size‐ and facet‐dependent properties with solution processing. They offer thus a compelling suite of materials for technological applications. Their size‐ and facet‐tunable features are studied in synthesis; however, to exploit their features in optoelectronic devices, it will be essential to translate control over size and facets from the colloid all the way to the film. Larger‐diameter colloidal quantum dots (CQDs) offer the attractive possibility of harvesting infrared (IR) solar energy beyond absorption of silicon photovoltaics. These CQDs exhibit facets (nonpolar (100)) undisplayed in small‐diameter CQDs; and the materials chemistry of smaller nanocrystals fails consequently to translate to materials for the short‐wavelength IR regime. A new colloidal management strategy targeting the passivation of both (100) and (111) facets is demonstrated using distinct choices of cations and anions. The approach leads to narrow‐bandgap CQDs with impressive colloidal stability and photoluminescence quantum yield. Photophysical studies confirm a reduction both in Stokes shift (≈47 meV) and Urbach tail (≈29 meV). This approach provides a ≈50% increase in the power conversion efficiency of IR photovoltaics compared to controls, and a ≈70% external quantum efficiency at their excitonic peak.     

Electrical characterization of n/p-type nickel silicide/silicon junctions by Sb segregation

In this paper, n/p-type nickel-silicided Schottky diodes were fabricated by incorporating antimony atoms near the nickel silicide/Si junction interface and the electrical characteristics were studied through measurements and simulations. The effective Schottky barrier height (SBH) for electron, extracted from the thermionic emission model, drastically decreased from 0.68 to less than 0.1 eV while that for hole slightly increased from 0.43 to 0.53 eV. In order to identify the current conduction mechanisms, the experimental current-temperature-voltage characteristics for the n-type diode were fitted based on various models for transport of charge carrier in Schottky diodes. As the result, the large change in effective SBH for electron is ascribed to trap-assisted tunneling rather than barrier height inhomogeneity.     

Reliability-based robust design optimization for torque ripple reduction considering manufacturing uncertainty of interior permanent magnet synchronous motor

Journal of Mechanical Science and Technology - This study performed reliability-based robust design optimization (RBRDO) of stator and rotor shape of the IPM type electric motor to reduce the...     

Smartphone user segmentation based on app usage sequence with neural networks

The term user segmentation refers to classifying users into groups depending on their specific needs, characteristics, or behaviors. It is a key element of product development and marketing in many industries, such as the smartphone industry, which employs user segmentation to gather information about usage logs, to produce new products for such specific groups of users. However, previous studies on smartphone user segmentation have been primarily based on demographics and reported usage, which are inherently subjective and prone to skew by the observers and participants. Hamka et al. (2014) was the first to conduct a study, in which smartphone user segmentation was performed using log data collected through smartphone measurements. However, they focused only on network usage and the number of apps used, and not on characteristics or preferences. In this study, we proposed novel ways of segmenting smartphone users based on app usage sequences collected from smartphone logs. We proposed a variant of seq2seq architecture combining the advantages of previous deep neural networks: neural embedding architecture and seq2seq architecture. Furthermore, we compared the user segmentation results of the proposed method with an answer set of segmentation results conducted by domain experts. These experiments demonstrated that the proposed method effectively determines similarities between usage sequences and outperforms existing user segmentation methods.     

Highly efficient gene silencing and bioimaging based on fluorescent carbon dots <Emphasis Type="Italic">in vitro</Emphasis> and <Emphasis Type="Italic">in vivo</Emphasis>

Small interfering RNA (siRNA) is an attractive therapeutic candidate for sequencespecific gene silencing to treat incurable diseases using small molecule drugs.However,its efficient intracellular delivery has remained a challenge.Here,we have developed a highly biocompatible fluorescent carbon dot (CD),and demonstrate a functional siRNA delivery system that induces efficient gene knockdown in vitro and in vivo.We found that CD nanoparticles (NPs) enhance the cellular uptake of siRNA,via endocytosis in tumor cells,with low cytotoxicity and unexpected immune responses.Real-time study of fluorescence imaging in live cells shows that CD NPs favorably localize in cytoplasm and successfully release siRNA within 12 h.Moreover,we demonstrate that CD NP-mediated siRNA delivery significantly silences green fluorescence protein (GFP) expression and inhibits tumor growth in a breast cancer cell xenograft mouse model of tumor-specific therapy.We have developed a multi functional siRNA delivery vehicle enabling simultaneous bioimaging and efficient downregulation of gene expression,that shows excellent potential for gene therapy.     

Past,present, and future of WCG technology in display

We will introduce the development trend of colorant and color technology along the grown of display industry. Wide color gamut (WCG) technology with high contrast ratio and transmittance has been developed from colorant design to color filter process, product reliability, and performance enhancement. In this paper, WCG technology for liquid crystal display (LCD) and organic light emitting diode (OLED) and trend of colorant, which is including color conversion material (CCM), were discussed. We hope that it will help you to understand the development flow of colorant in the display industry.     

The Characteristics of Seebeck Coefficient in Silicon Nanowires Manufactured by CMOS Compatible Process

Silicon nanowires are patterned down to 30 nm using complementary metal-oxide-semiconductor (CMOS) compatible process. The electrical conductivities of n-/p-leg nanowires are extracted with the variation of width. Using this structure, Seebeck coefficients are measured. The obtained maximum Seebeck coefficient values are 122 μV/K for p-leg and −94 μV/K for n-leg. The maximum attainable power factor is 0.74 mW/m K² at room temperature.     

Alterations of regional cerebral blood flow after NMDA receptor antagonist administration in patients with alcohol‐related dementia

Although N‐methyl‐d ‐aspartate (NMDA) receptor antagonists may have beneficial influences on cognition in patients with alcohol‐related dementia (ARD), their effects on regional cerebral blood flow (rCBF) remain unknown. This study evaluated changes in rCBF in ARD patients after administration of NMDA receptor antagonist for 12 weeks using technetium‐99m ethyl cysteinate dimer (Tc‐99m ECD) single‐photon emission computed tomography (SPECT). Twenty‐eight ARD patients were administered memantine for 12 weeks and underwent clinical evaluations and brain SPECT scans at baseline and follow‐up. Whole‐brain changes in perfusion were examined on a voxel‐by‐voxel basis. At follow‐up, the patients showed reduced rCBF in the left medial frontal gyrus, left cingulate gyrus, left claustrum, right brainstem, left superior temporal gyrus, bilateral fusiform gyrus, and left cerebellum. On the other hand, increased rCBF was found in the bilateral uncus, left parahippocampal gyrus, bilateral superior frontal gyrus, right inferior parietal lobule, left cuneus, and left superior temporal gyrus. Perfusion increases in various brain areas including the superior frontal, parahippocampal, and inferior parietal areas, which may play important roles in the pathophysiology of ARD, suggest potential benefits of NMDA receptor antagonists on brain functions in patients with ARD.     

Proteome analysis of virulence factor regulated by autoinducer-2-like activity in Escherichia coli O157:H7

Many pathogenic bacteria, including Escherichia coli O157:H7, can control gene expression in a cell density-dependent manner by producing small signaling molecules (autoinducers) in a process known as quorum sensing. In this study, the effects of the autoinducer-2-like activity on the expression of proteins, including virulence factors, in E. coli O157:H7 were characterized by proteomic analysis. Compared with the control, E. coli O157:H7 strains in the presence of autoinducer-2-like activity exhibited elevated virulence by more rapidly forming cell aggregates on epithelial cells and rapidly killing the nematode Caenorhabditis elegans, the surrogate host. Two-dimensional gel electrophoresis revealed 18 proteins that were upregulated by autoinducer-2-like activity and 4 proteins that were down-regulated. These proteins were further characterized by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry and are involved in the metabolic process, adaptation and protection, cell motility, secretion, envelope biogenesis, and protein translation. These results indicate that the newly identified proteins are associated with the control of virulence in E. coli O157:H7 and that these proteins can be potential targets for the development of antibiotics and other antimicrobial agents.