How does technology startups increase innovative performance? The study of technology startups on innovation focusing on employment change in Korea

As the fourth industrial revolution has been emerging, there are concerns of labor forces being replaced by technology, recent interest on the work-life balance, and the quality of employment has received attention. This study investigates the role of technology startups on employment and innovative performance. Using empirical data from workplace panel data provided by the Korea Labor Institute, this study reveals that technology startups impact the employment quality and innovative performance by the action of technological innovation. The results highlight the quality of employment as a driver for innovative performance in technology startups. The results of this study will provide practical implications for enhancing technology entrepreneurship

Spontaneous Formation of Gold Nanoparticles on Graphene by Galvanic Reaction through Graphene

We demonstrate an effective and facile method for the deposition of gold nanoparticles (AuNPs) on graphene by using spontaneous galvanic reaction. Despite the interest and importance of the hybrid structure of noble metal-deposited graphene has been considerably increased for its fundamental knowledge in chemical and physical sciences and for its various applications, the progress of this subject is very slow mainly because of the lack of synthetic methods for such structures, especially that are not free from chemical contamination and usage of complex and expensive equipment. Therefore, we developed a new method allowing chemically pure AuNPs/graphene hybrid structures employing galvanic reaction. The spontaneous galvanic reaction was derived from reductant/graphene/oxidant sandwich structures, such as Au ions/graphene/Ge wafer and Au ions/graphene/copper foil, by placing Au ion solution droplets on graphene transferred on a germanium wafer or as made graphene on Cu foil, respectively. According to scanning electron microscopy and atomic force microscopy results, it was confirmed that AuNPs were successfully formed on the graphene surface. This result implies two important points. One is that the formation of pure AuNPs on graphene is possible without using other chemicals frequently required for conventional NP preparation. The other one is that it was experimentally demonstrated that there are electronic communications between the oxidant and reductant that are separated by graphene, through which electrons can pass freely.11Ysciescopu

CONTROL OF COLUMNAR-TO-EQUIAXED TRANSITION IN CONTINUOUS CASTING OF 16% Cr STAINLESS STEEL

In continuous casting of 16%Cr ferritic stainless steel, columnar grains undesirably forming among equiaxedgrains make non-uniform microstructure and degrade ridging property. Since this phenomenon results fromthe change of solidification condition during continuous casting, we focused on Cellular-to-Equiaxed Transition(CET) in continuous casting of 16%Cr ferritic stainless steel to control the microstructure of as-cast slab.In order to find the CET condition, we carried out the one dimensional heat transfer analysis of the melt, andpredicted the CET condition by Hunt’s model. It was revealed that the secondary columnar grains usually formedat 0.5~0.8 solid fractions, and the formation of them resulted from a steep increase of G/V1/2 value as themelt was getting out of EMS field; however the increase of G/V1/2 was readily controlled by changing EMSpattern and the secondary cooling intensity. In result, secondary columnar grains were eliminated by optimizingthe upper and lower EMS intensity, and increasing secondary cooling intensity. We also investigatedthe effect of solidification parameters including superheat and casting speed as CET condition in continuouscasting process, and the results were also discussed by the terms of thermal condition of melt

Highly reproducible alkali metal doping system for organic crystals through enhanced diffusion of alkali metal by secondary thermal activation

In this paper, we report an efficient alkali metal doping system for organic single crystals. Our system employs an enhanced diffusion method for the introduction of alkali metal into organic single crystals by controlling the sample temperature to induce secondary thermal activation. Using this system, we achieved intercalation of potassium into picene single crystals with closed packed crystal structures. Using optical microscopy and Raman spectroscopy, we confirmed that the resulting samples were uniformly doped and became K2picene single crystal, while only parts of the crystal are doped and transformed into K2picene without secondary thermal activation. Moreover, using a customized electrical measurement system, the insulator-to-semiconductor transition of picene single crystals upon doping was confirmed by in situ electrical conductivity and ex situ temperature-dependent resistivity measurements. X-ray diffraction studies showed that potassium atoms were intercalated between molecular layers of picene, and doped samples did not show any KH- nor KOH-related peaks, indicating that picene molecules are retained without structural decomposition. During recent decades, tremendous efforts have been exerted to develop high-performance organic semiconductors and superconductors, whereas as little attention has been devoted to doped organic crystals. Our method will enable efficient alkali metal doping of organic crystals and will be a resource for future systematic studies on the electrical property changes of these organic crystals upon doping. © 2018 The Author(s

Extreme waves generated by Typhoon Bolaven (201215) in Southern Korean waters

Unusual extreme waves were generated by Typhoon Bolaven (201215) in the Southern Korean Waters\ud (SKW) and gave destructive damages to the breakwaters of Seogwipo Harbor at Jeju Island. The waves were far\ud exceeding the design wave height (Hs50yrs 9.3m) and their duration was 14hours. The duration is a very significant\ud factor as much as the design wave height for breakwater armor stability in terms of cumulative damages. A significant\ud increase in strong typhoon intensity and duration in North West Pacific (NWP) due to global warming has been reported\ud and also in landfall typhoons on Korea/Japan in a recent decade. The frequency of typhoon passed SKW region had an\ud inter-annual and also a decadal variation and decreased in recent years, but several strong typhoons were occurred.\ud Bolaven was affected by high pressure distribution located above the warm eddy region to track toward NNW rather\ud than NE as usual in August. The extreme waves were analyzed with respect to typhoon genesis, evolution of the waves\ud through extensive measured data and model simulation. Numerical models of TC96 for the wind fields and WAM4.5.2\ud for the waves were used after calibration with measured data and correction of Cd in wave growth term. They produced\ud reasonably good results. It was found that the extreme waves were evolved by combination of distant large swell and\ud strong wind seas generated by consistent strong winds from front right quadrant of typhoon track for such a long time.\ud The variation of those waves was relatively small as 1-2m, which might be due to limitation of wave growth for\ud U>30m/s and bottom energy dissipation of long period waves in the region. It is essential to hindcast accurately the\ud extreme waves for design of the breakwaters and also for assessment of coastal flooding and coastal erosion in a\ud warming climate

Three-Dimensional Superconductivity in the Infinite-Layer Compound Sr_{0.9}La_{0.1}CuO_2 in Entire Region below TcT_c

The infinite-layer compound ACuO$_{2}$ (A $=$ alkaline-earth ions) is regarded as the most suitable material for exploring the fundamental nature of the CuO$_2$ plane because it does not contain a charge-reservoir block, such as a rock-salt or a fluorite like block. We report that superconductivity in the infinite-layer compound Sr$_{0.9}$La$_{0.1}$CuO$_2$ is of a three-dimensional nature, in contrast to the quasi two-dimensional superconducting behavior of all other cuprates. The key observation is that the $c$-axis coherence length is longer than the $c$-axis lattice constant even at zero temperature. This means that the superconducting order parameter of one CuO$_{2}$ plane overlaps with those of neighboring CuO$_{2}$ planes all the temperatures below the $T_c$. Among all cuprates, only the infinite-layer superconductor shows such a feature.Comment: 4 pages and 4 figure

Benefits of active middle ear implants over hearing aids in patients with sloping high tone hearing loss: comparison with hearing aids

In questo studio retrospettivo, abbiamo confrontato i benefici oggettivi e soggettivi degli impianti attivi dell’orecchio medio (AMEI) rispetto alle tradizionali protesi acustiche (HA) nei pazienti con perdita dell’udito per le frequenze acute. Trentaquattro pazienti con ipoacusia neurosensoriale sono stati trattati con l’impianto di AMEI. Tra questi, sei avevano un audiogramma “in discesa” con perdita dell’udito per le frequenze acute, ed avevano usato per più di sei mesi HA. È stata quindi eseguita una valutazione oggettiva, tramite l’audiometria tonale e il test di riconoscimento delle parole, una versione coreana del “Hearing in Noise Test” (K-HINT), ed una valutazione soggettiva tramite il seguente questionario: Abbreviated Profile of Hearing Aid Benefit (APHAB). I pazienti sono stati sottoposti ai suddetti test in tre occasioni distinte: 1) prima della chirurgia, senza protesi; 2) prima della chirurgia, con HA; 3) tre mesi dopo l’impianto di AMEI. Il guadagno medio per le alte frequenze (≥ 2 kHz) si è rivelato migliore con AMEI che con HA. Sebbene il risultato non ha raggiunto un livello di significatività statistica, gli impianti attivi dell’orecchio medio hanno mostrato un punteggio di riconoscimento delle parole superiore rispetto a HA. Ad ogni modo, il livello di comoda udibilità al quale il punteggio di riconoscimento delle parole è stato testato si è rivelato significativamente più basso con AMEI rispetto ad HA. Al K-HINT i pazienti con AMEI hanno mostrato un migliore riconoscimento rispetto ai risultati ottenuti con HA, sia in condizione di quiete sia di rumore. Gli score APAHB hanno rivelato che i pazienti erano più soddisfatti con AMEI. L’uso degli impianti attivi dell’orecchio medio in pazienti con perdita dell’udito per le frequenze acute ha permesso di ottenere risultati migliori rispetto all’utilizzo delle protesi tradizionali. Basandoci su questi dati, gli AMEI hanno offerto risultati oggettivi e soggettivi migliori, e pertanto, potrebbero rappresentare una valida alternativa per il trattamento delle ipoacusie con audiogramma in discesa

Time and Amplitude of Afterpulse Measured with a Large Size Photomultiplier Tube

We have studied the afterpulse of a hemispherical photomultiplier tube for an upcoming reactor neutrino experiment. The timing, the amplitude, and the rate of the afterpulse for a 10 inch photomultiplier tube were measured with a 400 MHz FADC up to 16 \ms time window after the initial signal generated by an LED light pulse. The time and amplitude correlation of the afterpulse shows several distinctive groups. We describe the dependencies of the afterpulse on the applied high voltage and the amplitude of the main light pulse. The present data could shed light upon the general mechanism of the afterpulse.Comment: 11 figure