The electrical and optical properties of doped yttrium aluminum garnets

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1994.Includes bibliographical references (leaves 221-226).by Jimmy Kuo-Wei Chen.Ph.D

Pengaruh Struktur Modal, Ukuran Perusahaan, Kebijakan Deviden Terhadap Harga Saham Trade, Service, & Investment di Indonesia

Investment is carried out with the purpose of obtaining benefits. One of the investor benchmarks before invest their capital to a company is by monitoring its stock price. The objective of the research is to know the financial ratio indicated through a capital structure (DER), Firm size, dividend policy (DPR) towards the stock price. The researcher collects data by pulling documentation study sampling and purposive sampling to obtain 24 companies as research samples. In this research, data were analyzed using the Regression Testing method. The researcher found out that DER, Firm Size, DPR simultaneously affecting the stock price of Trade, Service & Investment companies from the year 2014 to 2018. Investors are expected to observe DER, Firm Size, DPR prior to investing. Investasi dilakukan dengan tujuan untuk memperoleh keuntungan sesuai dengan yang diharapkan. Salah satu hal yang menjadi tolak ukur bagi investor untuk menanamkan modalnya kepada suatu perusahaan adalah dengan melihat harga saham perusahaan tersebut. Berdasarkan hal tersebut, penelitian ini bertujuan untuk mengetahui rasio keuangan yang diwakili oleh struktur modal (DER), ukuran perusahaan (firm size), kebijakan dividen (DPR) terhadap harga saham. Teknik pengumpulan data menggunakan purposive sampling, dan di dapat sebanyak 24 sampel perusahaan dari 133 populasi perusahaan sector Trade, Service & Investment yang terdaftar di Bursa Efek Indonesia (BEI) periode 2014-2018. Model analisis mengunakan regresi linier berganda. Hasil penelitian menunjukkan bahwa secara simultan DER, Firm size, DPR berpengaruh terhadap harga saham pada perusahaan Trade, Service & Investment 2014-2018. Bagi investor di harapkan memperhatikan DER, Firm Size, DPR sebelum berinvestasi

Efecto del tamaño de pólipo y de los exudados de corales sobre la dinámica de picoeucariotas en un ambiente controlado

We examined the ability of scleractinian corals with different polyp sizes to remove picoeukaryotes by predation and the effect of coral exudates on picoeukaryote growth. Experiments were conducted by adding picoeukaryotes to Stylophora pistillata (SP) and Montipora stellata (MS). Within six hours the picoeukaryote concentration in the SP and MS tanks was significantly lower than the control without corals. SP showed higher overall activity than MS, and the particle removal activity of MS decreased in light conditions. Picoeukaryotes exposed to SP exudates grew significantly denser than those exposed to MS exudates or those in water without coral exudates. Dissolved organic carbon concentrations in the SP tanks were also significantly higher. We concluded that the picoeukaryote removal rates were higher in S. pistillata than in M. stellata, and coral exudates can reciprocally enhance picoeukaryote growth.Hemos estudiado la capacidad de corales escleractinios con diferentes tamaños de pólipo de depredar picoplancton eucariótico, y también el efecto de los exudados de los corales sobre el crecimiento de picoplancton eucariótico. Los experimentos se realizaron añadiendo picoplancton eucariótico a Stylophora pistillata (SP) y Montipora stellata (MS). Después de 6 horas, las concentraciones de picoplancton eucariótico en los tanques de SP y MS fueron significativamente reducidas, en comparación con las del tanque control sin coral. SP mostró en general una actividad depredadora algo más grande que MS, y éste redujo su actividad en condiciones de luz. Los picoeucariotas expuestos a exudados de SP llegaron a concentraciones más altas que cuando fueron expuestos a exudados de MS o a agua sin corales. La concentración de carbono orgánico disuelto en los tanques de SP también fué significativamente más alta. Se concluye que las tasas de depredación sobre los picoeukaryotes fueron más altas con S. pistillata que con M. stellata, y que los exudados del coral pueden recíprocamente mejorar el crecimiento de picoplancton eucariótico

Combinational effect of mutational bias and translational selection for translation efficiency in tomato (Solanum lycopersicum) cv. Micro-Tom

AbstractWe conducted a comprehensive analysis of codon usage bias (CUB) based on the available non-redundant full-length cDNA (nrFLcDNA) and expressed sequence tags (ESTs) data of cultivar Micro-Tom and evaluated the associations of observed CUB and measurements of transcriptional and translational effectiveness. The analysis presented in our study suggests a correlation, which is negative but highly correlated between Axis 1 and GC3s (r=−0.827, P<0.01), indicating that mutational bias has a significant and dominant repressive role to the choices of GC3. We also observed a strong positive correlation between codon adaptation index (CAI) and translational adaptation index (tAIg) (0.407, P<0.01), which demonstrates the facilitation of efficient translation by the optimal codon usage patterns of the highly expressed genes. We believe that the complete set of optimal codon usage patterns detected in this study will serve as a model to enhance the transgenesis in the studied cultivar of Solanum lycopersicum

Enhancement of average thermoelectric figure of merit by increasing the grain-size of Mg_(3.2)Sb_(1.5)Bi_(0.49)Te_(0.01)

Zintl compound n-type Mg_3(Sb,Bi)_2 was recently found to exhibit excellent thermoelectric figure of merit zT (∼1.5 at around 700 K). To improve the thermoelectric performance in the whole temperature range of operation from room temperature to 720 K, we investigated how the grain size of sintered samples influences electronic and thermal transport. By increasing the average grain size from 1.0 μm to 7.8 μm, the Hall mobility below 500 K was significantly improved, possibly due to suppression of grain boundary scattering. We also confirmed that the thermal conductivity did not change by increasing the grain size. Consequently, the sample with larger grains exhibited enhanced average zT. The calculated efficiency of thermoelectric power generation reaches 14.5% (ΔT = 420 K), which is quite high for a polycrystalline pristine material

Impacts of Seagrass on Benthic Microalgae and Phytoplankton Communities in an Experimentally Warmed Coral Reef Mesocosm

The effects of seagrass on microalgal assemblages under experimentally elevated temperatures (28°C) and CO2 partial pressures (pCO2; 800 μatm) were examined using coral reef mesocosms. Concentrations of nitrate, ammonium, and benthic microalgal chlorophyll a (chl-a) were significantly higher in seagrass mesocosms, whereas phytoplankton chl-a concentrations were similar between seagrass and seagrass-free control mesocosms. In the seagrass group, fewer parasitic dinoflagellate OTUs (e.g., Syndiniales) were found in the benthic microalgal community though more symbiotic dinoflagellates (e.g., Cladocopium spp.) were quantified in the phytoplankton community. Our results suggest that, under ocean acidification conditions, the presence of seagrass nearby coral reefs may (1) enhance benthic primary productivity, (2) decrease parasitic dinoflagellate abundance, and (3) possibly increase the presence of symbiotic dinoflagellates

Mg Deficiency in Grain Boundaries of n-Type Mg_3Sb_2 Identified by Atom Probe Tomography

Highly resistive grain boundaries significantly reduce the electrical conductivity that compromises the thermoelectric figure‐of‐merit zT in n‐type polycrystalline Mg_3Sb_2. In this work, discovered is a Mg deficiency near grain boundaries using atom‐probe tomography. Approximately 5 at% of Mg deficiency is observed uniformly in a 10 nm region along the grain boundary without any evidence of a stable secondary or impurity phase. The off‐stoichiometry can prevent n‐type dopants from providing electrons, lowering the local carrier concentration near the grain boundary and thus the local conductivity. This observation explains how nanometer scale compositional variations can dramatically determine thermoelectric zT, and provides concrete strategies to reduce grain‐boundary resistance and increase zT in Mg_3Sb_2‐based materials

High Thermoelectric Performance in PbSe–NaSbSe2 Alloys from Valence Band Convergence and Low Thermal Conductivity

PbSe is an attractive thermoelectric material due to its favorable electronic structure, high melting point, and lower cost compared to PbTe. Herein, the hitherto unexplored alloys of PbSe with NaSbSe2 (NaPbmSbSem+2) are described and the most promising p‐type PbSe‐based thermoelectrics are found among them. Surprisingly, it is observed that below 500 K, NaPbmSbSem+2 exhibits unorthodox semiconducting‐like electrical conductivity, despite possessing degenerate carrier densities of ≈1020 cm−3. It is shown that the peculiar behavior derives from carrier scattering by the grain boundaries. It is further demonstrated that the high solubility of NaSbSe2 in PbSe augments both the thermoelectric properties while maintaining a rock salt structure. Namely, density functional theory calculations and photoemission spectroscopy demonstrate that introduction of NaSbSe2 lowers the energy separation between the L‐ and Σ‐valence bands and enhances the power factors under 700 K. The crystallographic disorder of Na+, Pb2+, and Sb3+ moreover provides exceptionally strong point defect phonon scattering yielding low lattice thermal conductivities of 1–0.55 W m‐1 K‐1 between 400 and 873 K without nanostructures. As a consequence, NaPb10SbSe12 achieves maximum ZT ≈1.4 near 900 K when optimally doped. More importantly, NaPb10SbSe12 maintains high ZT across a broad temperature range, giving an estimated record ZTavg of ≈0.64 between 400 and 873 K, a significant improvement over existing p‐type PbSe thermoelectrics.The high solubility of NaSbSe2 in PbSe is exploited to facilitate convergence of L‐ and Σ‐valence bands and to produce strong point defect phonon scattering. These processes yield enhanced power factors and low lattice thermal conductivity over ≈300–700 K, which together give NaPb10SbSe12 outstanding thermoelectric performance with a maximum ZT ≈ 1.4 at 873 K and ZTavg ≈0.64 over 400–873 K.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151353/1/aenm201901377.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151353/2/aenm201901377-sup-0001-S1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151353/3/aenm201901377_am.pd