Perfect Grain Research Articles

An Investigation of Inorganic Arsenic Concentration in Whole Rice Grains and Ratio of Perfect Grain in ‘Koshihikari’/

An Investigation of Inorganic Arsenic Concentration in Whole Rice Grains and Ratio of Perfect Grain in ‘Koshihikari’/

Evaluation of mechanical and wear properties of aluminum 7075 alloy hybrid nanocomposites with the additions of SiC/Graphite

This research investigated the impact of graphite on Al 7075-SiC-Graphite hybrid composite's wear performance. The analysis demonstrates that effectiveness of graphite presence in the matrix to minimize wear. The hybrid metal matrix Nano composites were manufactured via Powder metallurgy process by reinforcing graphite at different weight fractions (0 percent, 5 percent) with 7075 aluminium alloy, the addition of Silicon Carbide (SiC) is fixed at 5 percent. The density, toughness, micro structural analysis, and wear performance of prepared hybrid nano composites have been analyzed and investigated. In the experimental investigation, it was observed that reinforcing particles are uniformly dispersed throughout the matrix alloy as perfect grain boundaries in alumnium solid solutions. The density and hardness of the reinforced composites have been significantly effected with the incorporation of the reinforcement when compared to a monolithic alloy. The significant increasing trend in mechanical properties and wear performance of aluminium hybrid composites was accomplished by the addition of solid lubricant (Gr) and strong ceramic reinforcing particles (SiC) in the matrix alloy.

Effects of Organic and Inorganic Fertilizer Application on Growth, Yield, and Grain Quality of Rice

Nutrient management and fertilizer application are influential elements for high yield and preferred grain quality. Negligible information is available regarding fertilizer application in the paddy fields in Afghanistan. This research elucidates the efficacy of different fertilizers’ application on growth attributes, yield potential, and grain quality of rice. The treatments included the traditional application rate of nitrogen and phosphorus (RD), animal manure (AM), animal manure with 50% nitrogen and phosphorus of the traditional application rate (AMRD), sawdust (SD), and sawdust with 50% nitrogen and phosphorus of the traditional application rate (SDRD). Growth parameters, grain yield and its components, physicochemical properties, and morphological observation using scanning electron microscopy were recorded. The results revealed that the greatest panicle number, spikelet number, and grain yield were recorded in AMRD and SDRD treatments. Both AMRD and SDRD treatments increased the percentage of protein, amylose, and lipid contents, as well as the percentage of perfect grain compared to the RD treatment. Rice grain in RD treatment had very few protein bodies and their traces (pits), as well as the formation of amyloplasts and starch granules, were normal. However, AMRD and SDRD increased the number of protein bodies and their pits in the rice endosperm. The shapes of the amyloplasts were round and polyhedral with diverse sizes. Starch granules were polygonal with sharply defined edges. This research encourages farmers to adopt the combined application of manures and fertilizers to decrease the dependence on inorganic fertilizers.

Characterization of spinel bubbles and preparation and properties of lightweight ceramics

During the selection of materials for anti-lithium ion corrosion, magnesium aluminate spinel has been found to have good corrosion resistance and low cost. During the preparation of light-weight spinel ceramics, it is considered to be kiln body material. In this work, spinel bubbles were prepared using electrofusion injection process. Bulk density, volume density and pressure resistance of spinel bubbles in different particle sizes were counted. Light-weight spinel bubble ceramics with different densities were prepared by using electrofused spinel bubbles as light aggregates and using ρ-Al2O3 and caustic burnt magnesia powder as matrix powders. The microstructure of spinel bubbles with different particle sizes and light spinel ceramics was analyzed using scanning electron microscope. Results show that the spinel bubble has complete structure, good sphericity, perfect grain crystallization, and clear edges and corners. Although there are some fine cracks and cavities, grains are tightly bound. Compressive strength and bending strength of light-weight spinel ceramics, whose density were found to lie within the range of 0.99–1.63 g cm−3, were found to be 5.19–36.33 MPa and 3.48–12.84 MPa, respectively.

Phonon Transmission Across Silicon Grain Boundaries by Atomistic Green's Function Method

Nanostructured materials are of great interest for many applications because of their special properties. Understanding the effect of grain boundaries on phonon transport in polycrystals is important for engineering nanomaterials with desired thermal transport properties. The phonon transport properties of Σ3 grain boundaries in silicon are investigated by employing atomistic Green’s function method. Results show that similar to electron transport, the perfect grain boundary does not significantly reduce the thermal conductance, while defective grain boundaries can dramatically reduce the thermal conductance. This work may be helpful for the understanding of the underlying thermal transport mechanism with grain boundaries and the design of grain boundaries for energy applications.

Production efficiency and effect of water management on rice yield in Japan: two-stage DEA model on 110 paddy fields of a large-scale farm

Water management is increasingly important for rice productivity to maintain soil temperature and fertility with the presence of global warming. Meanwhile, rice production in Japan is in urgent need to reduce the costs through improving the efficiency and market competitiveness. This paper aims to measure effect of water depth and water temperature on rice yield of individual paddy fields and improve the practice of water management for them. In the first stage, we measure the production efficiency of rice yield through the adoption of data envelopment analysis. The results indicate that enlarged scale of the paddy fields increases the efficiency, and rice quality can be improved more than quantity. Moreover, the most inefficiently used inputs include the amount of fertilizer nitrogen and the soil capacity, which is a compound measurement of 21 soil chemical properties. In the second stage, after comparing the 20 paddy fields with highest and lowest technical efficiency, an observation shows that the rice yield is much more affected by water temperature than by water depth. The data of all the variables used in this study were sampled in 2015 and comprised of 110 paddy fields of Koshihikari, one of the most popular Japanese rice varieties, from a large-scale farm located in Kanto Region of Japan. In the analysis, the outputs include yields of raw paddy, paddy with 15% moisture, unsorted brown rice, sorted brown rice, milled grain rice, and perfect grain rice. The inputs include the field area, air temperature, solar radiation, fertilizer nitrogen, soil capacity, and farming conditions.

Characteristics of growth and quality, and factors contributing to high yield in newly developed rice variety ‘Akidawara’

The newly developed rice variety ‘Akidawara’ (AKI) combines the traits of high yield and highly palatability, and its cultivation is expected to spread. We examined characteristics of growth and quality, and factors contributing to high yield in AKI by comparing with ‘Nipponbare’ (NIP). Grain yield for AKI were 703 g m−2 (9% more than NIP) and 781 g m−2 (14% more than NIP) under the standard and heavy fertilizer regimes. It was also suggested that increase in the sink capacity was the key contributors to the high yield in AKI resulting from a conspicuous increase in the number of spikelets, which is likely due to introgression of the high-yielding variety allele. Furthermore, AKI achieved the similar degree of sink filling in spite of its larger sink capacity. In this point, panicle dry weight increase during ripening (ΔP) was significantly higher for AKI than for NIP despite the fact that no differences in shoot dry weight increase were observed between varieties. The greater ΔP in AKI might be derived from its larger sink capacity and the difference between varieties involves the translocation of nonstructural carbohydrate. In the grain quality, the reduction in perfect grain ratio was negligible and regarded as a small trade-off for AKI’s 14% increase in yield, and grain protein content increased to a lesser degree in AKI at the same yield level. These results suggest that over 700 g m−2 high yield can be achieved with relative high grain quality and lower protein content in AKI.

Dust models compatible with Planck intensity and polarization data in translucent lines of sight

Context. Current dust models are challenged by the dust properties inferred from the analysis of Planck observations in total and polarized emission. Aims. We propose new dust models compatible with polarized and unpolarized data in extinction and emission for translucent lines of sight (0.5 < AV < 2.5). Methods. We amended the DustEM tool to model polarized extinction and emission. We fit the spectral dependence of the mean extinction, polarized extinction, total and polarized spectral energy distributions (SEDs) with polycyclic aromatic hydrocarbons, astrosilicate and amorphous carbon (a-C) grains. The astrosilicate population is aligned along the magnetic field lines, while the a-C population may be aligned or not. Results. With their current optical properties, oblate astrosilicate grains are not emissive enough to reproduce the emission to extinction polarization ratio P353∕pV derived with Planck data. Successful models are those using prolate astrosilicate grains with an elongation a∕b = 3 and an inclusion of 20% porosity. The spectral dependence of the polarized SED is steeper in our models than in the data. Models perform slightly better when a-C grains are aligned. A small (6%) volume inclusion of a-C in the astrosilicate matrix removes the need for porosity and perfect grain alignment, and improves the fit to the polarized SED. Conclusions. Dust models based on astrosilicates can be reconciled with Planck data by adapting the shape of grains and adding inclusions of porosity or a-C in the astrosilicate matrix.

RESPONCE OF CORN GRAIN TRAITS TO HARVESTING MOISTURE

This research was conducted during spring and fall seasons, 2015, at the fields of Field Crop Department– College of Agriculture– University of Baghdad. The objective was to evaluate response of corn synthetic variety 5018 traits in next generation to harvesting moisture in the first generation. In spring season 2015, seeds of the synthetic variety 5018 were planted. When moisture of the ear grains was reached the first treatment (37-42%), ten ears were harvested. Ears harvesting dates were performed manually when the grains had 37-42%, 34-36%, 30-33%, 25- 28% and 19-22% moisture content. In fall season 2015, varietal trail was carried out to the five treatment materials, using Randomized Complete Bock Design, with four replicates. The results showed, significant differences among treatments for all the studied traits, except grain filling duration. The highest grain growth rate (7.23 mg.grain.day-1) and grain yield (159.46 g.plant-1), were produced from plants grown it's seeds harvested with (19-22)%, which didn't differ significantly from the plants grown it's seeds harvested with moisture (25-28)%. It can be conclude that the perfect corn grain moisture for harvesting (19-22)% for the nex generation seeds .

Quantitative trait loci analysis of grain appearance in Oryza sativa L. 'Emi-no-kizuna'.

A quantitative trait locus (QTL) analysis was conducted on grain appearance in Emi-no-kizuna, a rice cultivar that has superior and stable appearance of the brown rice grain and high tolerance to high temperature stress, by using F3 lines derived from Emi-no-kizuna and Tomohonami. The investigation was performed 2013 and 2015. In summer 2013 the air temperature was higher and the larger differences in grain appearance were observed. In the QTL analysis, a highly contributing locus, qGA8, was detected at the end of the short arm of chromosome 8. Because trends of reduced the occurrence of white immature kernel and increased the percentage of perfect grain were observed in Emi-no-kizuna genotype in both years, qGA8 is likely to be an important QTL that is dominant in the superior grain appearance of Emi-no-kizuna. Also, qGA8 was linked to a QTL associated with days to heading. Another QTL, qGA7, associated with grain appearance was detected on chromosome 7 in 2013. Because no negative correlation was found between the genotype of qGA8 and thousand grain weight, it should be possible to breed cultivars that possess Emi-no-kizuna genotype qGA8 without a decrease in thousand grain weight.

Change of scattering mechanism and annealing out of defects on Ga-doped ZnO films deposited by radio-frequency magnetron sputtering

This study examines the change of carrier scattering mechanism and defects states in Ga-doped ZnO (GZO) thin films deposited by radio-frequency magnetron sputtering as a function of the substrate temperature (Ts) during deposition. The GZO films deposited at room temperature exhibited a high defect density that resulted in a lower carrier concentration, lower Hall mobility, and optical absorption in visible wavelength range. Such defects were created by ion bombardment and were eliminated by increasing the Ts. The defects related to the optical absorption disappeared at a Ts of 125 °C. The defects responsible for the suppression of the carrier concentration gradually decreased with increasing Ts up to 200 °C. As a result, the carrier concentration and in-grain carrier mobility gradually increased. The Hall mobility was also influenced by film structural properties depending on the Ts. In addition to the c-axis preferred orientation, other oriented grains such as the (101¯1) plane parallel to the substrate surface appeared below 150 °C. This orientation of the (101¯1) plane significantly reduced the Hall mobility via grain boundary scattering. The films deposited at a Ts higher than 175 °C exhibited perfect c-axis orientation and grain boundary scattering was thus negligible in these films. The appearance of the 101¯1 peak in x-ray diffraction profile was correlated with the contribution of grain boundary scattering in heavily doped GZO films.

Grain boundary character distribution and its effect on corrosion of Ni–23Cr–16Mo superalloy

Grain boundary character distribution (GBCD) of the Hastelloy C2000 alloy (Ni–23Cr–16Mo) and the effect of coincidence site lattice (CSL) grain boundaries on corrosion resistance were examined by electron backscattered diffraction and electrochemical experiments. Various deformation followed by annealing was applied to optimise the GBCD of the alloy. After grain boundary engineering (GBE) treatment, the proportion of CSL boundaries increased from 37.7% to 62.4% and the corrosion current density of the specimens decreased in NaCl solution. The results indicated that GBE treatment is responsible for preferable corrosion resistance due to the increase of the fraction of special low energy grain boundaries with perfect grain boundary atom arrangement after thermomechanical process.

Effects of field high temperature on grain yield and quality of a subtropical type japonica rice—Pon-Lai rice

Typical japonica type rice is sensitive to high temperature. Pon-Lai rice is a special japonica type with adaptation to the subtropical climate in Taiwan. Facing climate change, rising temperatures would damage the yield and quality of rice production. This research was conducted using Pon-Lai rice in the field of a subtropical climate. We conducted 2 experiments, including a year-round experiment and collection of samples from different districts for building different temperature conditions. We analyzed the correlation between rising temperature and rice yield or quality. In our results, the critical period of temperature effect is 0–15 days after heading (H15). The threshold of high temperature damage in yield and appearance quality was 25–27 °C. Grain weight decreased about 2–6%, while the temperature of H15 was raised 1 °C above the thresholds. Perfect grain ratio and chalky grain ratio decreased and increased, respectively, while the temperature of H15 was raised above the thresholds. However, the high temperature in H15 affected the physicochemical characteristics. In addition, we found positive correlation between grain length to width ratio and perfect grain ratio. Grain length to width ratio could be an index of temperature effects for grain quality. In our study, when the temperature was below 30 °C, a rising temperature of H15 could damage rice yield and appearance quality, and change grain shape. Our results could provide reference for dealing with the warming future in other temperate rice-cultivated countries.

Effect of High Temperature on Leaf Physiological Changes as Chlorophyll composition and Photosynthesis Rate of Rice

등숙기 고온이 잎의 생리적 활력과 등숙에 미치는 영향을 알아보고자, 동안과 일품 두 품종을 등숙기에 고온 처리하여 등숙 형질을 분석하고, 잎의 광합성, 엽록소 함량 및 엽록소 a/b율 등을 알아보았다. 등숙기 고온(<TEX>$27{\pm}4^{\circ}C$</TEX>)처리에서 두 품종 모두 등숙률, 완전립률, 천립중이 감소하였으나 일품은 동안에 비해 모두 감소율이 컸다. 엽록소 함량은 등숙초기 고온에서 적온보다 두 품종 모두 증가하였으며, 등숙중기이후 엽록소감소양상은 온도처리에 따른 차이가 없었다. 엽록소 a/b율은 고온에서 감소하였다가 출수후 15일 이후 증가하였으며 적온에서는 출수 이후 지속적으로 증가하였다. 잎의 단백질농도 변화는 고온에서 등숙초기 약간 높은 경향이었으나 이후 처리 간 차이없이 등숙후기까지 지속적으로 감소하였다. 최대 광합성량은 유숙기인 출수 후 14일에 고온이 적온보다 높았고 출수후 7일과, 등숙후기(출수후 34일)에는 유의한 차이가 없었다. 잎의 유리당 함량은 고온이 적온보다 낮았다. 결론적으로 등숙기 고온은 잎의 생리적 활력을 적온보다 오히려 증가 시켜 엽록소함량과 광합성율이 증가하였으므로, 고온에 의한 이삭의 등숙저하는 이삭으로의 전류나 전분축적기작 과정의 문제가 더 클 것으로 생각된다. High temperature impairs rice grain yield and quality. To understand the effect of high temperature on leaf physiological activity and grain filling, two cultivars of rice that Dongan and Ilpum were exposed to high temperature during ripening stage. Grain filling rate, perfect grain ratio and grain weight of high temperature (<TEX>$27^{\circ}C{\pm}4^{\circ}C$</TEX>) treated both rice cultivars were decreased than those of control temperature (<TEX>$22^{\circ}C{\pm}4^{\circ}C$</TEX>) treated. The reduction rates of grain filling ratio, perfect grain ratio and grain weight of high temperature treated to control treated rice were higher in Ilpum than Dongan. Chlorophyll contents of rice leaves under high temperature at early ripening stage were higher than those of control temperature, but those were slowly decreased with no difference between temperature treatment since at mid ripening stage. Although chlorophyll a/b ratio under high temperature was decreased from heading to 15 days after heading, that was gradually increased since 15 days after heading. Protein concentrations of rice leaves for ripening stage was a similar pattern with chlorophyll changes. The rate of photosynthesis at 14 days after heading under high temperature was higher than those of control temperature, but there was no difference at those of 7 and 34 days after heading between two temperature treatment. Free sugars under high temperature treated leaves were lower than control temperature. Consequently, these results exhibit that high temperature accelerate leaf physiological activity as chlorophyll synthesis and photosynthesis rate unlike the deterioration of grain filling.

Micromagnetic Simulations of Magnetization Reversal in Misaligned Multigrain Magnets With Various Grain Boundary Properties Using Large-Scale Parallel Computing

This paper reports on micromagnetic simulations of the magnetization reversal behavior in polycrystalline Nd-Fe-B sintered magnets using large-scale parallel computing. A multigrain model is introduced to calculate the grain alignment dependence of the coercivity of polycrystalline Nd-Fe-B magnets with various magnetic characteristics at grain boundaries (GBs). The magnetic domain wall motion is accurately treated by dividing the analyzed object into extremely small elements. The multigrain model with a soft magnetic GB phase and a reverse domain at the initial state well reproduces experimental results. The calculations of coercivity with several GB widths are also carried out to seek for the origin of the sudden decrease of coercivity with nearly perfect grain alignment.

Anisotropic resistivity tensor of melt-cast Bi2212 superconductors from QTA

Bi2Sr2CaCu2O8+δ HTSC superconductor is characterized by a very strong normal-state resistivity anisotropy, with ρc/ρab typically above 10E4. The aim of this study is to use Quantitative Texture Analysis from x-ray diffraction measurements to estimate the orientation effect on the anisotropic macroscopic resistivity in melt-cast bulk Bi2Sr2CaCu2O8+δ superconductors. Our approach uses the geometric mean [1] of the single crystal resistivity tensor weighted by the Orientation Distribution Function (ODF) to quantitatively estimate the macroscopic resistivity tensor of the samples. The ODF is obtained from x-ray Combined Analysis [2], using the E-WIMV algorithm of the MAUD software. The GMA applies to the rank-two resistivity tensor of the orthorhombic space group considered tetragonal due to the small difference of a- and b-axes of the phase, with only two independent tensor components. We relate a relatively good agreement between measured and calculated macroscopic anisotropic resistivity ratios. Even with ρc/ρab between 10E4 and 10E5 for Bi2212 at room temperature in single crystals [3], we experiment macroscopic ratio in our bulk samples of around only 2. This small ratio is explained by the weak planar- or fiber-like (Figure) texture achieved in the melt-cast samples, characterized by maxima of orientation distributions not larger than 10 mrd. Calculated resistivities, based on homogeneous crystallites, perfect grain boundaries and no secondary phases, are 10 times larger than the observed ones. This suggests that the observed minor phases positively affect conductive pathways between grains. Calculated and measured anisotropic resistive ratios are coherent with one another, and Combined Analysis gives good predictions of these former.

Fluid inclusion and geochemical signatures of the talc deposits in Kanda area, Kumaun, India: implications for genesis of carbonate hosted talc deposits in Lesser Himalaya

Talc deposits in the Deoban Formation of inner Lesser Himalaya in Kumaun are interpreted to have resulted from low-grade, regional burial metamorphism of the siliceous magnesium bearing carbonates consisting of magnesite and dolomite. These deposits are distributed over a large area, occurring in association with magnesite and rarely with dolomite. They are found as fine-grained, fibrous aggregates of talc restricted to small, irregular patches or pockets in carbonate host rocks. Their petrographic features represent different phases of reactions between magnesite and silica to produce talc, thus equilibrium conditions were attained by the assemblage of magnesite + quartz + talc. Scanning electron microscopy also demonstrates that magnesite has reaction margins, whereas dolomite has perfect grain boundary in the magnesite–dolomite–talc assemblage. The major and trace elements in magnesite/dolomite and talc rule out the possibility of any incursion of foreign material during talc formation. Early fluids in magnesite and dolomite were H2O + NaCl + KCl ± MgCl2 ± CaCl2 in composition, their microthermometry data suggest mixing of the fluids. The fluid inclusion studies also imply that talc was formed under the condition of very low $$ {\text{X}}_{{{\text{CO}}_{2} }} $$ . A peak temperature of 300–340 °C and pressure of 2–2.2 kbar are estimated from the coexisting immiscible fluids in talc–magnesite assemblage. It is attributed that the estimated PT $$ {\text{X}}_{{{\text{CO}}_{2} }} $$ conditions in the Upper Proterozoic Deoban carbonate rocks, favored the talc formation from magnesite + quartz, and were not conducive to convert siliceous dolomite to talc on a large scale.

Expression of rice sucrose transporter gene OsSUT1 in sink and source organs shaded during grain filling may affect grain yield and quality

Low irradiance (shading) during the early phase of grain filling in rice (Oryza sativa L.) results in low grain yield and quality. The effects of shading on partitioning of assimilated carbon within the panicle and the whole plant have been reported, but its effect on the ability to transport assimilated carbon has not been examined in detail. The objective of this study was to investigate the effects of shading on the transport of assimilated carbon and on the expression of the sucrose transporter gene OsSUT1 during the early phase of grain filling. Shading of the whole plant for 14 days after flowering reduced grain dry weight and OsSUT1 expression in grains, flag leaf, flag leaf sheath, first leaf blade, first leaf sheath, second leaf blade, and stem (but not in second leaf sheath), although initially (after 1 week) the expression in grains and second leaf sheath increased. We also shaded sink (panicle), source (leaf and leaf sheath), or whole plant from 7 to 14 days after flowering and examined the expression of OsSUT1 in grains and panicle branches. In grains, OsSUT1 expression increased in all shading treatments. In branches, OsSUT1 expression decreased upon shading of the whole plant or sink, but increased upon source shading. Additionally, 1000-grains dry weight and ratio of perfect grain significantly decreased upon shading of the whole plant, but not sink or source. These results suggest that the decrease in grain yield and quality by shading during the early phase of grain filling is caused not only by shortage of leaf-derived photoassimilates, but also by suppression of OsSUT1 in sink and source.

Effect of silicon content in grain refining hypoeutectic Al–Si foundry alloys with boron and titanium additions

The effect of Si content on the grain refinement of hypoeutectic Al–Si alloys was investigated. Alloying with Si refines the grain structure, which tends to be coarse and columnar in commercially pure aluminium. The smallest grain size occurs at ∼2 wt-%Si, where the solidification interval of hypoeutectic Al–Si alloys is the largest. Grains become increasingly coarser with increasing Si starting from this point. The grains of Al–Si alloys with 500 ppm Ti are smaller than those cast without Ti regardless of the Si content of the alloy. The fivefold reduction in grain size in commercially pure aluminium upon Ti addition is gradually reduced with increasing Si. Finally, the grain refinement provided by Ti fails to meet the expectations once Ti starts to be removed from the melt via the formation of Ti–Si compounds above 5 wt-%Si. The B addition relies on the formation of AlB2 particles to offer grain refinement. Analysis of the Al rich corner of the calculated Al–Si–B liquidus surface suggests that the primary AlB2 is formed at a Si concentration of ∼4 wt-%. While a perfect grain refiner for hypoeutectic Al–Si alloys with at least 4 wt-%Si, B fails to refine the grain structure when the Si content is less.

Optoelectronic performance of gallium nitride devices: the role of tilt grain boundaries and point defects

The electronic structures of perfect tilt grain boundaries in the gallium nitride (GaN) and the interaction of point defects with their boundaries have been investigated. Our calculations suggest that among the three possible atomic configurations describing the perfect tilt grain boundaries, namely, the 5/7-interface, the 4-interface and the 8-interface, it was found that the 8-interface introduces deep states in the very center and the upper half of the band gap whereas the 5/7-interface possess only states close to the conduction band. The N-vacancy in the 8-interface introduces filled or empty electronic states inside the band gap. Such states may give rise to transition towards the valence band, which could be a candidate to account for the yellow luminescence (YL) in GaN. For the gallium or nitrogen interstitial in interaction with the GaN tilt grain boundaries, it was shown that while the Ga-interstitial introduces empty deep-states in the very center and filled shallow-states in the half bottom of the band gap, the N-interstitial gives only rise to shallow-states at the band edges. Given that for an electrically neutral boundary the deep states are unoccupied (deep acceptors), such defects may contribute to the YL.