• Title, Summary, Keyword: Excess Phosphorous

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Synthesis of (Gd0.74Y0.11Tb0.15P1.15)OδPhosphors Using Combinatorial Chemistry (조합화학을 이용한 (Gd0.74Y0.11Tb0.15P1.15)Oδ 형광체 합성 및 발광특성)

  • 이재문;유정곤;박덕현;김지식;손기선
    • Journal of the Korean Ceramic Society
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    • v.41 no.5
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    • pp.381-387
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    • 2004
  • Recently developed Plasma Display Panels (PDP) require phosphors of high luminance at Vacuum Ultraviolet (VUV) excitation. The present investigation developed new PDP phosphors using combinatorial chemistry method. We applied T $b^{3+}$ -activated yttrium gadolinium phosphates system to our combinatorial fine-tuning technique. As a result, the optimum composition was determined to be (G $d_{0.74}$ $Y_{0.11}$T $b_{0.15}$) $P_{1.15}$ $O_{\delta}$ through the two-step combinatorial screening process including excess phosphorous and Gd replacement. We found that the sample of the optimum composition shows a higher luminescence efficiency at VUV excitation and a shorter decay time than the commercially available Z $n_2$ $SiO_4$:Mn phosphor.

Reliability Improvement of Thin Oxide by Double Deposition of Silicon (실리콘의 이중증착에 의한 산화막 신뢰성 향상)

  • 박진성;양권승
    • Journal of the Korean Ceramic Society
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    • v.31 no.1
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    • pp.74-78
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    • 1994
  • Degradation of thin oxide by doped poly-Si and its improvement were studied. The gate oxide can be degraded by phosphorous in poly-Si doped POCl3. The degradation is increased with the decrement of sheet resistance and poly-Si thickness. Oxide failures of amorphous-Si are higher than those of poly-Si. In-situ double deposition of amorphous-Si, 54$0^{\circ}C$/30 nm, and poly-Si, 6$25^{\circ}C$/220 nm, forms the mismatch structure of grain boundary between amorphous-Si and poly-Si, and suppresses the excess phosphorous on oxide surface by the mismatch structure. The control of phosphorous through grain boundary improves the oxide reliability.

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The Effect of Salinity on Biological Nutrient Removal in SBR (SBR공정에서 영양염류 제거에 대한 염분의 영향)

  • Song, Changsoo;Oh, Junseung
    • Journal of Korean Society on Water Environment
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    • v.18 no.3
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    • pp.237-243
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    • 2002
  • The effect of a salinity on the performance of a biological nutrient removal system was investigated using a model SBR(Sequencing Bach Reactor) system. The system was operated at a 12hr, 18hr, 24hr, and 36hr HRT with a salinity level of 20,000mg/L and compared with a system similarly operated with fresh water. The influent salinity level of 8,000 mg/L does not have a significant effect on BOD removal efficiency, there is a noticeable decrease in BOD removal rate from 10,000 mg Cl-/L. The Nitrogen could be removed from the saline wastewater with the same efficiency as for the fresh water because of low C/N ratio in anoxic period. The excess biological phosphorous removal is highly affected by the increase in the influent salinity. The efficiency is decreased from 96.6% to 43.4% when the influent salinity is increased from 0 to 20,000mg/L.

Fabrication of Zirconium Phosphate Nanoparticles through Solution Technique (수용액법에 의한 인산 지르코늄 나노입자의 합성)

  • 정영근;최현규
    • Journal of Korean Powder Metallurgy Institute
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    • v.9 no.5
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    • pp.336-340
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    • 2002
  • The $\alpha$-zirconium phosphate particles as fine as 20 nm were fabricated through solution technique using $ZrOCl_2{\cdot}8H_2O$ and $H_3PO_4$ as precursors. Stability of $\alpha$-Zirconium phosphate could be ensured by adding excess phosphoric acid to a stoichiometric composition Instead of using reflux route that resulted in coarsening of particles due to an inevitably long aging. The excess phosphorous incorporated in the crystal could be successfully eliminated afterwards through careful washing. Moreover, heavily agglomerated particles are observed before washing, but fairly dispersed state is found out after washing treatment. Thus, it is found that dispersed state as well as phase stability is ensured through proper washing treatment.

Plant Growth Monitoring Using Thermography -Analysis of nutrient stress- (열영상을 이용한 작물 생장 감시 -영양분 스트레스 분석-)

  • 류관희;김기영;채희연
    • Journal of Biosystems Engineering
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    • v.25 no.4
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    • pp.293-300
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    • 2000
  • Automated greenhouse production system often require crop growth monitoring involving accurate quantification of plant physiological properties. Conventional methods are usually burdensome, inaccurate, and harmful to crops. A thermal image analysis system can accomplish rapid and accurate measurements of physiological-property changes of stressed crops. In this research a thermal imaging system was used to measure the leaf-temperature changes of several crops according to nutrient stresses. Thermal images were obtained from lettuce, cucumber, and pepper plants. Plants were placed in growth chamber to provide relatively constant growth environment. Results showed that there were significant differences in the temperature of stressed plants and non-stressed plants. In a case of the both N deficiency and excess, the leaf temperatures of cucumber were $2^{\circ}C$ lower than controlled temperature. The leaf temperature of cucumber was $2^{\circ}C$ lower than controlled temperature only when it was under N excess stress. For the potassium deficiency or excess stress, the leaf temperaures of cucumber and hot pepper were $2^{\circ}C$ lower than controls, respectively. The phosphorous deficiency stress dropped the leaf temperatures of cucumber and hot pepper $2^{\circ}C$ and $1.5^{\circ}C$ below than controls. However, the leaf temperature of lettuce did not change. It was possible to detect the changes in leaf temperature by infrared thermography when subjected to nutrition stress. Since the changes in leaf temperatures were different each other for plants and kinds of stresses, however, it is necessary to add a nutrient measurement system to a plant-growth monitoring system using thermography.

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Photoluminescence Characteristics of Spherical-Shaped LaPO4:Tb Phosphor Particles Prepared by Spray Pyrolysis (분무열분해법에 의해 제조된 구형의 녹색 LaPO4:Tb 형광체의 발광특성)

  • Lee, Kyo-Kwang;Kang, Yun-Chan;Zeon, Il-Woon;Jung, Kyeong-Youl;Park, Hee-Dong
    • Korean Journal of Materials Research
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    • v.12 no.9
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    • pp.761-766
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    • 2002
  • Fine $LaPO_4$:Tb phosphor particles with spherical shape were prepared by spray pyrolysis. The influence of the precursor type of phosphorous such as ($NH_4$)$_2$$HPO_4$, $NH_4$$H_2$$PO_4$, ($NH_4$)$_3$$PO_4$ and $H_3$$PO_4$ on the morphology and brightness of particles was investigated. As-prepared particles by spray pyrolysis had spherical shape when ($NH_4$)$_2$ $HPO_4$ and $NH_4$$H_2$$PO_4$ were used as the precursor of phosphorous. The precursor type of phosphorous affected the photoluminescence intensity of $LaPO_4$:Tb phosphor particles, but not significant. With changing the content of activator(Tb) and excess of phosphorous, the optimal composition giving the highest photoluminescence intensity was found. The spherical morphology of prepared $LaPO_4$:Tb particles was completely maintained even after the posttreatment up to $1050^{\circ}C$. When the posttreatment temperature was over $1100^{\circ}C$, the particles did not have the spherical shape anymore. However, the highest photoluminescence intensity of prepared $LaPO_4$:Tb particles was obtained at $1050^{\circ}C$. The photoluminescence characteristics of prepared $_LaPO4$:Tb under the vacuum ultraviolet(VUV) illumination was comparable with that of the commercial $Zn_2$$V_4$:Mn and (La,Ce)PO$_4$:Tb phosphor particles. At the optimal condition, the decay time of prepared spherical $LaPO_4$:Tb phosphor particles was about 6.8ms.

Influence of Soil and Forage Minerals on Buffalo (Bubalus bubalis) Parturient Haemoglobinuria

  • Akhtar, M.Z.;Khan, A.;Sarwar, M.;Javaid, A.
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.3
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    • pp.393-398
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    • 2007
  • The present study was carried out to investigate the serum minerals profile in buffaloes (Bubalus bubalis) suffering from parturient haemoglobinuria (PHU) along with minerals profile of soils and fodders from the disease prone areas and their interrelationships. Serum samples were collected from 60 each of healthy and PHU affected buffaloes randomly selected from field cases. Serum samples were collected from each animal. Fifty composite soil samples were collected where PHU was prevalent. Fifty samples of fodders including leaves and stems being fed to the diseased buffaloes were collected. The difference in the levels of calcium and potassium between upper and lower soil surface of disease prone areas under study were statistically non-significant. The mean values of phosphorous, copper, iron, selenium and molybdenum in upper soil surface were significantly (p<0.05) higher than in lower soil surface. None of the fodders offered to the diseased animals met the dietary requirements of phosphorus and copper whereas none of the fodders was deficient in potassium, iron and selenium rather were having excess of potassium, iron and selenium. The concentration of calcium was adequate in lucerne, berseem, sarson and sorghum, while maize, sugarcane and wheat straw did not meet the required levels for dairy animals. Molybdenum contents in all fodders were adequate to meet the dietary requirements of the dairy buffaloes. Serum phosphorus, copper and selenium were significantly (p<0.001) lower whereas potassium, iron and molybdenum in buffaloes suffering from PHU were significantly (p<0.001) higher than in healthy buffaloes. It was concluded that phosphorous deficient soils play a major role by transferring this deficiency to plants and ultimately reaching to animals where hypophosphataemia is a consistent finding.

Tungsten silicide 의 이상산화

  • 이재갑;김창렬;김준기;나관구;김우식;최민성;이정용
    • Proceedings of the Materials Research Society of Korea Conference
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    • pp.22-22
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    • 1993
  • Tungsten silicide는 낮은 전도도, 높은 녹는점, pattern 형성에 용이함등으로 VLSI device Interconnect(Bit line)로 활발하게 이용되고 있다. 일반적으로 Tungsten silicide 는 polycide(WSi$_2$/poly-Si)구조로 사용이 되며, polycide 구조는 산화분위기에서 WSi$_2$위에 SiO$_2$막을 쉽게 형성시키는 장점이 있다. As-dep상태의 polycide를 산화시킬적에는 텅스텐 실리사이드에 존재하는 excess-silicon과 microcrystalline 구조 (grain size=3$\AA$)로 인하여 텅스텐 실리사이드 표면에 균일한 SiO$_2$가 형성이 된다. 그러나 post-anneal을 실시한 샘플 Furnace anneal ($N_2$:O$_2$유량비=2:1) 처리하면 성장된 텅스텐 실사이드 입자의 입계효과에 의하여 텅스텐 실리사이드의 표면에 SiO$_2$뿐만 아니라 WO$_3$가 형성되는 이상산화가 발생되어 공정의 어려움을 야기시키고 있다. 본 실험에서는 post anneal ($700^{\circ}C$, 30min, $N_2$ 분위기) 시킨 시편을 Implantation(As 또는 phosphorous)을 실시하여 실리사이드 표면을 비정질화 시킨후 Furnace anneal 실시하여 이상산화 발생 억제에 I/I처리가 미치는 효과를 관찰하였다. XPS를 이용하여 이상산화막 두께와 WO$_3$존재를 조사하였고, AES를 사용하여 W, Si, O 원소들이 깊이에 따라 변하는 것을 관찰하였다.

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Proteomics of ionic stresses in rice: An overview

  • Kim, Sang-Gon;Wang, Yiming;Huh, Hyun-Hye;Kim, Yong-Chul;Choi, In-Soo;Agrawal, Ganesh Kumar;Rakwal, Randeep;Kang, Kyu-Young;Kim, Sun-Tae
    • Journal of Plant Biotechnology
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    • v.38 no.2
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    • pp.130-136
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    • 2011
  • Ions deficiency or excess remains one of the critical ground level environmental problems, affecting crop productivity. In this overview, we will discuss an increased application of proteomics technology in addressing this issue using rice (Oryza sativa L.) as a model crop plant. Proteomics analyses have revealed that rice proteome undergoes changes in the proteins composition and expression in response to several ionic stresses, including mineral nutrients (aluminum, nitrogen, and phosphorous) and heavy metals (arsenic, cadmium, and copper). Developed inventory of responsive proteins and their correlation with changes in physiological symptoms and parameters are a major step forward in: (i) better understanding the underlying mechanisms of ionic stresses-triggered responses in rice; (ii) comparative proteomics studies; and (iii) designing a novel strategy to improve crop plants.

High energy swift heavy ion irradiation and annealing effects on DC electrical characteristics of 200 GHz SiGe HBTs

  • Hegde, Vinayakprasanna N.;Praveen, K.C.;Pradeep, T.M.;Pushpa, N.;Cressler, John D.;Tripathi, Ambuj;Asokan, K.;Prakash, A.P. Gnana
    • Nuclear Engineering and Technology
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    • v.51 no.5
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    • pp.1428-1435
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    • 2019
  • The total ionizing dose (TID) and non ionizing energy loss (NIEL) effects of 100 MeV phosphorous ($P^{7+}$) and 80 MeV nitrogen ($N^{6+}$) ions on 200 GHz silicon-germanium heterojunction bipolar transistors (SiGe HBTs) were examined in the total dose range from 1 to 100 Mrad(Si). The in-situ I-V characteristics like Gummel characteristics, excess base current (${\Delta}I_B$), net oxide trapped charge ($N_{OX}$), current gain ($h_{FE}$), avalanche multiplication (M-1), neutral base recombination (NBR) and output characteristics ($I_C-V_{CE}$) were analysed before and after irradiation. The significant degradation in device parameters was observed after $100MeV\;P^{7+}$ and $80MeV\;N^{6+}$ ion irradiation. The $100MeV\;P^{7+}$ ions create more damage in the SiGe HBT structure and in turn degrade the electrical characteristics of SiGe HBTs more when compared to $80MeV\;N^{6+}$. The SiGe HBTs irradiated up to 100 Mrad of total dose were annealed from $50^{\circ}C$ to $400^{\circ}C$ in different steps for 30 min duration in order to study the recovery of electrical characteristics. The recovery factors (RFs) are employed to analyse the contribution of room temperature and isochronal annealing in total recovery.