258 research outputs found

    Controlled energy-selected electron capture and release in double quantum dots

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    Highly accurate quantum electron dynamics calculations demonstrate that energy can be efficiently transferred between quantum dots. Specifically, in a double quantum dot an incoming electron is captured by one dot and the excess energy is transferred to the neighboring dot and used to remove an electron from this dot. This process is due to long-range electron correlation and shown to be operative at rather large distances between the dots. The efficiency of the process is greatly enhanced by preparing the double quantum dot such that the incoming electron is initially captured by a two-electron resonance state of the system. In contrast to atoms and molecules in nature, double quantum dots can be manipulated to achieve this enhancement. This mechanism leads to a surprisingly narrow distribution of the energy of the electron removed in the process which is explained by resonance theory. We argue that the process could be exploited in practice.Comment: Lette

    Electron-correlation driven capture and release in double quantum dots

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    We recently predicted that the interatomic Coulombic electron capture (ICEC) process, a long-range electron correlation driven capture process, is achievable in gated double quantum dots (DQDs). In ICEC an incoming electron is captured by one QD and the excess energy is used to remove an electron from the neighboring QD. In this work we present systematic full three-dimensional electron dynamics calculations in quasi-one dimensional model potentials that allow for a detailed understanding of the connection between the DQD geometry and the reaction probability for the ICEC process. We derive an effective one-dimensional approach and show that its results compare very well with those obtained using the full three-dimensional calculations. This approach substantially reduces the computation times. The investigation of the electronic structure for various DQD geometries for which the ICEC process can take place clarify the origin of its remarkably high probability in the presence of two-electron resonances

    Functional Zoning for Air Quality

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    Pola Agihan dan Intensitas Penyakit Busuk Pangkal Batang Lada di Provinsi Sulawesi Tenggara

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    The success of foot rot disease control is largely dependent on information data of pepper cultivation conditions, distribution pattern of the disease, and the magnitude of the intensity of the disease. This study aimed to determine the condition of pepper cultivation, distribution pattern of pepper foot rot disease, the development of disease symptoms, and intensity of pepper foot rot disease in Southeast Sulawesi. Data cultivation conditions, distribution of the disease, progression of symptoms, and the intensity of the disease were obtained by means of surveys in pepper plantations and interviews with pepper farmers. The results showed that the pepper plantations in Southeast Sulawesi were cultivated on flat to hilly topography, and the cultivation method was very conventional but herbicide use was very intensive. The development of wilt symptoms on pepper plants was very quick in dry weather but slow in the wet. Pepper foot rot disease has patch distribution. The highest intensity of the pepper foot rot disease was in less weedy plantations with intensive use of herbicides. The intensity of the pepper foot rot disease in Southeast Sulawesi was 61,2% with the spread in each district namely South Konawe at 53,8%, Konawe at 63,7% and Kolaka by 61,2%

    POTENTIAL OF CARBON DIOXIDE ABSORPTION IN CONCRETE

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    Abstract: Cement industry contributes to 5% of global CO2 emissions. To mitigate pollution, there is a need of CO2 sequestration into stable forms. Present research focusses on CO2 being channelized towards an important construction practice. This paper summarizes the potential of CO2 absorption in concrete. To verify CO2 absorption in concrete, an artificial CO2 environment for curing of concrete cubes using dry ice was created. Considering concrete of M20 grade, a comparative experimental study of water cured concrete cubes, CO2 cured concrete cubes, for penetration (using phenolphthalein indicator), and compressive strength was carried out. The result analysis of the tests indicated that CO2 cured concrete cubes showed 22.125% higher compressive strength than water cured concrete cubes and CO2 penetration of 13.5 mm after 2 hours. The rate of CO2 penetration and strength gain in concrete was found to be rapid in the early hours. It is shown that CO2 can prove to be a useful resource in the construction scenario, especially in the precast

    Review: common trouble shooting problems in RP-HPLC

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    High performance liquid chromatography is one the powerful analytical tool regularly employed for the analysis of the drugs in the pharmaceutical formulations. Day by day advancement in instrumentation is increasing but still the problems have been encountered while performing analysis. Here in this review article different troubleshooting has been described with their causative and preventive parameters during performing the method development for separation and identification by RP-HPLC

    Six Sigma: A novel approach to pharmaceutical industry

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    The statistical concept, six sigma is used to define problems systematically, provides tools to measure and influential factors and identifies the improvements that can be implemented easily. It is quality management tool which can be considered as a vision, a philosophy, a symbol, a metric, a goal, a methodology. It simply means a measure of quality that struggle for near perfection. It is a highly disciplined process that focuses on developing and deliveringNear perfect product and services It is based on three element Process improvement, Process. Design/re-design and Process management. When we use this technique for a process then process variation reduced to 3.4 DPMO (Defects per million Opportunities).Six sigma is divided in two sub methods DMAIC (Define, Measure, Analyze, Improve and Control) is improvement system for existing processes that doesnt meet specification. DMADV (Define, Measure, Analyze, Design, Verify) is used to develop new processes at six sigma level

    Deteksi Dan Penghitungan Kerapatan Inokulum Phytophthora Capsici Dalam Tanah Dengan Menggunakan Umpan Daun Lada

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    Phytophthora capsiciis a causal agent for footrot disease in pepper and classified as a soil-borne pathogen. The inoculums of P. capsici in the soilis difficultto detect. The dynamics of P. capsici population in the soil is frequently and rapidly fluctuates and hard to detect, causing the pathogen to produce disease rapidly. The aimsof this research were todetect the pathogen P.capsici using black pepper leaf baiting and to quantify the inoculum of the pathogen P.capsici in the soil belonging to several disease intensities of the black pepper foot rot in the field. The first experiment: detecting the pathogen P. capsici using black pepper leaf baiting in the soil artificially infested using several sporangia, anda second experiment: quantification of propagul of the P.capsici in various categories of intensity on the black pepper foot rot disease in the field. The research results showed that the black pepper leaf baiting could be used to detect the existence of the propagul of P.capsiciin the soil artificially infested in various densities of sporangia. The increase in disease intensity occurred in parallel with the greater density of P. capsici inocula in soil. The density of P. capsici inocula in the soil tended to decline when the disease intensity reached the highest level

    Epidemi Penyakit Busuk Pangkal Batang Lada Pada Kondisi Lingkungan Yang Bervariasi

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    Foot rot disease epidemic on black pepper in variety of environmental conditions. The foot rot disease on black pepper caused by Phytophthora capsici Leonian, is often destructive to farmers of black pepper. This research aims to study the infection rate and the pattern of development of the black pepper foot rot disease in various condition of the environment. The research was conducted in the areas of black pepper cultivation in the Ultisol and Entisol soils. In each location plots were set with few (75%) weeds. Variable observed was disease incidence. The data were used to analyze model of development of the black pepper foot rot disease and infection rate. Results of the research showed that the model of development of the black pepper foot rot disease was not affected by soil type, but the type of soil affected the infection rate. At the pepper plantation with abundance of weeds, the disease development followes Gompertz model. At the plantation with few weeds, however the disease developed in a logistic model. The rate of disease infection on the black pepper plant with abundant weeds lower compared with those with few weeds
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