28 research outputs found

    High-order Harmonic Generation from Hydrogen Molecular Ion in Coherent Superposition State

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    Atom in a coherent superposition state reveals an advantage in the enhancement conversion efficiency of high-order harmonic generation (HHG), which is meaningful in producing attosecond pulses. In this study, we expand to investigate a more complicated system, H2+_2^+ molecule in the superposition of the ground and second excited states, exposed to an ultrashort intense laser pulse by numerically solving the time-dependent Schrödinger equation. Firstly, we examine the enhancement of HHG from this system. Then, we study the depletion effect on the cutoff energy of HHG spectra with the coherent superposition state. We found that these effects on the HHG from molecules are similar to those from atoms. Finally, we study the signature of the interesting effect, which is absent for atoms -- two-center interference effect in the HHG from H2+_2^+ in the coherent superposition state. We recognize that the minimum positions in HHG from molecules in the superposition state, and in the pure ground state are the same. Especially, for weak laser intensity, in the HHG with the superposition state, the minimum due to the interference effect is apparent, while it is invisible in the HHG from pure ground state. As a result, in comparison with the ground-state molecule, the coherent molecule can be used as a more accurate tool to determine the internuclear distance of molecule

    Effect of Molecular Charge Asymmetry on Even-to-odd Ratio of High-order Harmonic Generation

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    Recently, asymmetric molecules, such as HeH2+_2^+, CO, OCS, HCl, have been evolved much attention since its rich information in the high-order harmonic generation (HHG), whose ratio of adjacent even and odd harmonics characterizes the asymmetry of molecules. In this paper, we study the dependence of even-to-odd ratio on the asymmetric parameters, in particular, the nuclear-charge ratio, and the permanent dipole, by exploiting a simple but general model of asymmetric molecules Z1Z2Z_1Z_2 subjected to an intense laser pulse. The HHG is simulated by the numerical method of solving the time-dependent Schrödinger equation. We find out that this even-to-odd ratio strongly depends on the nuclear-charge ratio. In particular, the even-to-odd ratio reaches its maximum when the nuclear-charge ratio is about from 0.5 to 0.7. Besides, the dependence on the permanent dipole of the even-to-odd ratio has a non-trivial law. To explain, we calculate the analytical ratio of the transition dipole according to the emission of even and odd harmonics, and this ratio is well consistent with the even-to-odd ratio of the HHG

    WATER QUALITY STATUS OF WHITE LEG SHRIMP FARMING AREAS IN BINH DAI DISTRICT, BEN TRE PROVINCE, VIETNAM

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    This study focused on water quality assessment of farmed shrimp ponds in Binh Dai District, Ben Tre Province. The goals of the study were to provide chemical parameters of pond water for farmers, to identify problems and causes in farmed shrimp related to water quality and disease, and to help managers find appropriate solutions to minimize damage to local shrimp farming. Water samples were collected monthly from January to June 2021 from 90 vannamei farmers in six different areas, including Vang Quoi Dong, Dinh Trung Binh Thoi, Phu Long, Phu Vang, and Binh Thang of Binh Dai District. Parameters investigated in this study included pH, alkalinity, NH4+, NH3, NO2- and three other minerals. Water quality parameters were analyzed based on APHA standard analysis methods. The results showed that the water quality of shrimp farming areas in Binh Dai fluctuated from time to time, and water quality parameters were suitable for vannamei shrimp farming. However, the concentration of NO2- was always higher than the permitted threshold. The results from cluster analysis and MANOVA testing showed that water quality of the shrimp farming areas in Binh Dai was significantly different (p < 0.05), especially NO2-, Ca, Mg and alkalinity. These findings suggest that farmers must apply proper solutions for water quality management in each farming area to maximize crop production

    Universality in odd-even harmonic generation and application in terahertz waveform sampling

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    Odd-even harmonics emitted from a laser-target system imprint rich, subtle information characterizing the system's dynamical asymmetry, which is desirable to decipher. In this Letter, we discover a simple universal relation between the odd-even harmonics and the asymmetry of the THz-assisted laser-atomic system -- atoms in a fundamental mid-IR laser pulse combined with a THz laser. First, we demonstrate numerically and then analytically formulize the harmonic even-to-odd ratio as a function of the THz electric field, the source of the system's asymmetry. Notably, we suggest a scaling that makes the obtained rule universal, independent of the parameters of both the fundamental pulse and atomic target. This universality facilitates us to propose a general pump-probe scheme for THz waveform sampling from the even-to-odd ratio, measurable within a conventional compact setup

    Extract and fraction of cashew nut testa ameliorate the hyperglycemic mice induced by Streptozotocin and high-fat diet

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    Drug strategy is a standard method for treating type 2 diabetes mellitus (T2D), a non-communicable disease with increasing prevalence, which may cause side effects. Therefore, natural compounds with limited adverse effects have come back into vogue for treating T2D. This study aims to evaluate the effects on rehabilitating hyperglycemic mice of cashew nut testa (husk) extract and fraction known as potential bio-substances for improvement in T2D. First, the hyperglycemic mice were induced with a high-fat diet (HFD) for 4 weeks and then were injected with streptozotocin (STZ, dozen for injection was 40 mg/kg/week) for 2 weeks. Next, the confirmed hyperglycemic mice were treated with pioglitazone (HG+PG group), total extract (HG+TE group), and saponin-rich fraction (HG+SRF group) for 3 weeks. Then, the evaluation was based on body mass; blood glucose (BG) level; BG tolerance, lipid profile, pancreatic histology and the expression IRS-1 in the pancreas. The results showed that body mass and BG level significantly increased in hyperglycemic mice. After substance treatment, there was no change in body mass in TE and SRF groups. However, BG level of HG+TE group mice significantly decreased compared to hyperglycemic mice and only BG tolerance of HG+SRF group was improved. Besides, HG+TE and HG+SRF groups modulated the triglyceride, HDL and LDL close to those expressed in normal mice. In addition, histological images of the pancreas revealed the restoration in both HG+TE and HG+SRF groups. Simultaneously, the IRS-1 expression in HG+TE group pancreas was restored to its expression in normal mice. These results demonstrate that the TE and SRF of cashew nut testa could ameliorate BG, lipid profile and pancreatic IRS-1 expression and restore the damaged pancreas and islets in hyperglycemic mice

    Measuring Supply Chain Smart Village Headman Performance

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    The supply chain management as the general tool can be used for supporting and delivering the goods to the villages. The village head is the leader of the village government. The tenure of the village head is 6 years, and can be extended for another one term is expected to run the government with a good performance in providing services to the community. So with the proper use of the supply chain the needs of the villages can be provide by the government. The Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method can help decision making in determining the performance index of the village head. This research is conduct by looking for the performance of positive and negative ideal solutions. Applications with the highest V value will occupy the top size in this system. Then the criteria in determining the performance index of the head of the village are: timeliness, discipline, responsibility, leadership, presence, value. The results of the decision-making system resulted in 6 alternative suggested performance indexes of village heads, with the highest score of Sending Agung Village

    Measuring Supply Chain Performance through Migrant Workers Placement

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    To facilitate existing procedures and improve decision making, a decision support system (SPK) needs to be built. This SPK aimed  to determine the placement of workers abroad using the Simple Additive Weighting (SAW) method and supply chain process. This method was chosen because it is  able to select the best alternative from a number of alternatives, in this case the alternative in question was  someone who was entitled to receive Placement based on predetermined criteria. This research was conducted by looking for weight values for each individual. The Decision Support System produced was  capable of ranking prospective Indonesian migrant workers and  making it easier for BP3TKI to make decisions about Indonesian migrant workers by supply chain resource management for who will depart abroad
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