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Synthesis, characterization and photophysical properties of meso-indole-boron-dipyrromethene derivatives and their cell imaging and viscosity sensing
摘要： Based on the molecular design and structural modification of boron-dipyrromethene (BODIPY), two new BODIPY derivatives with meso-substituted functional indole moieties were successfully prepared. These new compounds were characterized by NMR, HRMS and FTIR, exhibiting the different UV-vis and PL spectral phenomena because of their varied molecular structures in various solvents and different degrees of negative solvatochromism. Theoretical calculations and CV results show that the substituted NO2 group at 5-position of indole is favorable for increasing the oxidation potential of the molecules, while the NH2 group is the opposite. These two BODIPY derivatives have different sensitivities to pH changes, and can be appropriately applied as cell imaging materials due to their good physical chemical characteristics and excellent biocompatibility. In particular, the fluorescence characteristics of BODIPY derivative with the substituted NH2 group at 5-position of indole show a good solvent viscosity dependence, highlighting its potential application for testing the intracellular viscosity changes of the living cell in disease diagnosis.
关键词： meso-indole boron-dipyrromethene derivatives,photoluminescence,fluorescence characteristics,cell imaging,viscosity sensing
更新于2025-09-23 15:23:52
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[IEEE 2018 7th International Conference on Agro-geoinformatics (Agro-geoinformatics) - Hangzhou (2018.8.6-2018.8.9)] 2018 7th International Conference on Agro-geoinformatics (Agro-geoinformatics) - Monitoring of Rice Leaf Folder Damage Based on Remote Sensing Methods
摘要： Rice leaf folder (Cnaphalocrocis medinalis Guenée) is one of the most important pests that endanger rice development and yield, which has characteristics of large outbreak areas, high occurrence frequencies and heavy damages. At present, the monitoring methods of rice leaf folder damage is based on artificial investigation, which has the advantages of objective truth and high reliability, while there is a drawback of time-consuming, and it cannot used for a wide range of rice damage monitoring. An ASD (Analytical Spectral Devices, Inc.) Hand-held Spectroradiometer was used at jointing stage of rice. The results showed that, reflectance from rice canopy significantly decreased in the green (530-570 nm) and near infrared (700-1000 nm) regions, and significantly increased in the blue (450-520 nm) and red (580-700 nm) regions as the rice leaf folder population increased. Reflectance from rice canopy significantly decreased in the spectral regions from 737 to 1000 nm as the infestation scale of pest population increased, and the most correlation appeared at 941 nm. The more the numbers of rice leaf folder, the higher the changes of such characteristic parameters. The positive correlations were found between the damage of rice leaf folder and the discrepancy of characteristic parameters in these experimental fields. With China Remote Sensing career advancement, a large number of independent researches and development satellites have launched. Among a new generation of high-resolution satellites, GaoFen-1 (GF-1) stands out. It sets high spatial resolution (2 m-16 m), multi-spectral and high temporal resolution (4-day) with 60 km-800 km swath in a fusion technology with strategic significance. In order to explore the adaptability of Chinese GF-1 images in monitoring rice damage from rice leaf folder, nine rice fields were selected by damage severity in Xinghua City, Jiangsu Province at full heading stage in 2015, and the Ratio Vegetation Index (RVI), Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), 2-band Enhanced Vegetation Index (EVI2), Soil Adjusted Vegetation Index (SAVI), Optimized Soil Adjusted Vegetation Index (OSAVI) were used to characterize the occurrence of rice leaf folder damages, which were calculated from the satellite GF-1 retrieval data. A series of analyses were performed to disclose the relationship among these six indices and the severity of rice leaf folder. Quantitative correlation analyses showed that NDVI, EVI, EVI2, SAVI, OSAVI and leaf folding population had a highly significant correlation (P<0.01), and SAVI had a highest correlation of 0.94. While there was no significant correlation between RVI and leaf folding population. Therefore, it was feasible to using hyperspectral data and GF-1 satellite images to monitor and warn the outbreak and development of rice leaf folder, which provided a new possible method to monitor dynamically the damage of rice leaf folder.
关键词： pest population,spectral characteristics,rice leaf folder damage,GF-1 WFV image
更新于2025-09-23 15:23:52
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H-complexes in the “4-n-alkoxybenzoic acid: 4-pyridyl 4′-n-alkoxybenzoate” system. IR spectroscopy and quantum chemical calculations
摘要： IR spectra of individual 4-n-dodecyloxybenzoic acid (A) and 4-pyridyl 4'-n-dodecyloxybenzoate (B) compounds as well as IR spectra of 2A:1B and 1A:1B systems were recorded. For the assignment of the experimental vibrational spectra a series of quantum chemical calculations of DFT(B97-D)/6-311++G** level was carried out. Hydrogen-bonded complexes of types A···A, A···B, as well as various trimers that can be formed at different component ratios in system A-B were simulated. The geometric structure of these complexes was optimized and the vibrational frequencies were calculated. The conclusions on the molecular organization of system A-B for different ratios of the components A and B were based on the interpretation of IR spectra and the analysis of calculated thermodynamic characteristics of self-assembly processes. Thus, it is determined that the system A consists of cyclic A···Acycl dimers; in 1A:1B system the H-complexes of A···B type are formed. In the 2A:1B system in the process of self-assembly, instead of the complexes A···A···B and A···B···A of stoichiometric composition, the complexes A···B and A···Acycl are formed in the ratio 2:1. These results are confirmed by the dilatometric method data.
关键词： thermodynamic characteristics,4-pyridyl 4'-n-alkoxybenzoate,DFT,IR spectra,self-assembly,4-n-alkoxybenzoic acid,hydrogen bonded complexes
更新于2025-09-23 15:23:52
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A novel parameter derived from photoplethysmographic pulse wave to distinguish preeclampsia from non-preeclampsia
摘要： Objective: To describe the comparative hierarchical area ratio (CHAR), a novel parameter derived from the photoplethysmographic (PPG) pulse wave and differences in CHAR values in parturients with and without preeclampsia (PE). Methods: A total of 59 parturients (37 without and 22 with PE) was conducted at the Women’s Hospital of Zhejiang University in Hangzhou, China. We calculated the CHAR values derived from the PPG pulse wave and compared them in parturients with and without PE. Result: The values of CHAR derived from the parturients with PE were lower compared to those without PE (p<0.01). The ROC analysis indicated that the best threshold for the mean value of CHAR was 7.92 to predict PE with a sensitivity of 86.4% and a specificity of 87.1%, while the threshold for the standard deviation of CHAR was 0.76 with a sensitivity of 77.3% and a specificity of 77.4%. The area under the curve (AUC) was 0.91 for mean value of CHAR while 0.78 for standard deviation of CHAR. Meanwhile, a contrast of AUC between CHAR and the former parameter we proposed showed CHAR had better performance in distinguishing PE (0.908 over 0.615, p<0.01). Conclusion: The novel parameter, CHAR, derived from PPG pulse wave differs in parturients with and without PE with high sensitivity and specificity, suggesting that the CHAR might be an effective tool in differentiating the presence of PE.
关键词： Morphology,Characteristics Extraction,Comparative Hierarchical Area Ratio (CHAR),Photoplethysmographic pulse wave,Preeclampsia
更新于2025-09-23 15:23:52
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A 600V PiN diode with partial recessed anode and double-side Schottky engineering for fast reverse recovery
摘要： In this paper, a novel 600V PiN diode for fast recovery is proposed and the operation mechanism as well as the high dynamic ruggedness of the device are analyzed in detail. The proposed structure features the alternating P/N region with partial recessed P region at anode side and the P- Schottky as well as the N Schottky contacts at both sides. In on-state, the carrier injection efficiency can be modulated by adjusting the work function of the anode P- Schottky contact (WSA), which is based on MSC (Metal-Semiconductor-Contacts) concept. As a result, the fast recovery is realized due to the reduced amount of the stored carriers and the shortened carrier extraction path. In off-state, the leakage current can be effectively suppressed attributed to the rapid pinch-off of the depletion layer. The forward voltage drop (VF) and the reverse recovery time (trr) of the proposed structure can be adjusted by changing the depth of the P- Schottky contact (tra) on the sidewall, without sacrificing the breakdown voltage (BV). The proposed structure achieves a trr of 75ns which is 45.7% and 33% lower than that of the conventional PiN and the MPS structure at the same VF of 0.965V, respectively. Moreover, the total amount of holes in the N buffer layer can be supplemented by adjusting the work function of the cathode N Schottky contact (WSC) during reverse recovery, resulting in a high-dynamic ruggedness with suppressed voltage oscillation and voltage overshoot.
关键词： Schottky contact,leakage current,dynamic characteristics,PiN diode,voltage overshoot,reverse recovery
更新于2025-09-23 15:23:52
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Evaluation of Dosimetric Characteristics of Reproducibility, Linearity and Dose Dependence of Optically Stimulated Luminescence Dosimeters in Co-60 Gamma-rays
摘要： We aimed to evaluate the dosimetric characteristics of reproducibility, linearity and dose dependence of optical stimulated luminance dosimeter (OSLD) in the Co-60 Gamma-rays and to analyze with a precedent study in field of the diagnostic radiography and radiotherapy. The reproducibility was 0.76% of the coefficient of variation, the homogeneity was within 1.5% of the coefficient of variation and OSLD had supra-linear response more than 3 Gy. So the correlation between dose and count was fitted by quadratic function. The count depletion by repeated reading was 0.04% per reading regardless of the irradiated dose. And the half time of decay curve according to the irradiated dose was 0.68 min. with 1 Gy, 1.04 min. with 5 Gy, and 1.10 min. with 10 Gy, respectively. In case of annealing for 30 min, the removal rate was 88% with 1 Gy, 90% with 5 Gy, and 92% with 10 Gy, respectively and 99% in case of annealing time for 4 hour. It is feasible to use OSLDs for dose evaluation in Co-60 Gamma-rays when considering the uncertainty on the procedure according to the irradiated dose.
关键词： Dosimetric characteristics,Optical stimulated luminance dosimeters,Co-60
更新于2025-09-23 15:23:52
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Compensation of Distortions of Polarization Characteristics of Ring Resonators
摘要： The reasons of occurrence of polarization mode distortions and methods of their compensation are investigated. It is demonstrated that sensitivity of lasers with ring resonator to magnetic field may be reduced, if effect of induced polarization anisotropy to be compensated by means of installation of a mirror in resonator in certain position, which complies with the minimum ellipticity angle.
关键词： polarization characteristics of interference mirrors,ring optical resonators,phase anisotropy,information optics
更新于2025-09-23 15:23:52
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Analysis of a Fractal Josephson Junction with Unharmonic Current-Phase Relation
摘要： In this paper, a fractal Josephson junction with unharmonic current-phase relation is analytically and numerically analyzed. This system has two, four, or no equilibrium points depending on the external direct current source and unharmonic parameter. The stability analysis of the equilibrium points is carried out. The inclusion of unharmonic current-phase relation in an ideal Josephson junction leads to an increase in the hysteresis of current-voltage characteristics. While the inclusion of fractal characteristics in insulating layer of Josephson junction with harmonic current-phase relation leads to a decrease in the hysteresis of current-voltage characteristics. The inclusion of unharmonic current-phase relation on a fractal Josephson junction leads to an increase in the hysteresis of current-voltage characteristics. The dynamical behavior map of fractal Josephson junction with unharmonic current-phase relation in amplitude and frequency of modulation current plane is depicted. For a suitable choice of modulation parameters of external current source, fractal Josephson junction with unharmonic current-phase relation can exhibit excitable mode, bistable oscillatory mode, and periodic and chaotic behaviors.
关键词： Current-voltage characteristics,Unharmonic current-phase relation,Fractal Josephson junction,Bistability,Chaotic behavior,Hysteresis
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference and Exposition on Electrical And Power Engineering (EPE) - Iasi, Romania (2018.10.18-2018.10.19)] 2018 International Conference and Exposition on Electrical And Power Engineering (EPE) - Limits and Particularities of the Synthesis of Ba<inf>1-x</inf>Ca<inf>x</inf>TiO<inf>3</inf> for Piezoelectric Applications, by Topochemical Conversion from Molten Salt Solutions
摘要： Because of the unique properties of the ferroelectric perovskite particles with a well-defined anisotropic form like shape- and size dependent at low dimensions they have all the attention of the scientific world. Extensive morpho-structural techniques will be used to characterize the piezoelectric material.
关键词： synthesis,solid solutions,morpho-structural characteristics
更新于2025-09-23 15:22:29
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Volatile Memory Characteristics of a Solution-Processed Tin Oxide Semiconductor
摘要： In this paper, we demonstrate and study volatile memory characteristics of the sol-gel SnOx semiconductor. The SnOx exhibits a significant self-rectifying behavior and high nonlinearity. Low reverse-biased currents and high forward-biased currents are observed in the positive and negative voltage regions, respectively. The rectifying ratio can reach 3.7 × 10^5, and the selection ratio (I@Vread/I@0.5Vread) is 10^2. A pinched current hysteresis is found in the forward-biased region, which indicates the volatile memory characteristics of the SnOx memory. The resistance ratio between the high-resistance state (HRS) and low-resistance state (LRS) is ~10^5. In addition, the stability test reveals that the memory can repeatedly operate for over 1.5 × 10^3 cycles.
关键词： Hysteresis,Solution process,Oxide semiconductor,Thin film,Electrical characteristics
更新于2025-09-23 15:22:29