spectral profile
Recently Published Documents


TOTAL DOCUMENTS

188
(FIVE YEARS 34)

H-INDEX

23
(FIVE YEARS 4)

MAUSAM ◽  
2021 ◽  
Vol 59 (1) ◽  
pp. 111-118
Author(s):  
SUJAY DUTTA ◽  
V. K. DADHWAL ◽  
N. K. PATEL ◽  
J. S. PARIHAR

Spot-vegetation 10 day NDVI composites over Orissa state were analysed to study rice crop inventory and condition assessment. A total of 17 images from July to December during the monsoon (kharif) season of 1998 (S1) and 2001 (S2) a drought and normal year, respectively were analysed. A hierarchical decision rule-based approach that successively eliminated data loss, non vegetated land, forest cover, fallow and other crops was adopted for rice inventory. NDVI temporal profiles of rice could distinguish autumn and winter rice. The total monsoon rice area identified by RS in the state was 4.5 M ha in 1998 and 4.05 M ha in 2001 and was within 7 percent of the state level rice estimate given by Directorate of Economic Survey (DES) i.e., 4.26 and 4.22 M ha, respectively. A new profile fit i.e., a six parameter modified Gaussian approach was adopted.  The spectral profile indicated higher mean NDVI at peak growth profile of lowland winter rice (sown in June-July) in 2001-02 compared to 1998-1999. Thus, 2001-2002 rice was seen to be normal while in 1998-1999 a drought affected year. District-wise NDVI profiles of rice were generated and peak NDVI and date at peak profile were found to be correlated with rice yield at district and agro-climatic zone level. Use of rainfall with spectral profile parameters in yield model group of districts or zonal level improved coefficient of determination. This study demonstrates the utility of 1 km and 10 day NDVI composite data for rice crop assessment during monsoon season.


2021 ◽  
Author(s):  
David Moss

Abstract We demonstrate advanced integrated photonic filters in silicon-on-insulator (SOI) nanowires implemented by cascaded Sagnac loop reflector (CSLR) resonators. We investigate mode splitting in these standing-wave (SW) resonators and demonstrate its use for engineering the spectral profile of on-chip photonic filters. By changing the reflectivity of the Sagnac loop reflectors (SLRs) and the phase shifts along the connecting waveguides, we tailor mode splitting in the CSLR resonators to achieve a wide range of filter shapes for diverse applications including enhanced light trapping, flat-top filtering, Q factor enhancement, and signal reshaping. We present the theoretical designs and compare the CSLR resonators with three, four, and eight SLRs fabricated in SOI. We achieve versatile filter shapes in the measured transmission spectra via diverse mode splitting that agree well with theory. This work confirms the effectiveness of using CSLR resonators as integrated multi-functional SW filters for flexible spectral engineering.


2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 460-460
Author(s):  
L Cerna ◽  
P Yu

Abstract The objectives of this study were to evaluate the effect of varieties and heat processing methods on molecular structural, physicochemical, and nutritional characterization of feed chickpeas; evaluate the effect of heat processing methods, dry heat, wet heat and microwave irradiation processing method on feed chickpeas as an alternative source for protein and energy feed for ruminant livestock. To reveal the molecular structure spectral profile of chickpeas varieties and the molecular structure changes when applied heat processing methods, vibrational molecular spectroscopy was applied. Feed chickpea samples were determined for chemical profile, energy values, carbohydrate fractions. Subsequently, chickpea samples were incubated in the rumen of dairy cows for degradation kinetics analysis of nutrients. The intestinal digestion of feed chickpea samples was determined using three-step in vitro method with pre-incubation at 16h. Later, protein and carbohydrate related molecular spectral features before and after incubation were performed using vibrational ATR-FTIR molecular spectroscopy. The interactive relationship between processing induced molecular spectral profile changes and nutrient metabolism and availability were studied. The available results showed that varieties and heat processing methods significantly impacted molecular structural, physicochemical, and nutritional characterization of feed chickpeas.


Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5723
Author(s):  
Wei-Ling Chen ◽  
Shan-Yu Chen ◽  
Dun-Cheng Huang ◽  
Dian Luo ◽  
Hsueh-Wen Chen ◽  
...  

Organic light-emitting diodes (OLEDs) used as phototherapy light sources require sufficient spectral distribution in the effective wavelength ranges and low operating voltages. Herein, a double emitting layer structure consisting of a red-emitting Ir(piq)2acac and a deep-red Ir(fliq)2acac was designed to generate a broad electroluminescence spectrum. An efficient TCTA:CN-T2T exciplex system was used as the host of the emitting layer, facilitating effective energy transfer from the exciplex host to the red and deep-red phosphors. The materials used in the exciplex host were also used as the carrier transport layers to eliminate the energy barriers and thus increase the current density. The hole injection layer structures were varied to examine the hole injection capabilities and the carrier balance. The resulting optimized phosphorescent OLEDs with a broad spectral profile exhibit a 90% coverage ratio in the target ranges from 630 to 690 nm, together with a high peak efficiency of 19.1% (10.2 cd/A and 13.8 lm/W). The proposed device only needs 5.2 V to achieve a power density of 5 mW/cm2, implying that the device could be driven via two series-connected button cell batteries. These results illustrate the feasibility of our design concepts and demonstrate the realization of a portable and lightweight OLED phototherapy light source.


2021 ◽  
Author(s):  
Supratim Ray ◽  
Dinavahi V P S Murty ◽  
Wupadrasta Santosh Kumar ◽  
Keerthana Manikandan ◽  
Ranjini Garani Ramesh ◽  
...  

Visual stimulus-induced narrowband gamma oscillations in electroencephalogram (EEG) recordings have been recently shown to be compromised in subjects with Mild Cognitive Impairment or Alzheimer′s Disease (AD), suggesting that gamma could be an inexpensive and easily accessible biomarker for early diagnosis of AD. However, to use gamma as a biomarker, its characteristics should remain consistent across multiple recordings, even when separated over long intervals. Previous magnetoencephalography studies in young subjects have reported that gamma power remains consistent over recordings separated by a few weeks to months. Here, we assessed the consistency of slow (20-35 Hz) and fast gamma (36-66 Hz) oscillations induced by static full-field gratings in male (N=20) and female (N=20) elderly subjects (>49 years) in EEG recordings separated by more than a year and tested the consistency in the magnitude of gamma power, its temporal evolution and spectral profile. Gamma oscillations had distinct spectral and temporal characteristics across subjects, which remained consistent across recordings (average intraclass correlation, ICC of ~0.7). Alpha oscillations (8-12 Hz) and steady-state-visually-evoked-potentials (SSVEPs) were also found to be reliable. We further tested how EEG features can be used to identify two recordings as belonging to the same versus different subjects and found high classifier performance (area under ROC curve of ~0.89), with the temporal evolution of slow gamma and spectral profile emerging as the most informative features. These results suggest that EEG gamma oscillations are reliable across recordings and can be used as a clinical biomarker as well as a potential tool for subject identification.


Author(s):  
Neha Banerjee ◽  
Prashanth Prabhu

Background and Aim: The central auditory nervous system has the ability to perceptually group similar sounds and segregates different sounds called auditory stream segregation or auditory streaming or auditory scene analysis. Identification of a change in spectral profile when the amplitude of a component of complex tone is changed is referred to as Spectral profile analysis. It serves as an important cue in auditory stream segregation as the spectra of the sound source vary. The aim of the study was to assess auditory stream segregation in individuals with cochlear pathology (CP) and auditory neuropathy spectrum disorder. Methods: In the present study, three groups of participants were included. Experimental groups included 21 ears in each group with cochlear hearing loss or auditory neuropathy spectrum disorders (ANSD) and control group with 21 ears with normal hearing. Profile analysis was asse­ssed using "mlp" toolbox, which implements a maximum likelihood procedure in MATLAB. It was assessed at four frequencies (250 Hz, 500 Hz, 750 Hz, and 1000 Hz) for all three groups. Results: The results of the study indicate that the profile analysis threshold (at all four frequ­encies) was significantly poorer for individuals with CP or ANSD compared to the control group. Although, cochlear pathology group performed better than ANSD group. Conclusion: This could be because of poor spec­tral and temporal processing due to loss of outer hair cells at the level of the basilar membrane in cochlear pathology patients and due to the demyelination of auditory neurons in individuals with ANSD. Keywords: Auditory stream segregation; auditory scene analysis; spectral profiling; spectral profile analysis; cochlear pathology; auditory neuropathy spectrum disorders


2021 ◽  
pp. 24-27
Author(s):  
A.S. Mazmanishvili

The consideration is based on the study of the spectral profile of the synchrotron radiation (SR) line of a relativistic electron orbiting in a circular orbit in the uniform magnetic field. Fast stochastic fluctuations accompanying the motion of the electron during emission of SR quanta lead to the formation of spectral contour of each SR harmonic and it’s broadening. It is shown that the joint broadening of the set of harmonics causes broadening of the SR spectrum as the whole. The results of numerical calculations on the formation of the final SR spectral density of a relativistic electron are presented. In order to obtain precision characteristics, the formation of SR density in the frequency range exceeding the critical frequency has been studied.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3019
Author(s):  
Heejung Kim ◽  
Jihye Seong

Autophagy is an essential cellular process of self-degradation for dysfunctional or unnecessary cytosolic constituents and organelles. Dysregulation of autophagy is thus involved in various diseases such as neurodegenerative diseases. To investigate the complex process of autophagy, various biochemical, chemical assays, and imaging methods have been developed. Here we introduce various methods to study autophagy, in particular focusing on the review of designs, principles, and limitations of the fluorescent protein (FP)-based autophagy biosensors. Different physicochemical properties of FPs, such as pH-sensitivity, stability, brightness, spectral profile, and fluorescence resonance energy transfer (FRET), are considered to design autophagy biosensors. These FP-based biosensors allow for sensitive detection and real-time monitoring of autophagy progression in live cells with high spatiotemporal resolution. We also discuss future directions utilizing an optobiochemical strategy to investigate the in-depth mechanisms of autophagy. These cutting-edge technologies will further help us to develop the treatment strategies of autophagy-related diseases.


Sign in / Sign up

Export Citation Format

Share Document