Low Frequency Amplitude Research Articles

Noise Signal Modulation at the Ship Rolling and Pitching due to Fluctuating Interference of Beams

Amplitude modulation of a noise signal of the surface ship is formed both directly at noise emission, when the line of the shaft and the propeller is rotating, and in addition due to the ship rolling and pitching caused by the rough sea. At the same time additional low-frequency (no more than 0,2 Hz) amplitude modulation of the noise emission can be observed as a process of temporary variations of the received signal power. In this regard, it is interesting to find relation of the amplitude-phase modulation spectrum of the ship broadband signal at its rolling and pitching with the spectrum of rolling and pitching process. As a mechanism of formation of the noise signal modulation at the ship rolling and pitching the fluctuating interference of the beams, propagating from vertically dipping underwater point source near the water surface, is considered. The analytical ratios connecting the amplitude-phase modulation spectrum of the ship broadband signal at its rolling and pitching with the spectrum of rolling and pitching process are received.As a result, the parameter describing cumulative conditions by which it is possible to determine spectral properties of modulation is determined. The type of the power variation spectrum can be substantially different depending on values of parameter K = 2kσH sinα 1 where k — the wave number, σH-root mean square value of the vertical component (source shift) due to rolling and pitching, α — the beam grazing angle at the surface. At value 2kσHsinα< 1 results of observation of the signal modulation process can be identified with process of the ship rolling and pitching. At value 2kσHsinα> 1 the signal modulation spectrum will not correspond to the spectrum of rolling and pitching process. With the increase of parameter K value the modulation spectrum extends, goes beyond the spectrum of rolling and pitching process. Significantly lower and high harmonics emerge. Results of computer modeling and natural experiments confirmed dependence of the type of the modulation spectrum on parameter K. Thus, presence of the additional mechanism of noise signal modulation formation at the ship rolling and pitching, caused by the phenomenon of fluctuating interference of the beams propagating from vertically dipping underwater point source near the water surface is found.

Aberrant Spontaneous Brain Activity and its Association with Cognitive Function in Non-Obese Nonalcoholic Fatty Liver Disease: A Resting-State fMRI Study.

Nonalcoholic fatty liver disease (NAFLD) has been proven to be associated with an increased risk of cognitive impairment and dementia, and this association is more significant in non-obese NAFLD populations, but its pathogenesis remains unclear. Our study aimed to explore the abnormalities of spontaneous brain activity in non-obese NAFLD patients by resting-state fMRI (RS-fMRI) and their relationship with cognitive function. 19 non-obese NAFLD, 25 obese NAFLD patients, and 20 healthy controls (HC) were enrolled. All subjects underwent RS-fMRI scan, psychological scale assessment, and biochemical examination. After RS-fMRI data were preprocessed, differences in low-frequency fluctuation amplitude (ALFF), regional homogeneity (ReHo) and functional connectivity (FC) were compared among the three groups. Furthermore, the relationship between RS-fMRI indicators and cognitive and clinical indicators were performed using correlation analysis. The cognitive function was declined in both NAFLD groups. Compared with obese NAFLD patients, non-obese NAFLD patients showed increased ALFF and ReHo in the left middle temporal gyrus (MTG), increased ReHo in the sensorimotor cortex and reduced FC between left MTG and right inferior frontal gyrus (IFG). Compared with HC, non-obese NAFLD patients showed increased ALFF and ReHo in the left calcarine cortex and fusiform gyrus (FG), decreased ALFF in the bilateral cerebellum, and reduced FC between left FG and right IFG and left angular gyrus. In addition to the same results, obese patients showed increased activity in different regions of the bilateral cerebellum, while decreased ALFF in the right superior frontal gyrus and ReHo in the right orbitofrontal cortex (OFC). Correlation analysis showed that in non-obese patients, the ALFF values in the FG and the FC values between the left MTG and the right IFG were associated with cognitive decline, insulin resistance, and fasting glucose disorder. Non-obese NAFLD patients showed abnormal local spontaneous activity and FC in regions involved in the sensorimotor, temporo-occipital cortex, cerebellum, and reward system (such as OFC), some of which may be the potential neural mechanism difference from obese NAFLD patients. In addition, the temporo-occipital cortex may be a vulnerable target for cognitive decline in non-obese NAFLD patients.

Spectral Attributes in Onshore Fuba Field Niger-Delta, Nigeria, Using 3-D Seismic Time-lapse Data

Spectral attributes in Onshore Fuba Field Niger Delta, Nigeria, are here presented, using 3D seismic time-lapse data. The FUBA Field lies on latitudes 40 50’58’’- 4 0 55’19’’N and longitudes 60 18’41’’- 6 0 26’41’’E with aerial extent of 840km2 . The base (1997) and the monitor (2009) seismic surveys resulted in a 4D response difference. The Base and Monitor data have a root-mean-square repeatability ratio (RRR) of 0.38 implying a very good repeatability when considering the acquisition, processing and environmental noises. Data processing and interpretation were carried out using Petrel software. Reservoir pressure decline rate of 0.062psi/day resulted in production decline rate of 1192.21bbl/day. Structural interpretation of seismic data reveals a highly faulted field. Two distinct horizons were mapped. Fault and horizon interpretation shows closures that are collapsed crestal structures bounded by two major faults. All the interpreted faults are normal synthetic and antithetic faults which are common in the Niger Delta basin. The depth structure maps reveal anticlinal faults. Reservoirs are found at a shallower depth from 6500 to 7500 ft and at a deeper depth ranging from 11500 to 13000 ft. The variance values range from 0.0 to 1.0. The Variance edge analysis was used to delineate the prominent and subtle faults in the area. The results of spectral decomposition at the different frequencies indicates areas of low frequency and high amplitude associated with known hydrocarbon zones, meandering channels, lobes and the presence of small scale faults in the field. The results of the work will help in the recovery of more hydrocarbon as by-passed zones and subtle structures are revealed in the area of study.

Spatial Distribution of Very Low Frequency and Low-Frequency (VLF/LF) Transmitter Signal Amplitude Associated With Lower Ionospheric Perturbations: Numerical Modeling and Observations

Spatial Distribution of Very Low Frequency and Low-Frequency (VLF/LF) Transmitter Signal Amplitude Associated With Lower Ionospheric Perturbations: Numerical Modeling and Observations

Identification of fracturing behavior in thermally cracked granite using the frequency spectral characteristics of acoustic emission

The frequency characteristics of acoustic emission (AE) during triaxial compression of thermally cracked and unheated (“fresh”) granite samples were investigated with the aim of understanding the influence of pre-existing cracks on precursor information regarding macroscopic failure. The peak frequency during the damage process was the same for thermally cracked and fresh granites. Analysis of AE signals showed that signals with low peak frequency appeared before failure of the sample, implying the initiation of macrocracks with progressive growth of cracks. The peak amplitude of the frequency spectrum recorded in the thermally cracked samples was much lower than that in the fresh samples. This result suggests two reasons for the difference in peak amplitude: reduction in shear modulus and the attenuation filtering phenomenon caused by thermal cracks (i.e., the differences in overall bulk properties). In particular, the maximum value of peak amplitude in the low-frequency band for the thermally cracked samples was smaller than that for fresh samples. This characteristic can be related to the properties of source of AE signals, such as the stress drop and crack size. Assuming that pre-existing thermal cracks grow during the pre-failure stage, the events with low peak frequency and low peak amplitude in the heat-treated samples are interpreted as exhibiting a low stress drop for individual events. Therefore, although AE signals with low frequency can be considered as precursors to rock failure, cracking behavior suggested by events with low frequency depends on the initial damage condition of the rock sample.

Spatial Distribution of Very Low Frequency and Low-Frequency (VLF/LF) Transmitter Signal Amplitude Associated With Lower Ionospheric Perturbations: Numerical Modeling and Observations

Spatial Distribution of Very Low Frequency and Low-Frequency (VLF/LF) Transmitter Signal Amplitude Associated With Lower Ionospheric Perturbations: Numerical Modeling and Observations

Seismic Attributes for Enhanced Structural and Stratigraphic Interpretation in Onshore Fuba field, Niger Delta, Nigeria

Seismic attributes for enhanced structural and stratigraphic interpretation of Fuba Field, Onshore Niger Delta, Nigeria using Well-log and 3D Seismic data are here presented. Well-to-Seismic ties, faults and horizon mapping, time-surface generation, depth conversion and seismic attributes generation were carried out using Petrel software. The structural interpretation of seismic data reveal highly synthetic and antithetic faults which are in line with faults trends identified in the Niger Delta. Of the 29 interpreted faults, only synthetic and antithetic faults are regional, running from the top to bottom across the field. These faults play significant roles in trap formation at the upper, middle and lower sections of the field. Two distinct horizons were mapped. Fault and horizon interpretation reveal closures which are collapsed crestal structures bounded by these two major faults. The depth structure maps reveal anticlinal faults. Reservoirs are found at a shallower depth from 6500 to 7500ft and at a deeper depth ranging from 11500 to 13000ft. The synthetic and antithetic faults act as good traps for the hydrocarbon accumulation in the study area. The variance and chaos values range from 0.0 to 1.0. The dip magnitude and azimuth values range from 0 to 90 degrees and 0 to 360 degrees. The variance edge, chaos, dip magnitude and azimuth analysis were used to delineate the prominent and subtle faults in the area. The results of spectral decomposition at a frequency of 12-35Hz indicates areas of low frequency and high amplitude associated with known hydrocarbon zones, the presence of channels, lobes and small scale faults in the field. The result of the seismic attribute analysis has shown that the Fuba field has good hydrocarbon prospects.

Application of Time-Frequency Decomposition and Seismic Attributes for Stratigraphic Interpretation of Thin Reservoirs in Onshore Fuba Field Niger-Delta, Nigeria

Application of time-frequency decomposition and seismic attributes for stratigraphic interpretation of thin reservoirs in Onshore Fuba Field Niger Delta, Nigeria, are here presented, using Well-log and 3D Seismic data. Well-to-seismic tie, fault mapping, horizon mapping, time surface generation, depth conversion and seismic attributes generation were carried out using Petrel software. Structural interpretation of seismic data reveals a highly faulted field. Two distinct horizons were mapped. Fault and horizon interpretation shows closures that are collapsed crestal structures bounded by two major faults. All the interpreted faults are normal synthetic and antithetic faults which are common in the Niger Delta basin. The depth structure maps reveal anticlinal faults. Reservoirs are found at a shallower depth from 6500 to 7500 ft and at a deeper depth ranging from 11500 to 13000 ft. The variance and chaos values range from 0.0 to 1.0. The Variance edge and chaos analysis were used to delineate the prominent and subtle faults in the area while the produced spectra were used to delineate the stratigraphy and thickness of the thin-bedded reservoirs. The results of spectral decomposition at frequencies between 12Hz and 35Hz indicate some thin pay sand zones reservoirs which were characterized by of low frequency and high amplitude associated with known hydrocarbon zones, meandering channels, lobes and the presence of small scale faults in the field. Six new probable zones (Prospects A, B, C, D, E and F) of hydrocarbon accumulation were identified. The results of the study will help in the recovery of more hydrocarbon as by-passed zones and subtle structures are revealed in the area of study.

Low Cut-Off Frequency Extension and Amplitude Decoupling Analysis in Non-Contact Transient Measurement

Low Cut-Off Frequency Extension and Amplitude Decoupling Analysis in Non-Contact Transient Measurement

Utilizing Seismic Attributes to Enhance Deduction of the subtle stratigraphic trap in Mishrif Formation at Dujaila oil field, Southern East of Iraq

Three seismic instantaneous attributes (phase, frequency, and variance) were utilized on 3D-seismic poststack migrated data, covering 617.31 km2, integrated with data of two wells (Du-1 and Du-2) in Dujaila oil field, southeast of Iraq. They gave good results in detecting reef buildups and confirmed the existence of the stratigraphic hydrocarbon trap that was not obvious in the conventional seismic amplitude sections. They display several seismic criteria in attribute sections for recognizing reef buildups and hydrocarbon accumulation, such as phase reversal, low frequency, and high amplitude variance. The seismic attributes emphasized that the stratigraphic trap of reef rudist buildups with hydrocarbon content is constricted in the upper part of the Mishrif Formation (Cenomanian-Early Turonian) the vicinity around productive well Dujaila-1. It is located at a time from -1730 ms in the Top Mishrif to underneath at a time -1775 ms, which has correspondent the depth 2825 m to 2887.5 m, respectively. This stratigraphic trap covered 70 km2 (length is 10.0 km in direction N-S, and the width is about 7.0 km in the E-W direction). The enclosure of the stratigraphic trap extends about 7 km towards SW from the well Dujaila-1 and did not reach well Dujaila-2 (Du-2). That may explain why it was dry. As a result, the circular region around well Du-1 of a radius of about 4 km, and the area extended about 7 km toward SW from well Du-1 represent a zone of low risk-drill for new exploration wells.

Analysis of super-harmonic resonance and periodic motion transition of fractional nonlinear vibration isolation system

The precision instruments and equipment are often utilized in low-frequency and micro-amplitude vibration systems, in which many vibration isolators of rubber materials are widely used. Ignoring the low-frequency amplitude will result in errors in the fatigue life design of the vibration isolators and predicting the dynamic response of each frequency band accurately becomes necessary. However, integer-order models cannot describe the frequency dependence of rubber materials, while the fractional-order models can describe it instead. On the other hand, the elastic restoring force is strongly nonlinear under large deformation, and the vibration of the nonlinear system contains multiple harmonic components. In order to solve those issues, the fractional nonlinear Nishimura model is used to characterize the constitutive relation of vibration isolators such as air springs, which are made of carbon black filled natural rubber. The high-order harmonic balance method is used to obtain the steady-state response of the vibration system, while the fourth-order Runge–Kutta method is applied to simulate the dynamic response of the system in the low-frequency region, and the Lyapunov exponent is used to determine the stability of the system. Furthermore, the influence of parameters on the amplitude–frequency characteristics of different frequency bands is also studied, and a method to solve the optimal damping coefficient is proposed based on the primary resonance amplitude–frequency curves. The results show that there is a diversity of periodic motions in the process of adjacent super-harmonic resonance transition. Numerical simulations also demonstrate that multi-periodic motions coexist in the system. The motion transition law between the polymorphic coexistence region and its adjacent regions is summarized.

Impaired neural entrainment to low frequency amplitude modulations in English-speaking children with dyslexia or dyslexia and DLD

Neural synchronization to amplitude-modulated noise at three frequencies (2 Hz, 5 Hz, 8 Hz) thought to be important for syllable perception was investigated in English-speaking school-aged children. The theoretically-important delta-band (∼2Hz, stressed syllable level) was included along with two syllable-level rates. The auditory steady state response (ASSR) was recorded using EEG in 36 7-to-12-year-old children. Half of the sample had either dyslexia or dyslexia and DLD (developmental language disorder). In comparison to typically-developing children, children with dyslexia or with dyslexia and DLD showed reduced ASSRs for 2 Hz stimulation but similar ASSRs at 5 Hz and 8 Hz. These novel data for English ASSRs converge with prior data suggesting that children with dyslexia have atypical synchrony between brain oscillations and incoming auditory stimulation at ∼ 2 Hz, the rate of stressed syllable production across languages. This atypical synchronization likely impairs speech processing, phonological processing, and possibly syntactic processing, as predicted by Temporal Sampling theory.

Absolute displacement measurement using an inertial reference generated by linearised electromagnetic levitation

This paper proposes a novel passive absolute displacement measurement system (ADMS) utilising the electromagnetic levitation approach, instead of any mechanical spring. The most distinctive feature of the proposed ADMS is its measuring amplitude range of 30μm–1.2 mm with a lower frequency limit of 2 Hz. Consequently, a wider measuring bandwidth and higher measurement accuracy for absolute displacement signals can be realised without feedback/serve-type inertia sensors, which are usually expensive and vulnerable. Both features make the proposed system promising for of low-frequency measurement applications, such as precision vibration isolation of optical platforms in vibrational environments, anti-shake UAV platforms, monitoring of seismic wave signals, ship equipment protection and safety inspection of long-span bridges. First, the principles of the proposed ADMS are introduced. Subsequently, the measuring performance of the proposed ADMS is simulated and analysed. Finally, a prototype of the ADMS is constructed and tested. The experimental results confirm the validity of the proposed ADMS design and demonstrate its capability to measure the absolute displacement with a low-frequency and wider amplitude range.

Dynamic local metrics changes in patients with toothache: A resting-state functional magnetic resonance imaging study.

To study the dynamic changes of local metrics in patients with toothache (TA, Toothache) in the resting state, in order to further understand the changes of central neural mechanism in patients with dental pain and its effect on cognition and emotion. Thirty patients with TA and thirty matched healthy (HC) control volunteers were recruited, and resting-state functional magnetic resonance (rs-MRI) scans were performed on all subjects, and data were analyzed to compare group differences in three dynamic local indices: dynamic regional homogeneity (dReHO), dynamic low-frequency fluctuation amplitude (dALFF) and dynamic fractional low-frequency fluctuation amplitude (dfALFF). In addition, the association between dynamic local metrics in different brain regions of TA patients and scores on the Visual Analog Scale (VAS) and the Hospital Anxiety and Depression Scale (HADS) was investigated by Pearson correlation analysis. In this study, we found that The local metrics of TA patients changed with time Compared with the HC group, TA patients showed increased dReHo values in the left superior temporal gyrus, middle frontal gyrus, precentral gyrus, precuneus, angular gyrus, right superior frontal gyrus, middle temporal gyrus, postcentral gyrus and middle frontal gyrus, increased dALFF values in the right superior frontal gyrus, and increased dfALFF values in the right middle temporal gyrus, middle frontal gyrus and right superior occipital gyrus (p < 0.01, cluster level P < 0.05). Pearson correlation analysis showed that dReHo values of left precuneus and left angular gyrus were positively correlated with VAS scores in TA group. dReHo value of right posterior central gyrus was positively correlated with HADS score (P < 0.05). There are differences in the patterns of neural activity changes in resting-state brain areas of TA patients, and the brain areas that undergo abnormal changes are mainly pain processing brain areas, emotion processing brain areas and pain cognitive modulation brain areas, which help to reveal their underlying neuropathological mechanisms. In the hope of further understanding its effects on cognition and emotion.

Dynamic response of turbine blade considering a droplet-wall interaction in wet steam region

The high-speed impact of liquid droplets on blades in wet steam region seriously affects the safe operation of steam turbine. For blade stability and response characteristics, most studies utilized ideal gas as working medium and few studies focused on the role of droplets in the flow field. In this study, both the distribution information of droplet particles in the flow field and the impact of droplet particles on blades were comprehensively considered. First, the droplet distribution at the last stage inlet was calculated, and then the droplet-wall interaction model was determined and loaded into calculation process. The pressure distribution on blade surface, blade force variation, mechanical properties, and further dynamic response characteristics of blade were analyzed with ideal gas and wet steam models, respectively, by using one-/two-way fluid-structure interaction. Results show that the blade displacement of leading and trailing edges under wet steam model reaches the maximum at near 80% blade height, and there is a low frequency amplitude corresponding to 460 Hz–470 Hz with the peak value in the range of 22Pa–26Pa. The variations of the maximum displacement and maximum equivalent stress of the blade with time are more intense under wet steam model compared with those under ideal gas model.

Alteration of whole-brain amplitude of low-frequency fluctuation and degree centrality in patients with mild to moderate depression: A resting-state functional magnetic resonance imaging study.

Mild to moderate depressive disorder has a high risk of progressing to major depressive disorder. Low-frequency amplitude and degree centrality were calculated to compare 49 patients with mild to moderate depression and 21 matched healthy controls. Correlation analysis was conducted to explore the correlation between the amplitude of low-frequency fluctuation (ALFF) and the degree centrality (DC) of altered brain region and the scores of clinical scale. Receiver operating characteristic (ROC) curves were further analyzed to evaluate the predictive value of above altered ALFF and DC areas as image markers for mild to moderate depression. Compared with healthy controls, patients with mild to moderate depression had lower ALFF values in the left precuneus and posterior cingulate gyrus [voxel p < 0.005, cluster p < 0.05, Gaussian random field correction (GRF) corrected] and lower DC values in the left insula (voxel p < 0.005, cluster p < 0.05, GRF corrected). There was a significant negative correlation between DC in the left insula and scale scores of Zung's Depression Scale (ZungSDS), Beck Self-Rating Depression Scale (BDI), Toronto Alexithymia Scale (TAS26), and Ruminative Thinking Response Scale (RRS_SUM, RRS_REFLECTION, RRS_DEPR). Finally, ROC analysis showed that the ALFF of the left precuneus and posterior cingulate gyrus had a sensitivity of 61.9% and a specificity of 79.6%, and the DC of the left insula had a sensitivity of 81% and a specificity of 85.7% in differentiating mild to moderate depression from healthy controls. Intrinsic abnormality of the brain was mainly located in the precuneus and insular in patients with mild to moderate depression, which provides insight into potential neurological mechanisms.

Variation in the Low-frequency Fluctuation of the Cortex Among Patients with Paradoxical Insomnia: A Resting-State Functional Magnetic Resonance Imaging Study

Background: Paradoxical insomnia is one of the most prevalent subtypes of insomnia disorder and its symptom includes a discrepancy between subjective and objective sleep measures. Objectives: This study aimed to evaluate the amplitude differences of low-frequency fluctuation as a possible local characteristic in paradoxical insomnia by resting-state functional MRI among patients with paradoxical insomnia and healthy subjects. Methods: A t-test was used in this case-control study to investigate possible changes in low-frequency fluctuation amplitude in 15 paradoxical insomnia patients and 48 healthy subjects. Results: The results were far from the chance level by removing nuisance variables and controlling for multiple comparisons. In addition, there was a decrease in the amplitude of low-frequency fluctuation among people with paradoxical insomnia compared to the healthy group in the right region of the superior parietal lobule and precuneus regions. Conclusions: Based on these results, brain signals appear to play an important role in the pathophysiology of paradoxical insomnia, and further research may identify the mechanism behind this type in the future.

Design of chopper operational amplifier for leakage current protector chip

Due to the low frequency and small amplitude of the input signal of the leakage current protection chip, an operational amplifier with low offset and low power consumption is designed by using the chopper stabilization technique and the dynamic element matching technique. Based on the TSMC 0.18um process, the spectre environment in cadence is used for design and simulation. The power supply voltage is 1.8V. The post simulation results show that under the TT corner, the average current of the operational amplifier is 139uA, the loop gain is 85.9dB, the phase margin is 68.01°, and the power supply rejection ratio(PSRR) is 101.62dB@50Hz, the common mode rejection ration(CMRR) is 104.52dB@50Hz, the equivalent input noise is 129.86nv/sqrt(Hz)@50Hz, and the value of equivalent input offset voltage is 8.2uV(mean).

A Study on the Train-Induced Vibration Responses of Heavy Haul Railway Subgrade in Seasonally Frozen Regions Using Field Experiments

The dynamic response resulting from heavy haul train leads to the deterioration of the railway subgrade, especially those built in seasonally frozen regions. In this work, a typical heavy haul railway section in a seasonally frozen region is monitored on-site. The time domain and the frequency domain analysis of the subgrade vertical vibration acceleration, dynamic speed, and displacement during the non-frozen period and the frozen period are investigated. The results show that the vibration response of the subgrade is affected by various factors, including the train type, locomotive, traveling speed, train formation, heavy load, and the prevalent season. Further, it is observed that the maximum and average vertical acceleration of the subgrade, the vibration speed, and the dynamic displacement increase during the frozen period. However, the main frequency of the natural vibration remains significantly higher than that before freezing. Moreover, the frozen soil has a significant amplification effect both on the acceleration and the attenuation rate. Similarly, the subgrade’s vibration mode has a low frequency and high amplitude during the freezing period, and the dynamic response characteristics become increasingly apparent as the axle load increases.

Abnormal Regional Spontaneous Neural Activity and Functional Connectivity in Unmedicated Patients with Narcolepsy Type 1: A Resting-State fMRI Study.

Previous Resting-state functional magnetic resonance imaging (fMRI) studies have mainly focused on cerebral functional alteration in processing different emotional stimuli in patients with narcolepsy type 1 (NT1), but were short of exploration of characteristic brain activity and its remote interaction patterns. This study aimed to investigate the spontaneous blood oxygen fluctuations at rest and to elucidate the neural mechanisms underlying neuropsychiatric behavior. A total of 18 unmedicated patients with NT1 and matched healthy individuals were recruited in a resting-state fMRI study. Magnetic resonance imaging (MRI) data were first analyzed using fractional low-frequency amplitude of low-frequency fluctuation (fALFF) to detect changes in local neural activity, and regions with group differences were taken as regions of interest (ROIs). Secondly, functional connectivity (FC) analysis was used to explore altered connectivity between ROIs and other areas. Lastly, the relationship between functional brain activity and neuropsychiatric behaviors was analyzed with correlation analysis. fALFF analysis revealed enhanced neural activity in bilateral fusiform gyrus (FFG), right precentral gyrus, and left postcentral gyrus (PoCG) in the NT1 group. The patients indicated reduced activity in the bilateral temporal pole middle temporal gyrus (TPOmid), left caudate nucleus (CAU), left parahippocampus, left precuneus (PCUN), right amygdala, and right anterior cingulate and paracingulate gyri. ESS score was negatively correlated with fALFF in the right FFG. The NT1 group revealed decreased connectivity between left TPOmid and right PoCG, the bilateral middle frontal gyrus, left superior frontal gyrus, medial, and right supramarginal gyrus. Epworth Sleepiness Scale (ESS) was negatively correlated with FC of the left TPOmid with left putamen (PUT) in NT1. Compared with healthy controls (HCs), enhanced FC of the left CAU with right FFG was positively associated with MSLT-SOREMPs in patients. Furthermore, increased FC of the left PCUN with right PoCG was positively correlated with SDS score. We found that multiple functional activities related to the processing of emotional regulation and sensory information processing were abnormal, and some were related to clinical characteristics. fALFF in the left postcentral or right precentral gyrus may be used as a biomarker of narcolepsy, whereas fALFF in the right fusiform and the FC strength of the left temporal pole middle temporal gyrus with the putamen may be clinical indicators to assess the drowsiness severity of narcolepsy.