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This study investigated brain microstructural changes in patients with amnestic mild cognitive impairment (aMCI) by retrospectively analyzing neurite orientation dispersion and density imaging (NODDI) data with machine learning algorithms.A total of 26 aMCI patients and 24 healthy controls (HC) underwent NODDI magnetic resonance imaging (MRI) examinations. The NODDI parameters including neurite density index (NDI), orientation dispersion index (ODI), and volume fraction of isotropic water molecules (Viso) were estimated. Machine learning algorithms such as K‑nearest neighbor (KNN), logistic regression (LR), random forest (RF), and support vector machine (SVM) were used to evaluate the diagnostic efficacy of NODDI parameters in predicting aMCI. The differences in the NODDI parameter values between the aMCI and HC groups were analyzed using the independent sample t‑test, False discovery rate (FDR) correction was used for multiple testing. After adjusting for age, sex, and educational years, partial correlation analysis was used to evaluate the relationship between NODDI parameters and clinical cognitive status of aMCI patients.The NDI, ODI, and Viso values of white matter (WM) and gray matter (GM) structure templates combined with the KNN, LR, RF and SVM machine learning algorithms accomplished the discrimination between aMCI and HC groups. The NDI and ODI values decreased (p value range, 0.001-0.042) and Viso values increased (p value range, 0.001-0.043) in the aMCI group compared to the HCs. The NDI, ODI, and Viso values of the WM and GM structure templates with significant differences were significantly correlated with mini-mental state examination (MMSE) and Montreal cognitive assessment (MoCA) scores.NODDI combined with machine learning algorithms is a promising strategy for early diagnosis of aMCI. Moreover, NODDI parameters correlated with the clinical cognitive status of aMCI patients.

Microbial fuel cells are one of the most important elements in the renewable energy supply chain. To increase the efficiency and performance of the fuel cell, designing a suitable control method is essential to achieve reliable performance and output stability. By considering the parametric uncertainties on the microbial fuel cell model as well as nonlinear terms, this paper presents a novel finite time adaptive sliding mode control method that achieves optimal performance of fuel cell in a finite time and also ensures the stability of the closed loop system. Sliding mode method without linearization or elimination of nonlinear terms has been used as a robust method to overcome uncertainty effects and guarantees proper operation of the fuel cell in the presence of the effects. The finite time convergence of the states is also assured by using of the proposed method. Furthermore, it uses an adaptive method to determine the sliding mode control coefficients which eliminates the necessity to know the upper bound of uncertainty. Finally, the simulation results show the efficiency and stability of the proposed method in different operating conditions.

In this paper, a novel active control approach is designed for surge instability in the compressor system using the finite-time fuzzy sliding mode scheme. The primary novelty of this study lies in the development of a finite-time fuzzy sliding mode control for the surge instability in a compressor system in the presence of disturbance and uncertainty in the characteristic curve of the compressor and also throttle valve. To ensure the stability of the closed-loop system in Lyapunov's concept, a finite time active control method is proposed based on fuzzy estimation method and robust adaptive and sliding mode methods. Achieving finite time stability and rapid elimination of deep surge instability occurs through a fast sliding mode design, while fuzzy and adaptive techniques are used to estimate uncertainty and nonlinear terms, as well as to obtain optimal estimation weights. The simulation results in MATLAB environment and comparison show that the suggested method provides better quality control in terms of surge suppression, robustness, and overcoming uncertainty and disturbance effects.

The power generation subsystem represents one of the principal components of a space system and is usually assembled from solar arrays and PPT topology. This paper aims to design and implement an algorithm to continuously extract the maximum power from the solar cells and deliver it to the consumer with minimum loss. In this regard, a brief introduction to the various parts of the power generation subsystem is provided and through accurate modeling of the solar cell and exploring the contributing factors to its power generation (including temperature, radiation, and space radiation), the algorithm is proposed based on the impedance matching concept. Simulation studies using MATLAB software have estimated an approximate 0.25065W per square centimeter power extraction and delivery to the customer. Our results suggest that the proposed approach can reduce steady-state losses while ensuring accuracy.

The microbial fuel cell is one of the most important tools in the supply of renewable energy and its controller plays an important role in improving the performance and stability of its output. Using the advantages of adaptive and sliding mode methods, this paper presents a combined technique to ensure the stability and output voltage stabilization of the fuel cell in the presence of parametric uncertainties and nonlinear terms. The proposed control method is compared with classical control approaches and the simulation results confirm its efficiency.

This paper investigates the event-triggered consensus problem of multi-agent systems with uncertainties and input saturation. First, a fully distributed robust consensus low-gain feedback control strategy is proposed, in which some global information, such as the communication graph and the scale of network, is not needed. Then, by defining an internal dynamic variable to memory the past state, an adaptive dynamic event-triggering mechanism is proposed, which contributes to reducing the usage of communication resources and also does not rely on any global information. Furthermore, Lyapunov-based consensus analysis results are presented, and it is also formally shown that Zeno behavior can be excluded with the proposed consensus protocols. Finally, a numerical example is provided to illustrate the effectiveness of the proposed results.

Polycrystalline higher manganese silicides Mn1–xCrxSi1.74 (x = 0, 0.10, 0.20) with Cr single doping and Mn1–2yCryFeySi1.74 (y = 0.10, 0.20) with Cr–Fe double doping have been prepared by arc meltin...

Energy supply from renewable sources is one of the most attractive fields of study in recent years. Ensuring the efficient operation of the microbial fuel cell (MFC) due to its capabilities requires the development of appropriate control strategies. This paper presents a combination of fuzzy and adaptive control methods to control single-chamber single-population MFC. For estimating nonlinear terms as well as the parametric uncertainty in the model, fuzzy approximation method has been used and the effects of disturbances as well as fuzzy approximation gains have been covered by adaptive method. Using Liapunov theory, the robust stability of the system under the proposed controller is shown. The simulation results clearly show the ability of the proposed method to achieve MFC control goals.

Lu2O3 crystals have attracted intense attention due to their great potential in the field of high power solid-state lasers. Lu2O3 single crystal fibers (SCFs) with a length-to-diameter ratio of >200 : 1 were successfully grown by the laser heated pedestal growth (LHPG) method for the first time. The relationships between the crystal diameter and thermal stress were investigated in detail. Crystal cracking was effectively solved by reducing the diameter of the crystal fiber. Besides, the influence of the growth atmosphere on the crystal growth was also demonstrated. The crystals grown in a mixture of 95% O2 and 5% Ar were colorless and transparent. The XRD pattern showed that the phase of Lu2O3 was pure, and the crystal quality along the axial and radial directions was measured by Laue back-reflection measurements. Meanwhile, the diameter fluctuations of the obtained Lu2O3 crystal fibers were further reduced by using optimized source rods.

In this paper, a novel control approach is designed for surge instability in the compressor system using the finite-time adaptive sliding mode scheme. The primary novelty of this study lies in the development of a finite-time adaptive control for the surge instability avoidance in a compressor system in the presence of disturbance and uncertainty in the characteristic curve of the compressor and also throttle valve. The Lyapunov method is utilized to verify the finite-time stability of the closed-loop system. The performance of the presented method is compared against other methods in the literature through simulations in Matlab. The results suggest that our designed controller outperforms the existing ones in terms of surge avoidance and robustness against uncertainties and disturbances.

This study aimed to investigate the alterations in brain networks in patients with Alzheimer’s disease (AD) and mild cognitive impairment (MCI) based on a population-specific brain template. Previous studies on AD brain networks using graph theory rarely adopted brain templates specific for certain ethnicities. In this study, patients were divided into 3 groups: AD (n = 24), MCI (n = 27), and healthy controls (HCs, n = 33), and all of the subjects are Chinese. Functional brain networks were constructed for each group based on a Chinese brain template using resting-state functional magnetic resonance imaging (rs-fMRI) data; several graph metrics were calculated. Graph metrics with significant differences after false discovery rate (FDR) correction were analyzed with respect to correlations with four neuropsychological test scores: Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Activities of Daily Living (ADL), and Clinical Dementia Rating (CDR), which assessed the subjects’ cognitive functions and ability to engage in ADL. Graph metrics including assortativity coefficient, nodal degree centrality, nodal clustering coefficient, nodal efficiency, and nodal local efficiency of the frontal gyrus and cerebellum were significantly altered in AD and MCI compared with HC. Several graph metrics were significantly correlated with cognitive function and the ability to engage in daily activities. The findings suggest that altered graph metrics in the frontal gyrus may reflect brain plasticity, and that patients with MCI may have unique graph metric alterations in the cerebellum. Future graph analysis studies on functional brain networks in AD and MCI based on population-specific brain atlases for particular ethnicities may prove valuable.

Model-based control strategies for microbial fuel cell are able to create a balance between fuel supply, mass, charge and electric charge, performance efficiency. This paper designs a new adaptive sliding mode control scheme of single chamber single population microbial fuel cell. The adaptive method estimates parametric uncertainty and nonlinear terms while the sliding mode method achieves microbial fuel cell performance targets. The significant advantage of the suggested scheme is its capability to provide robustness against parametric uncertainties and handle systems nonlinearity. The Lyapunov technique has been used to demonstrate robust stability in the face of nonlinearity and uncertainty. Numerical simulations confirms that the proposed control method is able to meet the desired specification in the presence of varieties of parametric uncertainty.

Organic-inorganic halide single-crystal perovskite solar cells (PSCs) are promising for higher efficiency and better stability, while their development lags far behind polycrystalline counterpart. ...

BACKGROUND Dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease) is an extremely rare, slow-growing hereditary mass lesion that is mainly characterized by both specific neuroradiological features and secondary hydrocephalus. Patients may present with symptoms of cerebellar mass lesion and increased intracranial pressure. As an important part of Cowden syndrome, Lhermitte-Duclos disease in adults is typically marked by PTEN gene mutation. OBSERVATIONS The clinical management of a 31-year-old woman who suffered Lhermitte-Duclos disease was introduced in this case report. Subtotal resection was performed with the assistance of intraoperative sonography to relieve obstructive hydrocephalus, and prophylactic C1 laminectomy was performed to prevent possible postoperative progression of the residual lesion. Perioperative care and surgical process were clearly revealed in an accompanying video. Intraoperative sonography of Lhermitte-Duclos disease presents hyperechoic distorted thickening cortices surrounded by hypoechoic edema belt. The patient did not report any significant neurological complications or sequelae after the lesion resection. LESSONS The authors first reported the use of intraoperative sonography in resection of adult-onset Lhermitte-Duclos disease. Hopefully, the educative case report can provide a feasible experience in the diagnosis and treatment of Lhermitte-Duclos disease.

The sesquioxide Lu2O3 single crystal has enormous potential applications as host material for solid-state lasers operating at high average powers, and its development is limited by the lack of large sized single crystals with high quality. Compared with the traditional Czochralski (Cz) method, the edge-defined film-fed growth (EFG) method, employing a die or a shaper, doesn't make the grown crystal come into contact with the melt in crucible directly during the growth process. Therefore, the growth interface is stable and the serious bottleneck problems of a “w”-shaped isotherm in the Czochralski method could be avoided effectively. Herein, the EFG method may be a promising technique to obtain ultra-high temperature sesquioxide single crystals with a large size, and more importantly, high quality. Accordingly, the sesquioxide Lu2O3 single crystal has been grown controllably with an oriented seed by the EFG method for the first time and the EFG method is promoted to an extremely high temperature of 2450 °C. The dimensions of the grown crystal are Φ 25 × 30 mm3, and the difficulties encountered during the crystal growth have been discussed in detail. Furthermore, the quality of the crystal has been evaluated. The optical properties of the grown crystal have been investigated.

A novel disordered structure crystal has drawn intense interest as a promising ultrafast laser crystal host for its broad absorption and emission bands. Herein, a novel disordered crystal of Nd3+-doped CaYAl3O7 (CYAM) was successfully grown using the Czochralski method for the first time. The effective segregation coefficient of Nd3+ ions in CaYAl3O7 was calculated to be 0.76. To better understand the intrinsic optical properties, the transmission spectra and refractive index of pure CaYAl3O7 were measured. A systematic investigation of the crystal structure characteristics, fluorescence lifetime, and polarized absorption and emission cross-sections of the Nd:CYAM crystal at RT was reported. The maximal absorption cross-sections are 3.51 and 5.34 × 10−20 cm2 for π-polarization and σ-polarization, with a FWHM of 18 nm. The emission cross-sections of π- and σ-polarization are 5.97 and 4.55 × 10−20 cm2 with FWHM values of 14 and 14.4 nm, respectively. The results show that the Nd:CYAM crystal has broad, strong absorption and emission cross-sections. In particular, effective continuous-wave laser operation was realized with this crystal in the a-cut sample for the first time. A maximum output power of 714 mW was achieved, corresponding to an optical-to-optical conversion efficiency of 7.14% and a slope efficiency of 8.6%. Collectively, these results show that the Nd:CaYAl3O7 crystal is a promising disordered laser host.

High quality Er,Yb:CaGdAlO4 (Er,Yb:CALGO) single crystals with a diameter around 1 mm were successfully grown and investigated for the first time by the laser heated pedestal growth (LHPG) method. The cracking mechanism of (001) planes was studied via density functional theory (DFT). The doping concentration of Er3+ and Yb3+ was calculated by X-ray fluorescence analysis (XRF). The XRD pattern confirms that the phase of Er,Yb:CALGO is consistent with pure CALGO and the crystal quality was measured through Laue back-reflection measurements. The optical properties including absorption spectra, mid-infrared fluorescence spectra and fluorescence lifetime of the Er3+, Yb3+ co-doped CALGO crystal were measured at room temperature to assess its potential for improving absorption efficiency. Further research found that the disordered structure of the CALGO crystal could achieve wider absorption and emission bands accompanied with efficient energy transfer from the excited Yb3+ to Er3+. Our results indicated that the Er,Yb:CALGO crystal is a promising material for achieving tunable mid-infrared lasers.

To investigate microstructural alterations in white matter in mild cognitive impairment (MCI) and Alzheimer’s disease (AD) using neurite orientation dispersion and density imaging (NODDI) and to assess the potential diagnostic performance of NODDI-derived parameters. In this study 14 MCI patients, 14 AD patients, and 14 healthy controls (HC) were recruited. The diffusion tensor imaging(DTI)-derived fractional anisotropy (FA) and NODDI-derived neurite density index (NDI), orientation dispersion index (ODI), and volume fraction of isotropic water molecules (Viso) were calculated from the diffusion data. The tract-based spatial statistics (TBSS) method was used for statistical analysis with one-way ANOVA. The correlations between the parameter values and mini-mental state examination (MMSE) and Montreal cognitive assessment (MoCA) scores were examined. A receiver operating characteristic (ROC) curve was conducted to assess the diagnostic performance of different parameters. Compared with the HC group, the NDI and ODI values decreased significantly and the Viso values were significantly increased in the MCI and AD groups (p

N-type Mg2Si single crystal ingot has been successfully grown by the Vertical Bridgman technique. The Hall Effect measurement at RT revealed a moderate Hall mobility (~ 446 cm2/Vs), electrical resistivity (~ 1.4 Ω. cm) and carrier density (~1016 cm−3) for the grown crystal. The J-V characteristics of the fabricated Au/n-Mg2Si Schottky junction and Au/Ag-doped-p-type-Mg2Si/n-type-Mg2Si/Ag pn-junction diode showed better diode behavior with higher rectifying ratio in comparison with the same reported junctions. Analysis of the experimental forward J-V characteristics of our fabricated diodes based on the thermionic emission (TE) model demonstrated that our Schottky and pn-junction Mg2Si diode exhibited much lower series resistance in comparison with the survey data, confirming that precise polishing of Mg2Si surfaces with an oil-based diamond greatly improved the contact with the evaporated metal, enabling lower interfacial resistance between the evaporated metal and Mg2Si wafer. In addition, the manufactured Mg2Si pn-junction photodiode showed a clear photoresponsivity in the wavelength range from 0.95 to 1.8 µm with a maximum zero-biased photoresponse of 14 mA/W at 1.4 µm and a photon energy threshold of approximately 0.66 eV. These results indicate that our diode is promising to detect the SWIR light in the wavelength range from 0.95 to 1.8 µm.

This prospective study aimed to explore the white matter microstructural alterations in Alzheimer’s disease (AD) and amnestic mild cognitive impairment (aMCI) using the Tract-based Spatial Statistics (TBSS) method of diffusion kurtosis imaging (DKI).Diffusion images were collected from 45 AD patients, 42 aMCI patients, and 35 healthy controls (HC). The differences of DKI-derived parameters, including kurtosis fractional anisotropy (KFA), mean kurtosis (MK), fractional anisotropy (FA), and mean diffusivity (MD), were compared across the three groups using the TBSS method. Correlation between the altered DKI-derived parameters and the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) scores were analyzed. A receiver operating characteristic curve (ROC) was used to evaluate the diagnostic performance of different white matter parameters with the strongest correlations. As a result, compared with the HC group, KFA values decreased significantly in the aMCI group. Compared with both the HC and aMCI groups, the FA, KFA, and MK values decreased significantly and the MD value increased significantly in the AD group. FA, MD, KFA, and MK values of many white matter fiber tracts were significantly correlated with MMSE and MoCA scores. The area under the ROC curve (AUC) for the splenium of corpus callosum KFA values were highest for the diagnosis of aMCI and AD patients. In conclusion, the compactness and complexity of white matter microstructures were reduced in AD and aMCI patients. DKI can provide information about the severity of AD progression, and KFA might be more sensitive for the detection of white matter microstructural alterations.

A high-quality Er3+-doped (Gd1−xLux)3Ga5O12 (Er: LGGG) laser crystal with a size of Φ 36 × 45 mm3 was successfully grown by the Czochralski (Cz) method for the first time. The effective segregation coefficient of Er3+ was determined to be 0.97, close to 1, and, thus, the uniform high-quality Er: LGGG crystal can be grown. In addition, the thermal and spectroscopic properties of Er: LGGG were investigated. Based on the measured characteristics, the Er: LGGG crystal has a huge potential for use in the 3.0 µm mid-infrared laser because of its outstanding optical quality, extraordinary thermal conductivity and stable structure.

Fu, X.; Xu, X., and Wang, K., 2020. Design of an intelligent marine ship lighting power detection system based on Internet of things. In: Yang, D.F. and Wang, H. (eds.), Recent Advances in Marine Geology and Environmental Oceanography. Journal of Coastal Research, Special Issue No. 108, pp. 144–150. Coconut Creek (Florida), ISSN 0749-0208.The marine ship lighting system is a significant unit of navigation to improve the safety of the crew. The traditional oceangoing voyage lighting power system has low efficiency, delays in troubleshooting times, and high energy consumption in the detection of fault points. Based on the Internet of Things (IoT) and automation, the authors proposed an intelligent lighting power detection method to ensure the safe, efficient, and stable operation of the oceangoing voyage. Specifically, in the distinct lighting and dynamic circuit multifault environment of the oceangoing voyage, the illumination detection time limit of a traditional lighting power system and the proposed intelligent lighting system were compared; the current and voltage values of the intelligent lighting system were measured and analyzed. This method proved to be effective in detecting a variety of faults of an oceangoing voyage lighting system and has fast and stable performance as well as high accuracy. Therefore, the proposed method can effectively avoid unexpected accidents caused by power lighting failures and improve the green energy-saving performance of oceangoing voyage lighting systems.

This paper investigates the distributed event-triggered consensus control problem for multi-agent uncertain systems with input saturation. Frist, a fully distributed low gain feedback control strategy is proposed for each agent. It is shown that under this control strategy, we do not rely on any global information of the network graph and network’s scale. The proposed control law is then extended with a dynamic event-triggered mechanism, which removes the requirement for continuous communications. Under the event-triggered control law, we proved that each agent strictly excludes Zeno behavior. Finally, a numerical example is given to illustrate the effectiveness of the proposed control strategy.

Single-crystal fiber (SCF) combines the advantages of bulk crystal and glass fiber gain media and shows broad application prospects in all-solid-state lasers. In this work, high-quality crack-free Nd:YAG SCFs with diameters of 0.8–1 mm were successfully grown by the micro-pulling-down (μ-PD) method. The as-grown SCFs showed homogeneous Nd3+ distribution, with a diameter fluctuation of less than 5%. The X-ray Laue patterns on the different crystal positions also revealed good crystalline consistency. Moreover, the core stress problems were investigated in terms of growth orientation to improve the crystal quality, and seed crystals with orientation of , and to 15° were used for crystal growth. Continuous-wave laser operations at 1064 nm were realized with the as-grown Nd:YAG SCFs. The maximum output of 8.32 W with a laser beam quality factor M2 = 1.08 was achieved.

We report a self-Q-switched mode-locked Nd:LGGG waveguide laser with tunable dual-wavelength emission fabricated by femtosecond laser direct writing (FsLDW). The waveguide laser delivers pulses with a minimum temporal duration of approximately 30 ps at a fundamental repetition rate of up to 8.03 GHz, without using any modulation element. The maximum output power is determined to be 226 mW with a slope efficiency of 25.38%. This work indicates the promising applications of waveguide lasers based on mixed crystals for integrated optics.

Ca3TaAl3Si2O14 (CTAS) single crystal is attracting much attention for high temperature sensor applications due to its high electrical resistivity and excellent piezoelectric properties. However, it is a big challenge to grow high quality CTAS single crystals. In this work, its growth conditions are optimized. Crack- and inclusion-free crystals are grown, achieving even a high quality single crystal with a width over 2 in. In addition, the temperature dependence of electro-elastic properties is systematically studied. This crystal presents a high thermal stability of structure and electro-elastic properties. The dielectric loss is less than 3% from room temperature to 650 °C. Therefore, CTAS single crystal is promising for high temperature sensor applications.