Double-loop sliding mode control of reentry hypersonic vehicle with RCS

In order to solve the problem of insufficient aerodynamic moment caused by thin air in the re-entry stage of hypersonic vehicle, this paper establishes an attitude angle model of hypersonic vehicle with reaction control system (RCS), and derives its affine linear model to decoupled the internal and external loop. According to the dead zone and saturation characteristics of RCS thruster, a control method to convert continuous moment into discrete switching instruction using pulse width modulation (PWM) is proposed. Since the number of thrusters is usually redundant, the installation matrix of thrusters in the body coordinate is established, and the command moment is coordinately distributed to the individual thrusters. Then a double-loop sliding mode controller (DSMC) is designed to achieve attitude stability and trajectory tracking. Finally, the simulation results show that DSMC has higher maneuverability, fewer thruster switches and stronger robustness to interference

Atomic-layer molybdenum sulfide optical modulator for visible coherent light

Coherent light sources in the visible range are playing important roles in our daily life and modern technology, since about 50% of the capability of the our human brains is devoted to processing visual information. Visible lasers can be achieved by nonlinear optical process of infrared lasers and direct lasing of gain materials, and the latter has advantages in the aspects of compactness, efficiency, simplicity, etc. However, due to lack of visible optical modulators, the directly generated visible lasers with only a gain material are constrained in continuous-wave operation. Here, we demonstrated the fabrication of a visible optical modulator and pulsed visible lasers based on atomic-layer molybdenum sulfide (MoS 2), a ultrathin two-dimensional material with about 9-10 layers. By employing the nonlinear absorption of the modulator, the pulsed orange, red and deep red lasers were directly generated. Besides, the present atomic-layer MoS 2 optical modulator has broadband modulating properties and advantages in the simple preparation process. The present results experimentally verify the theoretical prediction for the low-dimensional optoelectronic modulating devices in the visible wavelength region and may open an attractive avenue for removing a stumbling block for the further development of pulsed visible lasers

Fine Structure of the Sensilla and Immunolocalisation of Odorant Binding Proteins in the Cerci of the Migratory Locust, Locusta migratoria

Using light and electron microscopy (both scanning and transmission), we observed the presence of sensilla chaetica and hairs on the cerci of the migratory locust, Locusta migratoria L. (Orthoptera: Acrididae). Based on their fine structures, three types of sensilla chaetica were identified: long, medium, and short. Males presented significantly more numbers of medium and short sensilla chaetica than females (p<0.05). The other hairs can also be distinguished as long and short. Sensilla chaetica were mainly located on the distal parts of the cerci, while hairs were mostly found on the proximal parts. Several dendritic branches, enveloped by a dendritic sheath, are present in the lymph cavity of the sensilla chaetica. Long, medium, and short sensilla chaetica contain five, four and three dendrites, respectively. In contrast, no dendritic structure was observed in the cavity of the hairs. By immunocytochemistry experiments only odorant-binding protein 2 from L. migratoria (LmigOBP2) and chemosensory protein class I from the desert locust, Schistocerca gregaria Forsskål (SgreCSPI) strongly stained the outer lymph of sensilla chaetica of the cerci. The other two types of hairs were never labeled. The results indicate that the cerci might be involved in contact chemoreception processes

Gut microbiota influences feeding behavior via changes in olfactory receptor gene expression in Colorado potato beetles

The Colorado potato beetle (CPB) is an internationally recognized plant quarantine pest that causes serious losses to potato agricultural production. The gut microbiota plays an important role in its growth and development, and the olfactory system plays an important role in insect feeding behavior. The gut microbiota is known to be capable of inducing changes in the olfactory systems of insects. However, the way these associated gut microbes influence the feeding-related behaviors of CPBs remains unclear. To explore the relationship between them, fresh potato leaves immersed in a mixture of five antibiotics (tetracycline, penicillin, ofloxacin, ciprofloxacin, and ampicillin) at specific concentrations for 1 h were fed to adult CPBs to reduce the abundance of gut microbes. We found that the feeding behavior of CPBs was significantly affected by the gut microbiota and that Pseudomonas was significantly higher in abundance in the control group than in the antibiotic group. We then used transcriptome sequencing to explore the differences in olfactory receptor genes in the heads of non-treatment and antibiotic-fed CPBs. Through Illumina Hiseq™ sequencing and screening of differential genes, we found that the olfactory receptor gene LdecOR9 was significantly upregulated and LdecOR17 was significantly downregulated after antibiotic feeding. A real-time polymerase chain reaction was used to verify the changes in olfactory receptor gene expression in the non-treatment groups and antibiotic-treated groups. The feeding behavior was partially rescued after CPBs were re-fed with intestinal bacteria. These results indicate that a certain amount of gut microbiota can result in the loss of the olfactory discrimination ability of CPBs to host plants. In summary, this study investigated the relationship between gut microbiota and olfactory genes, providing a reference for research on microbial control

Fs-laser-written thulium waveguide lasers Q-switched by graphene and MoS2

[EN]We report the generation of mid-infrared (~2 µm) high repetition rate (MHz) sub-100 ns pulses in buried thulium-doped monoclinic double tungstate crystalline waveguide lasers using two-dimensional saturable absorber materials, graphene and MoS2. The waveguide (propagation losses of ~1 dB/cm) was micro-fabricated by means of ultrafast femtosecond laser writing. In the continuous-wave regime, the waveguide laser generated 247 mW at 1849.6 nm with a slope efficiency of 48.7%. The laser operated at the fundamental transverse mode with a linearly polarized output. With graphene as a saturable absorber, the pulse characteristics were 88 ns / 18 nJ (duration / energy) at a repetition rate of 1.39 MHz. Even shorter pulses of 66 ns were achieved with MoS2. Graphene and MoS2 are therefore promising for high repetition rate nanosecond Q-switched infrared waveguide lasers

Modeling and Analysis of Resonance in LCL-Type Grid-Connected Inverters under Different Control Schemes

As a basic building block in power systems, the three-phase voltage-source inverter (VSI) connects the distributed energy to the grid. For the inductor-capacitor-inductor (LCL)-filter three-phase VSI, according to different current sampling position and different reference frame, there mainly exist four control schemes. Different control schemes present different impedance characteristics in their corresponding determined frequency range. To analyze the existing resonance phenomena due to the variation of grid impedances, the sequence impedance models of LCL-type grid-connected three-phase inverters under different control schemes are presented using the harmonic linearization method. The impedance-based stability analysis approach is then applied to compare the relative stability issues due to the impedance differences at some frequencies and to choose the best control scheme and the better controller parameters regulating method for the LCL-type three-phase VSI. The simulation and experiments both validate the resonance analysis results

Occurrence Status and Influencing Factors of Cognitive Dysfunction in Population Aged 60 and Above

Background With the accelerated aging process, the incidence of dementia is increasing year by year, but there is no effective cure and the prognosis is poor. The cognitive function is still plastic during subjective cognitive decline (SCD) , which as a preclinical stage of dementia, it is of great significance for the prevention and management of dementia to investigate the prevalence and influencing factors of SCD. Objective To investigate the prevalence and risk factors of SCD, MCI and dementia in population aged 60 and above in Baotou, Inner Mongolia. Methods From June 2021 to September 2022, a cross-sectional survey was conducted involving 1 120 objects in 21 neighborhood councils and 17 village committees randomly selected from 3 banner counties (Hondlon District, Jiuyuan District and Guyang County) of Baotou City, Inner Mongolia Autonomous Region by using the combination of multistage sampling, cluster sampling and random sampling. General information of the study subjects were collected by questionnaire and their cognitive function was assessed. According to cognitive function, the study subjects were divided into the normal group (n=206) , SCD group (n=491) , MCI group (n=320) and dementia group (n=103) . Multivariate Logistic regression was used to analyze the influencing factors of cognitive function. Results The median age of the study subjects was 68.0 (63.0, 73.0) years and the median number of years of education was 9.0 (5.0, 11.4) years. Absence of spouse〔OR=2.542, 95%CI (1.139, 5.674) , P=0.023〕, obesity〔OR=6.058, 95%CI (2.281, 16.093) , P&lt;0.001〕, predominant vegetarian type of diet〔OR=3.037, 95%CI (1.868, 4.936) , P&lt;0.001〕, nightly sleep duration &lt;6 hours〔OR=1.662, 95%CI (1.099, 2.516) , P=0.016〕, smoking history〔OR=1.971, 95%CI (1.231, 3.157) , P=0.005〕, diabetes history〔OR=1.975, 95%CI (1.140, 3.422) , P=0.015〕, coronary heart disease history〔OR=3.501, 95%CI (1.016, 12.062) , P=0.047〕, and vision loss history〔OR=2.454, 95%CI (1.638, 3.677) , P&lt;0.001〕were risk factor for the prevalence of SCD in population aged 60 and above. Rural residence〔OR=2.636, 95%CI (1.231, 5.641) , P=0.013〕, absence of spouse〔OR=2.843, 95%CI (1.228, 6.582) , P=0.015〕, obesity〔OR=5.626, 95%CI (2.046, 15.475) , P=0.001〕, predominant vegetarian type of diet〔OR=3.832, 95%CI (2.212, 6.640) , P&lt;0.001〕, predominant meat type of diet〔OR=2.619, 95%CI (1.536, 4.465) , P&lt;0.001〕, smoking history〔OR=1.912, 95%CI (1.133, 3.227) , P=0.015〕, diabetes history〔OR=2.544, 95%CI (1.378, 4.697) , P=0.003〕, coronary heart disease history〔OR=3.945, 95%CI (1.110, 14.016) , P=0.034〕, and vision loss history〔OR=2.846, 95%CI (1.780, 4.551) , P&lt;0.001〕were risk factors for the prevalence of MCI in population aged 60 and above, education level of junior high school〔OR=0.180, 95%CI (0.103, 0.314) , P&lt;0.001〕, high school and above〔OR=0.075, 95%CI (0.041, 0.136) , P&lt;0.001〕were protective factors for MCI in population aged 60 and above. Rural residence〔OR=5.511, 95%CI (2.306, 13.170) , P&lt;0.001〕, absence of spouse〔OR=2.987, 95%CI (1.152, 7.746) , P=0.024〕, obesity〔OR=7.303, 95%CI (2.436, 21.890) , P&lt;0.001〕, predominant vegetarian type of diet〔OR=7.025, 95%CI (3.626, 13.609) , P&lt;0.001〕, predominant meat type of diet〔OR=2.255, 95%CI (1.102, 4.616) , P=0.026〕, nightly sleep duration&lt;6 hours〔OR=2.164, 95%CI (1.206, 3.883) , P=0.010〕, smoking history〔OR=2.661, 95%CI (1.415, 5.004) , P=0.002〕, diabetes history〔OR=2.186, 95%CI (1.033, 4.624) , P=0.041〕, coronary heart disease history〔OR=6.830, 95%CI (1.809, 25.783) , P=0.005〕and vision loss history〔OR=3.267, 95%CI (1.785, 5.979) , P&lt;0.001〕were risk factors for the prevalence of dementia in population aged 60 and above. Age 60-69 years〔OR=0.211, 95%CI (0.074, 0.597) , P=0.003〕, 70-79 years〔OR=0.218, 95%CI (0.077, 0.620) , P=0.004〕, education level of junior high school〔OR=0.473, 95%CI (0.229, 0.977) , P=0.043〕, high school and above〔OR=0.227, 95%CI (0.105, 0.493) , P&lt;0.001〕were protective factors for the prevalence of dementia in population aged 60 and above. Conclusion The prevalence rates of SCD, MCI and dementia among the older adults aged 60 and above in Baotou region of Inner Mongolia is at a high national level. Rural residents, old age, absence spouse, low education level, obesity, predominant vegetarian or meat type of diet, sleep less than 6 hours per night, smoking, diabetes, coronary heart disease and vision loss are the main risk factors of the prevalence of SCD, MCI and dementia among the older adults in this region

Modeling and Analysis of Resonance in LCL-Type Grid-Connected Inverters under Different Control Schemes

As a basic building block in power systems, the three-phase voltage-source inverter (VSI) connects the distributed energy to the grid. For the inductor-capacitor-inductor (LCL)-filter three-phase VSI, according to different current sampling position and different reference frame, there mainly exist four control schemes. Different control schemes present different impedance characteristics in their corresponding determined frequency range. To analyze the existing resonance phenomena due to the variation of grid impedances, the sequence impedance models of LCL-type grid-connected three-phase inverters under different control schemes are presented using the harmonic linearization method. The impedance-based stability analysis approach is then applied to compare the relative stability issues due to the impedance differences at some frequencies and to choose the best control scheme and the better controller parameters regulating method for the LCL-type three-phase VSI. The simulation and experiments both validate the resonance analysis results