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BackgroundWith the rapid development of nuclear energy and the wide application of nuclear technology, the radioactivity level of bodies of water has become a highly concerning issue for the public and governments, especially after the Fukushima nuclear accident in Japan.PurposeThis study aims to develop an online γ radioactivitymonitoring system based on 4G Remote Terminal Unit (4G-RTU) to meet the needs of online and emergency monitoring of water radioactivity.MethodsFirst, the γ-ray monitoring device based on sodium iodide detector, 4G-RTU, an integrated power supply waterproof and compression resistant floating device and corresponding software were employed to compose an online monitoring. Second, Qt programming control software was used to realize the remote control of the system, real-time radioactivity monitoring, and data upload. Finally, the original data obtained by the system were used to test the performance indicators, applicability, accuracy, and software functions to verify the practicability of the system.ResultsWithin the coverage of the 4G network, the system realizes remote control of equipment, real-time online monitoring, and data upload throughout the day. The detectable energy range of the system is 30~3 000 keV, and the energy resolution of the system for 137Cs at 662 keV is 7.3% with minimum detectable activity of 0.75 Bq∙L-1. The spectral drift for 208Tl at 2 614 keV is 0.33%, and the linearity of the spectral energy is 0.999 970. The maximum value of energy spectrum stability is 2.28% for 7 h continuous operating, and the minimum value is -2.36%. The operating temperature range of the system is in the range of -5 ℃ to +50 ℃.ConclusionsThe on-line monitoring system meets the application demand and achieves the expected function. It has important popularization value and application prospects in the field of online radioactive monitoring of bodies of water such as oceans, lakes, and rivers.

In view of the urgent need for high-temperature corrosion prevention in high-parameter waste incineration power stations at home and abroad, a refined strategy and plan for high-temperature corrosion protection of flue were devised using the equal life design principle according to the change law of the actual temperature of each flue in the waste boiler and the corrosion rate of the pipeline. For instance, composite induction fusion welding coatings were applied to the mid and lower sections of the first flue’s water-cooled wall; the upper and ceiling portions of the first flue were welded with Inconel625; composite induction fusion welding techniques were used for the second flue’s water-cooled wall; the third flue’s water-cooled wall was treated using induction fusion welding; the high-temperature superheater in the horizontal flue adopted a composite induction fusion welding process; induction fusion welding was the chosen method for the medium and low-temperature superheaters. For the economizer, the use of high-temperature ceramic coatings was recommended. The refined anti-corrosion strategies of the flue according to the principle of equal life design could greatly reduce the one-time investment of the enterprise and bring significant economic benefits.

In this paper, a novel radar jamming method based on random phase modulation of digital coding metasurface was proposed. For typical radar system, the modulation model of coding metasurface and the echo model are deduced firstly. Then, the ordered statistics greatest of the constant false alarm rate (OSGO-CFAR) detection model was chosen to analyze the radar detection performance. Through serials of simulation, the influence of modulation modes, modulation switching interval, the number of coding elements and the signal-to-noise ratio (SNR) on radar detection performance is analyzed. Finally, the Monte Carlo simulation is performed. The result shows that as the modulation switching interval of metasurface decreases, the spectrum energy distribution of the target becomes more dispersed and the detection probability of the target decreases obviously. Traditional radar detectors will become ineffective, and the shielding of the target will be achieved. This implies a new radar jamming method which can realize target shielding instead of traditional stealth by reducing the radar cross section. [ABSTRACT FROM AUTHOR]

Background: The cashmere goat is a biological resource that mainly produces cashmere. Cashmere has a soft hand feel and good luster, with high economic value. The quality and yield of cashmere are determined by the process of hair follicle development during the embryonic period. Methods: In this study, the skin of the Inner Mongolia cashmere goat at different embryonic stages (45, 55, 65, and 75d) was collected, and the differentially expressed lncRNA MSTRG.20890.1 at 75d was obtained by screening. Dual luciferase reporter gene system, qRT-PCR, and EDU experiments were used to verify further the regulatory role and molecular mechanism of the lncRNA in dermal fibroblasts. Results: Based on the transcriptome database of Inner Mongolia cashmere goat skin at different embryonic stages, which was previously constructed by our group, according to the characteristics of hair follicle development in the embryonic stage, we screened out the lncRNA MSTRG.20890.1 that was down-expressed on the 75-SHFINI day of the embryonic stage. We found that lncRNA MSTRG.20890.1 was mainly located in the cytoplasm of cells, and it could inhibit the proliferation and directional migration of dermal fibroblasts through the chi-miR-24-3p/ADAMTS3 signaling axis, thereby inhibiting the formation of dermal papilla structure at embryonic stage. Conclusions: This study revealed that lncRNA MSTRG.20890.1 regulated secondary hair follicle morphogenesis and development in cashmere goats through the chi-miR-24-3p/ADAMTS3 signaling axis. [ABSTRACT FROM AUTHOR]

Single-mode semiconductor laser operating near the 2 μm wavelength is of great interest for trace-gas detection, remote sensing, and infrared spectroscopy. Here, we present the 2 μm-wavelength-range laser sources with high output power, precise wavelength control, and narrow spectral linewidth enabled by hybrid integration of a GaSb-based gain chip with silicon nitride Bragg gratings. Low-kappa gratings are used as the laser feedback component to accurately select the lasing wavelength and increase the photon lifetime to achieve narrow-linewidth laser emission. The hybrid laser outputs 33.7 mW optical power with a side mode suppression ratio better than 40 dB near the 2 μm wavelength at room temperature. More than 20 lasers with an excellent wavelength spacing of 2.68 nm is demonstrated. The wavelength deviation is less than ±0.1 nm for all lasers. The intrinsic linewidth of the hybrid integrated external cavity laser with a 4.35 mm long feedback grating is measured to be ∼8.8 kHz using the phase noise demodulation method. [ABSTRACT FROM AUTHOR]