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AIM: To evaluate the clinical efficacy of corneal stromal lenticule-combined accelerated transepithelial corneal collagen cross-linking(SC-A-TE-CXL)in the treatment of severe keratoconus.METHODS: Prospective before-after self-control study. A total of 10 cases(14 eyes)of severe keratoconus with the thinnest corneal thickness(including epithelium)less than 400 μm were collected from March 2019 to July 2022 at the ophthalmology department of Affiliated Eye Hospital of Nanjing Medical University. Among them, 8 males(12 eyes)and 2 females(2 eyes)were treated with SC-A-TE-CXL. Corneal curvature, uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA), the thinnest corneal thickness(TCT), central corneal thickness(CCT), non-contact intraocular pressure, endothelial cell density(ECD)and anterior or posterior elevations at the thinnest point before surgery and at 1, 3, 6 and 12 mo postoperatively were observed and recorded, as well as corneal cross-linking depth at 1 mo postoperatively.RESULTS: UCVA and BCVA at 1, 3, 6, and 12 mo after SC-A-TE-CXL were higher than those preoperatively, but there were no differences(F=0.793, P=0.535; F=0.783, P=0.542). K1, K2, Km and Kmax decreased at each time point postoperatively compared with those preoperatively, but there were no differences(F=0.627, P=0.574; F=1.264, P=0.296; F=0.727, P=0.520; F=1.115, P=0.359). Anterior and posterior elevations at the thinnest point both decreased compared with those preoperatively, but the differences were not statistically significant(F=1.046, P=0.359; F=1.164, P=0.337). The non-contact intraocular pressure at each time point postoperatively was higher than that preoperatively, but the differences were not statistically significant(F=0.814, P=0.522). There were no differences in CCT and TCT at any time points of the follow-ups compared with those preoperatively(F=0.931, P=0.453; F=0.782, P=0.542). There was no difference in ECD at 12 mo postoperatively versus preoperative value(t=1.266, P=0.228). At 1 mo postoperatively, anterior segment optical coherence tomography(AS-OCT)exhibited an increase of density in the anterior stroma, and there was a demarcation line with an average depth of 124.07±25.13 μm.CONCLUSION: SC-A-TE-CXL can be considered as a surgical treatment for severe keratoconus, which can delay the progression of severe keratoconus with high safety. However, the long-term efficacy of this treatment requires further observation.

The issue of energy supply for wireless sensors is becoming increasingly severe with the advancement of the Fourth Industrial Revolution. Thus, this paper proposed a thermoelectric self−powered wireless sensor that can harvest industrial waste heat for self−powered operations. The results show that this self−powered wireless sensor can operate stably under the data transmission cycle of 39.38 s when the heat source temperature is 70 °C. Only 19.57% of electricity generated by a thermoelectric power generation system (TPGS) is available for use. Before this, the power consumption of this wireless sensor had been accurately measured, which is 326 mW in 0.08 s active mode and 5.45 μW in dormant mode. Then, the verified simulation model was established and used to investigate the generation performance of the TPGS under the Dirichlet, Neumann, and Robin boundary conditions. The minimum demand for a heat source is cleared for various data transmission cycles of wireless sensors. Low−temperature industrial waste heat is enough to drive the wireless sensor with a data transmission cycle of 30 s. Subsequently, the economic benefit of the thermoelectric self−powered system was also analyzed. The cost of one thermoelectric self−powered system is EUR 9.1, only 42% of the high−performance battery cost. Finally, the SEPIC converter model was established to conduct MPPT optimization for the TEG module and the output power can increase by up to approximately 47%. This thermoelectric self−powered wireless sensor can accelerate the process of achieving energy independence for wireless sensors and promote the Fourth Industrial Revolution.

This paper proposes, for the first time, the research concept of comparing energy and economy between transcritical cycle high-temperature heat pumps and subcritical cycle high-temperature heat pumps with new refrigerants. Experiments and simulations are conducted to compare the system performance and economy of two heat pumps, and the effects of different factors on the performance of two heat pumps are analyzed. The results show that R744/R1234yf (90/10) and R515-1 are the preferred refrigerants for transcritical cycle heat pumps and subcritical cycle heat pumps, respectively. The COP of the R744/R1234yf (90/10) transcritical heat pump is generally higher than that of the R515B-1 subcritical heat pump, and compared to the R515B-1 subcritical heat pump, the cost recovery period of the R744/R1234yf (90/10) transcritical heat pump is about 9–15 years. Therefore, it is recommended that users who use heat pumps for a long time choose transcritical cycle heat pumps. Meanwhile, with the change of evaporation temperature, the system COP of the R515B-1 subcritical heat pump and R744/R1234yf (90/10) transcritical heat pump increases by 61.11% and 65.91%, respectively. In addition, the optimal charge amount for the R515B-1 subcritical heat pump is 81.8% of that of the R744/R1234yf (90/10) transcritical heat pump.

One of the effective methods to simultaneously achieve the thermal protection and friction reduction requirement of a scramjet engine is the usage of fuel film cooling. As the combustion process inside the combustor proceeds, the oxygen concentration in the burnt gas gradually decreases and will influence the thermal and friction characteristics of the hydrocarbon film. Therefore, the effects of oxygen concentration in the mainstream on the hydrocarbon film are evaluated by numerical simulations based on RANS framework. The results indicate that the cooling performance of the hydrocarbon film is not sensitive to the oxygen concentration, although the fuel film burns more intense as the oxygen concentration increases. While the friction reduction performance is sensitive to the oxygen concentration. Specifically, about 10% friction reduction can be obtained for 10% oxygen in the mainstream compared to that of inert cases, and the wall friction can be further reduced by 30% for 20% oxygen. Further analysis reveals that the mechanism of the above two drag reductions is different. For weak boundary layer combustion, the decrease of the molecular viscosity contributes to the reduction of friction. While for significant boundary layer combustion, a lower near-wall velocity gradient is the main reason.

Solid oxide fuel cells (SOFC) have gradually become possible to be used in the aviation field because of their high efficiency and fuel flexibility. The number of internal combustion engines (ICE) that are already in use is large, which makes it difficult to completely abandon them in a short period. Hence, finding low-carbon alternative fuels is significant for the development of cleaner internal combustion engines. In this paper, different hybrid power systems configured with different fuels, i.e., hydrogen, methanol, liquid ammonia, isooctane, natural gas and gasoline, which consist of a solid oxide fuel cell and an internal combustion engine, are constructed to help find the optimal set of fuel and system structure by analyzing the power generation performance and weight of different systems. The results show that the hybrid power system with ammonia or methanol (except gasoline) as fuel presents the lowest actual fuel consumption rate (around 310 g/kWh). The hybrid power system with ammonia as fuel performs the highest power generation efficiency of 61.58%, and the corresponding power density is estimated at 0.556 kW/kg. In conclusion, the proposed system with ammonia as fuel has obvious advantages in fuel consumption rate, power generation efficiency, carbon emission reduction and fuel storage.

In this paper,the control characteristic of cascaded hybrid high voltage direct current (HVDC) system is studied. The influence mechanism of modular multilevel converter (MMC) inverters to the whole hybrid HVDC are investigated,and the complete voltage-current characteristic curves of the hybrid HVDC are obtained in droop control modes. Compared with the master-slave control,MMCs in droop control have ability to control both DC voltage and DC power,and the power reverse transmission will not occur. However,MMCs in droop control cannot control DC voltage accurately. Thus,an adaptive droop control strategy of cascaded hybrid HVDC system is proposed. The droop curve can be moved in real time adaptively according to DC current,which avoid the fluctuations of DC voltage due to the change of DC current. Finally,the simulation results verify the effectiveness of the proposed strategy based on PSCAD/EMTDC. This strategy can adjust the droop curves adaptively and realize accurate control of DC voltage in hybrid HVDC system,which improves the stability of the hybrid HVDC system.

Closed-Brayton-cycle (CBC) is a potential scheme to provide high-power electricity for hypersonic vehicles, but finite cold source onboard limits its power level. A thermoelectric generator (TEG) combined with CBC is a feasible power enhancement approach by extending the available temperature range of cold source. In this study, a performance assessment of the CBC-TEG combined power generation system coupled with hydrocarbon-fueled scramjet is performed to exhibit its possible operation characteristics and performance limitations on hypersonic vehicles. Results indicate that, at a fixed flight Mach number, a larger fuel equivalence ratio (φ) leads to a higher total electric power and CBC power but a lower TEG power. There are three limitations on the fuel equivalence ratio, TEG temperature difference, and combustion heat dissipation adjustment for the operation of CBC-TEG. The total power of CBC-TEG can be adjusted by φ, but the adjustable range becomes smaller at higher Ma. The electric quantity at unit fuel mass increases with φ, mainly due to the higher thermoelectric conversion efficiency. Moreover, the maximum value of the electric quantity at unit fuel mass for CBC-TEG reaches 277.0 kJ/kg, which is about 33.4% higher than that of standalone CBC.

The growing demand for electricity in long-duration space missions has become a pressing concern. The space nuclear closed-Brayton-cycle (CBC) power generation system offers advantages in power output, operational lifespan, and range. However, a significant speed disparity exists between its compressor and alternator. To address this challenge, this paper proposes a double-rotor CBC configuration. A corresponding dynamic model that couples the nuclear reactor and radiator is formulated, and dynamic analysis is conducted to facilitate system control. The study delves into the dynamic start-up process of the double-rotor CBC system and examines how various component parameters impact its power generation performance. The findings indicate that through the introduction of suitable reactivity to regulate reactor power and the incorporation of a PID controller to manage flow distribution between two turbines, the system can achieve start-up within 5200 s. Moreover, the innovative double-rotor structure suggested in this paper enables the separation of compressor and alternator speeds. Consequently, the compressor and alternator can operate within their optimal speed ranges independently, which is a feature that holds potential benefits for the system’s practical implementation. In addition, the steady-state operation of the system showcases the recuperator’s heat transfer power at around 1127.60 kW, a parameter of significant importance. Following steady-state operation, the double-rotor CBC system demonstrated an electrical power output of 175.99 kW and a thermal efficiency of 32.38%.

After the AC system is short-circuited, voltage source converter-high voltage direct current (VSC-HVDC) can be equivalent to a current source with a certain amplitude and phase. In this paper, based on the equivalent model of VSC-HVDC when the receiving end grid fault occurs, the factors affecting the phase and amplitude of equivalent current source of VSC-HVDC are analyzed respectively. Studies show that the phase of the equivalent current source is mainly affected by the type of fault, and the amplitude is mainly affected by the control method, the amplitude limiter and the electrical distance. Because of the combination of different situations, the influence on the AC system short-circuit current is bceorning more complicated.The research results show that for AC side three-phase short-circuit fault, the influence of VSC-HVDC on short-circuit current can be divided into four situations, which contain zero feed in, limited amplitude of active control link, limited amplitude of reactive power control link and reference value of reactive power control link. The simulation results based on PSCAD software verify the relevant analysis.

Objective To investigate the effects of long non-coding RNA DUXAP8 on the proliferation, cell cycle and apoptosis of ovarian cancer cells by regulating miR-4677-3p. Methods The expression of DUXAP8 and miR-4677-3p in ovarian cancer tissues and cell lines (SKOV3, OV90 and CaOV3) was detected by RT-qPCR. Then SKOV3 cells were divided into 6 groups, namely, si-NC group, si-DUXAP8 group, miR-NC group, miR-4677-3p group, si-DUXAP8+anti-miR-NC group and si-DUXAP8+anti-miR-4677-3p group. CCK-8 assay and clone formation assay were adopted to detect cell viability, flow cytometry to observe cell apoptosis and cycle, Western blotting to measure the expression levels of Cyclin D1, Bcl-2 and Bax, and dual luciferase reporter assay system to analyze the relationship of DUXAP8 and miR-4677-3p. Results When compared with adjacent tissues and normal ovarian epithelial cells, the expression level of DUXAP8 was significantly lower in ovarian cancer tissues (0.98±0.25 vs 4.14±0.72) and that of SKOV3, OV90, CaOV3 was obviously higher (1.03±0.08 vs 3.26±0.33、2.75±0.29、2.54±0.26, all P < 0.05). Interference with DUXAP8 or overexpression of miR-4677-3p inhibited the proliferation, reduced the rate of apoptosis, and arrested the cell cycle of ovarian cancer cells (P < 0.05). DUXAP8 regulated the expression of miR-4677-3p, and inhibiting miR-4677-3p partially restore and interfere with the effects of DUXAP8 on the proliferation, cycle and apoptosis of ovarian cancer cells (P < 0.05). Conclusion Interference with DUXAP8 can inhibit the proliferation of ovarian cancer cells, induce cell apoptosis, and block cell cycle, the mechanism may be related to the up-regulation of miR-4677-3p.

For hydrocarbon-fueled turbojet engines with a precooling technology, the precooling technology with a low-temperature endothermic fuel is a great potential way to solve the problem of sharp reduction of the specific impulse caused by the insufficient heat sink of the hydrocarbon fuel. To study the heat transfer and flow characteristics of a precooler with a fuel endothermic reaction, methanol is chosen as the low-temperature endothermic fuel, and the numerical model of a precooler of tube bank arranged in-line is built, which considers the methanol with a cracking reaction. The results indicate that the methanol cracking reaction can enhance the cooling effect to the air by increasing the heat transfer temperature difference. When the cracking rate is not more than 20%, the cooling effect to the air increases and the cracking rate decreases with the methanol mass flow rate. When the longitudinal pitch-to-diameter ratio varies between 1.25 and 2.50, the cooling effect and the cracking rate increase with its increase, which is not conducive to the compactness of the precooler. When the transverse pitch-to-diameter ratio varies between 1.25 and 2.00, the cooling effect and cracking rate increase with its decrease but bring significant pressure loss.

In order to rapidly predict the performance of hydrocarbon-fueled regeneratively cooled scramjet engine in system design, a quasi-one-dimensional model has been developed. The model consists of a supersonic combustor model with finite-rate chemistry and a cooling channel model with real gas working medium, which are governed by two sets of ordinary differential equations separately. Additional models for wall friction, heat transfer, sonic fuel injection, and mixing efficiency are also included. The two sets of ordinary differential equations are coupled and iteratively solved. The SUNDIALS code is used since the equations for supersonic combustion flow are stiff mathematically. The cooling channel model was verified by electric heating tube tests, and the supersonic combustor model was verified by experimental results for both hydrogen and hydrocarbon-fueled scramjet combustors. Three cases were comparatively studied: (1) scramjet combustor with an isothermal wall, (2) scramjet combustor with an adiabatic wall, and (3) scramjet combustor with regenerative cooling. Results showed that the model could predict the axial distributions of flow parameters in the supersonic combustor and cooling channel. Differences on ignition delay time and combustion efficiency for the three cases were observed.

A ground-based multichannel microwave radiometer (GMR) is commonly used to observe the atmospheric radiation brightness temperature (TB) in order to retrieve atmospheric temperature and humidity profiles. At present, GMRs are used only in meteorology and climate monitoring. However, theoretical analysis showed that GMRs can be also used to observe the solar radiation. Therefore, we tried to improve the antenna servo control system of a GMR so that it could track and observe the sun, and the results showed that the GMR could respond to the variation of solar radiation. A further question was: can a GMR observe the variation of the sun during a solar eclipse? Fortunately, two solar eclipse events were captured by the GMR on 26 December 2019 and 21 June 2020 in Xi’an, China. We used the upgraded GMR to observe the variation of solar radiation during the two solar eclipses. The observation and analysis results showed that (1) the GMR could accurately track the sun and respond to the variation of solar radiation during the solar eclipse. We analyzed the variation features of the solar radiation by combining the solar phase during the two solar eclipses. (2) We found that the GMR could respond to the variation of the solar radiation arising from the Earth–Sun distance, and we further propose a novel method to measure the eccentricity of earth orbit with the GMR by using the passive solar observation. The results show that the eccentricity measured was 0.0169, which agreed quite well with the value of 0.0167 in the literature. (3) The average variation percentages of both the Earth–Sun distance and the intensity of the incident solar radiation throughout the year were estimated to be 3.44% and 6.6%, respectively. According to these results, the solar observation techniques can broaden the field usage of GMR.

A compact air-breathing jet hybrid-electric engine coupled with solid oxide fuel cells (SOFC) is proposed to develop the propulsion system with high power-weight ratios and specific thrust. The heat exchanger for preheating air is integrated with nozzles. Therefore, the exhaust in the nozzle expands during the heat exchange with compressed air. The nozzle inlet temperature is obviously improved. SOFCs can directly utilize the fuel of liquid natural gas after being heated. The performance parameters of the engine are acquired according to the built thermodynamic and mass models. The main conclusions are as follows. 1) The specific thrust of the engine is improved by 20.25% compared with that of the traditional jet engine. As pressure ratios rise, the specific thrust increases up to 1.7 kN/(kg·s−1). Meanwhile, the nozzle inlet temperature decreases. However, the temperature increases for the traditional combustion engine. 2) The power-weight ratio of the engine is superior to that of internal combustion engines and inferior to that of turbine engines when the power density of SOFC would be assumed to be that predicted for 2030. 3) The total pressure recovery coefficients of SOFCs, combustors, and preheaters have an obvious influence on the specific thrust of the engine, and the power-weight ratio of the engine is strongly affected by the power density of SOFCs.

In order to extend the cooling capacity of thermal protection in various advanced propulsion systems, dimple as an effective heat transfer enhancement device with low-pressure loss has been proposed in regenerative cooling channels of a scramjet. In this paper, numerical simulation is conducted to investigate the effect of the dimple depth-diameter ratio on the flow and heat transfer characteristics of supercritical hydrocarbon fuel inside the cooling channel. The thermal performance factor is adopted to evaluate the local synthetically heat transfer. The results show that increasing the dimple depth-diameter ratio h/dp can significantly reduce wall temperature and enhance the heat transfer inside the cooling channel but simultaneously increase pressure loss. The reason is that when h/dp is rising, the recirculation zones inside dimples would be enlarged and the reattachment point is moving downstream, which enlarge both the high Nu area at rear edge of dimple and the low Nu area in dimple front. In addition, when fluid temperature is nearer the fluid pseudocritical temperature, local acceleration caused by dramatic fluid property change would reduce the increment of heat transfer and also reduce pressure loss. In this study, the optimal depth-diameter ratio of dimple in regenerative cooling channel of hydrocarbon fueled is 0.2.

Solar radiation is a primary driver affecting several physical, chemical and biological processes in lake ecosystems. The attenuation of sunlight in water is directly controlled by optically active substances. Here, the seasonal and interlake heterogeneities of the diffuse attenuation coefficients (Kd(λ)) of ultraviolet radiation (UVR) and photosynthetically active radiation (PAR) were studied based on field investigations in six Yunnan Plateau lakes (i.e., Chenghai, Dianchi, Erhai, Fuxian, Lugu and Yangzong) of China, October 2014‒July 2016. The results revealed that Kd(λ) generally increased with decreasing wavelength and increasing trophic state and that Kd(UVR) presented higher interlake heterogeneity than Kd(PAR). The interlake heterogeneity surpassed the seasonal heterogeneity of Kd(λ), whereas the intralake seasonal heterogeneity, which is related to the lake trophic state and solar spectrum, was obvious. Although the main factors affecting Kd(λ) were chromophoric dissolved organic matter (CDOM) and phytoplankton in general, the interlake heterogeneity was found. In eutrophic, turbid shallow Lake Dianchi, CDOM primarily affected UV-B, whereas total suspended solids (TSS) and/or phytoplankton had important effects on Kd(UV-B), Kd(UV-A) and Kd(PAR). CDOM, TSS and phytoplankton influenced the Kd(UV-B), Kd(UV-A) and Kd(PAR) in the deep mesotrophic Lake Chenghai and Lake Erhai, but the main particulate factors were different between these two lakes. In the deep, oligotrophic clear Lake Fuxian and Lake Lugu, only the significant effect of CDOM on Kd(UVR) in Lake Fuxian was detected. Additionally, the factors affecting Kd(λ) in Lake Yangzong were atypical, possibly due to the artificial addition of massive amounts of ferric chloride.

Atmospheric pressure hydrolysis without stirring and a combustion–calcination method were utilized to fabricate magnetic Fe _3 O _4 / α -Fe _2 O _3 heterogeneous nanorods. First, the β -FeOOH nanorods were fabricated via hydrolysis, and the concentration of Fe ^3+ , hydrolysis temperature, and hydrolysis time were optimized. The optimal fabrication conditions were as follows: a 0.1 M FeCl _3 solution was hydrolyzed at 90 °C for 2 h. The average length and diameter of the β -FeOOH nanorods fabricated under the optimal conditions were approximately 216 and 58 nm, respectively. Subsequently, Fe _3 O _4 / α -Fe _2 O _3 heterogeneous nanorods were fabricated via a combustion–calcination process. The volume of absolute ethanol, calcination temperature, and calcination time were investigated to optimize the fabrication conditions of Fe _3 O _4 / α -Fe _2 O _3 heterogeneous nanorods under the following conditions: absolute ethanol: 50 ml; calcination temperature: 300 °C; and calcination time: 2 h. Magnetic Fe _3 O _4 / α -Fe _2 O _3 heterogeneous nanorods fabricated under optimal conditions were characterized with an average length of 199 nm, an average diameter of 51 nm, a zeta potential of +17.2 mV, and a saturation magnetization of 13 emu·g ^–1 .

Ground-based multichannel microwave radiometers (GMRs) can observe the atmospheric microwave radiation brightness temperature at K-bands and V-bands and provide atmospheric temperature and humidity profiles with a relatively high temporal resolution. Currently, microwave radiometers are operated in many countries to observe the atmospheric temperature and humidity profiles. However, a theoretical analysis showed that a radiometer can be used to observe solar radiation. In this work, we improved the control algorithm and software of the antenna servo control system of the GMR so that it could track and observe the sun and we use this upgraded GMR to observe solar microwave radiation. During the observation, the GMR accurately tracked the sun and responded to the variation in solar radiation. Furthermore, we studied the feasibility for application of the GMR to measure the absolute brightness temperature (TB) of the sun. The results from the solar observation data at 22.235, 26.235, and 30.000 GHz showed that the GMR could accurately measure the TB of the sun. The derived solar TB measurements were 9950 ± 334, 10,351 ± 370, and 9217 ± 375 K at three frequencies. In a comparison with previous studies, we obtained average percentage deviations of 9.1%, 5.3%, and 4.5% at 22.235, 26.235, and 30.0 GHz, respectively. The results demonstrated that the TB of the sun retrieved from the GMR agreed well with the previous results in the literature. In addition, we also found that the GMR responded to the variation in sunspots and a positive relationship existed between the solar TB and the sunspot number. According to these results, it was demonstrated that the solar observation technique can broaden the field usage of GMR.

The well-preserved dinosaur egg fossilsrecently found in Qiyunshan area, Anhui Province are the key to studying the living environment and the extinction of dinosaur fauna in the Late Cretaceous period. In order to discuss the palaeoenvironment and palaeoclimate, X-ray Diffraction (XRD), Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES), and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) were used to analyze the composition of macro minerals, major elements and trace elements of the dinosaur eggshells, egg core and the surrounding rock. The results show that the main minerals of dinosaur eggshells are calcite and quartz whereas the mineral of the interior is the same as the exterior of the eggshell and is mainly quartz. Major elements include Ca, Na, Mg, K, Al, Fe, whereas trace elements include Sr, Zn, Ba, As, Ti, V, Cr, Co, Ni, Cu, Mn, Pb, La, U, Ir. The average content of Sr in the eggshells was 6199.3×10-6, higher than most of the eggshells from Xixia of Henan province and Nanxiong of Guangdong province. The average content of Ir in the eggshells was 59.6×10-12. Sr and Ir show an obvious abnormality compared with the background values, which may be caused by absorption of harmful elements during material exchange between dinosaur body and the outside world. The accumulation of As, Mn, and Pb and the lack of Zn may lead to the poisoning of dinosaurs and then extinction. The increased Fe content in the surrounding rock indicates that the palaeoclimate in Qiyunshan area during the Late Cretaceous was dry and hot, and the content of Ir, which has a positive correlation with Fe, increased with the increase of Fe. Moreover, the closer to the Cretaceous-Paleogene (K/T) boundary, the higher is the content of Sr and Ir in the surrounding rock, which may be one of the reasons for the extinction of the dinosaur fauna in the area. This conclusion provides a basis for the study of the living environment of the dinosaur fauna in Qiyunshan area.

Ground-based multichannel microwave radiometers can observe the atmospheric microwave radiation brightness temperature and continuously provide temperature and humidity profiles of the troposphere. At present, microwave radiometers are operated in many countries for monitoring climate and meteorological phenomena, and there have been many microwave radiometers of this kind presently implemented in China, but they lack a unified monitor for their operational condition, which is necessary if they are taken as a network. For this reason, a real-time monitoring receiving system of radiometer is fundamental and important. In order to check the system stability and the antenna performances, this paper studied the feasibility of applying the solar signals to monitor the antenna alignment, antenna pattern and stability of a radiometer system in working for operational field applications. An experiment was performed and the results from the analysis of the annual variation features with long-term solar observation data at four frequencies, 22.235, 26.235, 30.000 and 51.250 GHz, show that an antenna pattern retrieved from solar observations agrees well with that retrieved from the traditional method. In addition, a daily analysis of the solar signals in online data of a radiometer can be used for monitoring the alignment of the antenna and the stability of the ground-based microwave radiometer system.

Whipple pneumonia is a rare, chronic, multiorgan disease, with symptoms including arthritis, diarrhea, and weight loss. Diagnosis is traditionally confirmed by a histologic examination of a small bowel biopsy (1). [...]

The risk factors influencing the analysis of power grid investment are complicated and highly coupled. The analysis of the interaction of risk factors based on the traditional interpretative structural model, using the expert score to form correlation matrix, which is subjective. To increase the quantitative analysis and overcome the drawbacks of traditional model relying on experts’ experience, this paper proposes a new method to construct the interpretative structural model. Firstly, the evaluation index system of power grid investment is constructed, based on this, the collected history data of risk factors are processed and analysed through the correlation analysis of SPSS and the quantitative correlation matrix of risk factors is obtained, then the construction of interpretative structural model is finished. The constructed model provides the basis for the analysis and management of power grid investment.

Supersonic film cooling is an efficient method to cool the engine with extremely high heat load. In order to study supersonic film cooling in a real advanced engine, a two-dimensional model of the hypersonic inlet in a scramjet engine with supersonic film cooling in the isolator is built and validated through experimental data. The simulation results show that the cooling effect under different coolant injection angles does not show clear differences; a small injection angle can ensure both the cooling effect and good aerodynamic performances (e.g., flow coefficient) of the hypersonic inlet. Under selected coolant injection angle and inlet Mach number, the cooling efficiency increases along with the injection Mach number of the coolant flow, only causing a little total pressure loss in the isolator. Along with the increase of the inlet Mach number of the hypersonic inlet, the cooling efficiency does not present a monotonic change because of the complex shock waves. However, the wall temperature shows a monotonic increase when the inlet Mach number increases. The mass flow rate of coolant flow should be increased to cool the engine more efficiently according to the mass flow rate of the main stream when the inlet Mach number increases.