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When geothermal fluid flows to the wellhead along the wellbore, there is a thermal transfer from the high-temperature geothermal fluid to the low-temperature formation. This process can directly lead to the decrease of wellhead temperature and loss of geothermal energy. Even though previous studies have confirmed that reducing the thermal conductivity of cement could validly cut down the heat loss of geothermal fluid, the influence factors of thermal conductivity are limited. In this research, we conducted detailed studies of the influence factors of thermal conductivity and compressive strength for cement. The results show that with the increase of water-cement ratio and thermal insulation materials, thermal conductivity and compressive strength decline. Furthermore, curing temperature is another important factor to improve the thermal preservation effect, but the testing temperature has the opposite influence. Based on these results, the present study concluded that porosity, Skeleton ingredients, curing temperature, and test temperature are vital factors for thermal conductivity. This research provides theoretical guidance for increasing the wellhead temperature of geothermal fluid and enhancing the efficiency of geothermal energy.

The scientific and reasonable layout of jack-up drilling platform can improve the efficiency and safety of drilling platform operation. Through the application of analytic hierarchy process (AHP) and the establishment of comprehensive evaluation and analysis model, this paper analyzes the commonly used drilling platform layout scheme and optimizes the scheme to meet operational requirements and to improve the ability of the drilling platform operation.

Objective Human uveal melanoma (UM) is a common ocular malignant tumor with a high risk of metastasis. Emerging evidence indicates that long non-coding RNAs (lncRNAs) are correlated with the development of UM. Here, we aimed to determine the biological significance of lncRNA growth arrest-specific transcript 5 (GAS5) in UM. Methods The expression levels of GAS5 and microRNA-21 (miR-21) in UM tissues and cells were detected by qRT-PCR analysis. CCK-8 assay was performed to investigate the viability of UM cells after cell transfections, and the migration and invasion of UM cells were determined by transwell assay. The protein expression levels were detected by Western blot assay. The relationship between miR-21 and GAS5 in UM cells was confirmed by bioinformatics prediction and luciferase report assay. Results Our experiments demonstrated that GAS5 was markedly downregulated in UM cells and clinical specimens. Overexpression of GAS5 inhibited, whereas knockdown of GAS5 promoted the viability, migration, and invasion of UM cells. The epithelial-to-mesenchymal transition (EMT) process of UM cells was also suppressed by upregulating of GAS5 and enhanced by downregulating of GAS5. Additionally, as a competitive endogenous RNA (ceRNA), GAS5 directly binded to the oncogenic miR-21 in UM cells, and overexpression of miR-21 attenuated the EMT-suppressing effect of GAS5. Conclusion Taken together, our findings suggest that GAS5/miR-21 axis is implicated in the pathogenesis of UM and might serve as a potential therapeutic target.

Wellbore instability caused by the dispersion of the clay is one of the most important challenges in drilling operation of fractured formations. The synthesis of new plugging inhibitors and the research of drilling fluid systems are key steps to keep the wellbore stabilization. In this paper, the limitations of conventional drilling fluid inhibitors are discussed and a new plugging inhibitor PAS-5 is synthesized by using amine inhibitor, polyethylene glycol and asbestos fiber as the main monomers. The detailed synthesis step of the plugging inhibitor PAS-5 is illustrated and its action mechanism is explained by scanning electron microscopy. In order to express the good effect of the PAS-5, a new evaluation system is used to indicate its plugging performance. At the same time, the plugging inhibitor PAS-5 was used on-site drilling operation in the Ordos Basin. The results of research show that the synthesis process of PAS-5 is simple and the effect of plugging inhibition is obvious. Compared with conventional treatment agents? PAS-5 outperforms sulfonated asphalt FT-1 and emulsified asphalt RHJ-3 in terms of plugging inhibition performance, with a plugging rate of 90.5% and roller recovery rate of 93.7%. It also has better temperature resistance, there is almost no change in viscosity and filtrate loss when the temperature rises from room temperature to 80°C. The field application results indicated that PAS-5 meets the requirements of drilling, that the reaming time of the trips of the wells is shortened considerably, that the ROP is improved, and that the hole enlargement rate is less than 6%. During the drilling process, PAS-5 can inhibit formation hydration and seal small cracks, thus maintaining the stability of the borehole. This study synthesized a novel plugging inhibitor PAS-5 and an evaluation system was adopted to reveal its plugging performance, and achieved good application effect in on-site drilling operations.

Purpose: Previous studies have revealed that microRNA-665 (miR-665) is dysregulated in a variety of human cancers. However, little is known regarding its expression profiles and functions in retinoblastoma (RB). Therefore, the aims of our study were to evaluate miR-665 expression in RB and determine the precise roles of miR-665 in the progression of RB. Patients and methods: Herein, RT-qPCR was used to determine miR-665 expression levels in RB tissues and cell lines, and a series of functional experiments were performed to explore the influence of miR-665 on RB cell proliferation, colony formation, apoptosis, migration, and invasion as well as tumor growth. The molecular mechanisms underlying the tumor-suppressive action of miR-665 in RB were also explored. Results: We found that miR-665 was markedly reduced in RB tissues and cell lines and that lower miR-665 expression was strongly associated with tumor size, TNM stage, and differentiation in patients with RB. Exogenous expression of miR-665 suppressed cell proliferation, colony formation, migration, and invasion, and induced cell apoptosis in RB cells, while silencing miR-665 expression had the opposite effects. In addition, upregulation of miR-665 decreased the tumor growth of RB cells in vivo. High-mobility group box 1 (HMGB1) was identified as a direct target of miR-665 in RB cells, and decreasing the expression of HMGB1 simulated the regulatory effects of miR-665 overexpression in RB cells, while knockdown of HMGB1 expression counteracted the miR-665-mediated antitumor effects in RB cells. Moreover, miR-665 was shown to regulate the Wnt/β-catenin signaling pathway by targeting HMGB1 in vitro and in vivo. Conclusion: Taken together, our in vitro and in vivo results suggest that miR-665 acts as a tumor-suppressive miRNA in RB by directly targeting HMGB1 and inactivating the Wnt/β-catenin pathway. Hence, this miRNA is a candidate prognostic biomarker and therapeutic target in patients with RB.

A method for the determination of the content of olive oil in olive blend oil by headspace gas chromatography-mass spectrometry (SH-GC/MS) was established. The amount of the sample, the heating temperature, the heating time, the amount of injection, the injection mode and the chromatographic column were optimized. The characteristic compounds of olive oil were found by chemometric method. A sample of 1.0 g was placed in a 20 mL headspace flask, and heated at 180℃ for 2700 s. Then, 1.0 mL headspace gas was taken into the instrument. An HP-88 chromatographic column was used for the separation and the analysis was performed by GC/MS. The results showed that the linear range was 0-100%(olive oil content). The linear correlation coefficient (r2) was more than 0.995, and the limits of detection were 1.26%-2.13%. The deviations of olive oil contents in the olive blend oil were from -0.65% to 1.02%, with the relative deviations from -1.3% to 6.8% and the relative standard deviations from 1.18% to 4.26% (n=6). The method is simple, rapid, environment friendly, sensitive and accurate. It is suitable for the determination of the content of olive oil in olive blend oil.

It is believed that renewable energy can help to ease the shortage of fossil fuels, and to protect environment. Moreover, microgrid provides a practical way for renewable energy and electric vehicles to access the grid easily. In this paper, a PV hybrid DC/AC microgrid which based on the DC microgrid is proposed. It combines the advantages of simple control of DC microgrids and the novel uninterruptible inverter to provide high-quality uninterruptible power for the electric vehicle charging station equipment. At first, the topology analysis of the PV hybrid DC/AC microgrid is carried out, and the structure of the novel uninterruptible inverter is described in details. Then, the operation control strategy of the microgrid is systematic studied, as a result we design three working modes of the system. The control strategy and running status of the PV hybrid DC/AC microgrid system applied to the electric vehicle charging station are simulated and verified in particular.

Due to the defects of the way of the traditional grid power supply, microgrid arises at the historic moment. At present, DC microgrid is an effective solution to integrate renewable energy sources which are DC power supply with DC loads. In allusion to the power unbalance intra-microgrid and the wide fluctuation of DC bus voltage due to unstable output of DC micro resources in DC microgrid, A DC microgrid structure consisting of photovoltaic generation system, hybrid energy storage systems and AC main grid, is researched in this paper. A novel power management strategy for this DC microgrid is proposed. The control strategy divides the DC bus voltage into seven ranges by six critical voltage values which are employed as the represents of power states, and according to the range which the bus voltage belongs to, the operation mode of the system can be automatically judged and switched freely. A hybrid energy storage system in this microgrid that contains two complementary type storage elements—battery and super-capacitor, can enhance the reliability and flexibility of the system based on their special supply logical. Experimental results show that above-mentioned control strategy is feasible through the MATLAB/SIMULINK simulation platform.

This paper discussed the advantages and challenges of DC microgrid for commercial building. The data obtained from the DC microgrid constructed at Xiamen University shows that DC microgrid with rooftop solar system is an efficient way to power varies DC loads inside the building. The capacity of the solar system on the rooftop normally will be enough to power the LED light loads in commercial buildings, even for high rise buildings. In order to power heavy loads such as air conditioning and EV charging stations, extra power are required, which can be obtained from the BIPV on the sidewall, glass window, or adjacent parking lots. To ensure the stable bus voltage and continuous operation of the DC microgrid, a suitable energy storage unit and two way AC/DC invertors are needed. Therefore we believe to use the solar power only for the matched DC loads, and keep existing AC power in the building to power the rest loads (or an AC and DC hybrid microgrid) maybe a more viable solution. The economical analysis shows that installation cost of a DC microgrid system is about $2.2/W, which is becoming a marketable technology.

The number and variety of electric vehicles connected to grid continue to grow rapidly, which results in a heavy burden on grid. To solve this problem, the concept of V2G (Vehicle to Grid) that electric vehicles could act as a new power source for grid was proposed. With distributed renewable energy developing fast recent years, charging EVs is a good way to use it. The DC micro-grid program being conducted at the Xiamen University (China) consists of a 150kW peak photovoltaic system. A unique charging station has been proposed designed on the basis of the DC micro-grid, featuring three-way energy flow among the power grid, PV modules and electric vehicles. The paper proposes a charging station based on DC micro-grid which also can provide V2G service. The control strategy of converters is investigated. Finally, simulation based on MATLAB is built to validate the availability and effectiveness of the proposed system and control strategy.