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ABSTRACT: Hydraulic fracturing is the key technique in the development of unconventional resources. Many optical experimental studies have been made to qualitatively study the hydraulic fracturing process. However, due to the time of fracture propagation being extremely short (ms), real-time quantitative description of the fracturing process is challenging. To clarify the process of fracture propagation, a novel triaxial optical hydraulic fracturing experimental apparatus is developed which mainly includes an ISCO displacement pump, triaxial servo control devices, high-intensity illumination devices, high-speed camera, and data acquisition systems. The fracturing process could be captured visually in real-time by using a high-resolution camera. This study also proposes an accurate and effective analysis method, Digital Image Correlation (DIC), for characterizing fracture and measuring the strain field. The results show that the pressure-time curve of hydraulic fracturing can be divided into three stages: pressure rise stage, the crack initiation and propagation stage, and the pressure plateau stage; the initiation pressures of water and CO2 fracturing in tight sandstone are 10.1 MPa and 5.2 MPa respectively; hydraulic fractures active the natural fractures, resulting in a complex fracture network structure; hydraulic fractures will turn and gradually become vertical to the minimum principal stress during the extension process. The results of this paper can provide guidance for the field application of hydraulic fracturing in tight sandstone resources. 1. INTRODUCTION With the rapid development of the economy, the energy demand has increased rapidly, and unconventional oil and gas resources such as tight gas, coalbed methane, and shale gas have become an important guarantee for the national energy strategy1. Hydraulic fracturing technology is an important technology for the exploitation of unconventional oil and gas resources2, among which the geometry of hydraulic fractures is the key to evaluating hydraulic fracturing operations, still needs further research3-7.

The composite rice straw-cement brick is analysed with simulations and experiments using mechanical and heat transfer theory, and data demonstrate excellent characteristic of such brick including heat retaining, light weight and fire resistance, which is beneficial to save the precious clay resource, reduce energy consumption during production and enhance the safety and comfort of high-rise building. In the future, the processing of such brick should be optimized, and this new type of manufacturing apparatus is expected to be designed to satisfy the requirements of commercial application.

To characterize functions of long non-coding RNA (lncRNA) in the progression of epithelial ovarian cancer.Epithelial ovarian cancer tissues and matching normal tissues were collected from two individual patients for RNA microarray analysis. Besides, twenty-two ovarian cancer samples and ten healthy ovarian epithelial tissues were collected for Reverse Transcription-quantitative Polymerase Chain Reaction (RT-qPCR). Microarray assay suggested that a list of cancer relating mRNAs and lncRNAs were upregulated. The identified lncRNAs were validated via RT-qPCR, which led to the identification of long intergenic non-protein coding RNA 152 (LINC00152). To determine the function of LINC00152 in ovarian cancer, we knocked down the expression of LINC00152 in epithelial ovarian cancer cell line SKOV3 with small interference RNAs (siRNAs). The effects of LIN00152 on the proliferation and cell cycle were determined by comparing the cell viability of SKOV3 cells with LIN00152 knockdown and the control cells with negative siRNA. The cell viability was assessed using Cell Counting Kit-8 (CCK-8) and flow cytometry assay. RNA microarray assay was used again in control and LINC00152 knockdown SKOV3 cells to identify downstream signaling pathways.Fourteen ovarian cancer relating lncRNAs were identified by RNA microarray assay. Up-regulation of LINC00152 was validated via RT-qPCR. A higher expression of LINC00152 in late cancer stage (III-IV) compared to the early stage tumors was also demonstrated. Inhibition of LINC00152 in SKOV3 cells inhibited cell proliferation and induced cell cycle arrest that involved prolonged G1 phase and shortened S phase. The microarray assay data of SKOV3 cells suggested that Cyclin-Dependent Kinase Inhibitor 1C (CDKN1C) was a potential downstream target of LINC00152.LINC00152 is upregulated in epithelial ovarian cancer tissues comparing to normal tissues. Knockdown of LINC00152 expression inhibits cell proliferation and induces cell cycle arrest. LINC00152 possibly interacts with Tumor Necrosis Factor (TNF) signaling pathway. CDKN1C is a potential downstream target of LINC00152.