Upper Palaeozoic gas accumulations of the Yimeng Uplift, Ordos Basin

This paper analyzes the Upper Palaeozoic gas accumulations and conditions of the study area by using the definition and method of petroleum system, and summarizes the natural gas accumulation pattern. The Upper Palaeozoic natural gas in the Yimeng Uplift is mainly from source rocks of Taiyuan and Shanxi Formations in the southern part and Wushenqi area. Braided channel sandbodies of alluvial fan, river channel sandbodies and distributary channel sandbodies of delta plain in the Shanxi and Xiashihezi Formations are the most favorable reservoirs. The thick mudstone layers of the Shangshihezi and Shiqianfeng Formations which cover the whole region constitute the regional seal rock, and there are also many local seal rocks. Oil source, reservoir and seal rocks form a good relationship in time and space and they form two types of assemblage which are the self-generating and self-preserving assemblage in the southern part of the Yimeng Uplift and the lower-generating and upper-preserving assemblage in the southern and northern parts. Natural gas migrated to the north through the migration pathways composed by advantageous sandbody, unconformity, faults and cracks. Structural traps and the distal accumulation pattern dominate in the northern part, while the southern part is characterized by lithologic traps and the proximal accumulation pattern. Key words: Yimeng Uplift, Upper Palaeozoic, geologic accumulation element, migration, trap, accumulation patter

Flow Characteristics and Energy Loss of a Multistage Centrifugal Pump with Blade-Type Guide Vanes

Multistage pumps with blade-type guide vanes are widely used in offshore oil production, the petrochemical and coal-chemical industries, and nuclear power fields for its advantages of large flow rate, high pressure, and excellent operation stability. However, the internal flow of this kind of pump is complex; in particular, the hydraulic, flow, and pressure pulsation characteristics of the different stages are quite different, which has a great impact on the design and performance predictions of this kind of pump. Thus, in this paper, the hydraulic performance, unsteady flow characteristics, evolution of vortex structures and pressure pulsation characteristics in a 10 stage centrifugal pump are investigated numerically. The results show that inverse flow, jet-wake flow, and rotor-stator interaction flow are the key factors causing energy loss and efficiency decline at every stage and in the whole pump. The vortex evolution at the rotor–stator interaction regions is actually the process that the vortex structures fall off and impact on the pressure surface at the leading edge of the guide vane blade at a frequency that equals to the impeller blade passing frequency. Furthermore, under the actions of the guide vane with confluence cavity, the pressure pulsation within the final-stage guide vane contains low-frequency components with large bandwidths, which mainly results from the confluence flow disturbance at the outlet of the cylindrical guide passage

Investigation of buffer traps in AlGaN/GaN-on-Si devices by thermally stimulated current spectroscopy and back-gating measurement

Thermally stimulated current (TSC) spectroscopy and high-voltage back-gating measurement are utilized to study GaN buffer traps specific to AlGaN/GaN lateral heterojunction structures grown on a low-resistivity Si substrate. Three dominating deep-level traps in GaN buffer with activation energies of Delta E-T1 similar to 0.54 eV, Delta E-T2 similar to 0.65 eV, and Delta E-T3 similar to 0.75 eV are extracted from TSC spectroscopy in a vertical GaN-on-Si structure. High back-gate bias applied to the Si substrate could influence the drain current in an AlGaN/GaN-on-Si high-electron-mobility transistor in a way that cannot be explained with a simple field-effect model. By correlating the trap states identified in TSC with the back-gating measurement results, it is proposed that the ionization/deionization of both donor and acceptor traps are responsible for the generation of buffer space charges, which impose additional modulation to the 2DEG channel. (C) 2014 AIP Publishing LLC

High Dynamic Range Organic Temperature Sensor

A thermistor-transistor integrated organic temperature sensor is reported. By inserting a thin layer of silver nanoparticles the organic thermistor shows strong temperature sensitivity and the total dynamic range of sensing is around 10 bits, which is larger than most organic temperature sensors. The measuring temperature range is from 20 to 70 °C with an operating voltage down to 6 V. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

The Circular RNA Cdr1as Act as an Oncogene in Hepatocellular Carcinoma through Targeting miR-7 Expression

<div><p>CircRNAs are a class of endogenous RNA that regulates gene expression at the post-transcriptional or transcriptionallevel through interacting with other molecules or microRNAs. Increasing studies have demonstrated that circRNAs play a crucial role in biology processes. CircRNAs are proved as potentialbiomarkers in many diseases including cancers. However, the role of Cdr1as in Hepatocellular carcinoma (HCC) remains to be elucidated. We demonstrated that Cdr1as expression was upregulated in HCC tissues compared with the adjacent non-tumor tissues. In addtion, miR-7 expression was downregulated in HCC tissues compared with the adjacent non-tumor tissues. Moreover, the expression level of miR-7 was inversely correlated with that in HCC tissues. Knockdown of Cdr1as suppressed the HCC cell proliferation and invasion. Overexpression of miR-7 inhibited the HCC cell proliferation and invasion. Overexpression of miR-7 could suppress the direct target gene CCNE1 and PIK3CD expression. Knockdown of Cdr1as suppressed the expression of miR-7 and also inhibited the CCNE1 and PIK3CD expression. Furthermore, knockdown of Cdr1as suppressed the HCC cell proliferation and invasion through targeting miR-7. These data suggested that Cdr1as acted as an oncogene partly through targeting miR-7 in HCC.</p></div

Bioinspired Strong and Tough Organic–Inorganic Hybrid Fibers

High‐strength and high‐toughness bio‐based fibers attract broad interest in biomechanical applications. Herein, strong and tough organic–inorganic regenerated silk fibroin/hydroxyapatite (RSF/HAP) hybrid fibers are prepared using a single‐channel microfluidic device. Calcium phosphate oligomers (CPOs) dispersed in the RSF matrix first grow into spherical amorphous calcium phosphates (ACPs), which then crystallize into needle‐like HAPs under a humidity condition, mimicking the biomineralization in collagen bundles. HAPs are better aligned along the RSF/HAP fiber direction after poststretching, forming a highly ordered and densely packed microstructure within the fiber and thus facilitating highly dense noncovalent interactions between rigid inorganic HAP nanocrystals and flexible organic RSF matrix. The highly dense noncovalent interactions endow the organic–inorganic hybrid fibers with superior mechanical properties and twisted RSF/HAP fiber bundles demonstrate a remarkable tensile strength of 778 MPa, a high Young's modulus of 17.8 GPa, a large tensile strain of 19.9%, and an excellent toughness of 121 MJ m−3 after proper twisting treatments. RSF/HAP hybrid fibers also show good performances against static loading, dynamic impact, and extreme cold condition and they can maintain their mechanical properties down to −50 °C. Therefore, the fibers are strong and tough and the strategy is facile and efficient

Knockdown of Cdr1as suppressed the HCC cell proliferation and invasion.

<p>(A) The expression of Cdr1as in the HCC cell lines were measured by using qRT-PCR. (B) Knockdown of Cdr1as expression could suppress the Cdr1as expression. (C) Knockdown of Cdr1as expression inhibited the HCC cell line (SMMC-7721) proliferation. (D) The HepG2 cell proliferation was measured by CCK-8 assay. (E) Knockdown of Cdr1as expression inhibited the SMMC-7721 cell invasion. (F) The HepG2 cell invasion was detected by cell invasion assay. *p<0.05, **p<0.01 and ***p<0.001.</p

Knockdown of Cdr1as promoted the miR-7 and its target gene CCNE1 and PIK3CD expression.

<p>(A) The mRNA expression of miR-7 in the SMMC-7721 cell was measured by qRT-PCR. (B) The mRNA expression of CCNE1 was detected by qRT-PCR in the SMMC-7721 cell. (C) The protein expression of CCNE1 was detected by western blot. (D) The mRNA expression of CCNE1 in the SMMC-7721 cell was detected by qRT-PCR. (E) The protein expression of CCNE1 was detected by western blot. (F) The mRNA expression of PIK3CD was detected by qRT-PCR in the SMMC-7721 cell. (G) The protein expression of PIK3CD was measured using western blot. (H) The mRNA expression of PIK3CD was detected by qRT-PCR in the SMMC-7721 cell. (J) The protein expression of PIK3CD was determined by western blot.</p