314 research outputs found

    The Influence of Higher Education on China’s Macro-Economy

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    Education contributes to economic growth. China’s economy has shifted from high growth to higher-quality development, creating a new demand to reform and develop higher education. This paper first measures the composite index of higher education in China from 2009 to 2019 by combining the Cobb-Douglas production function and Denison’s economic growth factors analysis method. Results showed that higher education in China has an increasing contribution rate to economic growth from 2009 to 2019 but is still lagging behind developed countries. Second, it analyzes the new trends of higher education development in developed countries, compares the development models of higher education in different countries, and reveals the problems in China’s higher education. Finally, it examines the impact of higher education on China’s macro-economy from the human capital theory and the economies of scale theory. Furthermore, it proposes strategies for the higher-quality development of higher education and provides a reference for adjusting and optimizing the development model of higher education

    A Flexible Electronic Helical Guide Controller

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    AbstractIn this paper, an Electronic Helical Guide Controller (EHGC) is proposed, for helical gear shaping processes. In most traditional gear shaper machines, the cutter's reciprocating movement is driven by a crank-connecting rod mechanism. Therefore, this study adopts this kind of gear shaper as the machine platform to establish an accurate mathematical model. The control algorithm is embedded in the interpolation module of the CNC system using electronic gearbox techniques to realize special multi-axis linkage control requirements. The crankshaft's angular position is measured and the rotational speed is calculated in each control cycle. The actual position and velocity of the cutter along the Z-axis can be calculated using the geometric relations of the crank-connecting mechanism, and motion in the other axes can be controlled by the electronic gearbox. A special G code with parameters (G83) is also designed and the EHGC control through NC programming is realized in an improvised gear shaping CNC machine. The proposed EHGC is low cost and easy to implement in practice since it does not need a linear grating ruler and a probe on the Z-axis. Furthermore, EHGC allows the flexibility to change a part's helix angle to compensate for distortions caused by heat treatment. Simulations and experiments are performed to verify the effectiveness of the proposed EHGC

    Fostering public climate change discussions from a social interaction perspective

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    Public discussions on climate change, as a form of social interaction, are widely recognized as effective tools for promoting collective action. However, there is limited research on examining the factors that influence climate change discussions from a social interaction perspective. In the present study, we conducted a large sample (N = 1,169) survey to investigate personal (such as self-efficacy and personal response efficacy) and others' (such as perceived others' response efficacy and social norms) factors influencing climate change discussions from a social interaction perspective. The results showed that (i) for people with high climate change perceptions, personal response efficacy, self-efficacy, and social norms have positive effects on climate change discussions, but the effect of perceived others' response efficacy on climate change discussion is not significant; (ii) for people with low climate change perceptions, self-efficacy and social norms have positive effects on climate change discussions, but the effects of personal response efficacy and perceived others' response efficacy on climate change discussion are not significant; (iii) irrespective of individuals' high or low perceptions of climate change, social norm remains the most important predictor of climate change discussions. These findings make valuable contributions to the theoretical literature and intervention efforts regarding climate change discussions from a social interaction perspective

    Diagnostic utility of LunX mRNA in peripheral blood and pleural fluid in patients with primary non-small cell lung cancer

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    <p>Abstract</p> <p>Background</p> <p>Progress in lung cancer is hampered by the lack of clinically useful diagnostic markers. The goal of this study was to provide a detailed evaluation of lung cancer tumor markers indicative of molecular abnormalities and to assess their diagnostic utility in non-small cell lung cancer (NSCLC) patients.</p> <p>Methods</p> <p>Quantitative real-time RT-PCR was used to determine <it>LunX, CK19, CEA, VEGF-C </it>and <it>hnRNP A2/B1 </it>mRNA levels in peripheral blood and pleural fluid from NSCLC patients, compared with those from patients with other epithelial cancer (esophagus cancer and breast cancer), benign lung disease (pneumonia and tuberculo pleurisy) and from healthy volunteers.</p> <p>Results</p> <p>In peripheral blood <it>LunX </it>mRNA was detectable in 75.0% (33/44) of patients with NSCLC, but not in patients with other epithelial cancer (0/28), benign lung disease (0/10) or in healthy volunteers (0/15). In contrast, all other genetic markers were detected in patients with either NSCLC, other epithelia cancer or benign lung disease, and in healthy volunteers. The expression level and positive rate of <it>LunX </it>mRNA in peripheral blood correlated with the pathologic stage of NSCLC (P < 0.001 and P = 0.010 respectively). Furthermore, <it>LunX </it>mRNA was detected in 92.9% (13/14) of malignant pleural fluid samples and was the only marker whose expression level was significantly different between malignant and benign pleural fluid (P < 0.001). Additionally, expression of <it>LunX </it>mRNA in the peripheral blood of NSCLC patients decreased shortly after clinical treatment (P = 0.005).</p> <p>Conclusion</p> <p>Of several commonly used genetic markers, <it>LunX </it>mRNA is the most specific gene marker for lung cancer and has potential diagnostic utility when measured in the peripheral blood and pleural fluid of NSCLC patients.</p

    3D-modelling of the thermal circumstances of a lake under artificial aeration

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    A 3D-model was developed to study the effects of hypolimnetic aeration on the temperature profile of a thermally stratified Lake Vesijärvi (southern Finland). Aeration was conducted by pumping epilimnetic water through the thermocline to the hypolimnion without breaking the thermal stratification. The model used time transient equation based on Navier–Stokes equation. The model was fitted to the vertical temperature distribution and environmental parameters (wind, air temperature, and solar radiation) before the onset of aeration, and the model was used to predict the vertical temperature distribution 3 and 15 days after the onset of aeration (1 August and 22 August). The difference between the modelled and observed temperature was on average 0.6 °C. The average percentage model error was 4.0% on 1 August and 3.7% on 22 August. In the epilimnion, model accuracy depended on the difference between the observed temperature and boundary conditions. In the hypolimnion, the model residual decreased with increasing depth. On 1 August, the model predicted a homogenous temperature profile in the hypolimnion, while the observed temperature decreased moderately from the thermocline to the bottom. This was because the effect of sediment was not included in the model. On 22 August, the modelled and observed temperatures near the bottom were identical demonstrating that the heat transfer by the aerator masked the effect of sediment and that exclusion of sediment heat from the model does not cause considerable error unless very short-term effects of aeration are studied. In all, the model successfully described the effects of the aerator on the lake’s temperature profile. The results confirmed the validity of the applied computational fluid dynamic in artificial aeration; based on the simulated results, the effect of aeration can be predicted.Peer reviewe

    Transmission electron microscopy structure and platinum-like temperature coefficient of resistance in a ruthenate-based thick film resistor with copper oxide

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    As an alternative to thin-film platinum temperature sensor elements, thick film resistor ones are of interest for circuits which can withstand a near-engine environment. From a pyrochlore paste (DuPont 5091D), a close match is obtained (after firing) to the positive temperature coefficient of resistance (TCR) of Pt. Within the glassy matrix during 850 °C850 °C firing, needle-like RuO2RuO2 grains grow by a mechanism consistent with periodic bond chain theory. The acicular growth habit is attributed to a Cu2OCu2O additive, which is assumed to oxidize upon firing. The needles provide direct paths for metallic conduction and a characteristic positive TCR to the thick film in spite of having a low RuO2RuO2 volume fraction. © 2000 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70506/2/JAPIAU-88-2-1124-1.pd

    Microwave-Assisted Oxidation of Electrospun Turbostratic Carbon Nanofibers for Tailoring Energy Storage Capabilities

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    We report the systematic structural manipulation of turbostratic electrospun carbon nanofibers (ECNFs) using a microwave-assisted oxidation process, which is extremely rapid and highly controllable and affords controlled variation of the capacitive energy storage capabilities of ECNFs. We find a nonmonotonic relationship between the oxidation degree of ECNFs and their electrocapacitive performance and present a detailed study on the electronic and crystalline structures of ECNFs to elucidate the origin of this nonmonotonic relation. The ECNFs with an optimized oxidation level show ultrahigh capacitances at high operation rates, exceptional cycling performance, and an excellent energy–power combination. We have identified three key factors required for optimal energy storage performance for turbostratic carbon systems: (i) an abundance of surface oxides, (ii) microstructural integrity, and (iii) an appropriate interlayer spacing

    Optimal Streaming Codes for Channels with Burst and Arbitrary Erasures

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    This paper considers transmitting a sequence of messages (a streaming source) over a packet erasure channel. In each time slot, the source constructs a packet based on the current and the previous messages and transmits the packet, which may be erased when the packet travels from the source to the destination. Every source message must be recovered perfectly at the destination subject to a fixed decoding delay. We assume that the channel loss model introduces either one burst erasure or multiple arbitrary erasures in any fixed-sized sliding window. Under this channel loss assumption, we fully characterize the maximum achievable rate by constructing streaming codes that achieve the optimal rate. In addition, our construction of optimal streaming codes implies the full characterization of the maximum achievable rate for convolutional codes with any given column distance, column span and decoding delay. Numerical results demonstrate that the optimal streaming codes outperform existing streaming codes of comparable complexity over some instances of the Gilbert-Elliott channel and the Fritchman channel.Comment: 36 pages, 3 figures, 2 table
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