265 research outputs found

    Functions of Conversation in Detective Fiction: An Analysis of Smiley’s Duplicate Keys From Grice’s Theory of Conversational Implicature

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    Duplicate Keys, published in 1984, is a detective novel written by Pulitzer Laureate Jane Smiley. The novel develops around a murder discovered by Alice, the heroine, in Manhattan, in which two band members, Denny and his adopted brother Craig, were shot dead in Denny’s apartment. Since besides Alice, some of their other friends, and even their friends’ friends have duplicate keys, it’s extremely distracting and difficult for Police Detective Honey to solve the case. With suspense resolved and mystery unraveled, it turns out that the killer is Denny’s girlfriend and Alice’s best friend Susan, who pretends to be on a trip far away at the occurrence of the murder. The novel contains an abundance of conversations, which play a crucial part in plot advancement as well as characterization. Guided by Paul Grice’s theory of conversational implicature, the paper analyzes some conversations from Duplicate Keys, especially the disobedience of the cooperative principle in the conversations, deciphers the reasons behind the disobedience, while at the same time exposes characters’ inner world, and exhibits their personality traits. In so doing, functions of conversation in detective fiction are revealed.

    Framework Design of Emergency Management Information System for Cloud Computing in Chemical Park

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    Collaborative emergency management mode provides a new idea for further reducing system safety risk in the chemical park. In this paper, the cloud computing and the expert system were used for the framework design of the emergency management information system to enhance emergency response capability of collaborative emergency managementmechanisms. The use of middleware integrated with multi-source data achieved the unified data manipulation interface. Intelligent delivery of information system was provided. Using agent-middleware technology to build decision layer could make massive data analysis, data mining and decision from the “cloud computing” platform access for every user. It can provide the necessary theoretical and technical support for enterprises in the chemical park, to give full play to the collaborative emergency management capability.</p

    Fault Diagnosis of Train Axle Box Bearing Based on Multifeature Parameters

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    Failure of the train axle box bearing will cause great loss. Now, condition-based maintenance of train axle box bearing has been a research hotspot around the world. Vibration signals generated by train axle box bearing have nonlinear and nonstationary characteristics. The methods used in traditional bearing fault diagnosis do not work well with the train axle box. To solve this problem, an effective method of axle box bearing fault diagnosis based on multifeature parameters is presented in this paper. This method can be divided into three parts, namely, weak fault signal extraction, feature extraction, and fault recognition. In the first part, a db4 wavelet is employed for denoising the original signals from the vibration sensors. In the second part, five time-domain parameters, five IMF energy-torque features, and two amplitude-ratio features are extracted. The latter seven frequency domain features are calculated based on the empirical mode decomposition and envelope spectrum analysis. In the third part, a fault classifier based on BP neural network is designed for automatic fault pattern recognition. A series of tests are carried out to verify the proposed method, which show that the accuracy is above 90%

    Calcium-magnesium-alumino-silicate induced degradation of La2(Zr0.7Ce0.3)2O7/YSZ double-ceramic–layer thermal barrier coatings prepared by electron beam-physical vapor deposition

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    During last decades, much effort has been made to develop new alternative thermal barrier coating (TBC) to traditional YSZ for applications above 1250oC. La2(Zr0.7Ce0.3)2O7(LZ7C3) is deemed as a very promising TBC candidate for advanced gas turbine because of its extremely low thermal conductivity, high sintering resistance and phase stability from room temperature to 1600oC. Thermal cycling with a gas burner showed that the LZ7C3/YSZ double-ceramic-layer (DCL) coatings prepared by electron beam-physical vapor deposition (EB-PVD) or atmospheric plasma spraying had a much longer lifetime than that of YSZ coating at 1250± 50oC.The use of the new TBC can allow higher gas temperatures, resulting in further improved thermal efficiency and engine performance. However, at these high operating temperatures, TBCs become susceptible to attack by calcium-magnesium-alumino-silicate (CMAS, relative to the main chemical components Ca, Mg, Al and Si) deposits resulting from the ingestion of siliceous minerals (dust, sand, volcanic ash, runway debris) with the intake air. CMAS becomes molten at temperatures above 1200oC and then rapidly penetrates the TBCs by capillary force, resulting in the loss of strain tolerance and premature failure of the coatings. In this paper, CMAS induced degradation of LZ7C3/YSZ DCL coatings prepared by EB-PVD method were investigated. Hot corrosion tests were performed at 1250oC at durations varying from 0.5 h to 24 h. It is observed that the infiltration of CMAS in the intercolumnar gaps was largely suppressed in the case of EB-PVD LZ7C3 coating. The penetration depth rarely exceeded 40 ÎŒm below the original surface even after 24 h exposure at 1250oC. This was ascribed to rapid dissolution of the LZ7C3 and essentially concurrent formation of a sealing layer made of crystalline apatite and fluorite phases, which is consistent with the observation on Gd2Zr2O7. However, large vertical cracks would form in the EB-PVD LZ7C3 coating during thermal cycling as a result of re-crystallization, sintering and thermal expansion mismatch between ceramic coating and substrate. These vertical cracks can also act as channels to CMAS melt infiltration. Since the kinetics of the dissolve-reprecipitation reaction was slower than the infiltration rate of CMAS in the vertical crack, the majority of vertical cracks were not sealed. As a result, CMAS flowed down to the LZ7C3/YSZ interface along the vertical cracks, and then easily penetrated the YSZ buffer layer by capillary force. Chemical interaction also occurred in the YSZ buffer layer. What\u27s more, the YSZ layer in the DCL coating even underwent a severer CMAS attack than the single YSZ coating. After 4 h CMAS exposure, the YSZ layer of the LZ7C3/YSZ bilayer coating was totally dissolved by molten CMAS followed by precipitation of a large number of globular ZrO2 particles, while the single YSZ coating just suffered a slight degradation in the same experimental conditions and still kept its columnar structure. The probable reason was that the CMAS melt in the YSZ layer of the DCL coating had a higher CaO/SiO2 ration than the original CMAS composition due to the formation of apatite phase when CMAS reacted with the upper LZ7C3 layer. The initial Si: Ca ratio (Si: Ca≈1.4) in CMAS melt is less than the corresponding apatite (Si: Ca≈3), leading to progressive CaO enrichment during apatite crystallization. For this reason, it is suggested that the effectiveness of the CMAS mitigation strategy for YSZ TBCs by adopting a so-called CMAS-resistant top layer needs to be assessed in the context of more realistic conditions. If the formation of large vertical cracks in TBCs was not avoided, this CMAS mitigation approach may not as effective as expected

    MicroRNA-223 Delivered by Platelet-Derived Microvesicles Promotes Lung Cancer Cell Invasion via Targeting Tumor Suppressor EPB41L3

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    Background: Patients with hematogenous metastatic lung cancer displayed significantly increased platelet count and aggregation compared to lung cancer patients without hematogenous metastasis. The mechanism underlying the correlation between the lung cancer hematogenous metastasis and platelet activation remains unknown. Results: In the present study, we explored the role of microRNA-223 (miR-223) derived from platelets in modulating lung cancer cell invasion. Our results demonstrated that platelets from NSCLC patients contain higher level of miR-223 than that from healthy subjects. The concentration of miR-223 in the platelet-secreted microvesicles (P-MVs) from NSCLC patients was also increased compared to that from healthy subjects. Incubation of human lung cancer A549 cells with P-MVs resulted in rapid delivery of miR-223 into A549 cells, in which platelet miR-223 targeted EPB41L3 and thus promoted A549 cell invasion. The effect of P-MVs on reducing EPB41L3 in A549 cells but promoting tumor cell invasion could be largely abolished by depletion of miR-223 via transfection with miR-223 antagomir. The role of EPB41L3 in inhibiting A549 cell invasion was further validated by directly downregulating EPB41L3 via transfecting cells with EPB41L3 siRNA or miR-223 mimic. Conclusions: Our study demonstrates for the first time that platelet-secreted miR-223 via P-MVs can promote lung cancer cell invasion via targeting tumor suppressor EPB41L3
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