Search

In this paper, innovative test methods including aerodynamic acceleration, PIV measurement, separate statistics of incidence and rebound information were used to systematically investigate the rebound characteristics of flaky oxide particles and angular quartz sand impacting stainless steel at high temperature. Through the statistical analysis of a large number of experimental results and the measurement of the microscopic erosion morphology of the target surface, combined with the numerical simulation of the gas-solid two-phase flow of the test section, the intrinsic relationship between the rebound behavior of the particles and their erosion behavior was systematically explored for the first time. Meanwhile, the effects of the incident parameters, particle size and accelerated airflow on the rebound characteristics of the particles were revealed. The results have important guiding significance for further understanding the physical properties of particle-wall interaction and predicting the particle erosion characteristics and erosion distribution of industrial equipment components.

Aviation and ground compressors are susceptible to the erosion of hard particles in the sandy environment, leading to lower performance and shorter service life of the equipment. Although many studies have been performed on this topic, current literature mainly focused on the steady ideal operating conditions of compressors. In this paper, particle motion behavior and erosion characteristics in the blade passage of a 3.5-stage axial compressor under actual service environment are investigated with the RANS numerical simulation method systematically. By comparing the particle trajectories, erosion rate density and other indicators, effect of particle diameter, particle mass concentration, compressor speed and inlet conditions on erosion characteristics are explored in detail. Results show that the value of erosion rate density on the blade pressure side is overall higher than the suction side. The erosion area and intensity of the rotors are generally more serious than stators, especially on the first rotor blade. With variation in particle size, particle diameter of 100 μm becomes the turning point to change the erosion trend of the blades. Moreover, the overall erosion rates increase linearly with increasing mass concentration of inhaled particles. However, its impact on the erosion position and morphology are not obvious. When the compressor speed increases from 6050 rpm to 6650 rpm, the eroded mass of R1 increases by 10.7%, and the casing erosion rate increases about 11 times. Compared with the winter condition, the overall erosion rate in summer increases by 62%. The results of this paper will provide a technology basis for the prediction on particle erosion behavior and formulation of operation and maintenance programs for aero engines and ground gas turbines under the actual service environment.

The symbiosis between a host and its microbiome is essential for host fitness, and this association is a consequence of the host’s physiology and habitat. Sinocyclocheilus, the largest cavefish diversification of the world, an emerging multi-species model system for evolutionary novelty, provides an excellent opportunity for examining correlates of host evolutionary history, habitat, and gut-microbial community diversity. From the diversification-scale patterns of habitat occupation, major phylogenetic clades (A–D), geographic distribution, and knowledge from captive-maintained Sinocyclocheilus populations, we hypothesize habitat to be the major determinant of microbiome diversity, with phylogeny playing a lesser role. For this, we subject environmental water samples and fecal samples (representative of gut-microbiome) from 24 Sinocyclocheilus species, both from the wild and after being in captivity for six months, to bacterial 16S rRNA gene profiling using Illumina sequencing. We see significant differences in the gut microbiota structure of Sinocyclocheilus, reflective of the three habitat types; gut microbiomes too, were influenced by host-related factors. There is no significant association between the gut microbiomes and host phylogeny. However, there is some microbiome related structure at clade level, with the most geographically distant clades (A and D) being the most distinct, and two geographically overlapping clades (B and C) being similar. Microbes inhabiting water were not a cause for significant differences in fish-gut microbiota, but water quality parameters was. Transferring from wild to captivity, the fish microbiomes changed significantly and became homogenized, signifying adaptability and highlighting the importance of environmental factors (habitat) in microbiome community assembly. The core microbiome of this group closely resembled that of other teleost fishes. Our results suggest that divergent selection giving rise to evolutionary novelties also includes the microbiome of these fishes, which provides a functional advantage for life in the resource-depleted cave environment.SIGNIFICANCE STATEMENTThe largest diversification of cavefishes of the world, Sinocyclocheilus, not only show that habitat, and phylogenetic clade is important in determining their gut microbiome, but also that they reach a common microbiome in captivity irrespective of their phylogenetic position, region of origin and habitat, indicating that they are adaptable in the context of microbe related changes in their environment.

Troglomorphism— any morphological adaptation enabling life to the constant darkness of caves, such as loss of pigment, reduced eyesight or blindness, over-developed tactile and olfactory organs—has long intrigued biologists. However, inferring the proximate and ultimate mechanisms driving the evolution of troglomorphism in freshwater fish requires a sound understanding of the evolutionary relationships between surface and troglomorphic lineages. We use Restriction Site Associated DNA Sequencing (RADseq) to better understand the evolution of theSinocyclocheilusfishes of China. With a remarkable array of derived troglomorphic traits, they comprise the largest cavefish diversification in the world, emerging as a multi-species model system to study evolutionary novelty. We sequenced a total of 120 individuals throughout theSinocyclocheilusdistribution. The data comprised a total of 646,497⍰bp per individual, including 4378 loci and 67,983 SNPs shared across a minimum of 114 individuals at a given locus. Phylogenetic analyses using either the concatenated RAD loci (RAxML) or the SNPs under a coalescent model (SVDquartets, SNAPP) showed a high degree of congruence with similar topologies and high node support (> 95 for most nodes in the phylogeny). The major clades recovered conform to a pattern previously established using Sanger-based mt-DNA sequences, with a few notable exceptions. We now recognize six major clades in this group, elevating the blind cavefishS. tianlinensisand the micro-eyedS. microphthalmusas two new distinct clades due to their deep divergence from other clades. PCA plots of the SNP data also supports the recognition of six major clusters of species congruent with the identified clades based on the spatial arrangement and overlap of the species in the PC space. A Bayes factor delimitation (BFD) analysis showed support for 21 species, recognizing 19 previously described species and two putative new cryptic ones. Two species whose identities were previously disputed,S. furcodorsalisandS. tianeensis, are supported here as distinct species. In addition, our multi-species calibrated tree in SNAPP suggests that the genusSinocyclocheilusoriginated around 10.5 Mya, with most speciation events occurring in the last 2 Mya, likely favored by the uplift of the Qinghai-Tibetan Plateau and cave occupation induced by climate-driven aridification during this period. These results provide a firm basis for future comparative studies on the evolution ofSinocyclocheilusand its adaptations to cave life.

Background Natural model systems are indispensable for exploring adaptations in response to environmental pressures. Sinocyclocheilus of China, the most diverse cavefish clade in the world (75 species), provide unique opportunities to understand recurrent evolution of stereotypic traits (such as eye loss and sensory expansion) in the context of a deep and diverse phylogenetic group. However, they remain poorly understood in terms of their morphological evolution. Therefore, we explore key patterns of morphological evolution, habitat utilization and geographic distribution in these fishes. Results We constructed phylogenies and categorized 49 species based on eye-related condition (Blind, Micro-eyed, and Normal-eyed), habitat types (Troglobitic—cave-restricted; Troglophilic—cave-associated; Surface—outside caves) and existence of horns. Geometric-morphometric analyses show Normal-eyed morphs with fusiform shapes segregating from Blind/Micro-eyed deeper bodied morphs along the first principal-component axis; second axis accounts for shape complexity related to horns. The body shapes showed a significant association with eye-related condition and horn, but not habitat types. Ancestral reconstructions suggest at least three independent origins of Blind morphs, each with different levels of modification in relation to their ancestral Normal-eyed morphs; Sinocyclocheilus are also pre-adapted for cave dwelling. Our geophylogeny shows an east-to-west diversification spanning Pliocene and Pleistocene, with early-diversifying Troglobitic species dominating subterranean habitats of karstic plains whereas predominantly Surface forms inhabit hills to the west. Evolutionary rates analyses suggest that lineages leading to Blind morphs were characterized by significant rate shifts, such as a slowdown in body size evolution and a 5–20 fold increase in rate of eye regression, possibly explained by limited resource availability. Body size and eye size have undergone reversals, but not horns, a trait entailing considerable time to form. Conclusions Sinocyclocheilus occupied cave habitats in response to drying associated with aridification of China during late Miocene and the Pliocene. The prominent cave-adaptations (eye-regression, horn-evolution) occur in clades associated with the extensive subterranean cave system in Guangxi and Guizhou provinces. Integration of morphology, phylogeny, rate analyses, molecular-dating and distribution show not only several remarkable patterns of evolution, but also interesting exceptions to these patterns signifying the diversification of Sinocyclocheilus as an invaluable model system to explore evolutionary novelty.

Low altitude open a worldwide topic and the use of low altitude airspace resource exploitation. Through the reading and analysis of the existing literature, this paper combs the related research results of low-altitude airspace management reform and low-altitude opening in recent years. To sum up, the current research results related to low-altitude airspace management reform and low-altitude opening focus on market potential analysis, general aviation industry development forecasting, air traffic supervision and risk prevention.

Literatures regarding the prevalence and clinical significance of compound EGFR mutations are limited. Until now, none of retrospective or prospective research has focused on in cis compound EGFR mutations except case reports. In this study, we screened a cohort of 3,000 treatment-naïve Chinese advanced NSCLC patients using capture-based ultra-deep targeted sequencing to evaluate the prevalence of EGFR in cis compound mutations and the efficacy of EGFR-TKI in this population. Of the 3,000 patients screened, 1,266 (42.2%) had EGFR mutation; among them, 15 patients (1.2%) harboring in cis compound EGFR mutations, with 10 patients carrying EGFR L858R in combination with a rare mutation and five patients carrying two rare EGFR mutations. No patient with EGFR 19del was observed. Interestingly, no in trans configuration was identified in this cohort. All of the patients harboring in cis compound EGFR mutations were non-smokers, histologically diagnosed with adenocarcinoma and received first-generation EGFR-TKI. Furthermore, our data also revealed that patients with in cis compound EGFR mutations exhibit comparable PFS to first generation EGFR-TKI comparing to patients with single activating EGFR mutation. This observation was further supported by in silico molecular modeling analyses which demonstrated in cis compound mutations do not alter the ATP-binding pocket of EGFR, thus having no effect on the interaction between gefitinib and EGFR.

Based on the erosion rate model and the particle rebound model of blade material obtained through accelerated erosion test under high temperature, systematic numerical simulations of the complex gas-particle flows in inlet volute and cascade of a large capacity gas pressure recovery turbine are performed in this paper. The influence of inlet volute structure and cascade channel structure on the aerodynamic performance and erosion characteristics of turbine is first investigated. Results show that although mixing flows and vortex flows are formed in turbine intake volute, total pressure loss of volute is less than 0.7% because of low gas velocity. Erosion damage on the trailing edge of nozzles and rotating blades is mainly caused by high-speed cutting behavior of ash particles. The typical inlet volute structure results in an uneven erosion of first stage nozzles along circumferential direction. Nozzles located below the horizontal split are mainly eroded in blade root area, while erosion distribution of nozzles located above the horizontal split is irregular, and worse than the erosion degree of the lower half circle. Flow acceleration characteristics and cascade circumferential structure must be comprehensively considered so as to simultaneously improve the aerodynamic and anti-erosion performance of turbine.

Accelerating future water shortages in the world require a development of operational water governance models as illustrated by the case studies. Conversion process and its coupling simulation of surface water and groundwater are the foundation of water resources development, utilization, and scientific evaluation. In order to simulate the impact of climate change on the water cycle in basins, the quasi-distributed watershed Surface Water (SW) model was coupled with the fully-distributed Ground Water (GW) model in the simulation. The Hydrologic Response Units (HRU) in the SW model were exchanged with cells in the GW model. By using the HRU–CELL conversion interface, the distributed groundwater recharge rate (RCH) and the groundwater evapotranspiration (EVT) calculated by the SW model were imported into the RCH and EVT modules of the GW model. The application of groundwater simulation in the Heihe River basin demonstrated that the correlation coefficient between the simulation results and the measured values was 0.89, the deterministic coefficient of the simulation results was 0.86. Under future predictions the discharge from the Heihe River will decrease in the first 20 years (2020–2039). In the later 20 years (2040–2059) the discharge will increase. The simulation groundwater along with the recharge value showed the same change trend of the measured groundwater level. The coupled SW–GW model was capable of predicting the future water cycle.

With the actual situation of the reform of teaching mode of general elective course "China's peripheral security environment and security strategy", discusses the countermeasures and suggestions of the general education curriculum teaching paradigm reform, point out the general education predicament, promote the general education curriculum teaching reform should seek new breakthroughs in the aspects of concept, system and the techniques and methods etc.

In order to investigate the influence of meteorological factors on the variation characteristics of PM

The infection with high-risk human papillomavirus is linked to cervical cancer, nevertheless, the role of miRNAs regulated by HPV oncogenes in cancer progression remain largely unknown. Here, we knocked down endogenous E6/E7 in HPV16-positive CaSki cell lines, screened differences in miRNA expression profile with control using miRNA array. 38 miRNAs were down-regulated and 6 miRNAs were up-regulated in the E6/E7 silenced CaSki cells (>2-fold changes with P

Reflector antennas with mesh surfaces have been extensively used in satellite antenna systems. The electrical contact at the metal–insulator–metal (MIM) junction points may cause the degradation of reflectivity performance, and the concept of MIM junctions is mainly used for the analysis of passive intermodulation (PIM) arising from metallic contact in the practical antennas. In this work, a three-dimensional (3-D) modeling of mesh surfaces is presented, which introduced impedance connections at the wire junctions of metallic contact area. The electrical contact model of impedance connections is equivalent to a circuit model, which is considered as lumped boundary condition extended to the modeling of mesh. The planar mesh reflection coefficients are constructed using a full-wave frequency domain method with Floquet mode expansion. To calculate the electrical performance of curved mesh antenna, a solid surface with an equivalent loss is adopted to replace the mesh surfaces. The reflection coefficients of the equivalent loss material are the same as for the mesh surfaces. The analysis of the planar mesh reflectors with three different connections (solid surface, perfect contact, and lumped connection) at junction points is performed as an example for the proposed model. The results demonstrate the usefulness of the model in accurate performance prediction of mesh reflector antennas. Finally, a mesh reflector antenna with 3-D mesh structures is analyzed to predict the electrical performance of the antenna.

Reducing solid particle erosion of blades is one of the most urgent problems for high-parameter steam turbine power generation technology. Based on the erosion rate model and particle rebound model of blade materials obtained through accelerated erosion test under high temperature, erosion characteristics of flaky particles in control stage of a typical supercritical steam turbine were systemically studied using three-dimensional numerical simulation method. The erosion mechanism of hard coatings on nozzle suction surface is first revealed, and erosion resistance of boride coating with large oxide particles is validated through high-temperature erosion test. Results show that serious erosion damage of boride coating on the latter half of nozzle suction surface is caused by the combined rebounded impingement of large particles between 1000 µm and 2000 µm after their initial impingement on the nozzle pressure surface and the leading edge of rotating blade. The average particle impingement velocity can reach up to 150–180 m/s, and the impingement angle is in the range of 18°–28°. High-temperature erosion test results show that boride coating will soon broken and fall off under the continuing impact of millimeter-sized particles, which confirms that hard coatings are difficult to resist the high-intensity impingement from these large particles. Therefore, separating particles before entering the nozzle chamber with the employment of an inertial separator should be the optimal choice for improving the erosion resistance of turbine. The results of this study enrich the types of blade erosion damage and provide a new idea for reducing erosion damage of control stage blades.

The full cavitation model introduced by Singhal et al. was partly improved based on experimental results. The improved cavitation model is used to simulate cavitating flow in multiple nozzle oil jet pump for lubrication system in steam turbine. The influence of noncondensible gas on flowing characteristics of multiple nozzle oil jet pump was studied with noncondensible gas content in the range of 0.01–500 ppm. Results show that noncondensible gas has little influence on nonchoking flow while imminent choking flow and deep choking flow are greatly affected. With the increase of noncondensible gas, multiple nozzle oil jet pump enters choking flow earlier. The maximum suction flow rate per unit throat area of multiple nozzle oil jet pump remains constant with varying pressure ratios and area ratios under choking flow, which is only determined by the noncondensible gas content. It is suggested that the maximum suction flow rate per unit throat area is used for the prediction of choking flow in multiple nozzle oil jet pump. This study also provides qualitative criteria for the upper limit of water content in lubrication oil, which avoids multiple nozzle oil jet pump working under choking flow.

Reducing solid particle erosion of blades is one of the most urgent problems for supercritical steam turbine power generation technology. Based on the erosion rate models and the particle rebound models of blade materials obtained through accelerated erosion test under high temperature, systematic numerical simulations of the complex steam-particle flow in high pressure inlet flow channel and governing stage cascade of a supercritical steam turbine with four control valves was performed in this paper. The influence the typical nozzle chamber structure and partial-arc admission on the erosion characteristics of control stage blades was first investigated. Results show that erosion condition of nozzles in the same nozzle segment vary greatly along circumferential direction, while erosion damage to the leading edge of different circumferential rotating blades is uniform. Compared with four-valve opening condition, erosion weight-loss of the whole nozzle segment increases by 14% and 25% under three-valve opening condition and two-valve opening condition, respectively. Besides, under the partial-arc admission conditions, some large particles coming from the steam admission nozzle segment will collide back and forth between vanes and rotating blades in the downstream nozzle segment without steam admission, thus causing certain erosion to the trailing edge of nozzle suction side.

Control valves are used as flow regulators for steam turbines, which operate under wide ranges of valve openings and pressure ratios. The inherent throttling action and complex 3D flow in control valves result in vibration and intolerable noise at small and medium valve openings. The vibration and noise clearly are firmly with the flow pattern. Experiments and numerical simulation are the primary means of determining the mechanisms. In this paper, a phenomenon of sound mutation in control valve was experimentally observed by continuously changing the pressure ratio. This phenomenon is explained for the first time. Different noise and pressure fluctuations can appear even under the same condition, depending on the process of changing the pressure ratio. A method of continuously changing the pressure ratio was used in the unsteady numerical simulation to reveal the mechanism. The results show that sound mutation occurs due to the change of annular flow and core flow. The annular flow has a lower noise and a more stable flow pattern than the core flow. Sound mutation can be used as a simple way of determining the ranges of the core flow and the annular flow.

Low cost operation models are developing rapidly in the airline industry. However, Taiwan had no national low cost carriers (LCCs) until 2014, although the first foreign LCC began operating in Taiwan in 2004. Currently, most foreign LCCs operate at the Taoyuan International Airport (TPE), which is a primary gateway airport in Taiwan and handles a large number of passengers. This study aims to explore the determinants, beyond demand, that influence the airport choice of foreign LCCs. A hierarchical framework is applied to examine experts' opinions with a rank pair-wise comparison (RPC) approach. A fuzzy analytic hierarchy process (FAHP) is used to evaluate the relative weights of all factors and this finds that the airport authority's promotion policy is the key factor. Based on an evaluation of three potential airports in Taiwan (TPE), Taipei Songshan Airport (TSA) and Kaohsiung International Airport (KHH), the airports' individual strengths and weaknesses can be easily distinguished. TPE remains the most contestable airport to attract foreign LCCs because of its corporatized operations.

Since the late Han Dynasty was introduced into China, Buddhism has quickly harmonized with local Confucian and Taoist culture in the fields of religion, art and literature by adhering to great compassion for all the common people and equality of all living creatures, to the extraordinary ideological level of detachment from secular world and the pursuit of peace, happiness and wisdom. After two thousand years spread, inheritance, development and evolution, Buddhism gradually integrated into the local culture, converged and formed the trinity culture pattern of Confucianism, Buddhism and Taoism, which highlights the value concept of pluralism and the spirit of tolerance of coexistence of Chinese traditional culture. On the one hand, the active guide of Buddhism for people’s yearning for the value pursuit of peace, happiness and wisdom, equality, and the reflections on life of equality of all living creatures and cause-and-effect transmigration are intrinsically in accordance with the harmonious development between people and nature, economic construction and environmental protection advocated by ecological civilization, which conforms to the value concept of sustainable economic and social development and exerts the important enlightenment significance to the protection of Guizhou ethnic characteristic culture under the background of urbanization. On the other hand, the experience and practice of localization of Buddhist culture exert the vital significance to the development of Guizhou ethnic characteristic culture under the background of urbanization.

In the face of constant increasing process of new type of urbanization and industrialization, more diverse and open social transition, the past sole government administrative control mode in western ethnic areas has been in a dilemma. Transforming government function, realizing the fundamental transformation from the administrative controls by the government to diversified cooperation governance as soon as possible are not only the inevitable requirement for promoting the innovation in government management and perfecting the system of social governance, but also the choice to maintain and realize the unity and stability of the good situation, explore development model of social democracy and politics with the western characteristics of ethnic areas under the new situation. Based on the on-the-spot investigation and empirical analysis on Buyi autonomous country in Miao village, Kaiyang County, we probe into the issue of diversity of social governance system of the western national regions. Among them, we hold the view that system of social governance structure has multiple major structure and multi-dimensional elements and emphasize that when focusing on government management, we should pay attention to social organization, religion, mass organizations and individual citizens as well as enterprises and institutions and give full play to their roles in social governance system.

In this paper, high temperature erosion tests are performed on four typical anti-erosion coatings for high-parameter steam turbine blades using pneumatic accelerated erosion method to simulate the actual erosion environment in power units. With the employment of scanning electron microscope, energy-dispersive X-ray spectroscopy, glancing-angle X-ray diffraction, and Vickers indentation testing techniques, detailed microscopic analysis of samples is conducted to reveal the underlying causes affecting the anti-erosion performance of coatings. Results show that, under the solid particle erosion at high temperature, boride coatings with more compact structure and higher hardness have stronger anti-erosion ability, whose erosion rate is only 30–50% that of HVOF Cr3C2 coatings under the same erosion condition. Boride coatings composed of duplex phase (FeB and Fe2B) have lower anti-erosion damage capability than that of boride coatings composed of single Fe2B phase. Under high-speed large incidence angle impingement, the surface layer of FeB cracks easily and rapidly propagates to the subsurface layer Fe2B phase under the sustained impingement from particles, resulting in the flaking off and failure of coatings. Single Fe2B phase boride coatings have smaller hardness gradient in the depth direction and higher fracture toughness than boride coatings composed of duplex phase, so that exhibit more stable excellent erosion resistance under different erosion parameters. Therefore, single Fe2B phase boride coatings should be used as the preferred wear resistant coating for turbine blades solid particle erosion problem.

Combining an improved particle image velocimetry technique with a far-field microscope, a high-resolution quantitative measurement of the transient secondary flow field in an annular turbine cascade is conducted through moving the laser light sheet to follow the primary flow. The measuring results revealed the transient behavior and strong unsteadiness of the secondary flow in a cascade for the first time. It is confirmed that the suction side leg of the horseshoe vortex rotates around the passage vortex along the rotating direction of passage vortex. In the secondary flow of cascade, the formation, development and decay of Hopf bifurcations caused by the competition between the tensile deformation and the dissipation, have become a major behavior of vortex evolution. Driven by the interaction between the passage vortex and the suction side leg of the horseshoe vortex as well as the transverse pressure gradient, the passage vortex was pushed to the suction surface and ultimately formed the wall vortex. Furthermore, the strength of secondary vortex was enhanced with the increase of aerodynamic parameters, though the scale of vortex was gradually shrinking and the limit cycle concentrated at the core of vortex. However, no change happened to the location of vortex core and the structure of vortex. The computational fluid dynamics results revealed that the results using the SST k- ω model was the closest to the experiment results in the topological structure, the evolution process of secondary flow and the magnitude estimation, followed by those with the RNG k- ɛ model. The results with standard k- ɛ model were clearly inconsistent with the experimental results.

The actual industrial erosion caused by the impingement of particles swarming from different perspectives is often different from the single-angle impingement of solid particle in the erosion test. In order to predict the erosion problems in practical engineering more reasonably, a series of elevated temperature erosion tests were conducted to study the surface ripple and enduring erosion behavior of heat-resistance stainless steel suffering from the single-angle impingement or multiangle alternative impingement of angular particles. The test results indicated that the surface of target materials with good ductility produced large-scaled transverse ripples and small-scaled longitudinal ripples after experienced a long-time single-angle impingement of angular solid particles under a 773–873-K high-temperature environment. The longitudinal ripples could accelerate the emergence and development of large-scaled transverse ripples. Initial erosion scars caused the differentiation of material deformability and plastic flow in the different locations of concave–convex scars, which further drove the evolution of the surface morphology from disordered scars to coherent ripples under the sustained attack of high-velocity particles. The more dimples the eroded surface of target material produced, it was easier for the target materials to produce coherent ripple. However, the interactions among the erosion behaviors with different attack angles made initial concave–convex scars difficult to evolve to coherent ripples under the multiangle alternative erosion. Further statistical results of erosion tests indicated that it can basically satisfy the practical engineering need by taking the erosion rate of initial surface layer as the erosion rate of the target material within the whole life cycle.

Propofol (2,6-diisopropylphenol) is probably the most widely used intravenous hypnotic agent in daily practice. However, its anti-inflammatory properties have seldom been addressed. In this study, we evaluated the anti-inflammatory activity and mechanisms of propofol on lipopolysaccharide (LPS)-induced inflammation in vivo and in vitro and found that propofol markedly inhibited LPS-induced production of pro-inflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6, and expression of inducible nitric oxide synthase (iNOS). At the same time, the expression of hepatocyte nuclear factor-1α (HNF-1α) and apolipoprotein M (APOM) was inhibited by treatment with LPS and LPS-induced down-regulation of HNF-1α expression and APOM expression could be compensated by propofol treatment. However, propofol could not compensate LPS-induced down-regulation of APOM expression by treatment with HNF-1α siRNA and the suppressive effect on LPS-induced pro-inflammatory cytokines production by propofol was significantly compensated by treatment with APOM siRNA. These results provide evidence that propofol may first up-regulate APOM expression by enhancing HNF-1α expression and then inhibit pro-inflammatory cytokine production in LPS-stimulated cells. Therefore, our study may be useful in understanding the critical effect of propofol in patients with systemic inflammatory response syndrome.

Based on experiments and numerical simulation, the influence of the inlet flow channel of a steam turbine on the solid particle erosion of nozzle segments was investigated systematically. The results indicate that the upstream channels of the nozzle segment, such as the regulating valve, nozzle chamber and connection pipe, concentrate the solid particle erosion to a small number of nozzles or local regions of the nozzle, which greatly reduces the time for nozzle damage. Compared with the present erosion situation, measures adopted to distribute particles at the inlet of a nozzle chamber uniformly can double the service life of a nozzle segment, while the service life can be increased by eight to ten times through measures to distribute particles uniformly at the inlet of a nozzle segment. This article shows that the service life of a nozzle segment can be doubled through substituting a nozzle chamber with a tangential steam intake for one with a normal steam intake. Moreover, a boride layer with 0.04 mm effective thickness or a CrN layer with 0.01 mm effective thickness can further double the service life of a nozzle segment. In addition, a pocket-trap arranged in the particle-aggregated area after an elbow can reduce the weight loss at nozzle sites with the most serious erosion by over 85%. These investigations are of great significance to the long-term, safe and high-efficiency running of a steam turbine.

The basic idea of designing E-plane rectangular corrugated horn antenna which works at the frequency of 10GHz was introduced. Comparison was made between smooth wall horn and corrugated horn, and research on the far field pattern influenced by corrugated duty cycle and depth was carried out. Through the numerical modeling and simulating, higher gain and lower side lobe of corrugated horn than the smooth wall horn have been achieved. The effect of different corrugated duty cycle and different depth on corrugated horn was studied by changing the parameters.

MicroRNAs (miRNAs) have been reported to be involved in multiple biological pathways that can influence tumor progression and metastasis. High-risk human papillomavirus (HR-HPVs) is aetiologically correlated to cervical cancer. Recently, miRNAs were reported to be regulated by virus and play pivotal roles in HPV-related tumor progression. However, the underlying mechanism remains poorly understood. In the present study, we report that HPV16 E7 upregulated miR-27b to promote proliferation and invasion in cervical cancer. The results showed that PPARγ, as a target of miR-27b, played a significant role in suppressing cervical cancer progression by downregulating the sodium-hydrogen exchanger isoform 1 (NHE1). It was also shown that the inhibition of miR-27b diminished the ability of HPV16 E7 to suppress PPARγ or activate NHE1 expression. In addition, we observed high expression of miR-27b and NHE1, but low expression of PPARγ in HPV16-positive cervical cancer tissues. In summary, the present study revealed that miR-27b is upregulated by HPV16 E7 to inhibit PPARγ expression and promotes proliferation and invasion in cervical carcinoma cells.

One of the most outstanding limitations in the evolution of the power scaling of fiber laser with near diffraction limited beam quality has been the mode instability since it was found in 2010. For a long time, researchers have focused on the dynamic mode instability (DMI) theoretically and experimentally, and it was not until 2016 that a new analytical model called quasi-static mode instability (QSMI) was proposed. Unlike DMI, because of the one-way energy transfer characteristic on a specific time scale, QSMI will show no apparent fluctuations with respect to the time domain traces. In this paper, based on a counter-pump few-mode fiber amplifier schematic system, the output power, beam quality and time traces of the amplifier under changing seed laser power are measured to investigate its mode instability effect. The ytterbium-doped fiber of the amplifier has a core diameter of 25 μm and inner cladding diameter of 400 μm, which can support 4-5 modes to be transmitted in the amplifier. The experimental results reveal that QSMI happens in the few-mode fiber amplifier. Taking 234 W seed power for example, it is found that when the output power reaches 2030 W, the optical-to-optical efficiency begins to fell from 86% to 32%, and at the same time the M2 value has an abrupt degradation from 2.2 to 2.8, which indicates that MI happens. On the other hand, it can be seen from the time traces of the output laser that there exist no rapid fluctuations, and the Fourier analysis shows no sign of DMI characteristic frequency components either. Quoting the definition of drifting ratio σ, when the output power is 2030 W under 234 W seed power, it is only 4%, and thus verifying that it is QSMI instead of DMI. The experiment also indicates that increasing the seed power has an effective influence on enhancing the mode instability power. When the seed power is raised from 86 W to 528 W, the corresponding threshold power is increased from 1560 W to 3090 W. And for 528 W seed power, when the output laser surpasses 3000 W, the optical-to-optical efficiency does not decline as fast as other relatively low seed power. To sum up, the mode instability effect represents a kind of quasi-static property in these large core diameter few-mode fiber amplifiers, which needs further studying.

The efficiency of the multiple nozzle oil jet pump was systematically investigated using the Mobile DTE Light Oil based on the similarity theory in experiment. The experimental condition is the same as that for the multiple nozzle oil jet pump in lubrication system of steam turbine in the power plant. Thus, the influence of the area ratio and the pressure ratio on the efficiency and the pressure ratio interval of variable conditions with stable efficiency was studied in the area ratio range of 4∼9. Results show that there is a fixed relationship between the area ratio and the pressure ratio, which leads to the high efficiency of multiple nozzle oil jet pump. However, the high efficiency value and the pressure ratio interval of variable conditions with stable efficiency show different tendencies with the changing area ratio of multiple nozzle oil jet pump. In the area ratio range of 4∼9, the pressure ratio with the high efficiency value increases by 0.03 with the decrement of 1 for the area ratio. When the area ratio is larger than 6.3, the high efficiency value increases by 1% absolutely with the area ratio decreasing by 1, but remains almost unchanged for the area ratio less than 6.3. Furthermore, the increasing area ratio widens the pressure ratio interval of variable conditions with stable efficiency. The increase of the area ratio by 1 leads to the increment of 9.7% relatively for the pressure ratio interval of variable conditions with stable efficiency. This study provides the quantitative criteria for the determination of the area ratio and the pressure ratio of multiple nozzle oil jet pump, which keeps the high and stable efficiency simultaneously. Apparently, this study has significant engineering contribution.Copyright © 2014 by ASME

Control valve is an accident prone equipment in high-parameter steam turbine, and its safety directly influences the economy and safety of the unit. In this study, a control valve of a 600 MW subcritical unit used in the power plant was investigated to reveal the mechanism of flow induced vibration of the control valve. It is found that the intermittent vibration of the control valve is a fluid-solid interaction phenomenon, which occurs in middle-opening and transonic flow condition. The phenomenon is a variable damping and nonlinear vibration for the valve stem system. The experimental results show that as the valve head tilts to different positions, the pressure fluctuation at the valve seat changes significantly at the same time. Unsteady numerical simulation is conducted when valve head is in the center and tilts toward three different directions with the same angle. The results indicate that the separation point between the high jet flow and valve head is changing with time. The thick boundary layer caused by transonic flow and the moving high-pressure region induced by impinging jet flow are the two main reasons for the flow pattern alternation. The average unbalanced force of fluid acting on valve head varies as the flow pattern alternates. And its direction is from center to the narrower side of the annular channel in the oblique section when valve head is tilted.Copyright © 2014 by ASME

Reducing solid particle erosion (SPE) of blades is one of the most urgent problems for supercritical steam turbine power generation technology. Based on the erosion rate models and the particle rebound models of blade materials obtained through the accelerated erosion test under high temperature, erosion characteristics of the first reheat stage blades in a supercritical steam turbine was simulated and analyzed by three-dimension numerical simulation method in this paper. The influence of operating conditions, particle size distribution in the inlet of nozzle and axial clearance between vanes and rotating blades on the erosion distribution of cascade were explored quantitatively. Results show that: the erosion damage of the first-reheat stage stator is mainly caused by suction surface impingement from oxide particles. In designed loading condition, small and median size of particles mainly eroded the trailing edge (TE) of nozzle pressure surface, while large particles mainly impinge the leading edge (LE) of rotating blades and the TE of vane suction surface, and erosion increase along the blade height. When the turbine is running under part-load condition, particle impingement angle on stator pressure surface is basically unchanged, while impingement velocity slightly reduced. However, the amount of particles that impinge the stator TE suction side after their first-time impingement on rotor LE increase rapidly, leading to the more severe erosion damage of stator suction surface. The particle size distribution in the inlet of nozzle has a significant effect on the erosion simulation of first reheat stage blades, and the size distribution sampled in one unit may not be used to other units. When axial clearance changes, the erosion weight loss of vane pressure surface near TE is basically held constant, while the erosion weight loss in vane suction surface near TE decreases with the increase of axial clearance. For the supercritical 600MW unit simulated in this article, the anti-SPE performance and the unit efficiency can be balanced well when the axial clearance increases to 13mm. The results in this paper will provide a technology basis for reducing oxide particle erosion in the first reheat stage blades of supercritical steam turbine.Copyright © 2014 by ASME

GRECO method is often used in far field RCS studies because of its computational efficiency for electrically large structures. It uses the graphical hardware to greatly reduce the computational resource requirements. However, GRECO method has its limitation because of the limit of graphical hardware. This paper presents the mathematical derivation of the errors caused by the limitation of graphical hardware. Based on the Error analysis, Numerical results are used to compare with the PO method.

Reducing the solid particle erosion (SPE) of blades is one of the most important problems for high-parameter steam turbine. Based on the erosion rate models and the particle rebound models of blade materials obtained through the accelerated erosion test under high temperature, a lot of three dimension numerical simulations were conducted in this paper. The influence of particle size on the impingement point distribution on the nozzle surface and the erosion characteristics of control stage nozzle in a supercritical steam turbine were analyzed quantitatively. The size range of the oxide scale particles participating in the erosion damage were extended to 500μm, and some special anti-erosion measures corresponding to different size particles were proposed to reduce the erosion of nozzle. Results show that the erosion of pressure surface in the trailing edge of nozzle is mainly from the high-intensity impingement of particles smaller than 160μm, especially those with the size range from 20μm to 60μm. For the impingement of these small particles, optimizing the profile and cascade structure as well as coating the hard coating on the surface of nozzle can improve the erosion resistance of nozzle. However, these small particles do not impinge the nozzle trailing edge suction surface. The severe erosion damage of suction surface of nozzle was from the impingement again of the particles with the size range from 200μm to 500μm after rebounding from nozzle pressure surface. It is very difficult to resist the erosion damage of these large particles for the hard coating, and separating large particles from main steam before entering the nozzle chamber should be a good choice for improving the erosion resistance of turbine. These studies will provide a technical basis for selecting anti-erosion measures of control stage nozzle.Copyright © 2013 by ASME

AIMSAtherosclerosis is a chronic inflammatory disease and represents the major cause of cardiovascular morbidity and mortality. There is evidence that dihydrocapsaicin (DHC) can exert multiple pharmacological and physiological effects. Here, we explored the effect of DHC in atherosclerotic plaque progression in apoE(-/-) mice fed a high-fat/high-cholesterol diet.METHODS AND RESULTSapoE(-/-) mice were randomly divided into two groups and fed a high-fat/high-cholesterol diet with or without DHC for 12 weeks. We demonstrated that cellular cholesterol content was significantly decreased while apoA1-mediated cholesterol efflux was significantly increased following treatment with DHC in THP-1 macrophage-derived foam cells. We also observed that plasma levels of TG, LDL-C, VLDL-C, IL-1β, IL-6, TNF-α and CRP were markedly decreased while plasma levels of apoA1 and HDL-C were significantly increased, and consistent with this, atherosclerotic lesion development was significantly inhibited by DHC treatment of apoE(-/-) mice fed a high-fat/high-cholesterol diet. Moreover, treatment with both LXRα siRNA and PPARγ siRNA made the up-regulation of DHC on ABCA1, ABCG1, ABCG5, SR-B1, NPC1, CD36, LDLR, HMGCR, apoA1 and apoE expression notably abolished while made the down-regulation of DHC on SRA1 expression markedly compensated. And treatment with PPARγ siRNA made the DHC-induced up-regulation of LXRα expression notably abolished while treatment with LXRα siRNA had no effect on DHC-induced PPARγ expression.CONCLUSIONThese observations provide direct evidence that DHC can significantly decrease atherosclerotic plaque formation involving in a PPARγ/LXRα pathway and thus DHC may represent a promising candidate for a therapeutic agent for the treatment or prevention of atherosclerosis.

Distance-based indexing is a widely used technique for general purpose search. Pivot selection is the most crucial step of bulkloading a metric-space indexing tree. Current pivot selection methods are mainly based on linear methods. A non-linear method based on Locally Linear Embedding is proposed. Empirical results demonstrate that the performance of new method is superior to existing methods. Keywords-similarity search; metric-space indexing; pivot selection; locally linear embedding; dimensional reduction