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Recently, an algorithm of surface turbulent heat fluxes over snow/sea ice has been developed based on the theory of maximum entropy production (MEP), which is fundamentally different from the bulk flux algorithm (BF) that has been used in sea ice models for a few decades. In this study, we first assess how well the MEP algorithm captures the observed variations of turbulent heat fluxes over Arctic sea ice. It is found that the calculated heat fluxes by the MEP method are in good agreement with in-situ observations after considering the absorption of incoming radiation in a snow/ice surface layer with infinitesimal depth. We then investigate the effects of two different schemes (MEP vs. BF) in the sea ice model of CICE6 on simulated turbulent heat fluxes and sea ice processes in the Arctic Basin. Our results show that the two different schemes give quite different representations of seasonal variations of heat fluxes, particularly for sensible heat fluxes in summer. The heat fluxes simulated by the MEP produce weak cooling effect on the ice surface in summer, whereas the BF generates a warming effect. As a result, compared to the BF, the MEP leads to a reduced seasonal cycle of Arctic sea ice mass flux by modulating snow-to-ice conversion, basal ice growth, surface ice melt and basal ice melt.

Whether Arctic sea-ice loss has significant impacts on climate extremes in mid- and high-latitudes remains uncertain. Here we show the full response of cold and warm extremes under two Arctic sea-ice loss scenarios utilizing a coupled global climate model that permits the air-sea coupling. Our results show that the amount of Arctic sea-ice loss determines the spatial extent and magnitude of the weakening of atmospheric circulation in mid- and high-latitudes of the northern hemisphere, leading to nonlinear changes in cold and warm extremes. A relatively localized and moderate weakening of atmospheric circulation induced by the projected sea-ice loss in the next two decades would contribute to less winter cold extremes over the Northern Hemispheric continents. The risks of winter cold spells would be dramatically reduced as the amount of sea-ice loss is increased to the ice-free state. In contrast, as sea-ice loss increases, the continental regions would have increased risk of heat waves over all mid- and high-latitudes.

Background Labor represents a period of significant physical activity. Inefficient energy supply may delay labor process and even lead to cesarean delivery. Herein we investigated whether ingestion of a carbohydrate-rich beverage could reduce cesarean delivery in laboring women with epidural analgesia. Methods This multicenter randomized trial was conducted in obstetrician-led maternity units of nine tertiary hospitals in China. Primigravidae with single term cephalic pregnancy who were preparing for vaginal birth under epidural analgesia were randomized to intake a carbohydrate-rich beverage or commercially available low-carbohydrate beverages during labor. The primary outcome was the rate of cesarean delivery. Secondary outcomes included maternal feeling of hunger, assessed with an 11-point scale where 0 indicated no hunger and 10 the most severe hunger, and maternal and neonatal blood glucose after childbirth. Results Between 17 January 2018 and 20 July 2018, 2008 women were enrolled and randomized, 1953 were included in the intention-to-treat analysis. The rate of cesarean delivery did not differ between the two groups (11.3% [111/982] with carbohydrate-rich beverage vs. 10.9% [106/971] with low-carbohydrate beverages; relative risk 1.04, 95% CI 0.81 to 1.33; p = 0.79). Women in the carbohydrate-rich beverage group had lower subjective hunger score (median 3 [interquartile range 2 to 5] vs. 4 [2 to 6]; median difference − 1; 95% CI − 1 to 0; p < 0.01); their neonates had less hypoglycemia (1.0% [10/968] vs. 2.3% [22/956]; relative risk 0.45; 95% CI 0.21 to 0.94; p = 0.03) when compared with those in the low-carbohydrate beverage group. They also had higher rates of maternal hyperglycemia (6.9% [67/965] vs. 1.9% [18/953]; p < 0.01) and neonatal hyperglycemia (9.2% [89/968] vs. 5.8% [55/956]; p < 0.01), but none required special treatment. Conclusions For laboring primigravidae with epidural analgesia, ingestion of a carbohydrate-rich beverage compared with low-carbohydrate beverages did not reduce cesarean delivery, but relieved maternal hunger and reduced neonatal hypoglycemia at the expense of increased hyperglycemia of both mothers and neonates. Optimal rate of carbohydrate supplementation remains to be determined. Trial registration www.chictr.org.cn; identifier: ChiCTR-IOR-17011994; registered on 14 July 2017.

Background: Ulcerative colitis (UC) is a chronic non-specific intestinal inflammatory disease with unknown etiology. In recent years, the global incidence has been increasing. Sijunzi decoction (SJZD) is a traditional Chinese medicine that has been used for treatment of other diseases in previous studies as it has no side effects and it has a pharmacological effect in gastrointestinal function, immune system, ulcers, and tissue repair. Methods: PubMed, Embase, Cochrane Library, GeenMedical, China National Knowledge Infrastructure, Chinese Sci-tech Journals full-text Database, Chinese Biomedical Database, and Chinese Science Citation Database were searched to screen the related literatures of “ulcerative colitis” and “Jiawei Sijunzi decoction”. The research data extracted from above studies was analyzed by Review Manager 5.3 and Stata14.2 software. Results: This systematic review and meta-analysis will evaluate the efficacy and safety of Jiawei SJZD in the treatment of UC and provide effective evidence for clinical use. Conclusion: In this study, the published evidence of modified SJZD in the treatment of UC was systematically summarized and evaluated, so that it can be better applied in clinic. INPLASY registration number: INPLASY2020100102

In this paper, we have studied the double-slit interference experiment phenomena of the large molecule $${C_{60}}$$ with quantum theory approach. We calculate the double-slit wave functions of $${C_{60}}$$ molecule by the Schrodinger equation, and calculate the diffraction wave function behind the slits with the Feynman path integral quantum theory, and then give the relation between the interference intensity and interference pattern position. On this basis, we compare the calculation results with the double-slit interference experiments of $${C_{60}}$$ , which are in accordance with the experimental data, which shows that the matter-wave interference is a quantum phenomenon, it should be studied by the quantum theory method, and the decoherence effect should be considered.

Satellite-derived surface radiative fluxes have been recently improved and extended. However, the accuracy of recent satellite-derived surface radiative fluxes in the Arctic is not well characterized. Here, the authors assess the accuracy of the net surface radiative flux (NETSRF) in the Arctic, focusing on the ice-covered ocean, for three satellite products against four in situ measurements collected from different areas in the Arctic. The three satellite products are the Surface Radiation Budget project (SRB), the International Satellite Cloud Climatology Project (ISCCP), and the Extended AVHRR Polar Pathfinder version-2 (APP-x). Our comparisons suggest that: (1) in terms of the overall bias, root-mean-square error, and correlation, the NETSRF of ISCCP is closer to in situ observations than that of SRB and APP-x; (2) in terms of the diurnal variation of the biases, it is not very clear which satellite product is superior to the others; and (3) in terms of the interannual variability of the bias, the NETSRF of ISCCP is more accurate than that of SRB and APP-x. This comparison may provide useful guidance to the community as to which data-set may provide the smallest bias in NETSRF.

In this paper, we have proposed the theory of gravity gauge, and the gravity theory has been introduced into quantum field theory. We have further given the tensor equation of gravity field in the flat space, and found the gravity field equation is the Lorentz covariant and gauge invariant. The gravity theory can be quantized and can be unified with the electroweak and strong interaction at a new gauge group .

In this paper, we have studied the evolution curve of two-level atomic system that the initial state is excited state. At the different of environmental reservoir models, which include the single Lorentzian, ideal photon band-gap, double Lorentzian and square Lorentzian reservoir, we researched the influence of these environmental reservoir models on the evolution of energy level population. At static no modulation, comparing the four environmental models, the atomic energy level population oscillation of square Lorentzian reservoir model is fastest, and the atomic system decoherence is slowest. Under dynamic modulation, comparing the photon band-gap model with the single Lorentzian reservoir model, no matter what form of dynamic modulation, the time of atoms decay to the ground state is longer for the photonic band-gap model. These conclusions make the idea of using the environmental change to modulate the coherent evolution of atomic system become true.

With the nonlinear Jaynes-Cummings model, we have studied the atom and light field quantum entanglement of multiphoton transition in nonlinear medium, and researched the effect of the transition photon number N and the nonlinear coefficient χ on the quantum entanglement degrees. We have given the quantum entanglement degrees curves with time evolution, we find when the transition photon number N increases, the entanglement degrees oscillation get faster. When the nonlinear coefficient α > 0, the entanglement degrees oscillation get quickly, the nonlinear term is disadvantage of the atom and light field entanglement, and when the nonlinear coefficient α

We have proposed a new two-dimensional function photonic crystals, which the dielectric constants of medium columns are the function of space coordinates r → . The photorefractive nonlinear optical effect or electro-optic effect can turn the dielectric constants of medium column into the function of space coordinates. In this paper, we studied the dielectric constants of medium columns are the linear function of space coordinates, i.e., e ( r → ) = k r + b , and calculated the band gaps structures of TE and TM waves. We have found there are absolute band gaps and semi-Dirac points in the two-dimensional function photonic crystals. When the parameters k, b and the medium column radius ra change, the band gaps number, location and width, the absolute band gaps and semi-Dirac points should be changed, which can realize the adjustability of band gaps structures. The two-dimensional function photonic crystals should provide a new method for designing optical device.

In this paper, we have proposed S U(2) non-Abelian electromagnetism gauge theory. In the theory, photon has self-interaction and interaction between them, which can explain photon entanglement phenomenon in quantum information. Otherwise, we find there are three kinds photons γ +, γ − and γ 0, they have electric charge + e γ , − e γ and 0, respectively, these prediction are accordance with some experiment results.

Background VEGFR-2 inhibitors have been widely used in the treatment of cancer. In our continued efforts to search for potent and novel VEGFR-2 inhibitors as antitumor agents, we have identified a series of ureas and amides bearing a oxazolopyrimidine scaffold. Aim of the Study To discover more potent VEGFR-2 inhibitors with stronger binding affinity and better physical and chemical properties. Methods 23 pyrimidinylacetamide-based ureas were designed and synthesized. Replacement of oxazolopyrimidine with a pyrimidinylacetamide generated a series of novel VEGFR-2 inhibitors. Results and Conclusions In HUVEC inhibition assay, the most potent compound (compound 16) possessed an IC 50 value of 0.43 μM. Compound 16 also inhibited the migration and capillary like tube formation of HUVECs with inhibition rate at 22% (1 μM) and 17.5% (0.8 μM) respectively. These results support the further investigation of compound 16 as a potential anti-cancer agent.

At present, the research of single-photon is a hot topic, it has been widely applied in quantum measurement, quantum entanglement and quantum information. In this paper, we have proposed a new single photon theory, which is the vector potential A rotation at the vertical motion direction of photon, it can produce the microscopic electric field and magnetic field, and they satisfy the Maxwell equations. We have calculated photon spin, momentum, energy, and found there are left-handed and right-handed photon. In addition, we study the multi-photon theory and the dynamics theory between photons interaction. On this basis, we have further given the compound structures of electron, proton, neutron, neutrino, π meson, dark matter with the photon structural theory, and calculated their mass, charge and spin.

Angiogenesis is crucial for tumor growth and inhibition of angiogenesis has been regarded as a promising approach for cancer therapy. Vascular endothelial growth factor receptor-2 (VEGFR-2) is an important factor in angiogenesis. In this work, a novel series of thiazolo[5,4-d]pyrimidine derivatives inhibiting angiogenesis were rationally designed and synthesized. Their inhibitory activities against human umbilical vein endothelial cells (HUVEC) were investigated in vitro. 1-(4-Fluorophenyl)-3-{4-[(5-methyl-2-phenyl[1,3]thiazolo[5,4-d]pyrimidin-7-yl)amino]phenyl}urea (19b) and 1-(3-Fluorophenyl)-3-{4-[(5-methyl-2-phenyl[1,3]thiazolo[5,4-d]pyrimidin-7-yl)amino]phenyl}urea (19g) exhibited the most potent inhibitory effect on HUVEC proliferation (IC50 =12.8 and 5.3 μm, respectively). Compound 19g could inhibit the migration of human umbilical vein endothelial cells. These results support the further investigation of these compounds as potent anticancer agents.

During insect larval-pupal metamorphosis, proteins in the hemolymph are absorbed by the fat body for the maintenance of intracellular homeostasis; however, the type of proteins and how these proteins are internalized into the fat body are unclear. In Bombyx mori, the developmental profiles of total proteins in the hemolymph and fat body showed that hemolymph-decreased protein bands (55-100 kDa) were in accordance with those protein bands that increased in the fat body. Inhibition of clathrin-dependent endocytosis predominantly blocked the transportation of 55-100 kDa proteins from the hemolymph into the fat body, which was further verified by RNA interference treatment of Bmclathrin. Six hexamerins were shown to comprise ∼90% of the total identified proteins in both the hemolymph and fat body by mass spectrum (MS) analysis. In addition, hemolymph-specific proteins were mainly involved in material transportation, while fat body-specific proteins particularly participated in metabolism. In this paper, four hexamerins were found for the first time, and potential proteins absorbed by the fat body from the hemolymph through clathrin-dependent endocytosis were identified. This study sheds light on the protein absorption mechanism during insect metamorphosis.

A series of oxazolopyrimidine-based ureas and amides were designed, synthesized, and biologically evaluated for their antiproliferative and antiangiogenic activities. These compounds were identified to exhibit inhibitory activities against human umbilical vein endothelial cells (HUVEC) in vitro. Among these compounds, compound 22 effectively inhibited the migration and capillary-like tube formation of human umbilical vein endothelial cells. It also exhibited a concentration-dependent inhibition on capillary sprouting from the rat aorta rings. Preliminary mechanistic studies revealed that compound 22 suppressed protein kinases activation, by decreasing PI3K and ERK 1/2 phosphorylation. These results support the further investigation of this class of compounds as potential anticancer agents.

Whether recent Arctic sea ice loss is responsible for recent severe winters over mid-latitude continents has emerged as a major debate among climate scientists owing to short records of observations and large internal variability in mid- and high-latitudes. In this study, the authors divide the evolution of autumn Arctic sea ice extent during 1979–2014 into three epochs, 1979–1986 (high), 1987–2006 (moderate), and 2007–2014 (low), using a regime shift identification method. The authors then compare the associations between autumn Arctic sea ice and winter climate anomalies over central and eastern Eurasia for the three epochs with a focus on extreme events. The results show robust and detectable signals of Arctic sea ice loss in weather and climate over western Siberia and East Asia. Associated with sea ice loss, the latitude (speed) of the jet stream shifts southward (reduces), the wave extent amplifies, and blocking high events increase over the Ural Mountains, leading to increased frequency of ...

Low pressure laser-induced breakdown spectroscopy was employed to measure mercury, strontium, and cesium under different conditions. Mercury was measured in detail to discuss the effects of pressure, laser pulse energy, delay time, and buffer gas. The continuum emission from plasma reduced dramatically to enhance signal to background ratio due to the change of influence of electron impact ionization process when reducing pressure and decreasing laser pulse energy to some extent. The comparison of mercuric chloride and mercury, as well as strontium and cesium measurements, demonstrates the enhancement of detection ability for trace species measurement using low pressure laser-induced breakdown spectroscopy.

Autophagy and apoptosis, which could be induced by common stimuli, play crucial roles in development and disease. The functional relationship between autophagy and apoptosis is complex, due to the dual effects of autophagy. In the Bombyx Bm-12 cells, 20-hydroxyecdysone (20E) treatment or starvation-induced cell death, with autophagy preceding apoptosis. In response to 20E or starvation, BmATG8 was rapidly cleaved and conjugated with PE to form BmATG8–PE; subsequently, BmATG5 and BmATG6 were cleaved into BmATG5-tN and BmATG6-C, respectively. Reduction of expression of BmAtg5 or BmAtg6 by RNAi decreased the proportion of cells undergoing both autophagy and apoptosis after 20E treatment or starvation. Overexpression of BmAtg5 or BmAtg6 induced autophagy but not apoptosis in the absence of the stimuli, but promoted both autophagy and apoptosis induced by 20E or starvation. Notably, overexpression of cleavage site-deleted BmAtg5 or BmAtg6 increased autophagy but not apoptosis induced by 20E or starvation, whereas overexpression of BmAtg5-tN and BmAtg6-C was able to directly trigger apoptosis or promote the induced apoptosis. In conclusion, being cleaved into BmATG5-tN and BmATG6-C, BmATG5 and BmATG6 mediate apoptosis following autophagy induced by 20E or starvation in Bombyx Bm-12 cells, reflecting that autophagy precedes apoptosis in the midgut during Bombyx metamorphosis.

Methylglyoxal (MGO)-induced carbonyl stress and pro-inflammatory responses have been suggested to contribute to endothelial dysfunction. Curcumin (Cur), a polyphenolic compound from Curcuma longa L., may protect endothelial cells against carbonyl stress-induced damage by trapping dicarbonyl compounds such as MGO. However, Cur-MGO adducts have not been studied in depth to date and it remains to be known whether Cur-MGO adducts are able to attenuate endothelial damage by trapping MGO. In the present study, 1,2-diaminobenzene was reacted with MGO to ensure the reliability of the reaction system. Cur was demonstrated to trap MGO at a 1:1 ratio to form adducts 1, 2 and 3 within 720 min. The structures of these adducts were identified by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry. The kinetic curves of Cur (10(-7), 10(-6) and 10(-5) M) were measured from 0-168 h by fluorescent intensity. Cur significantly inhibited the formation of advanced glycation end products (AGEs). The differences in oxidative damage and the levels of pro-inflammatory cytokines following MGO + HSA or Cur-MGO treatment were investigated in human umbilical vein endothelial cells (HUVECs). Exposure of HUVECs to the Cur-MGO reaction adducts significantly reduced the intracellular ROS levels and improved cell viability compared with MGO alone. Furthermore, there was a significant reduction in the expression levels of transforming growth factor-β1 and intercellular adhesion molecule(-1) following treatment with Cur-MGO adducts compared with MGO alone. These results provide further evidence that the trapping of MGO by Cur inhibits the formation of AGEs. The current study indicates that the protective effect of Cur on carbonyl stress and pro-inflammatory responses in endothelial damage occurs via the trapping of MGO.

The environmental pollution by trace heavy metals is a severe problem for the environment and human health. In this paper, the liquid jet of CsNO3 solution employed was introduced to the measurement chamber and detected using laser-induced breakdown spectroscopy (LIBS) directly at low pressure to determine the detection features of trace Cs element in liquid. The distinct and round plasma can be acquired when reducing the pressure. The interaction between the plasma core of the liquid jet and the surrounding gas can be controlled to enhance Cs detection ability. Cs emission was mainly in the surrounding area in the plasma. The influences of laser focal point and plasma measurement area on the measured signals were studied under low-pressure condition. When employing the defocus mode and varying the measurement area within a certain range, Cs signal and the signal-to-background ratio were improved. Cs detection limit can reach to 22.8 ppb (3σ/ms) at pressure of 26 kPa in this paper. According to the discussion, the detection limit will be enhanced when improving the experimental conditions using this method, which shows the great application potential of liquid sample measurement.

For over last couple of decades, there has been a robust activity aimed towards the discovery of novel anti-cancer therapeutics. An approach to identify starting points for new drug candidates is high throughput screening of compound library collection. In this work, we describe the application of a Tetrazolium-based, 96-well small scale screening assay to screen a mini library of 19 compounds bearing Oxazolo[5,4-d]pyrimidine structures against human umbilical vein endothelial cells. Primary actives identified against HUVEC were retested and the IC50 value compounds were estimated for HUVEC. The screening program (Primary screening) identified 4 compounds with inhibition rate percentage ≥ 70% each. Retest screening of these compounds, taking into account criteria required for high cytotoxic compounds, afforded a panel of 1 compound for further biological analysis. This compound had IC50 value of 12.19µM, 12.16µM, 10.24µM, 20.43µM for HUVECs, SGC7901, MCF7, and HeLa respectively. Furthermore, a clonogenic assay was performed in order to confirm the cytotoxic activity of the selected compound on the survival and proliferation of MCF7. This compound was found to significantly effect the survival and proliferation of MCF7. Taken together, the selected compound, namely SCYJ32, was found to be highly cytotoxic against the numerous cell lines. Further studies are ongoing in order to unravel various mechanisms of action of this novel small compound.

The laser breakdown time-of-flight mass spectrometry was developed and applied to detect the breakdown patterns of hydrocarbons that are significant to improve the detectability of heavy metals compounded in various mixtures such as particles and hydrocarbons. The laser wavelength dependence of this method was evaluated using 1064, 532, and 266 nm laser outputs. Breakdown processes using 1064 and 532 nm outputs showed less interference of fragmentation for the detection of various heavy metals. The method was applied to various hydrocarbons and it showed the possibility of categorization of hydrocarbon groups using the pattern of breakdown products.

Objectives Shikonin is an active naphthoquinone pigment isolated from the root of Lithospermum erythrorhizon. This study was designed to explore the inhibition of Shikonin on cell viability, adhesion, migration and invasion ability of gastric cancer (GC) and its possible mechanism. Methods 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed for cell viability and adhesion ability of MGC-803 cells. Cell scratch repair experiments were conducted for the determination of migration ability while transwell assay for cell invasion ability. Western blot analysis and real-time polymerase chain reaction assay were used for the detection of protein and mRNA expressions. Key findings Fifty per cent inhibitory concentration of Shikonin on MGC-803 cells was 1.854 μm. Shikonin (1 μm) inhibited significantly the adhesion, invasion and migratory ability of MGC-803 cells. Interestingly, Shikonin in the presence or absence of anti-Toll-like receptor 2 (TLR2) antibody (2 μg) and nuclear factor-kappa B (NF-κB) inhibitor MG-132 (10 μm) could decrease these ability of MGC-803 cells markedly, as well as the expression levels of matrix metalloproteinases (MMP)-2, MMP-7, TLR2 and p65 NF-κB. In addition, the co-incubation of Shikonin and anti-TLR2/MG-132 has a significant stronger activity than anti-TLR2 or MG-132 alone. Conclusions The results indicated that Shikonin could suppress the cell viability, adhesion, invasion and migratory ability of MGC-803 cells through TLR2- or NF-κB-mediated pathway. Our findings provide novel information for the treatment of Shikonin on GC.

In the actual production process, Zhengli Coal Mine has a problem to make sure that the width of chain pillars. This paper from the view of field application with theoretical calculation and numerical simulation method to calculate and verify the stability and security of the chain pillars, It achieved good effect and finally determined the width of chain pillars.

In the process of production of Zhengli mine 14-1103 working face, found that though the existing supporting system can satisfy the requirement of support, there will be a bulge in a few places, anchor invalidation etc. In order to guarantee safe production and high efficiency production requirements, it is necessary to optimize the working face support. In this paper, by the method of numerical simulation, compared the original support and optimized system, test the optimized supporting effect. It’s proved that lengthen the top bolt is an important measure for optimizing the support system.

It has been highly recognized that heavy metals and other trace species pollution concerns the environment, as well as human health. This paper describes the rapid detection of mercury and iodine using laser breakdown time-of-flight mass spectrometry at high sensitivity without partial fragmentation interference from other species. Two irradiation wavelengths 1064 and 532 nm were employed under various experimental conditions. The second harmonic 532 nm performs excellent measurement results. The influence of pressure on signal intensity displays a linear growth when increasing the pressure. The power dependence shows that as the laser power increased, mercury ion and iodine ion signal intensity increased first and then decreased. Experiment with different buffer gases clarified the recombination of mercury ion and iodine ion with electrons when increasing the laser power, resulting in the decrease of mercury ion and iodine ion signal intensity. Mercury ion signal intensity can be enhanced 3.8 times and t...

There is a series of features of the strata-pressure behavior of hard surrounding rock which is affected by dynamic pressure, such as the caving of the roof is difficult, sudden and large-area. In this paper we focus on the mining and support of 14-1103 working face, In view of the problems of the mine such as the roof is hard to caving, the suspension-area is huge and the safe of the working face is under a great threat, theoretical analysis and field monitoring is used in the study of the strata-pressure behavior. The study indicates that the influence of the advance on the surrounding rock stress is in the range of 100m, the scope in which the surrounding rock stress is remarkably affected is 20~30m; the stress of the surrounding rock is more affected in the scope of fault; the growing time of the roof stress is 2~3 days and is much shorter than the time of roadway’s sides which is 5~9 days.

Tweeter, which is very popular as a micro blogging services, offers numerous of information. It is necessary to find more useful information with less effort. This paper purposed a method of information processing when collecting the latest tweets by specific keywords, such as user screen name, keywords of tweets, username and location. For each query, no more than 200 latest tweets will be gathered. During the implementation of information processing, Twitter Search API [1] is adopted to collect tweets. Once those tweets are collected, they will be stored into database firstly which makes sure the database is always up to date. Tweets will be fetched from database when there is a query.

Polyimide/nano-SiO2 (PI/SiO2) composites with different contents of SiO2 were prepared by in situ polymerization. The transmittance, solubility, thermal property, flame retardant properties and mechanics properties of PI/nano-SiO2 composites were investigated. The results showed that with the increased addition of SiO2 content, the transmittance of PI/SiO2 compositions reduced; tensile strength changed with the amount of nanometer powder, when the addition content was 10 wt%, it achieve the maximum value. Thermal resistance of the composite was improved obviously while with the amount of nanometer powder increased, volume resistivity coefficient of volume resistance would have decreased.

In this paper, we have proposed the spinor wave equation of free and non-free photon, and given the quantum transfer matrix, dispersion relation, quantum transmissivity and quantum reflectivity of one-dimensional photonic crystals with the quantum theory of photon. On that basis, we have studied the effect of different incident angle, refractive index and thickness of medium on quantum and classical dispersion relation, transmissivity and reflectivity. We have found the results of quantum and classical are identical, which indicate the quantum theory approach for photonic crystals is reasonable and true, it will be studied the quantum edge state, quantum Zak phase and Chern number of the quantum topological property for photonic crystals.

In this paper, we have given the quantum transfer matrix, quantum dispersion relation, quantum transmissivity and reflectivity of one-dimensional photonic crystals with the quantum theory of photon. We have studied the quantum transmission characteristic of different structure one-dimensional photonic crystals, which include mirror and nonmirror structures, with and without defect, and the defects are active and inactive media. On that basis, we compared the dispersion relation, transmissivity and reflectivity of quantum with classical for one-dimensional photonic crystals, and found they are identical, which indicate the quantum theory approach of photonic crystals is true, it can further study the quantum topological property of photonic crystals, such as quantum Zak phase, Chern number and quantum edge state and so on.

Nitro humic acid was extracted from lignite of Guizhou Anshun, which production condition and process were studied. The results show that the optimum conditions of dry process are concentration of nitric acid of 40%, reaction temperature of 95°C, reaction time of 5 min. The optimum conditions of wet process production are concentrations of nitric acid of 20% ~ 25%, the solid-liquid ratio of 1:1.25 (weight ratio), reaction temperature of 80 ~ 85°C, and reaction time of 30 min.

Laser-induced breakdown spectroscopy (LIBS) technology is an appealing technique compared with many other types of elemental analysis because of the fast response, high sensitivity, real-time, and noncontact features. One of the challenging targets of LIBS is the enhancement of the detection limit. In this study, the detection limit of gas-phase LIBS analysis has been improved by controlling the pressure and laser pulse width. In order to verify this method, low-pressure gas plasma was induced using nanosecond and picosecond lasers. The method was applied to the detection of Hg. The emission intensity ratio of the Hg atom to NO (IHg/ INO) was analyzed to evaluate the LIBS detection limit because the NO emission (interference signal) was formed during the plasma generation and cooling process of N2 and O2 in the air. It was demonstrated that the enhancement of IHg/ INO arose by decreasing the pressure to a few kilopascals, and the IHg/ INO of the picosecond breakdown was always much higher than that of the nanosecond breakdown at low buffer gas pressure. Enhancement of IHg/ INO increased more than 10 times at 700 Pa using picosecond laser with 35 ps pulse width. The detection limit was enhanced to 0.03 ppm (parts per million). We also saw that the spectra from the center and edge parts of plasma showed different features. Comparing the central spectra with the edge spectra, IHg/ INO of the edge spectra was higher than that of the central spectra using the picosecond laser breakdown process.

In order to simulate coal combustion and develop optimal and stable boiler control systems in real power plants, it is imperative to obtain the detailed information in coal combustion processes as well as to measure species contents in fly ash, which should be controlled and analyzed for enhancing boiler efficiency and reducing environmental pollution. The fly ash consists of oxides (SiO 2 , Al 2 O 3 , Fe 2 O 3 , CaO, and so on), unburned carbon, and other minor elements. Recently laser-induced breakdown spectroscopy (LIBS) technique has been applied to coal combustion and other industrial fields because of the fast response, high sensitivity, real-time and non-contact features. In these applications it is important to measure controlling factors without any sample preparation to maintain the real-time measurement feature. The relation between particle content and particle diameter is also one of the vital researches, because compositions of particles are dependent on their diameter. In this study, we have detected the contents of size-segregated particles using LIBS. Particles were classified by an Anderson cascade impactor and their contents were measured using the output of 1064 nm YAG laser, a spectrograph and an ICCD camera. The plasma conditions such as plasma temperature are dependent on the size of particles and these effects must be corrected to obtain quantitative information. The plasma temperature was corrected by the emission intensity ratio from the same atom. Using this correction method, the contents of particles can be measured quantitatively in fixed experimental parameters. This method was applied to coal and fly ash from a coal-fired burner to measure unburned carbon and other contents according to the particle diameter. The acquired results demonstrate that the LIBS technique is applicable to measure size-segregated particle contents in real time and this method is useful for the analysis of coal combustion and its control because of its sensitive and fast analysis features.