Effect of matrix thermal properties on laser-induced plasma

The matrix thermal properties have an important impact on laser-induced plasma,as the thermal effect dominates the interaction between ns-pulsed laser and matter,especially in metals.We used a series of pure metals and aluminum alloys to measure plasma temperature and electron density through laser-induced breakdown spectroscopy,in order to investigate the effect of matrix thermal properties on laser-induced plasma.In pure metals,a significant negative linear correlation was observed between the matrix thermal storage coefficient and plasma temperature,while a weak correlation was observed with electron density.The results indicate that metals with low thermal conductivity or specific heat capacity require less laser energy for thermal diffusion or melting and evaporation,resulting in higher ablation rates and higher plasma temperatures.However,considering ionization energy,thermal effects may be a secondary factor affecting electron density.The experiment of aluminum alloy further confirms the influence of thermal conductivity on plasma temperature and its mechanism explanation.

Rapid hydrate formation and efficient gas separation based on aqueous solid carrier

The long hydrate induction time and limited gas-liquid contact area leads to slow hydrate formation rate and low water-hydrate conversion rate.Porous media are often used to promote hydrate formation because of their large specific surface area.Consequently,we used 3A molecular sieve as a water-carrying solid in this work,and investigated the dynamic renewal of the gas-liquid interface and its effect on hydrate formation.The formation kinetics of ethane hydrate was first measured in an aqueous molecular sieve system.Then the separation of(H_(2)+CH_(4)+C_(2)H_(6)+C_(3)H_(8))gas mixture was conducted via hydrate formation.The results show that the formation rate and gas storage capacity of ethane hydrate can be greatly improved by using aqueous molecular sieve.Compared with a pure water system under the same temperature and pressure,aqueous molecular sieve has obvious advantages in separation effect and energy consumption for separating gas mixtures.

Trusted Blockchain Oracle Scheme Based on Aggregate Signature

With the development of blockchain technology, more and more applications need out-of-chain data. Thus, blockchain oracles have become an important bridge for transferring data on and off the chain. This paper studies the mainstream blockchain oracles scheme, summarizes the shortcomings of the existing schemes and proposes a new blockchain oracle scheme based on BLS (Bohen-Lynn-Shacham) aggregation signature to ensure that off-chain data can be transferred into the blockchain in a trusted and reliable way. Specifically, the scheme uses multiple blockchain oracles to avoid the single point of failure or even a small number of malicious oracles, and improve the credibility of data. At the same time, it not only uses BLS aggregate signature to reduce the storage cost and communication overhead, but also uses commitment mechanisms to ensure the reliability and authenticity of the data. Besides, the simulation results show that the scheme can meet the practical application requirements.

反应挤出原位阴离子聚合尼龙6/石墨烯复合微球的连续制备与表征

以己内酰胺(CL)、苯乙烯(St)及氧化石墨烯(GO)为主要原料,首先在熔融的CL中经自由基聚合得到聚苯乙烯(PS)/CL/GO混合熔体,然后在双螺杆挤出机中引发CL阴离子聚合生成尼龙6(PA6),获得PS为连续相、GO选择性分布于球状PA6分散相的PA6/PS/GO三元混合物,最后去除PS相制备PA6/GO复合微球。采用扫描电镜、透射电镜、热失重及差示扫描量热等方法,研究了GO在三元混合物中的选择分布、PA6/GO复合微球的结构及耐热性。结果表明,在三元混合物中GO选择性分布于PA6相中;随着GO含量增加,PA6/GO复合微球的直径减小;与纯PA6微球相比,PA6/GO复合微球具有更高的热稳定性。

Review of the characteristics and graded utilisation of coal gasification slag

The characteristics of the energy structure of rich coal,less oil and less gas,coupling with a high external dependence on oil and natural gas and the emphasis on the efficient and clean utilisation of coal,have brought opportunities for coal chemical industry.However,with the large-scale popularisation of coal gasification technology,the production and resulting storage of coal gasification slag continue to increase,which not only result in serious environmental pollution and a waste of terrestrial resources,but also seriously affect the sustainable development of coal chemical enterprises.Hence,the treatment of coal gasification slag is extremely important.In this paper,the production,composition,morphology,particle size structure and water holding characteristics of coal gasification slag are introduced,and the methods of carbon ash separation of gasification slag,both domestically and abroad,are summarised.In addition,the paper also summarises the research progress on gasification slag in building materials,ecological restoration,residual carbon utilisation and other high-value utilisation,and ultimately puts forward the idea of the comprehensive utilisation of gasification slag.For large-scale consumption to solve the environmental problems of enterprises and achieve high-value utilisation to increase the economic benefits of enterprises,it is urgent to zealously design a reasonable and comprehensive utilisation technologies with simple operational processes,strong adaptability and economic benefits.

Abrupt Summer Warming and Changes in Temperature Extremes over Northeast Asia Since the Mid-1990s: Drivers and Physical Processes

This study investigated the drivers and physical processes for the abrupt decadal summer surface warming and increases in hot temperature extremes that occurred over Northeast Asia in the mid-1990s. Observations indicate an abrupt increase in summer mean surface air temperature （SAT） over Northeast Asia since the mid-1990s. Accompanying this abrupt surface wanning, significant changes in some temperature extremes, characterized by increases in summer mean daily maximum temperature （Tmax）, daily minimum temperature （Train）, annual hottest day temperature （TXx）, and annual warmest night temperature （TNx） were observed. There were also increases in the frequency of summer days （SU） and tropical nights （TR）. Atmospheric general circulation model experiments forced by changes in sea surface temperature （SST）/sea ice extent （SIE）, anthropogenic greenhouse gas （GHG） concentrations, and anthropogenic aerosol （AA） forcing, relative to the period 1964- 93, reproduced the general patterns of observed summer mean SAT changes and associated changes in temperature extremes, although the abrupt decrease in precipitation since the mid-1990s was not simulated. Additional model experiments with different forcings indicated that changes in SST/SIE explained 76% of the area-averaged summer mean surface warming signal over Northeast Asia, while the direct impact of changes in GHG and AA explained the remaining 24% of the surface warming signal. Analysis of physical processes indicated that the direct impact of the changes in AA （through aerosol- radiation and aerosol-cloud interactions）, mainly related to the reduction of AA precursor emissions over Europe, played a dominant role in the increase in TXx and a similarly important role as SST/SIE changes in the increase in the frequency of SU over Northeast Asia via AA-induced coupled atmosphere-land surface and cloud feedbacks, rather than through a direct impact of AA changes on cloud condensation nuclei. The modelling results also imply that the abrupt summer surface warming and increases in hot temperature extremes over Northeast Asia since the mid-1990s will probably sustain in the next few decades as GHG concentrations continue to increase and AA precursor emissions over both North America and Europe continue to decrease.

聚丙烯胺盐酸盐/蒙脱土层层自组装涂层对苯二甲酸乙二醇酯阻隔性能的影响

本文采用层层自组装的方法在对苯二甲酸乙二醇酯(PET)薄膜表面制备聚丙烯胺盐酸盐(PAH)/蒙脱土(MMT)复合涂层,并探究PAH溶液的pH值对涂层厚度的影响。结果表明,PAH/MMT涂层厚度随PAH溶液pH值的升高而升高,且在PET表面线性增长。在PAH溶液pH=9时,PAH/MMT每一个双层的厚度约为6.3nm。湿度为0%时,25个PAH/MMT涂层可使PET膜的氧气透过率从纯PET膜的4.13 cm^3/m^2·atm·day降至0.14 cm^3/m^2·atm·day;湿度为100%时,水蒸汽透过率从纯PET膜的6.62 g/m^2·24h降低至4.11 g/m^2·24 h。热重分析表明,表面改性的PET膜的热稳定性比纯PET有所提升,残炭量从14.2%提高至19.1%。

The Hong Kong–Zhuhai–Macao Bridge

The Hong Kong–Zhuhai–Macao Bridge (HZMB) is located at the Pearl River Estuary on the southeast coast of China;it is the longest as-build marine crossings made of island, tunnel, and bridge. It links Hong Kong in the east with Zhuhai–Macao in the west with a total length of 55 km. The link was built according to the highway standard of six lanes with three lanes going each way;it has a design speed of 100 km·h^-1 and a design life of 120 years. The HZMB has improved traffic conditions on the east and west sides of the coast of the Pearl River Estuary and strengthened the communication, transportation, and economic integration of the three regions, thus accelerating the formation of the Guangdong–Hong Kong–Macao Greater Bay Area. This paper introduces the design and construction of the HZMB, with a focus on the new technologies involved in building the artificial islands and immersed tunnel.

Marginal optimization method to improve the inconsistent comparison matrix in the analytic hierarchy process

To improve the inconsistency in the analytic hierarchy process(AHP), a new method based on marginal optimization theory is proposed. During the improving process, this paper regards the reduction of consistency ratio(CR) as benefit, and the maximum modification compared to the original pairwise comparison matrix(PCM) as cost, then the improvement of consistency is transformed to a benefit/cost analysis problem. According to the maximal marginal effect principle, the elements of PCM are modified by a fixed increment(or decrement) step by step till the consistency ratio becomes acceptable, which can ensure minimum adjustment to the original PCM so that the decision makers’ judgment is preserved as much as possible. The correctness of the proposed method is proved mathematically by theorem. Firstly, the marginal benefit/cost ratio is calculated for each single element of the PCM when it has been modified by a fixed increment(or decrement).Then, modification to the element with the maximum marginal benefit/cost ratio is accepted. Next, the marginal benefit/cost ratio is calculated again upon the revised matrix, and followed by choosing the modification to the element with the maximum marginal benefit/cost ratio. The process of calculating marginal effect and choosing the best modified element is repeated for each revised matrix till acceptable consistency is reached, i.e., CR<0.1. Finally,illustrative examples show the proposed method is more effective and better in preserving the original comparison information than existing methods.

Role of Microphysical Parameterizations with Droplet Relative Dispersion in IAP AGCM 4.1

Previous studies have shown that accurate descriptions of the cloud droplet effective radius （Re） and the autoconversion process of cloud droplets to raindrops （At） can effectively improve simulated clouds and surface precipitation, and reduce the uncertainty of aerosol indirect effects in GCMs. In this paper, we implement cloud microphysical schemes including two-moment Ar and Re considering relative dispersion of the cloud droplet size distribution into version 4.1 of the Institute of Atmospheric Physics＇s atmospheric GCM （IAP AGCM 4.1）, which is the atmospheric component of the Chinese Academy of Sciences＇ Earth System Model. Analysis of the effects of different schemes shows that the newly implemented schemes can improve both the simulated shortwave and longwave cloud radiative forcings, as compared to the standard scheme, in lAP AGCM 4.1. The new schemes also effectively enhance the large-scale precipitation, especially over low latitudes, although the influences of total precipitation are insignificant for different schemes. Further studies show that similar results can be found with the Community Atmosphere Model, version 5.1.

Overexpression of Sirt6 ameliorates sleep deprivation induced-cognitive impairment by modulating glutamatergic neuron function

Sleep benefits the restoration of energy metabolism and thereby suppo rts neuronal plasticity and cognitive behaviors.Sirt6 is a NAD+-dependent protein deacetylase that has been recognized as an essential regulator of energy metabolism because it modulates various transcriptional regulators and metabolic enzymes.The aim of this study was to investigate the influence of Sirt6 on cerebral function after chronic sleep deprivation(CSD).We assigned C57BL/6J mice to control or two CSD groups and subjected them to AAV2/9-CMV-EGFP or AAV2/9-CMV-Sirt6-EGFP infection in the prelimbic cortex(PrL).We then assessed cerebral functional connectivity(FC) using resting-state functional MRI,neuron/astrocyte metabolism using a metabolic kinetics analysis;dendritic spine densities using sparse-labeling;and miniature excitato ry postsynaptic currents(mEPSCs) and action potential(AP) firing rates using whole-cell patchclamp recordings.In addition,we evaluated cognition via a comprehensive set of behavioral tests.Compared with controls,Sirt6 was significantly decreased(P<0.05) in the PrL after CSD,accompanied by cognitive deficits and decreased FC between the PrL and accumbens nucleus,piriform cortex,motor co rtex,somatosensory co rtex,olfactory tubercle,insular cortex,and cerebellum.Sirt6 ove rexpression reve rsed CSD-induced cognitive impairment and reduced FC.Our analysis of metabolic kinetics using [1-13C] glucose and [2-13C] acetate showed that CSD reduced neuronal Glu4and GABA2synthesis,which could be fully restored via forced Sirt6 expression.Furthermore,Sirt6 ove rexpression reversed CSD-induced decreases in AP firing rates as well as the frequency and amplitude of mEPSCs in PrL pyramidal neurons.These data indicate that Sirt6 can improve cognitive impairment after CSD by regulating the PrL-associated FC network,neuronal glucose metabolism,and glutamatergic neurotransmission.Thus,Sirt6 activation may have potential as a novel strategy for treating sleep disorder-related diseases.

Robust Artificial Noise-Aided Beamforming for A Secure MISO-NOMA Visible Light Communication System

Visible light communication(VLC)and non-orthogonal multiple access(NOMA)have been deemed two promising techniques in the next wireless communication networks.In this paper,secure communications in the presence of potential eavesdropper are investigated for a multiple-input single-output VLC system with NOMA.The artificial noise jamming and beamforming technologies are applied to improve secure performance.A robust resource allocation scheme is proposed to minimize the total transmit power taking into account the constraints on the quality of service requirement of the desired users and the maximum tolerable data rate of the eavesdropper,and the practical imperfect channel state information of both the desired users and the eavesdropper.The formulated non-convex optimization problem is tackled based onS-Procedure and semi-definite programming relaxation.Simulation results illustrate that our proposed resource allocation scheme can effectively guarantee communication security and achieve transmit power saving.Moreover,the height and number of LED can significantly affect system performance and the optimum LED height can be obtained for different LED numbers.

Constraints on granite-related uranium mineralization in the Sanjiu uranium ore field,SE China provided by pyrite mineralogy,major and trace elements,S-He-Ar isotopes

The Sanjiu uranium ore field,located in the central of Zhuguangshan granitic batholith,is a newly discovered granite-related uranium ore field in South China.The main sulfide in the ore field is pyrite,which is closely related to uranium mineralization.The textures major and trace elements,S-He-Ar isotopes compositions of pyrites in ores of different grade were observed and/or analyzed by optical microscope,scanning electron microscope,electron microprobe,laser ablation inductively coupled plasma mass spectrometry,and noble gas mass spectrometer(Helix-SFT).It is observed that these U-related pyrites are generally euhedral-subhedral with dissolution textures,anhedral variety with colloform texture veinlet and fine particles,and the color of the associated minerals is mostly dark hue,such as purple-black fluorite dark-red hematite,and dark-green chlorite,etc.The analytical results show that the average compositions of major elements in pyrite are FeS1.944.Pyrites are characterized by S-deficiency,low content of Co and Th,and Co/Ni>1which indicate that these ores are of low-temperature hydrothermal origin.We found that the higher the grade of ore,the more deficient in S,the more obvious negative δ^34S,and the higher REE content(close to U-rich granitic pluton)of pyrite.The S-He-Ar isotopic compositions of various varieties of pyrites indicate that the ore-forming fluids mainly come from crust-derived fluids and mixed with mantle-derived fluids.

Data-driven Product Functional Confguration:Patent Data and Hypergraph

The product functional confguration(PFC)is typically used by frms to satisfy the individual requirements of customers and is realized based on market analysis.This study aims to help frms analyze functions and realize functional confgurations using patent data.This study frst proposes a patent-data-driven PFC method based on a hypergraph network.It then constructs a weighted network model to optimize the combination of product function quantity and object from the perspective of big data,as follows:(1)The functional knowledge contained in the patent is extracted.(2)The functional hypergraph is constructed based on the co-occurrence relationship between patents and applicants.(3)The function and patent weight are calculated from the patent applicant’s perspective and patent value.(4)A weight calculation model of the PFC is developed.(5)The weighted frequent subgraph algorithm is used to obtain the optimal function combination list.This method is applied to an innovative design process of a bathroom shower.The results indicate that this method can help frms detach optimal function candidates and develop a multifunctional product.

Resource Allocation and Trajectories Design for UAV-Assisted Jamming Cognitive UAV Networks

Unmanned aerial vehicle(UAV)communications are subject to the severe spectrum scarcity problem.Cognitive UAV networks are promising to tackle this issue while the confidential information is susceptible to be eavesdropped.A UAV jamming assisted scheme is proposed.A joint resource allocation and trajectories optimization problem is formulated in a UAV-assisted jamming cognitive UAV network subject to diverse power and trajectory constraints.An alternative optimization algorithm is proposed to solve the challenging non-convex joint optimization problem.Extensive simulation results demonstrate the superiority of our proposed scheme and many meaningful insights are obtained for the practical design of cognitive UAV networks.

3D hierarchical architecture collaborating with 2D/2D interface interaction in Ni Al-LDH/Ti_(3)C_(2) nanocomposite for efficient and selective photoconversion of CO_(2)

Photocatalytic conversion of CO_(2)into a special chemical fuel with high yield and selectivity is still a major challenge.Herein,a 3 D hierarchical Ni Al-LDH/Ti_(3)C_(2)MXene(LDH/TC)nanocomposite is constructed through in situ loading of Ti_(3)C_(2)nanosheets on the Ni Al-LDH scaffold during the hydrothermal process.The formation of a uniform and well-defined 2 D/2 D heterogeneous interface can be realized by optimizing the ratio of Ti_(3)C_(2)and the precursors for Ni Al-LDH.The 3 D hierarchical scaffold with high specific surface area contributes to the favourable photon adsorption and utilization.The intimate contact between Ti_(3)C_(2)and Ni Al-LDH with numerous interfaces effectively promotes the separation of the photoinduced electron-hole pairs in Ni Al-LDH.Together with the highly exposed oxidation-reduction active sites and the enhanced CO_(2)capture and activation.The maximum photocatalytic CO production rate on Ni AlLDH/Ti_(3)C_(2)reaches 11.82 lmol g^(-1)h^(-1)with 92%selectivity and superior stability.This work provides an effective approach for the development of an ideal photocatalyst by collaborative utilization of materials with different dimensionalities.

Pathology of spleen in chickens fed on a diet deficient in methionine

The purpose of this 42-day study was to investigate the effects of methionine deficiency on spleen by determining the relative weight, morphological changes of spleen, cell cycle and apoptosis of splenocytes, and oxidative markers of serum and spleen. One hundred and twenty one-day-old avian broilers were randomly divided into two groups and fed on a control diet (starter diet, methionine 0.50%;grower diet, methionine 0.40%) and methionine deficient diet (starter diet, methionine 0.26%;grower diet, methionine 0.28%) for 6 weeks. The relative weight of spleen was lighter in methionine deficiency than control group. Histopathologically, lymphopenia and congestion were observed. Ultrastructurally, there were more apoptosis lymphocytes in spleen and the mitochondria of lymphocytes were swelled in methionine deficiency. By flow cytometry, the G0/G1 phase of the cell cycle of the spleen was much higher (P < 0.01), and the S, G2+M phases and proliferating index were lower (P < 0.01) in methionine deficiency than in control group. And the percentage of apoptotic cells in the spleen was significantly increased in methionine deficiency (P < 0.01).The superoxide dismutase and glutathione peroxidase activities, and abilities to inhibit hydroxyl radicals were greatly decreased while the malondialdehyde contents were markedly increased in methionine deficiency. It was concluded that methionine deficiency could restraine the development of the spleen by cell cycle arrest and increased apoptosis, cause splenic lesions and reduce splenic antioxidant function. The splenic function should be finally impaired and then the immune function could be impacted in chickens.

SMK-means:An Improved Mini Batch K-means Algorithm Based on Mapreduce with Big Data

In recent years,the rapid development of big data technology has also been favored by more and more scholars.Massive data storage and calculation problems have also been solved.At the same time,outlier detection problems in mass data have also come along with it.Therefore,more research work has been devoted to the problem of outlier detection in big data.However,the existing available methods have high computation time,the improved algorithm of outlier detection is presented,which has higher performance to detect outlier.In this paper,an improved algorithm is proposed.The SMK-means is a fusion algorithm which is achieved by Mini Batch K-means based on simulated annealing algorithm for anomalous detection of massive household electricity data,which can give the number of clusters and reduce the number of iterations and improve the accuracy of clustering.In this paper,several experiments are performed to compare and analyze multiple performances of the algorithm.Through analysis,we know that the proposed algorithm is superior to the existing algorithms.

CLM3-simulated soil moisture in East Asia and its possible response to global warming during 1979 through 2003

Hydrological processes related to soil moisture play an important role in determining regional and global climate. In this study, using a state-of-art Community Land Model (CLM) developed by the National Center for Atmospheric Research (NCAR), we simulated soil moisture in East Asia and its possible response to global warming through a long off-line experiment under 0.5° (longitude) × 0.5° (latitude) resolution and real atmospheric forcing of the National Center for Environmental Protection/ Department of Energy (NCEP/DOE) reanalysis during 1979 through 2003. The 25-year simulation is examined and compared with limited observations. The results can be summarized as follows: (1) Soil moisture takes time in response to the atmospheric forcing. The equilibration time depends on the depth of the soil and is as much as 20 years in deep layers (>1.5 m); (2) In comparison with observations, the CLM reasonably reproduces the seasonal and inter-annual variability, spatial structure, and vertical pattern of soil moisture in East Asia; (3) The soil tends to be drier in the past 25 years in northeastern Asia—including northern China north of 30°N—while wetter in the southern China and the Tibetan Plateau, especially in summer. Our analysis shows that the regional drying is attributed to increase of the land-surface evaporation induced by global warming.

CEMA-LSTM:Enhancing Contextual Feature Correlation for Radar Extrapolation Using Fine-Grained Echo Datasets

Accurate precipitation nowcasting can provide great convenience to the public so they can conduct corresponding arrangements in advance to deal with the possible impact of upcoming heavy rain.Recent relevant research activities have shown their concerns on various deep learning models for radar echo extrapolation,where radar echo maps were used to predict their consequent moment,so as to recognize potential severe convective weather events.However,these approaches suffer from an inaccurate prediction of echo dynamics and unreliable depiction of echo aggregation or dissipation,due to the size limitation of convolution filter,lack of global feature,and less attention to features from previous states.To address the problems,this paper proposes a CEMA-LSTM recurrent unit,which is embedded with a Contextual Feature Correlation Enhancement Block(CEB)and a Multi-Attention Mechanism Block(MAB).The CEB enhances contextual feature correlation and supports its model to memorize significant features for near-future prediction;the MAB uses a position and channel attention mechanism to capture global features of radar echoes.Two practical radar echo datasets were used involving the FREM and CIKM 2017 datasets.Both quantification and visualization of comparative experimental results have demonstrated outperformance of the proposed CEMA-LSTMover recentmodels,e.g.,PhyDNet,MIM and PredRNN++,etc.In particular,compared with the second-rankedmodel,its average POD,FAR and CSI have been improved by 3.87%,1.65%and 1.79%,respectively on the FREM,and by 1.42%,5.60%and 3.16%,respectively on the CIKM 2017.