Anti-aging performance improvement and enhanced combustion efficiency of boron via the coating of PDA

Boron is an ambitious fuel in energetic materials since its high heat release values,but its application is prohibited by low combustion efficiency and oxidization during storage.The polydopamine(PDA)was introduced into boron particles,investigating the impact of PDA content on the energetic behavior of boron.The results indicated that the PDA coating formed a fishing net structure on the surface of boron particles.The heat release results showed that the combustion calorific value of B@PDA was higher than that of the raw boron.Specifically,the actual combustion heat of boron powder in B@10%PDA increased by 38.08%.Meanwhile,the DSC peak temperature decreased by 100.65℃under similar oxidation rate compared to raw boron.Simultaneously,the B@PDA@AP and B@AP composites were prepared,and their combustion properties were evaluated.It was demonstrated that B@10%PDA@AP exhibited superior performance in terms of peak pressure and burning time,respectively.The peak pressure is 12.43 kPa more than B@AP and burning time is 2.22 times higher than B@AP.Therefore,the coating of PDA effectively inhibits the oxidization of boron during storage and enhances the energetic behavior of boron and corresponding composites.

A Blind Batch Encryption and Public Ledger-Based Protocol for Sharing Sensitive Data

For the goals of security and privacy preservation,we propose a blind batch encryption-and public ledger-based data sharing protocol that allows the integrity of sensitive data to be audited by a public ledger and allows privacy information to be preserved.Data owners can tightly manage their data with efficient revocation and only grant one-time adaptive access for the fulfillment of the requester.We prove that our protocol is semanticallly secure,blind,and secure against oblivious requesters and malicious file keepers.We also provide security analysis in the context of four typical attacks.

Creating Benchmarks in Urban Planning and Architecture

While learning from others,China can contribute new technologies,work capacity,and industrial strength to restore harmony with nature.AS an architect and designer I have had the opportunity to combine my profession with teaching in several universities such as the National Autonomous University of Mexico and the Elisava Barcelona School of Design and Engineering where I was a professor for more than 20 years.Now at Ekkoabit,an educational project on environmental awareness in Barcelona,I teach,share,and explore knowledge and experiences with students from all over the world.

Challenges and Countermeasures for Private Universities in Providing Education for International Students

Private universities are one of the forces driving the internationalization of higher education in China.Private universities are taking advantage of the trend to provide education for international students,playing an important role in the high-quality development of higher education in China.However,they also face challenges such as insufficient policy support,lack of management experience,and limited enrollment channels.Breakthroughs can be made through methods such as refining content,expanding enrollment channels,and attracting talent.

New application notion of pipeline transport——integrated in industry solid waste innocuous and efficient disposition

In order to solve transport problems of industry solid,firstly,a new applicationnotion of pipeline transport was presented,that is to say,combining pretreatment andtransport with disposal techniques of industry solid waste.Secondly,the integrated dis-posal and transport system for industry solid waste was introduced,in particular,the oper-ating principles,equipment set-up,key technology and technical parameters.Next,thispaper illustrated the application of this integrated system.Such as it can transport coalsludge with sufficiently high solids content(about 72%～77%)and high apparent viscosity(about 1 000～3 000 Pa.s)directly by pipeline having no use for water and addition agent.Generally,the transport distance is about 1 000 m.This system has been successfullyused in innocuous disposition and efficient utilization of other industrial byproducts or solidwastes,such as city sludge and paper making waste.The integrated system causes nopollution to the environment for its complete seal and realizes protecting the environment,conserving the energy,promoting the development of cycling economic.Finally,the paperdiscussed the research works that were needed for studying such pipeline transport sys-tem and narrates the relevant condition and application status.

Microstructure and fatigue crack growth behaviour of electron beam welding in 30CrMnSiNi2A steel

The effects of two post-weld heat treatment processes on the microstructure and fatigue properties of the electron beam welded joints of 30CrMnSiNi2A steel were studied. Electron beam local post-weld heat treatment (EBLPWHT), in a vacuum chamber, immediately after welding and a traditional furnace whole post-weld heat treatment (FWPWHT) were accepted. The experimental results show that, after EBLPWHT, the main microstructure of weld is changed from coarse acicular martensite into lath martensite, and base metal is changed from ferrite and perlite into upper bainite and residual austenite, however the microstructures of different zones of joints in FWPWHT conditions are tempered sorbite. The fatigue crack growth rate da/dN of welds and base metal are not obviously changed among EBLPWHT, FWPWHT test and as-welded (AW) test, as the mechanical properties of materials have a certain but not large effect on the da/dN of welded joints. The resistance to near threshold fatigue crack growth data of welded joints can be largely improved by EBLPWHT and it is related to microstructure and crack closure effect.

Coupling model for unsteady MHD flow of generalized Maxwell fluid with radiation thermal transform＊

This paper introduces a new model for the Fourier law of heat conduction with the time-fractional order to the generalized Maxwell fluid. The flow is influenced by magnetic field, radiation heat, and heat source. A fractional calculus approach is used to establish the constitutive relationship coupling model of a viscoelastic fluid. We use the Laplace transform and solve ordinary differential equations with a matrix form to obtain the velocity and temperature in the Laplace domain. To obtain solutions from the Laplace space back to the original space, the numerical inversion of the Laplace transform is used. According to the results and graphs, a new theory can be constructed. Comparisons of the associated parameters and the corresponding flow and heat transfer characteristics are presented and analyzed in detail.

Fabrication of Macro-porous β-zeolite by Using Colloidal Polystyrene Spheres as a Template

A β-zeolite/polystyrene composite material was synthesized by co-deposition of mono-disperse polystyrene spheres and nano β-zeolite particles in aqueous suspension on a vertical substrate. Macro-porous β-zeolite was obtained after the polystyrene template was removed by calcination. The micro/macro-pore structure of the prepared β-zeolite was highly ordered. In comparison with other assembly methods, the co-deposition method could obtain a highly ordered macro-porous material with relatively large zeolite filling particles, and therefore the co-deposition of particles with different size is a promising method for the fabrication of macro-porous materials.

An improved yield criterion characterizing the anisotropic and tension-compression asymmetric behavior of magnesium alloy

A novel yield criterion based on CPB06 considering anisotropic and tension-compression asymmetric behaviors of magnesium alloys was derived and proposed(called M_CPB06).This yield criterion can simultaneously predict the yield stresses and the Lankford ratios at different angles(if any)under uniaxial tension,compression,equal-biaxial and equal-compression conditions.Then,in order to further describe the anisotropic strain-hardening characteristics of magnesium alloy,the proposed M_CPB06 criterion was further evolved to the M_CPB06ev model by expressing the parameters of the M_CPB06 model as functions of the plastic strain.As the model was developed,the stresses and Lankford ratios of AZ31B and ZK61M magnesium alloys at different angles under tensile,compressive and through-thickness compressive conditions were used to calibrate the M_CPB06/M_CPB06ev and the existing CPB06ex2 model.Calibration results reveal that compared with the CPB06ex2 yield criterion with equal quantity of coefficients,the M_CPB06 criterion exhibits certain advancement,and meanwhile the M_CPB06ev model can relatively accurately predict the change of the yield locus with increase of the plastic strain.Finally,the M_CPB06ev model was developed through UMAT in LS-DYNA.Finite element simulations using the subroutine were conducted on the specimens of different angles to the rolling direction under tension and compression.Simulation results were highly consistent with the experimental results,demonstrating a good reliability and accuracy of the developed subroutine.

Numerical Simulation and Moist Potential Vorticity Analysis of Torrential Rain in Jiangxi Province during June 2010

Based on the conventional ground observational data,a numerical simulation and moist potential vorticity( MPV) analysis has been carried on heavy rainfall event over Jiangxi province from 19 June to 20 June 2010,with a meso-scale rainstorm model. The results show that this rare rainstorm is a typical heavy rainfall over Meiyu front. The cold air flow behind North China vortex joined up the southwestern flow located in the northwest part of the strong and stable subtropical high,thus the cold air and warm air converged and maintained over the northern part of Hunan and Jiangxi province. The simulated precipitation of the high resolution model is very similar to the observational rainfall. The model has a good predictive skill for the location,intensity and center of heavy rainfall. By moist potential vorticity analysis,it is found that the distribution characteristic of MPV which heavy rainfall happens ahead has an obvious indication for precipitation forecast. The vertical overlapping of the positive and negative MPV1 areas is favorable to the generation and development of rainstorm. This zone is also the conjoint area of convective instability and baroclinic instability.

Accuracy Analysis on the Automatic Registration of Multi-Source Remote Sensing Images Based on the Software of ERDAS Imagine

The automatic registration of multi-source remote sensing images (RSI) is a research hotspot of remote sensing image preprocessing currently. A special automatic image registration module named the Image Autosync has been embedded into the ERDAS IMAGINE software of version 9.0 and above. The registration accuracies of the module verified for the remote sensing images obtained from different platforms or their different spatial resolution. Four tested registration experiments are discussed in this article to analyze the accuracy differences based on the remote sensing data which have different spatial resolution. The impact factors inducing the differences of registration accuracy are also analyzed.

Correlation between aquaporin-4 and brain edema in an animal model of astrocytic oxygen-glucose deprivation and reintroduction

BACKGROUND：Previous studies have demonstrated that aquaporin-4 （AQP4） plays a key role in the formation and resolution of brain edema.However,the molecular mechanisms and role of AQP4 in hypoxia-ischemia-induced brain edema remain poorly understood.OBJECTIVE：To establish a newborn animal model of astrocytic oxygen-glucose deprivation and reintroduction,to observe the correlation between AQP4 and cellular volume,and to investigate the role of AQP4 in the development of brain edema following oxygen deprivation and reintroduction.DESIGN,TIME AND SETTING：A comparative experiment was performed at the Experimental Center of West China Second University Hospital between October 2007 and April 2009.MATERIALS：Astrocytes were derived from the neocortex of Sprague Dawley rats aged 3 days.METHODS：Astrocytes were incubated in glucose/serum-free Dulbecco＇s modified Eagle＇s medium,followed by 1% oxygen for 6 hours.Finally,oxygen-glucose deprivation and reintroduction models were successfully established.MAIN OUTCOME MEASURES：Real-time polymerase chain reaction and Western blot analysis were used to measure expression of AQP4 mRNA and protein in cultured rat astrocytes following oxygen-glucose deprivation and reintroduction.Astrocytic cellular volume,as determined by [3H]-3-O-methyl-D-glucose,was used to represent the extent of astrocytic swelling.RESULTS：During oxygen-glucose deprivation,AQP4 mRNA and protein expression gradually decreased in astrocytes,whereas cellular volume increased in a time-dependent manner （P〈 0.01）.Following oxygen-glucose reintroduction,AQP4 mRNAand protein expression was upregulated,peaked at day 7,and then gradually decreased,but still higher than normal levels （P 〈 0.05）.However,cellular volume gradually decreased （P 〈 0.01）,and then reached normal levels at day 7.CONCLUSION：AQP4 expression highly correlated with cellular volume changes,suggesting that AQP4 played an important role in modulating brain water transport in an astrocytic oxygen-glucose deprivation and reintroduction model.

Synthesis and Characterization of Star-branched Polyisobutylene by Combination of Anionic Polymerization and Cationic Polymerization

A star-shaped multifunctional styrene-isoprene copolymer was synthesized with n-BuLi as initiator, divinyl benzene as coupling agent, cyclobexane as solvent by living anionic polymerization. Using this polymer as grafting agent, a novel star-shaped branched polymer, containing several polyisobutylene, was prepared via cationic ~aolymerization. The star PS-b-PI and star-branched polyisobutylene were characterized by GPC, ＇HNMR and FT-IR, and the effects of different adding order and the amount of grafting agent were investigated.

Finite element analysis on electron beam brazing temperature and stresses of stainless steel radiator

Based on thermal-elasto-plastic finite element theory, a two-dimensional finite element model for calculating electron beam brazing temperature and residual stress fields of stainless steel radiator are presented. The distributions of temperature and residual stress are studied. The resuhs showed that temperature distribution on brazing surface is rather uniform, ranging from 1 026 ℃ to 1 090 ℃. The residual stresses are varied from initial compressive to tensile , and the variation of residual stress is very little in total zone of brazing surface.

Biological characteristics of brain natriuretic peptide and its association with central nervous system diseases

OBJECTIVE： To explain the mechanisms of tuhe synthesis, secretion and regulation of brain natriuretic peptide （BNP）, and analyze its role in central nervous system diseases. DATA SOURCES： An online search of Pubmed was undertaken to identify articles related to BNP published in English from January 1990 to February 2007 by using the key words of ＂brain natriuretic pepfide （BNP）, central nervous system, subarachnoid hemorrhage （SAH）, brain edema, epilepsy＂. Other articles were searched in China Hospital Knowledge Database （CHKD） by concrete name of journals and title of articles. STUDY SELECTION： The collected articles were primarily screened, those about BNP and its association with central nervous system diseases were selected, whereas the obviously irrelative ones excluded, and the full-texts of the other literatures were searched manually. DATA EXTRACTION： Totally 96 articles were collected, 40 of them were enrolled, and the other 56 were excluded due to repetitive studies or reviews. DATA SYNTHESIS： At present, there are penetrating studies on BNP in the preclinical medicine and clinical medicine of cerebrovascular and cardiovascular diseases, and the investigative outcomes have been gradually applied in clinical practice, and satisfactory results have been obtained. However, the application of BNP in diagnosing and treating central nervous system diseases is still at the experimental phase without - outstanding outcomes, thus the preclinical and clinical studies should be enhanced. CONCLUSION： As a kind of central medium or modulator, BNP plays a certain role in the occurrence, development and termination of central nervous system diseases, the BNP level in serum has certain changing law in SAH, brain edema, epilepsy, etc., but the specific mechanisms are unclear.

Novel Design Method of COG Measurement System Via Supporting Reaction Method

Center of gravity(COG)is an important parameter of projectiles and rockets,for which supporting reaction method(or support reaction method)is an important COG measurement method.Based on this supporting reaction method a novel design method is proposed to determine the key design parameters of the COG measurement system.The method can quantitatively analyze the influence of the design parameters on the COG accuracy,in the measurement system designed with supporting reaction method.Using the principle of static balance,the error propagation theory,and the system accuracy analysis method,the equal-range required sensor precision(RSP)surface and non-equal-range required sensor pair precision(RSPP)adapted surface are adopted.The influence of random errors(like sensor accuracy and distance calibration accuracy)is analyzed.The selection strategy of equal-range and non-equal-range sensors is chosen,and then the recommended calibration accuracy values are obtained.For the quality detection accuracy of±0.6 kg and the axial COG detection accuracy of±1.5 mm,the RSP surface is drawn by the proposed method,and the force sensor with±0.23 kg detection accuracy is selected.The experimental verification meets the accuracy requirements and verifies the effectiveness of the proposed design method for the system parameters of the COG measurement equipment.

The Ascent of Chinese Charity

CHINESE charities are playing ever-greater roles in earthquake relief, poverty alleviation,education,disability aid and other causes.But where does philanthropy stand in Chinese society today? And how do non-governmental organizations deal with the government?

Analysis of the Effectiveness of Thermosiphon, Awning and Insulations Board on Permafrost Roadbed

In this paper, the effect of the thermosiphon, insulation board and awning in cooling the permafrost roadbed base was simulated numerically. The computed results were analysed and compared, some practical conclusion were presented.

Multi-Panel Extra-Large Scale MIMO Based Joint Activity Detection and Channel Estimation for Near-Field Massive IoT Access

The extra-large scale multiple-input multiple-output(XL-MIMO)for the beyond fifth/sixth generation mobile communications is a promising technology to provide Tbps data transmission and stable access service.However,the extremely large antenna array aperture arouses the channel near-field effect,resulting in the deteriorated data rate and other challenges in the practice communication systems.Meanwhile,multi-panel MIMO technology has attracted extensive attention due to its flexible configuration,low hardware cost,and wider coverage.By combining the XL-MIMO and multi-panel array structure,we construct multi-panel XL-MIMO and apply it to massive Internet of Things(IoT)access.First,we model the multi-panel XL-MIMO-based near-field channels for massive IoT access scenarios,where the electromagnetic waves corresponding to different panels have different angles of arrival/departure(AoAs/AoDs).Then,by exploiting the sparsity of the near-field massive IoT access channels,we formulate a compressed sensing based joint active user detection(AUD)and channel estimation(CE)problem which is solved by AMP-EM-MMV algorithm.The simulation results exhibit the superiority of the AMP-EM-MMV based joint AUD and CE scheme over the baseline algorithms.