Multi-layer phenomena in petawatt laser-driven acceleration of heavy ions

Laser-accelerated high-flux-intensity heavy-ion beams are important for new types of accelerators.A particle-in-cell program(Smilei) is employed to simulate the entire process of Station of Extreme Light(SEL) 100 PW laser-accelerated heavy particles using different nanoscale short targets with a thickness of 100 nm Cr, Fe, Ag, Ta, Au, Pb, Th and U, as well as 200 nm thick Al and Ca. An obvious stratification is observed in the simulation. The layering phenomenon is a hybrid acceleration mechanism reflecting target normal sheath acceleration and radiation pressure acceleration, and this phenomenon is understood from the simulated energy spectrum,ionization and spatial electric field distribution. According to the stratification, it is suggested that high-quality heavy-ion beams could be expected for fusion reactions to synthesize superheavy nuclei. Two plasma clusters in the stratification are observed simultaneously, which suggest new techniques for plasma experiments as well as thinner metal targets in the precision machining process.

Study on Ecological Carrying Capacity of Land in Henan Province

In order to explore the technical methods to improve the ecological carrying capacity of regional land under the premise of limited land use area,an open ecological footprint model is established based on the traditional ecological footprint model.Using the two models,this paper evaluates the ecological carrying capacity of Henan Province in 2017.The results indicate that the ecological productive footprint of cultivated land in Henan Province is much larger than the ecological carrying capacity,but the ecological consumption footprint is lower than the ecological carrying capacity.The open ecological footprint model can clearly distinguish the internal and the external ecological consumption footprint after corrected by the consumption adjustment coefficient and the land-use structure adjustment coefficient.Based on the open ecological footprint model,the ecological carrying capacity evaluation results of Henan Province are more realistic.The comprehensive ecological carrying capacity in Henan Province has a surplus,but there are significant differences among different land use types.The cultivated land has the largest ecological carrying capacity surplus,while the fossil energy land has a larger ecological carrying capacity deficit.In the process of achieving sustainable development,Henan Province should focus on reducing energy consumption and improving the ecological carrying capacity of fossil energy land.The paper concludes that the open ecological footprint model can simulate the ecological carrying capacity under different land use structures and different consumption structures.According to the simulation results,the technical methods to improve the ecological carrying capacity under the premise of limited land use scale can be proposed.The research can provide reference for land use structure adjustment,land use planning and land protection in Henan Province.It can also provide scientific basis for ecological protection and high-quality development of the Yellow River basin.

Fabrication and gas sensing property of honeycomb-like ZnO

We report the structural characterization and proposed formation mechanism of honeycomb-like ZnO conglomerations fabricated by direct precipitation method. X-ray diffraction （XRD）, energy-disperse X-ray spectrometry （EDS）, scanning electron microscopy （SEM） showed that the as-prepared ZnO calcined at 700 ℃ were micron sphere particles with honeycomb-like structure. In the UV-vis absorbing spectrum, it was observed that there is a new additional absorption band at 260 nm, and it was speculated that the absorption may be caused by defects on the surface and interface of honeycomb-like ZnO. The as-products showed high sensitivity and short response time to sulfured hydrogen gas. These results demonstrate that honeycomb-like ZnO conglomerations are very promising materials for fabricating H2S gas sensors.

Radiation pre-vulcanization effect on properties of the truck tyre's transition layer and the truck tyre

In this paper,the natural rubber is chosen as the main constituents for the transition layer of all-steel load radial tyre,which is pre-vulcanized by 500-keV E-beam irradiation of up to 60 kGy.The results show that the green strength of transitional layer increases with the dose,reaching four times as much as the control(without irradiation) at 60 kGy.The final mechanical properties do not differ significantly from those of the control except that the aging and fatigue performance increased.However,thickness of the natural rubber transitional layer for an average single tyre can be reduced by 1 mm(or 1.5 kg) without obvious adverse effect on tyre performance.

Synthesis and Characterization of Y-Doped SnO_2 as Sensor Materials

Yttrium-doped SnO2 powders were successfully synthesized by solution co-precipitation method and characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The sensitivity of sensors based on Y-doped SnO2 and SnO2 nanocrystals were investigated comparatively. The results indicated that Y-doped SnO2 was with the result of enhancement of sensitivity and selectivity to ethanol and reduction of sensitivity to other gas components. The enhancements of selectivity and sensitivity could be contributed to for two reasons. The first is that rare metal yttrium has a high alkalescence and good catalysis, and the second is that the nanosized crystallite and large specific surface area of Y-doped SnO2 is advantageous for gas-diffusion control as well as an increase in active sites for gas detection.

Structural and Electrochemical Properties of Ceria-Doped SnO_2 Prepared by Sol-Gel Method

Tin dioxide (SnO2) and Ce-doped SnO2 were successfully synthesized by sol-gel method and electrochemical properties were studied in cell with Li as counter electrode. The samples were characterized by X-ray diffraction (XRD) and Transmission electron microscopy (TEM). XRD patterns presented that a second phase (CeO) was observed when the Ce content reached 5%. TEM micrograph indicated that Ce-doped SnO2 had a small particle with mean size of 30 nm. The electrochemical properties were also characterized at room temperature, and the results demonstrated that the Ce-doped SnO2 samples exhibited promising electrochemical properties and Ce doped in as-prepared samples plays an important role.

Synthesis of Some Novel 2,3-diaryl-Butadiene Analogues

In present paper, the 2,3-diaryl-butadiene analogues were synthesized as anti-cancer agents. The structures were confirmed by (HNMR)-H-1 and elemental analysis.

Synthesis and Anti-SIV Activity in vitro of Novel 4,4'-Dimethoxy-5,6,5',6'- dimethenedioxy-2-alkyloxycarbonyl Biphenyl Derivatives

4,4'-Dimethoxy-5,6,5',6'-dimethenedioxy-2,2'-dimethoxycarbonyl biphenyl (DDB, 1) and its derivatives show anti-HBV and anti-HIV activities.[1] However, their poor solubility was not in favor of bioavailability.[2,3] In addition,other anti-HIV agents[4] with piperazine moiety have been investigated. Their saturated nitrogen-containing heterocyclic groups play the role of pharmaco-effectivity.[5] It was assumed that the combination of DDB with substituted benzyl piperazines would produce some new compounds with activity against anti-HIV. Therefore, we designed and synthesized a class of novel 4,4'-dimethoxy-5,6,5',6'-dimethenedioxy biphenyls modified by substituted piperazines, and partly evaluated their anti-SIV activity.……

SPAGINS:semiempirical parameterization for fragments in gamma-induced nuclear spallation

From the empirical phenomena of fragment distributions in nuclear spallation reactions,semiempirical formulas named SPAGINS were constructed to predict fragment cross-sections in high-energyγ-induced nuclear spallation reactions(PNSR).In constructing the SPAGINS formulas,theoretical models,including the TALYS toolkit,SPACS,and Rudstam formulas,were employed to study the general phenomenon of fragment distributions in PNSR with incident energies ranging from 100 to 1000 MeV.Considering the primary characteristics of PNSR,the SPAGINS formulas modify the EPAX and SPACS formulas and efficiently reproduce the measured data.The SPAGINS formulas provide a new and effective tool for predicting fragment production in PNSR.

微波辅助磁性固体酸催化纤维素水解的研究

以生物质基磁性固体酸为催化剂,采用微波相结合的辅助手法对预处理的微晶纤维素进行水解研究。以还原糖得率为指标,通过单因素试验和正交试验(四因素三水平)考察水解时间、水解温度、纤维素与催化剂量的比例和微波功率对纤维素水解的影响,利用红外光谱(FT-IR)分析纤维素水解残渣。结果表明,微波辅助生物质基磁性固体酸催化剂催化纤维素水解的最佳工艺条件为:水解时间30 min、水解温度80℃、催化剂量与纤维素的比例2:1、微波功率450 W,此时还原糖得率最高,达57.4%;4个因素对纤维素水解影响的主次顺序为:微波功率>催化剂量>水解时间>水解温度。FT-IR分析表明微波辅助纤维素水解残渣中几乎没有纤维素存在,即纤维素基本被完全水解。

响应面优化生物质玉米秸秆催化液化工艺研究

以获取高得率的生物质液化油为目的,利用生物质玉米秸秆为原料,液化时间、液化温度、催化剂的量为影响因素设计Box-Behnken试验,得到试验因素之间的定量数学模型和交互作用对玉米秸秆液化率的影响,采用响应面法确定玉米秸秆催化液化的最佳工艺条件。结果表明,试验数据建立的二次多项式数学模型显著性极高(P<0.000 1),相关系数R^2=0.953 8,预测值与试验值具有很好的拟合度。当液化时间为63.66 min、液化温度为162.43℃和催化剂的量为4.02%时为最佳的催化液化条件;在该工艺条件下,玉米秸秆的液化率为98.88%,预测值为98.87%,二者相差0.01%;由此得出响应面法优化玉米秸秆催化液化工艺参数更加精准可靠,具有一定的参考价值。

A New Flavone Glycoside from Epimedium koreanum

A novel flavone glycoside named 3＇＇＇-carbonyl-2＇＇-β-L-quinovosyl icariside Ⅱ was isolated from the aerial parts of Epimedium koreanum. Its chemical structure was elucidated on the basis of spectral analysis.

Method for pests detecting in stored grain based on spectral residual saliency edge detection

Pests detecting is an important research subject in grain storage field.In the past decades,many edge detection methods have been applied to the edge detection of stored grain pests.Although some of them can realize the stored grain pests detecting,precision and robustness are not good enough.Spectral residual(SR)saliency edge detection defines the logarithmic spectrumof image as novelty part of the image information.The remaining spectrumis converted to the airspace to obtain edge detection results.SR algorithm is completely based on frequency domain processing.It not only can effectively simplify the target detection algorithm,but also can improve the effectiveness of target recognition.The experimental results show that the edge results of stored grain pests detected by SR method are effective and stable.

Orthogonal Test About Biogas Upgrading by Pressured Water Scrubbing

Biogas is a kind of regenerable energy which is inexpensive and friendly to the environment, but the potential ofbiogas is difficult to develop fully in China, for most biogas have badly qualities and the utilization of it is monotonous. The suitable operation term about biogas upgrading by pressurized water scrubbing was researched through the orthogonal test in this study. Two sorts of scrubber packing included the random multidimensional hollow sphere packing and the structured screen packing were also used, and the effects of experiment factors included packing, water temperature, gas flow speed, water flow speed and washing pressure were studied. The results showed that better effect was got when the screen structured packing was used; all the five test factors affected the processing significantly in the arrange as before and had better and better significant effects.

Elucidating the removal mechanism of N,N-dimethyldithiocarbamate in an anaerobic-anoxic-oxic activated sludge system

N,N-Dimethyldithiocarbamate （DMDTC） is a typical precursor of N-nitrosodimethylamine （NDMA）. Based on separate hydrolysis, sorption and biodegradation studies of DMDTC, a laboratory-scale anaerobic-anoxic-oxic （AAO） system was established to investigate the removal mechanism of DMDTC in this nutrient removal biological treatment system. DMDTC hydrolyzed easily in water solution under either acidic conditions or strong alkaline conditions, and dimethylamine （DMA） was the main hydrolysate. Under anaerobic, anoxic or oxic conditions, DMDTC was biodegraded and completely mineralized. Furthermore, DMA was the main intermediate in DMDTC biodegradation. In the AAO system, the optimal conditions for both nutrient and DMDTC removal were hydraulic retention time 8 hr, sludge retention time 20 day, mixed-liquor return ratio 3：1 and sludge return ratio 1：1. Under these conditions, the removal efficiency of DMDTC reached 99.5%; the removal efficiencies of chemical organic demand, ammonium nitrogen, total nitrogen and total phosphorus were 90%, 98%, 81% and 93%, respectively. Biodegradation is the dominant mechanism for DMDTC removal in the AAO system, which was elucidated as consisting of two steps： first, DMDTC is transformed to DMA in the anaerobic and anoxic units, and then DMA is mineralized to CO2 and NH3 in the anoxic and oxic units. The mineralization of DMDTC in the biological treatment system can effectively avoid the formation of NDMA during subsequent disinfection processes.

FARADAY EFFECT OF CHARGE-TRANSFER TRANSITION IN POLY(4-VINYLPYRIDIN)-Fe^(3+) COMPLEX

Ⅰ. INTRODUCTIONIn the theory of magnetic optical activity on the basis of Faraday effect and Zeeman effect, Buckingham and Stephens have shown that the contribution of an isolated transition to the experimental MCD band can be written as a sum of three terms, A, B and C, each with its own molecular properties, i. e.

Correlation of Substituted Effect of Benzo-15crown-5 Derivatives With MCD

The research of the complex compounds between the crown ethers and metal ions has become more extensive since the first study of Pedrsen in 1967. The catalysis and separation property of crown ethers are important. It is necessary to study the nature of these compounds. The present note reports the MCD spectra of 4-substituted benzo-15-crown-5.