微波辐射下香草醛改性壳聚糖的制备及其对金属离子的吸附

应用微波辐射法合成了香草醛接枝壳聚糖,用NaBH4进行还原。探讨了改性壳聚糖在25℃下对Ni2+、Mn2+、Cr6+的吸附及时间、离子浓度、pH值对吸附效果的影响。结果表明,还原后的改性壳聚糖比壳聚糖吸附性能明显改善,其对Ni2+、Mn2+和Cr6+的吸附容量分别可以达到116.23,63.83,47.27 mg/g。     

反舰导弹末制导雷达选择性作用分析

通过蒙特卡洛和数值仿真的方法对末制导雷达选择性对导弹作战效果的影响进行了仿真与分析．仿真结果表明，在编队间隔为(2～4)km时对目标的捕捉概率，末制导雷达具有选择性普遍高于末制导雷达无选择性．在作战双方大量使用各种干扰(如冲淡干扰距离一般为(1～3)km)的现代战争条件下，末制导雷达具有选择性仍具有重要的作用．同时，为进一步科学地确定末制导雷达选择区大小提供了仿真模型．     

Hydrodynamic numerical modelling of storm surges — Application to the Bay of Bengal

A hydrodynamic numerical model and a tide-surge interaction model are described for the evaluation of storm surges and their interaction with the tides in the Bay of Bengal. Numerical experiments are performed with the help of these models to simulate the surges generated by three recent severe cyclonic storms which struck the east coast of India and Bangladesh. The predicted peak sea-surface elevations compare well with the limited observed values.     

Simulation of Solar Radiation based on Three Machine Learning Methods

Quantitative simulation of solar radiation is essential for understanding climate change 0n the Loess Plateau, Many machine learning methods were developed to estimate solar radiation well, but different machine learning methods have different simulation accuracy in different regions, In order to achieve optimal simulation of solar radiation on the Loess Plateau, this provides more higher precision solar radiation data for crop models, hydrological models, and climate change models. In this study, three machine learning methods, including Random Forest (RF), Artificial Neural Network (ANN) and Support Vector Machine (SVM), were applied to estimate solar radiation on the Loess Plateau, three machine learning methods were trained using ground measurements at fourteen radiation sites from 2003 to 2009 and ten radiation sites from 2010 to 2016 and corresponding parameter pressure, cloud fraction, cloud optical thickness, ozone, precipitation water vapor and DEM, slope, and aspect to train the three model, The solar radiation estimates based on three machine learning methods were evaluated using ground measurements at four radiation sites from 2010 to 2016. The validation results show that the RF model has the best simulation effect on the Loess Plateau and surrounding areas. The average deviation is -0.17 MJ·m^-2, the root mean square error is 1.48 MJ·m^-2, and has a good fit of 0.96. The results show that combined RF model and meteorological data and remote sensing data can effectively solve the problem about solar radiation simulation on the non-radiation observation area of the Loess Plateau, which is of great significance to the research of regional solar radiation.     

The effect of solar radiation on the flavonol content in broccoli inflorescence

The effect of solar radiation on the quercetin and kaempferol contents in the inflorescence of three broccoli cultivars (‘Lord’, ‘Marathon’ and ‘Fiesta’) was investigated from 1999 to 2001. Great differences in the contents of both flavonols, dependent on growing time and cultivar, were found. Quercetin and kaempferol contents varied from 14.3 to 81.0 mg kg⁻¹ f.w. and from 35.9 to 213 mg kg⁻¹ f.w., respectively. Inflorescences of the cultivar ‘Lord’ were characterised by the highest mean content of quercetin and those of cultivar ‘Fiesta’ of kaempferol. The contents of both flavonols were highly positively correlated with total solar radiation in the period from planting to the harvest of broccoli inflorescences.     

One-minute global irradiance probability density distributions conditioned to the optical air mass

Knowledge of the temporal variability of the solar irradiance is important to study solar energy systems involving thermal and photovoltaic processes. The differences between hourly and instantaneous values of the clearness index considerably affect the utilizability of photovoltaic systems. In this work, we analyzed the probability density distributions of one-minute values of global irradiance, conditioned to the optical air mass, considering those as an approximation to the instantaneous distributions. The study reveals that the bimodality that characterizes these distributions increases with optical air mass. We propose the use of a functional form based on Boltzmann's statistics in order to describe these distributions. This function can be used for the generation of synthetic radiation data. Expressing the distribution as a sum of two functions provides an appropriate modeling of the bimodality feature that can be associated with the existence of two levels of irradiation corresponding to two extreme atmospheric situations, cloudless and cloudy conditions.     

葡萄糖-氯化钠晶溶发光剂量计研究

利用化学方法来测量混合场中的n、γ成分已有很多方法。其中,氯代烃体系较为普遍,但方法复杂,对器皿和试剂以及操作要求都比较高;四氯乙烯化学剂量计体系则不能用于500rad以下的测量;含硼与不含硼的硫酸亚铁体系也只能测量较高剂量。测量混合场中D_n、D_γ的方法多是使用“对”剂量计,即其中一个体系对中子不敏感而另一个体系对中子和γ射线都敏感的原理来测量。其计算D_n和D_γ公式为:     

改性蒙脱土对聚丙烯的抗紫外老化作用

研究了少量有机蒙脱土对聚丙烯力学性能及其耐紫外老化性能的影响，并用红外光谱研究了紫外辐照对聚聚丙烯及其与蒙脱土的复合材料的基团变化情况。结果表明，添加少量有机蒙脱土可以使聚丙烯的模量和冲击强度以及耐紫外老化性能明显提高。     

回字形抗辐射环栅LDMOS建模与验证

介绍了一种回字形抗辐射环栅LDMOS器件。分析了该器件在版图绘制中的结构优势,并结合Sentaurus仿真结果,通过区域划分和类MOS结构拟合阈值电压,给出了该器件的等效宽长比模型和饱和电流模型。在标准商用0.18 μm BCD工艺下流片,测试结果表明,理论模型在一定栅压范围内误差可低于10%。在总剂量测试中,关态泄漏电流随剂量增加变化较小,有一定的抗辐射加固能力。     

Elastic strain evolution and ε-martensite formation in individual austenite grains during in situ loading of a metastable stainless steel

The (hcp) ε-martensite formation and the elastic strain evolution of individual (fcc) austenite grains in metastable austenitic stainless steel AISI 301 has been investigated during in situ tensile loading up to 5% applied strain. The experiment was conducted using high-energy X-rays and the 3DXRD technique, enabling studies of individual grains embedded in the bulk of the steel. Out of the 47 probed austenite grains, one could be coupled with the formation of ε-martensite, using the reported orientation relationship between the two phases. The formation of ε-martensite occurred in the austenite grain with the highest Schmid factor for the active {111}<12¯1> slip system.