高光谱技术结合化学计量法鉴别黑色染料笔墨迹

采用高光谱技术结合化学计量法,对市面上常见的42种不同品牌、型号的黑色染料笔墨迹进行分类鉴别。首先,对42种黑色染料笔的墨迹样品进行450-950 nm区间的高光谱扫描;借助SPSS 26软件和Origin Pro 2023,采用系统聚类分析方法对墨迹样品进行分类,并用主成分分析来验证分类的结果。对高光谱数据进行系统聚类分析,能将42种墨迹样品分为两大类共7小类,其中油基笔4类,水基笔3类;经主成分分析验证其分类效果合理。结果表明,高光谱技术结合化学计量法能够对黑色染料笔墨迹进行分类和鉴别,为实际案件中黑色染料笔墨迹的检验提供了技术支撑。

低压空气辅助喷射甲醇发动机冷起动试验研究

针对甲醇发动机难以形成浓度合适的混合气而造成冷起动困难的问题,以一台应用自主开发的进气道低压空气辅助喷射系统(air assisted port injection,AAPI)的单缸甲醇发动机为研究对象开展试验研究,探究不采用辅助措施通过AAPI喷射实现甲醇高雾化对甲醇发动机冷起动的影响及规律。试验表明AAPI明显加快了甲醇发动机冷起动前可燃混合气的形成速率。AAPI甲醇发动机着火前过量空气系数λ的平均变化率值和峰值变化率分别是普通喷射方式的3.2倍和2.26倍。点火时刻对AAPI甲醇发动机冷起动影响较大,为使AAPI甲醇发动机的冷起动性能最优,需配合合适的点火时刻,试验条件下最佳点火时刻为活塞压缩上止点前20°。AAPI甲醇发动机的冷起动性能受环境温度影响较大,随着环境温度的降低,甲醇发动机冷起动时间增长;不采用辅助措施,AAPI甲醇发动机在5℃时能实现可靠冷起动。

Sensitivity of green and blue-green algae to methyl tert-butyl ether

The toxicity of methyl tert-butyl ether （MTBE） to Chlorella ellipsoidea and Aphanizomenon flos-aquae was tested and assessed for a 15-d incubation with concentrations of MTBE from high （2.00×10^4 mg/L） to low （2 mg/L）. The results showed that the toxicity was low when the concentration of MTBE was in the range 1.00× 10^4-2.00× 10^4 mg/L （the greatest inhibition of growth-rate was 70%-71%, occurred during the day 1-5）. Low concentrations （2-500 rag/L） stimulated algal growth up to the greatest effect of 85%-200% when the concentration of MTBE was 50-100 mg/L during day 3-5. The toxicity of MTBE （72-120 h EC50） was 6.65×10^3-9.58×10^3 mg/L for C. ellipsoidea and that is 1.14× 10^4-2.00× 10^4 mg/L for A. floc-aquae. We found that the toxicity and ecological risk of MTBE for the algal community structure were low and the toxicity was influenced by the duration time of the test.

轻压下和拉速对42CrMo钢410mm×530mm铸坯轧成Φ195mm材的低倍和中心C偏析的影响

对比试验了铸坯的轻压下量(0~8 mm)及拉速(0.42~0.49 m/min)对42CrMo钢Φ195 mm轧材低倍组织和偏析的影响。结果表明,在现有工艺条件下,42CrMo钢过热度控制在20~30℃,二冷比水量0.30 L/kg,结晶器电搅100A/1.5 Hz,末端电搅400A/8 Hz,连铸拉速控制在0.49 m/min,总压下量6~8 mm,能有效改善42CrMo钢轧材的内部质量。

Thermodynamics for nonequilibrium solvation and numerical evaluation of solvent reorganization energy

This work presents a thermodynamic method for treating nonequilibrium solvation. By imposing an extra electric field onto the nonequilibrium solvation system, a virtual constrained equilibrium state is prepared. In this way, the free energy difference between the real nonequilibrium state and the con-strained equilibrium one is simply the potential energy of the nonequilibrium polarization in the extra electronic field, according to thermodynamics. Further, new expressions of nonequilibrium solvation energy and solvent reorganization energy have been formulated. Analysis shows that the present formulations will give a value of reorganization energy about one half of the traditional Marcus theory in polar solvents, thus the explanation on why the traditional theory tends to overestimate this quantity has been found out. For the purpose of numerical determination of solvent reorganization energy, we have modified Gamess program on the basis of dielectric polarizable continuum model. Applying the procedure to the well-investigated intramolecular electron transfer in biphenyl-androstane-naphthyl and biphenyl-androstane-phenanthryl systems, the numerical results of solvent reorganization energy have been found to be in good agreement with the experimental fittings.

Some Inequalities about the General Lp-Mixed Width-Integral of Convex Bodies

The Brunn-Minkowski type and cyclic Brunn-Minkowski type inequalities for the i-th general L_(p)-mixed widthintegral of convex bodies are established.Further,two cyclic inequalities for the differences of i-th general L_(p)-mixed widthintegral of convex bodies.