Specific ion effects on soil aggregate stability and rainfall splash erosion

Soil interparticle forces can pose important effects on soil aggregate stability and rainfall splash erosion. Meanwhile, these interparticle forces are strongly influenced by specific ion effects. In this study, we applied three monovalent cations (Li⁺, Na⁺, and K⁺) with various concentrations to investigate the influence of specific ion effects on aggregate stability and splash erosion via pipette and rainfall simulation methods. The specific ion effects on soil interparticle forces were quantitatively evaluated by introducing cationic non-classical polarization. The results showed that aggregate stability and splash erosion had strong ion specificity. Aggregate breaking strength and splash erosion rate at the same salt concentration followed the sequence as Li⁺ > Na⁺ > K⁺. With decreasing salt concentration, the difference in aggregate breaking strength or splash erosion rate between different cation systems increased initially (1–10^–2 mol L^–1) and later was nearly invariable (10^–2–10^–4 mol L^–1). The experimental results were well quantitatively explained by soil interparticle forces considering cationic non-classical polarization. Furthermore, both aggregate breaking strength and splash erosion rate of three cations revealed a strong positive linear relation with net force subjected to cationic non-classical polarization (R² = 0.81, R² = 0.81). These results demonstrated that different non-classical polarization of cations resulted in different soil interparticle forces, and thus led to differences in aggregate stability and splash erosion. Our study provides valuable information to deeply understand the mechanisms of rainfall splash erosion.     

黄土丘陵区针叶纯林养分循环和枯落物分解导致土壤极化风险分析

【目的】分析3种针叶人工纯林发生土壤极化的风险。【方法】2011-2012年,在黄土丘陵区,选择侧柏、油松和落叶松3种针叶人工纯林作为研究对象,分别测算了3种针叶人工林的林分生物量、生产力和养分循环量;此外,将采集的土壤分别与枯落物(枯落叶和根系)混合,进行分解培养试验,研究枯落物分解对土壤生物学性质的影响。【结果】不同针叶人工纯林中,N、P、K积累量在不同器官中存在差异。侧柏纯林中,N、P、K主要积累在干中;落叶松纯林中,N、P、K主要积累在根和干中;在油松纯林中,N、P、K主要积累在根中。在生长季节短期内,侧柏和油松纯林的养分循环特征导致土壤存在K负向极化风险,落叶松纯林土壤存在N负向极化风险,而长期生长季节内3种纯林土壤都存在P负向极化风险。枯落物混土分解培养试验结果表明,侧柏和落叶松枯落叶分解会引起土壤多酚氧化酶活性发生负向极化,侧柏根系分解会引起土壤微生物数量、蔗糖酶和过氧化氢酶活性发生明显负向极化;油松枯落叶分解会引起土壤多酚氧化酶和过氧化氢酶活性发生负向极化。【结论】侧柏和油松纯林土壤生物学性质发生负向极化的风险高于落叶松纯林;在生长季节应向侧柏和油松纯林土壤补充K肥,向落叶松纯林土壤补充N肥,并长期向3种纯林土壤补充P肥。     

电脉冲法在电池激活中的探讨

文章阐述了电脉冲法在电池激活中的探讨及蓄电池修复仪控制系统的硬件结构和软件设计的思想。     

磁化甘蔗混合汁微滤过程中膜面吸附对传质模型的影响

为研究磁化甘蔗混合汁微滤膜分离过程,分析膜面吸附作用对传质过程的影响。以甘蔗混合汁为原料,研究了磁化甘蔗混合汁在微滤过程中质量传递模型。在不考虑膜表面层的吸附作用下,0.45和0.20μm陶瓷微滤膜分离的传质系数分别为-81.406和-83.130,回归方程的决定系数R2分别为0.921和0.920,P值分别为0.002和0.010;考虑膜表面层的吸附作用,0.45和0.20μm陶瓷微滤膜分离的传质系数分别为-323254.006和573281.937,吸附系数分别为0.995和0.994,回归方程的决定系数R2分别为0.939和0.999,P值分别为0.015和0.0008,可见,对于上述磁化条件和膜分离过程进出口操作压力差0.03~0.04 MPa,控制温度(35±1)℃,全回流试验条件下,膜面吸附作用对微滤膜分离过程传质模型影响显著(P0.05)。该研究有助于微滤膜分离设备的选型设计参数和操作条件的优化。     

Influence of Edge Polarization Upon the Excitons in Different Thickness and Different Thin Films

The authors discusss exciton energies in a thin film with d thickness and influence of the edge polarization upon the excitons.The polarization is described as interaction between electron(hole) and its image charge.It is found that the interaction decreases the exciton energies to some extent and the influence of the interaction upon the films possessing different dielectric constants and with different thickness are different.     

Studies on the Structure Model of Coal and Its Polarization Characteristics

The macromolecular structures of coal samples collected from Yutianbao, Nantong and Qingnian coal mines in Sichuan were studied and a model of structure for these coals was set up. On the basis of above mentioned work,experimental studies and theoretical analyses were made to investigate the characteristics of coal polarization in applied electric field. The results indicate that the rotation polarzation and the space polarization are the essential reason for the attenuation of electric current through coal samples,and that the space polarization is the main form of coal polarization.     

高温高压下P110钢CO2腐蚀电化学行为研究

运用电化学测量技术,研究了P110油套管钢在模拟油田现场腐蚀环境中的腐蚀电化学行为.研究结果表明,随着试验时间的延长,腐蚀速率逐渐降低.在试验时间达到72 h后,腐蚀速率降低的趋势变缓;阳极极化曲线上出现了类似于钝化的现象.阴极极化曲线的Tafel斜率变化较大,P110钢的阴极反应趋势已经不同;P110钢的EIS表明极化电阻逐渐增大,电极反应由最初的活化控制变为由扩散和活化共同控制.     

Dielectric relaxation due to the heterogeneous structure of wood charcoal

Delignified hinoki wood and cellulose as well as hinoki and lauan woods were carbonized at 590°C for 1 h. The dielectric properties of these specimens were measured at 20°C in a frequency range of 20 Hz to 1 MHz. Inflection points in the dielectric constant (ε′) versus the logarithm of frequency (log f) curves as well as in the logarithm of the electric conductivity (log σ) versus log f curves for all specimens prepared were recognized. Peaks in the dielectric loss and the imaginary part of the complex conductivity versus the log f curves were detected in the frequency location corresponding to the inflection point in the ε′ and log σ versus log f curves. It was considered that this relaxation was responsible for the interfacial polarization observed in heterogeneous materials because no permanent dipoles existed in the specimens carbonized above 500°C. The Cole–Cole circular arc law was applied to account for this relaxation. Similar average relaxation times were obtained for all specimens. These results suggested that the observed relaxation was ascribed to interfacial polarization at microscopic levels in the cell walls.     

理性看待贫富差距

贫富差距是经济发展的客观规律,既要承认贫富差距的合理性,又要理性地遏制日益扩大的贫富差距。     

安徽城镇居民收入水平及差异分析与政策建议

1996到2001年，安徽城镇居民收入增速明显偏慢，收入差距进一步扩大。此外，从近几年的数据看，低收入人口的实际收入的增长幅度出现了下降的势头，两极分化的苗头己经显现，城镇居民贫困问题己经成为不容忽视的一个大问题。为此，我们建议通过有效的税收政策、加快发展开放流动的劳动力市场，在兼顾经济发展与产业优化的基础上实施就业优先政策，增加城镇居民收入，缓解两极分化和城镇居民贫困问题的压力。