济南泉群滞迟效应及泉流量预测分析

对济南泉群的滞迟效应进行了分析,并建立了月平均泉流量预测模型和泉单位预测模型。结果表明：①济南泉域地下水的动态变化主要受降水量、开采量、地下水回灌量、邻区地下水侧向补给量等因素的影响,其中大气降水补给因素对地下水的动态影响最为明显,济南泉群泉流量、水位相对于降水的滞迟时间约为2个月;②根据月平均泉流量预测模型计算的月平均泉流量相对误差为2.6%~23.5%,只有1个月的预测值不合格;③月平均泉水位预测值与实测值吻合很好,采用相对高程后的相对误差为0.2%~3.8%。

济南岩溶含水系统滞迟效应分析

济南岩溶含水系统的泉水位和泉流量明显滞迟于降水量。利用峰值时段差、原始序列回归等方法,并考虑了降水量、泉水位、泉流量周期性的影响,计算出济南岩溶含水系统的滞迟时间为2～6个月。以不同滞迟时间建立了泉流量预测模型,并进行了对比分析,滞迟时间6个月预测模型,预测精度较高,物理概念不明确;滞迟时间2个月预测模型,预测精度稍差,但物理概念明确,建议采用该模型进行泉流量预测。

Effect of Initial Concentration on Adsorption-Desorption Characteristics and Desorption Hysteresis of Hexachlorobenzene in Soils

Adsorption and desorption are important processes that influence the transport, transformation, and bioavailability of hexachlorobenzene (HCB) in soils. To examine the adsorption-desorption characteristics of HCB, equilibrium batch experiments were carried out using two soils (red soil and paddy soil) with different initial HCB concentrations (0.25, 0.50, 0.75, 1.00, 1.50, 2.50, 3.50, and 5.00 mg L-1 ) by using 0.01 mol L-1 calcium chloride as the background solution. The successive desorption experiments (48, 96, 144, 192, and 240 h) were conducted after each adsorption equilibrium experiment. The results revealed that adsorption and desorption isotherms of HCB on two soils were nonlinear, which can be best described by the Freundlich equation with the square of the correlation coefficient (r 2 ) ranging from 0.97 to 0.99. Desorption of HCB from the two soils exhibited hysteresis at all HCB concentrations because the Freundlich desorption coefficients were always higher than the Freundlich adsorption coefficients. The hysteretic effect was enhanced with increasing initial HCB concentration, and positive hysteresis was observed at different concentrations.

lon migration suppression mechanism via 4-sulfobenzoic acid monopotassium salt for 22.7%stable perovskite solar cells

The deep-level traps at grain boundaries(GBs)and halide ion migration are quite challenging for further enhancement of the stability and efficiency of perovskite solar cells(PSCs)as well as for the elimination of notorious hysteresis.Herein,we report a large-sized strongly coordinated organic anion GB anchoring strategy for suppressing ion migration and passivating defects in planar PSCs.The practical implementation of this strategy involves the incorporation of potassium salts containing a large-sized organic counter anion(4-sulfobenzoic acid monopotassium salt,SAMS)into the perovskite precursor.It has been found that anions within SAMS can be firmly anchored at GBs due to the strong coordination interaction between C=O and/or S=O at both ends of bulky anion and undercoordinated Pb^(2+)and/or halide vacancies,along with the hydrogen bond between–OH and formamidinium.SAMS can not only passivate shallowlevel defects but also cause more effective passivation of the deep-level defects.The GB manipulation strategy results in a reduced defect density,an increased carrier lifetime as well as suppressed ion migration,which in turn contributed to enhanced efficiency and stability of PSCs together with a thorough elimination of hysteresis.As a result,the SAMSmodified device with an outstanding fill factor of 0.84 delivers a significant improvement in efficiency(22.7%)in comparison with the control device(20.3%).The unencapsulated modified device demonstrates only little degradation after 1320 h at 60℃.

Grain boundary passivation with triazine-graphdiyne to improve perovskite solar cell performance

Detrimental defects on perovskite grain boundaries(GBs)are critical factors that lead to non-radiative recombination and hysteresis.In this work,triazine-graphdiyne(Tra-GD),a nitrogen-rich two-dimensional(2 D)material,was incorporated into the active layer of perovskite to modify the GBs.Tra-GD was found to distribute evenly over the bulk of the perovskite and has a strong interaction with the Pb^2+ exposed at GBs,which enables it to effectively passivate GB defects and prevent ion migration.The results of Kelvin probe force microscopy and photoluminescence studies proved that the highly conjugated Tra-GD located at GBs could promote charge extraction and transport.Benefiting from defect passivation and more efficient carrier transport,the Tra-GD based device showed less non-radiative recombination loss.Consequently,the resultant device presented negligible hysteresis and yielded a high power conversion efficiency(PCE)of 20.33%in the MAPbI3-based perovskite solar cell.This approach was extended to the FAPbI3 system with a PCE of 21.16%.Our Tra-GD passivation strategy provides a useful approach to effectively improving the device performance and addressing hysteresis issues.

Acupuncture for Promoting Intelligence of Children—An Observation on 37 Cases with Mental Retardation

Objective: To observe the effect of acupuncture on intelligence quotient (IQ) in children with mental retardation (MR). Methods: One hundred children with MR were randomly divided into an acupuncture group and a control group, 50 in each. There were 37 and 36 cases with complete data in the former and latter group respectively. Four-week treatment constituted a course, the comprehensive therapeutic effect of two groups was compared after 3 courses of treatment, and the influence of acupuncture on IQ was estimated. Results: The total effective rate in the acupuncture group was 78.4%, better than 30.56% in the control group, the difference being significant (P<0.01). Both groups were improved in IQ but the effect of the former group was better than that of the latter group (P<0.05). Conclusion: Acupuncture can obviously improve IQ of children suffering from MR.