"合作学习法"在排球教学中的研究

笔者以文献资料法、数理统计法、调查法、实验法为研究方法,在防灾科技学院排球基本技术教学中进行了合作教学的实验研究.结果表明:"合作学习法"是适合防灾科技学院排球基本技术教学的一种有效的教育理论;在防灾科技学院排球基本技术的教学中运用"合作学习法",学生出勤率高,学习态度踏实,教学效果明显,课外自觉参加排球运动的次数明显增加.     

边坡稳定性影响因素敏感性的两种分析结果比较

作者在刘立鹏,于红杰发表的论文基础上,采用通径系数分析方法,对影响边坡稳定性的因数进行了敏感性分析,并将分析结果与刘立鹏,于红杰灰的灰色关联分析进行了比较,结果表明：土质边坡的稳定性受土体的物理力学因素影响大,受地形地貌因素影响小;在土体的物理力学因素中,粘聚力的影响最大;在地形地貌因素中,坡角的影响最大。     

Modified accumulation of selected heavy metals in Bt transgenic rice

Safety assessment of genetically modified crops generally does not take into account the potential hazard of altered patterns of heavy metal accumulation in plants. A pot experiment was conducted under greenhouse conditions to evaluate the impact of heavy metal amendments on the accumulation of Cd, Cu, Pb and Zn in a Bt transgenic rice Ke-Ming-Dao (KMD) and its wild-type Xiushui 11 (Xs11). In control soils, significant di erence was only found in contents of Cu (p < 0.01) and Pb (p < 0.05) in straw between KMD and Xs11. At three levels of Cd amendments (5, 10, and 20 mg/kg), the Cd contents in grain and straw of KMD were significantly higher than those of Xs11, and all grain Cd contents were significantly higher than the International Criteria (0.2–0.4 mg/kg) as specified by the Codex Alimentarius Commission (CAC). These results implied that it may be unsafe for growing Bt transgenic rice in heavily Cd-polluted areas. No significant di erence in Zn was found between the two varieties with the exception of roots at Zn amendment level of 600 mg/kg, while Pb contents in KMD were much higher in the straw at the lead amendment level of 1000 mg/kg and in the root at 250 mg Pb/kg. Data on the heavy metal accumulation patterns for the genetically modified rice may be used for the selection of growing areas as well as for plant residue management for Bt rice.     

Stabilization of hexavalent chromium with pretreatment and high temperature sintering in highly contaminated soil

• Separate reduction and sintering cannot be effective for Cr stabilization. • Combined treatment of reduction and sintering is effective for Cr stabilization. • Almost all the Cr in the reduced soil is residual form after sintering at 1000°C. This study explored the effectiveness and mechanisms of high temperature sintering following pre-reduction with ferric sulfate (FeSO₄), sodium sulfide (Na₂S), or citric acid (C₆H₈O₇) in stabilizing hexavalent chromium (Cr(VI)) in highly contaminated soil. The soil samples had an initial total Cr leaching of 1768.83 mg/L, and Cr(VI) leaching of 1745.13 mg/L. When FeSO₄ or C₆H₈O₇ reduction was followed by sintering at 1000°C, the Cr leaching was reduced enough to meet the Safety Landfill Standards regarding general industrial solid waste. This combined treatment greatly improved the stabilization efficiency of chromium because the reduction of Cr(VI) into Cr(III) decreased the mobility of chromium and made it more easily encapsulated in minerals during sintering. SEM, XRD, TG-DSC, and speciation analysis indicated that when the sintering temperature reached 1000°C, almost all the chromium in soils that had the pre-reduction treatment was transformed into the residual form. At 1000°C, the soil melted and promoted the mineralization of Cr and the formation of new Cr-containing compounds, which significantly decreased subsequent leaching of chromium from the soil. However, without reduction treatment, chromium continued to leach from the soil even after being sintered at 1000°C, possibly because the soil did not fully fuse and because Cr(VI) does not bind with soil as easily as Cr(III).     

有毒物质对水生态系统效应研究的进展

本文总结了近年来有毒物质对水生态系统的生态效应研究现状及发展趋势,提出了今后测定有毒物质生态效应应该注意的问题。     

应急监测中样本有无放射性的讨论

利用统计学方法提出了如何在应急监测中判断样本有无放射性,并结合实际监测做出了具体应用。     

藻红外辐射测试环境重金属急性毒性

快速、简便、有效地检测环境中重金属毒性是环境保护的一项重要内容.敏感藻是指藻红外测试中对毒物响应的温差大、种类多、时间快、剂量低的特殊藻类,为探寻对重金属急性毒性响应的敏感藻,2006年5月至2007年10月,进行了8种藻对10种重金属的温度响应测试试验.结果表明:平均响应温差短线脆杆藻(Fragilaria brevistriata)最大,为0.24 ℃,高出8种藻的0.19 ℃总平均温差0.05 ℃;较好药品响应率短线脆杆藻最高,为80%;平均响应时间短线脆杆藻居中,为4.65 min,低于8种藻的总平均响应时间5.21 min;短线脆杆藻对重金属的灵敏度在0.06～7.0 mg?L-1之间,发光细菌在0.07~15.3 mg?L-1之间,表明短线脆杆藻对重金属响应的剂量低.根据敏感藻的定义和分析结果,确定短线脆杆藻为本试验的敏感藻.     

环保中的博弈论

环境保护是我国的基本国策 ,采取何种措施保护环境使之更为有效是一个值得探讨的问题。应用博弈论分析了排污收费制度的可行性 ,指出此制度的不足之处 ,最后分析了新兴起的产业———环保产业投资中出现的一些特点 ,目的在于指出影响各环保措施效果的因素。     

烟气脱硫石膏和园林废弃物堆肥混合施用对滨海盐渍土壤的改良

为克服烟气脱硫石膏改良盐碱地存在的土壤盐分升高、营养物质降低等不足,通过对不同重量配比的园林废弃物堆肥与适量烟气脱硫石膏混合施用,且开展了其对上海南汇滨海盐渍土的改良效应研究。结果表明:2种改良剂混合施用能显著降低滨海盐渍土pH和全盐含量,增加土壤营养物质含量和植物生物量,并提高植物对营养物质的吸收能力;与对照相比,当烟气脱硫石膏施用量为25 g·kg~(-1)时,土壤pH降低了10.9%,EC升高了8.4%,有效磷、有效氮和速效钾含量分别降低了30.1%、 40.5%和36.1%,黑麦草发芽率下降了8.0%,植株内全氮、全钾含量均有所升高,但全磷含量减少了25.4%;混合施加不同重量配比的园林废弃物堆肥后,土壤pH降幅为6.8%～13.8%, EC降幅为4.2%～11.6%;土壤有效磷、有效氮和速效钾含量增幅分别为96.0%～182.7%、40.0%～186.7%和71.7%～157.5%;黑麦草发芽率和生物量逐渐增加,在园林废弃物堆肥施用量为40%时,与对照处理相比,此时植物发芽率达到90.0%,总湿重、地上干重、株高和根长等分别增加了154.1%、100.0%、89.2%和103.6%,植株体内氮和钾含量分别增加了139.9%和40.8%,磷的含量则接近对照处理。通过分析可知,烟气脱硫石膏和园林废弃物混合施用可较好地改良滨海盐渍土壤,并为城市固废的适合处置方式和综合利用途径提供了参考。     

脉冲喷吹金属滤袋的压力分布影响因素分析

金属纤维滤袋可直接过滤高温烟气粉尘,解决高温烟气粉尘导致的环境、安全问题,对高温烟气的余热能源回收利用有非常重要的意义。目前,金属滤袋除尘器脉冲喷吹参数是依照传统纤维滤袋器设计的,存在着脉冲瞬时气流导致喷吹清灰失效问题。针对此问题,在脉冲喷吹实验平台上,通过改变喷吹压力、喷吹距离以及喷吹孔径,针对?130 mm×2 000 mm的金属滤袋,利用压力数据采集系统测试喷吹压力0.2～0.6 MPa、喷吹孔径6～14 mm、喷吹距离50～250 mm时,金属滤袋距顶部80、200、600、1 000、1 400和1 800 mm 6个部位的侧壁压力峰值,以探求针对金属滤袋的脉冲喷吹的合理参数。结果表明:2 m金属滤袋的最佳脉冲喷吹孔径为8 mm,最佳喷吹距离为200 mm,最佳喷吹压力为0.5 MPa;此条件下的P1(80 mm)、P2(200 mm)、P3(600 mm)、P4(1 000 mm)、P5(1 400 mm)、P6(1 800 mm)的侧壁压力峰值分别为1 000、1 686、839、746、749和2 005 Pa。金属滤袋的侧壁压力峰值大小排列呈下上中的规律。随着喷吹孔径的增大,最优喷吹距离有逐渐减小的趋势。金属滤袋的中、下部(距滤袋口600～1 400 mm)清灰将是未来金属滤袋清灰的重点关注部位。上述研究结果可为金属滤袋的推广发展提供参考。