1980—2020年延河甘谷驿流域土壤侵蚀评价与驱动因子分析

采用日降雨量、DEM、土壤类型、泥沙含量及多期NDVI等数据,基于修正通用土壤流失方程(RUSLE)和地理探测器,研究了国家生态退耕还林还草工程实施前后近41年延河甘谷驿流域土壤侵蚀动态与驱动因子。结果表明,1980—2020年研究区土壤侵蚀强度总体呈波动变化趋势,1980年、1990年、2000年、2010年和2020年平均侵蚀模数分别为6 746.30、5 740.28、6 389.56、5 450.46、5 480.56 t/(km~2·年)。1980—2000年研究区整体侵蚀强度逐渐增强,强烈及以上等级侵蚀面积占比逐渐增加,表现为“增蚀升级”的特点;2000年后研究区内土壤侵蚀强度开始降低,强烈及以上等级的侵蚀面积减少,总体表现为“减蚀降级”的特点。研究区土壤侵蚀强度随着坡度的升高而加剧,同时发现海拔1 000~1 200 m和1 200~1 400 m是研究区内侵蚀发生的主要高程带。2020年土地利用类型因子解释力最为突出,表明退耕还林还草工程实施效果显著,大面积的耕地向林草地转换是使得研究区2000年后土壤侵蚀强度降低的最主要原因。土壤侵蚀各影响因子的协同作用明显强于单一因子的影响。

dl-酒石酸的合成工艺研究

改进了外消旋酒石酸(dl-酒石酸)的合成工艺:以顺丁烯二酸酐为原料,经环氧化反应合成相应的环氧丁二酸(氢)钙中间体,然后经酸化、抽滤除去钙离子,滤液通过水解反应获得目标产物dl-酒石酸。最后调节母液pH值获得产物酒石酸氢钾。同时考察了反应温度、反应时间、催化剂用量、氧化剂用量等对收率的影响,得到适宜的反应条件:制备环氧丁二酸钙,摩尔比n(顺丁烯二酸酐):n(碳酸钙):n(过氧化氢):n(催化剂)=1:0.98:1.50:0.006,50℃反应4 h,收率为92.5%;制备环氧丁二酸氢钙,n(顺丁烯二酸酐):n(碳酸钙)=1:0.54,70℃反应4 h,收率为95.0%;制备dl-酒石酸,n(Ca2+):n(H2SO4)=1:1.50,室温下酸化4 h,收率为82.2%。中间体母液套用3次,收率仍然稳定;dl-酒石酸母液套用3次,每次收率均大于95%。中间体和产品结构经熔点仪、傅里叶红外光谱仪(FTIR)表征,均与标准样品一致。

中国养老护理员培训体系的困境及国际经验借鉴

养老护理服务市场需求激增与养老护理员培训体系不完善的“尖锐矛盾”是当前中国社会正在面临的重大挑战。通过文献分析法、比较分析法、归纳法,客观梳理英、美、德、日、澳等国养老护理人员入职培训及在职继续教育的成熟经验,对比中国现行培训体系中的突出问题,旨在寻找借鉴及引入他国经验并实现“本土化”的潜在可能与路径。

无人机核辐射探测吊舱系统设计

为满足小型无人机搭载辐射探测器对核辐射事故应急现场检测的需要,设计了无人机吊舱系统。该系统涵盖了核辐射探测、卫星定位、激光测距和无线通信等模块。在此基础上对吊舱系统进行搭建并结合无人机进行了实际测量,实验测试表明:该吊舱系统工作稳定,测量灵敏,可满足日常环境本底剂量率测量以及核应急响应等任务。

Investigation of acupuncture in improving sleep,cognitive and emotion based on attenuation of oxidative stress in prefrontal cortex in sleep-deprived rats

Objective To explore whether acupuncture can improve sleep disturbance,cognitive impairment and emotional disorders caused by sleep deprivation,and its association with the attenuation of oxidative stress injury in prefrontal cortex.Methods Fifty-two male Sprague-Dawley rats were randomly divided into a control group(n=10),a model group(n=14),a manual acupuncture(MA)group(n=14),and a sham-MA group(n=14).All the groups were established as sleep deprivation models via the modified multiple platform method,except for the control group.Rats in both the MA group and the sham-MA group received corresponding intervention,respectively.After modeling and intervention,the four groups received three behavioral tests,namely sleep monitoring,by comprehensive lab animal monitoring system(CLAMS),Morris water maze(MWM)test and open-field test(OFT),followed by oxygen free radical level test and Western blot(WB)detection for the expression levels of Bax and Bcl-2.Results The MA group derived more sleep time within 24 h than either the model group or the sham-MA group(both P<0.05).On MWM orientation navigation test day 1,there were no significant differences in escape latency among the control,MA and sham-MA groups(P>0.05),and the escape latency was significantly shorter in these three groups than that in the model group(all P<0.05).On test day 4,the escape latency was markedly shorter in the MA group than that in either the model group or the sham-MA group(both P<0.05);meanwhile,the MA group showed significantly better performance compared with these two groups in space probe test(both P<0.05).In OFT,compared with the control group,there was a significant decline in the horizontal movement score in the other three groups(all P<0.05),and the decrease was more significant in the model group and the sham-MA group than that in the MA group(both P<0.05).The superoxide dismutase(SOD)content was markedly higher and the malondialdehyde(MDA)content was markedly lower in the MA group than those in the model group and the sham-MA group(all P<0.05).Compared with the model group and the sham-MA group,the expression of Bax was significantly lower and the expression of Bcl-2 was significantly higher in the MA group(all P<0.05).Conclusion MA therapy can lengthen the sleep time in sleep-deprived rats and improve learning and memory impairments induced by sleep deprivation,and the underlying mechanism may be associated with the enhancement of antioxidant capacity in the prefrontal cortex and the inhibition of hippocampal neuronal apoptosis.