不同保水固沙措施对沙培番茄生长和基质环境的影响

针对我国荒漠化危害严重,不利于植物种植等系列问题,以番茄为试验材料,结合纸膜、保水剂、生物基固沙剂等不同保水固沙措施,分析各处理下基质的理化性质以及番茄的生物学性状,以探明各处理对沙地环境的改善效果及对番茄生长的影响,为沙漠的防治及沙产业的发展提供参考。结果表明:瓦楞纸处理显著提高了番茄果实的有机酸、可溶性糖含量,分别比CK高27. 78%、8. 87%,其pH值比CK高0. 89,速效氮含量是CK的40倍;牛皮纸处理20~40 cm含水量比CK高73. 40%;保水剂处理可明显促进根系的生长发育,其根长、根直径以及体积分别比CK高16. 25%、29. 17%、56. 58%,番茄可溶性固形物含量比CK高7. 17%,沙子的比重和总孔隙度分别比CK高12. 88%、38. 35%,但容重比CK低6. 88%;生物基B处理可明显提高果实内可溶性糖含量,比CK高15. 53%,可显著提高沙子中的速效钾含量,比CK高55. 99%,有机质含量比CK高10. 91%;生物基A处理对番茄的株高有明显的促进作用,比CK高19. 81%,叶绿素含量比CK高8. 24%,番茄根系的总长比CK高45. 95%,叶片净光合速率是CK的1. 66倍,蒸腾速率以及气孔导度都相对较高,果实内可溶性固形物以及可溶性糖的含量分别比CK高6. 33%、8. 87%,容重比CK高3. 33%,速效氮含量是CK的16倍。通过主成分分析,生物基A的综合得分最高。因此,生物基A处理对促进番茄生长发育以及改善沙地生态环境效果最显著。宁夏回族自治区“十三五”重大研发项目(2016BZ0902);;“十二五”国家科技支撑计划项目(2014BAD05B02);;吴忠国家园区专项(2016BN05);;宁夏回族自治区科技创新领军人才项目(KJT2017001

Imposex of Thais clavigera and Cantharus cecillei in the coastal waters of Xiamen

海产腹足类性畸变以其对有机锡的敏感性、特异性和不可逆性而成为海洋有机锡污染的理想指示种。调查研究了厦门海域岩相海岸带疣荔枝螺(THAIS ClAVIgErA)和甲虫螺(CAnTHAruS CECIllEI)的性畸变情况,通过生物学指标IOI(性畸变率)、rPSI(相对阴茎发展指数)、VdSI(输精管发展指数)及SrI(性比指数)综合评价其性畸变发展程度,间接指示厦门周边海域的有机锡污染程度。研究结果发现,在采集疣荔枝螺的17个站点中有5个站点种群性畸变率为100%,其中宝珠屿种群性畸变程度最为严重,VdSI达4,采集甲虫螺的4个站点的种群性畸变率均为100%。性畸变程度较严重的种群普遍集中于厦门西港,并且表现出由港内到港外逐渐减轻的趋势,而白城、会展中心和大嶝岛等位于开阔的厦门东海域的种群性畸变程度最轻,与往年厦门西海域有机锡污染监测数据相比一致,体现出性畸变程度与有机锡污染程度及海港码头远近之间的相互关系。The degree of imposex,i.e.the imposition of male characteristics onto females,in neogastropods can be used as a sensitive and accurate biomarker to evaluate organotin contamination in coastal marine environment.Now,the imposex status in females of Thais clavigera and Cantharus cecillei in 17 sites was investigated to evaluate the organotin contamination along Xiamen Bay during 2006 and 2007.The four indices including incidence of imposex(IOI),relative penis size index(RPSI),vas deferens sequences index(VDSI) and sex ratio index(SRI) were used comprehensively to assess the imposex status in order to ascertain the extent of organotin bioavailability in Xiamen Bay.Based on this research,T.clavigera in 5 sites and C.cecillei in all survey sites exhibited the IOI of 100%.At Bao ZhuYu Islet,the imposex level was the most serious with maximum VDSI value of 4.In general,the imposex level decreased from the inner to the outer of Xiamen Western Harbour,and the populations in the open Xiamen Eastern Waters including Bai Cheng,Convention and Exhibiton Center and Dadeng Island showed a lower imposex level.These results were accordant with the concentrations of organotins in 2005.The imposex degree also increased with increasing organotin contamination and decreasing distance from shipping facilities.国家自然科学基金资助项目(40476048);厦门大学近海海洋环境科学国家重点实验室开放基金资助项目;厦门大学新世纪优秀人才计划基金资助项

Electrocatalytic reduction of CO2 to ethylene and ethanol through hydrogen-assisted C-C coupling over fluorine-modified copper

精准控制C1分子C-C偶联合成特定C2+化合物是C1化学中极具挑战性的难题。由于C2+化合物(如乙烯和乙醇)在化工和能源领域具有重要用途，将CO2直接转化为C2+产物极具吸引力。发展高效催化剂，实现高电流密度、高C2+选择性、高稳定性的“三高”性能，是推进电催化还原CO2走向实际应用的关键。研究团队针对电催化还原CO2中高CO2还原法拉第效率的催化剂常常活性低的问题，提出了适当提高催化剂活化水的能力对增加CO2还原活性的重要性，发展出氢助碳碳偶联(hydrogen-assisted C-C coupling)的新策略，在氟修饰的铜(F-Cu)催化剂上实现了CO2电催化还原制乙烯和乙醇的新突破。该研究工作实验部分主要由王野、张庆红教授指导，能源材料协同创新中心iChEM2016级博士生马文超、固体表面物理化学国家重点实验室高级工程师谢顺吉(共同第一作者)完成；理论计算部分由程俊教授指导，2017级硕士生刘彤彤(共同第一作者)、2016级博士生樊祺源完成。叶进裕博士为原位红外测试提供了支持。上海光源姜政研究员、孙凡飞博士、杨若欧为同步辐射表征提供了支持。 这是投稿的最终版本，正式出版的论文版本请访问官方链接（https://doi.org/10.1038/s41929-020-0450-0）。Electrocatalytic reduction of CO2 into multi-carbon (C2+) products is a highly attractive route for CO2 utilization. However, the yield of C2+ products remains low because of the limited C2+ selectivity at high CO2 conversion rate. Here, we report a fluorine-modified copper catalyst that exhibits an ultrahigh current density of 1.6 A cm−2 at C2+ (mainly ethylene and ethanol) Faradaic efficiency of 80% for electrocatalytic CO2 reduction in a flow cell. The C2-4 selectivity reaches 85.8% at a single-pass yield of 16.5%. We show a hydrogen-assisted C−C coupling mechanism between adsorbed formyl (CHO) intermediates for C2+ formation. Fluorine enhances water activation, CO adsorption and hydrogenation of adsorbed CO to CHO intermediate that can readily undergo coupling. Our findings offer an opportunity to design highly active and selective CO2 electroreduction catalysts with potential for practical applicationThis work was supported by the National Key Research and Development Program of the Ministry of Science and Technology of China (No. 2017YFB0602201), the National Natural Science Foundation of China (Nos. 21690082, 91545203, 21503176 and 21802110), We thank staffs at the BL14W1 beamline of the Shanghai Synchrotron Radiation Facilities (SSRF) for assistance with the EXAFS measurements.研究工作得到科技部重点研发计划（批准号：2017YFB0602201）和国家自然科学基金（批准号：21690082、91545203、21503176、21802110）项目的资助

The distributions of radionuclides in a sediment core and sedimentary rate in the intertidal zone of Xinghuawan Bay

利用2007年8月31日采集于福建兴化湾西岸的潮间带沉积物岩心样品,用γ谱方法测量了其放射性核素含量,对岩心中核素的分布及其成因进行了讨论,估算了研究区沉积物的沉积速率,探讨了沉积物的物源,结果表明:(1)238u2、28TH2、28rA2、26rA2、10Pb1、37CS和40k的含量分别为35.0--60.6、52.6--69.3、49.0--66.5、22.7--36.2、26.3--84.8、0.5--1.3和775--831 bQ/kg;(2)用238u2、26rA1、37CS和40k作为示踪剂进行物源分析发现,兴化湾潮间带沉积物主要源于邻近的福州和莆田地区的土壤,所占比率分别为54%和46%;(3)用210PbEX和137CS方法估算得兴化湾西岸潮间带沉积物的平均沉积速率分别为0.38 CM/A和0.36 CM/A。岩心中210PbEX分布表明,自20世纪末,研究区潮间带沉积速率加快。One sediment core was collected from intertidal zone located west coast of Xinghuawan Bay,Fujian,China.The radionuclide contents in the cores were measured by γ spectrometry and the vertical distributions of the nuclides were discussed.The sources of sediment were evaluated using 238U,226Ra,137Cs and 40K as tracers.The sedimentary rate was estimated by 210Pbex and 137Cs methods.The detectable nuclides in this core are 238U,228Th,228Ra,226Ra,210Pb,137Cs and 40K.The contents of these nuclides are 35.0--60.6,52.6--69.3,49.0--66.5,22.7--36.2,26.3--84.8,0.5--1.3 and 775--831 Bq/kg,and with the averages of 45.4,61.2,61.2,31.4,45.6,0.9 and 804 Bq/kg respectively.The 238U activities in the 0--40 cm zone were comparable within the measuring error and high 238U contents were found in the depth of 50～60 cm and below which 238U activities fluctuate with no trend.With the similar trend,from surface to 22 cm depth the activities of 228Th and 228Ra are lower and increase slowly with increasing depth,and they are consistent within the error.Throughout the entire core length the 228Ra and 228Th is decay equilibrium.226Ra activities increase with increasing depth from surface to 22 cm depth,and the contents comparable from 22 cm to 72 cm,occurring fluctuation deeper than 72 cm.The 210Pb activities decrease exponentially both from surface to 12 cm and in the zone of 16～40 cm,but below the depth of 40 cm 210Pb is decay equilibrium with 26Ra.The distribution has a maximum activity at the depth of 16 cm,above which the 137Cs contents are consistent within measuring error but below which decrease with depth.40K is uniform distribution through entire length of the core.The sedimentation sources of Xinghuawan Bay are mainly from the surface soil of Fuzhou and Putian Prefectures surrounding it.Using 238U,226Ra,137Cs and 40K as tracer,by the content data of these four nuclides in the sediments measured in this study and in the land soil reported by literature,we calculated the contributions of the soils of Fuzhou and Putian Prefecture are 54% and 46% respectively.That means that natural radionuclides can be used as tracers to analyse material source of sediment.Sedimentation rate based on 210Pbex and 137Cs was estimated,that was 0.38 cm/a and 0.36 cm/a.From the 210Pbex distribution,we can deduce the sedimentation rate had changed at about 2000.The sedimentation rate was 0.27cm/a before 2000 and 1.07cm/a after that time,which was considered as abundant terrigenous material supplied by human activities after 2000.国家自然科学基金资助项目(40306018

直齿轮传动误差激励分析与齿廓修形曲线设计

探讨了直齿轮轮齿交替啮合过程、单/双齿对啮合变形曲线、修形曲线三要素、传动误差及其振动激励频谱特性,提出了基于传动误差振动激励的修形曲线优化设计三原则,并分析了满载、轻载及兼顾两者的修形曲线优化规律和设计方法

基于BP神经网络模型模拟塔里木河下游潜水埋深变化——以英苏断面C5井为例

本文以塔里木河下游英苏断面350 m处C5井为研究对象,分析了影响下游英苏断面的潜水埋深影响因素,通过三层BP神经网络模型模拟了潜水埋深变化.以Matlab7.0为工作平台,将2000.7-2008.12期间的英苏C5井的步长为3个月数据资料作为一个样本,选取每个样本的输水量、输水持续天数、上季度该井的潜水埋深平均值作为模型输入量,输出量为相应的C5井的本季度的潜水埋深平均值,建立3-11-1的BP神经网络模型,模拟了C5井潜水埋深.结果表明,网络模拟相对误差小于5%,模型具有较高的精度.通过BP模型模拟潜水埋深,为塔河下游生态恢复和水资源决策提供一定的依据

Blisk single-face/double-face laser shock peening light path system

本发明公开了一种整体叶盘单/双面激光冲击强化光路系统，属于整体叶盘激光冲击强化加工领域。主要由光学平台、数控滑台、数控转台、反射镜、聚焦镜、匀光镜片、摆臂、能量计、防护板、防护罩、导光管等一起组成四套光路。这四套光路可以通过手动/自动的方式选择任意一套光路工作，也可以选择光路二和光路四同时工作，其中，光路一和光路三为聚焦光路，当输入直径＜27mm的激光束时，输出的激光光斑为直径2-5mm的光强均匀的圆形光斑，光路二和光路四为匀光光路，当输入直径＜27mm的激光束时，输出边长2-5mm的光强均匀的方形光斑。本发明结构简单，使用方面，在提高生产效率的同时，保证了激光冲击强化质量的均匀性和稳定性