Identifying sources of soil inorganic pollutants on a regional scale using a multivariate statistical approach: role of pollutant migration and soil physicochemical properties

Principal components analysis (PCA) and correlation analysis were used to estimate the contribution of four components related to pollutant sources on the total variation in concentrations of Cu, Zn, Pb, Cd, As, Se, Hg, Fe and Mn in surface soil samples from a valley in east China with numerous copper and zinc smelters. Results indicate that when carrying out source identification of inorganic pollutants their tendency to migrate in soils may result in differences between the pollutant composition of the source and the receptor soil, potentially leading to errors in the characterization of pollutants using multivariate statistics. The stability and potential migration or movement of pollutants in soils must therefore be taken into account. Soil physicochemical properties may offer additional useful information. Two different mechanisms have been hypothesized for correlations between soil heavy metal concentrations and soil organic matter content and these may be helpful in interpreting the statistical analysis.     

电气火灾产生的机理及其对策

火灾是各种灾害中,发生频繁、损失重大的灾种。为此,集中讨论在火灾中占有较大比例的电气火灾;分析研究输电线路产生火灾的机理及其发展规律;特别指出提高全民防火意识,对减少火灾损失、保护人民生命和财产的安全有十分重要的作用     

基于方位轴旋转的平台惯导系统对准策略研究

目的解决平台惯导静基座自对准精度受到平台转位、锁定及惯性仪表误差影响的问题。方法提出一种绕方位轴变速旋转的平台惯导连续自对准方法。该方法基于平台按照方位陀螺力矩指令绕方位轴变速旋转,采集水平陀螺的力矩电流输出信息估计平台失准角及仪器误差系数。通过输出灵敏度理论对系统的可观测度进行分析后,采用建立虚拟平台系的参数估计方案使得方位失准角估计精度得到提高。结果当测量噪声为0.01(°)/h(1σ),方位失准角对准精度在10″以内,对准过程可以在10 min内完成。结论该方案及算法使惯导平台静基座自对准精度得到显著提高。     

基于CFD的土工离心机风阻及流场特性分析

目的估计土工离心机的风阻功率。方法针对一稳态运行的中低速土工离心机,利用多参考坐标系(MRF)模拟转臂与墙壁之间的相对运动,对离心机稳态运行时机室内的空气流场进行CFD仿真,对计算流体力学仿真、解析公式方法和试验的风阻功率进行对比。结果三种方法得到的风阻功率较为接近,验证了数值仿真方法的正确性。同时,研究了机室内空气流速和压力的空间分布特征,验证了经典解析公式的假设合理性。结论 CFD仿真方法避免了传统解析方法对试验数据的依赖和参数选取主观性,能够得到较高精度的分析结果,该研究为基于计算流体力学的土工离心机的高置信度风阻计算打下了基础。     

Early prenatal diagnosis of short rib-polydactyly (SRP) syndrome type I (Majewski) by ultrasound in a case at risk

Short rib-polydactyly (SRP) syndrome Type I was diagnosed accurately in an at-risk fetus at 16 weeks of gestation by real-time sonography. The most important findings were a narrow thorax, significant shortening of the long bones, particularly the tibiae, and–by directed search–the polydactyly.     

一种新型除尘器在梅山铁矿选厂的应用

介绍了喷雾双向旋流除尘器的原理及在矿山选厂除尘中的应用。     

黑龙江省森林火灾灾情年际变化与地球自转异常的遥联关系

根据天地生相互作用原理，针对地球自转因子的多年变化情况以及与在此期间森林火为灾情的关系的研究，揭示了森林火灾和地球自转有密切的联系，为林火预测提供了新的思路。     

秸秆/生物炭施用对关中地区小麦-玉米轮作系统净增温潜势影响的对比分析

为探讨秸秆、生物质炭施用对小麦-玉米轮作系统固碳减排效应,利用静态暗箱-气相色谱原位监测小麦-玉米轮作系统条件下秸秆、生物质炭施用对土壤CO_2、CH4和N_2O 3种温室气体排放、作物产量、土壤有机碳以及净增温潜势的影响.试验处理设置为:空白对照(CK)、常规施肥(F)、施肥并施用8 t·hm-2秸秆(FS)、施肥并施用8 t·hm-2生物质炭(FBlow)和施肥并施用16 t·hm-2生物质炭(FBhigh)共5个处理.结果表明:与F处理相比,FS、FBlow及FBhigh处理下小麦产量分别提高了30.9%、66.3%和36.6%;对于玉米产量而言,FS,CK及FBhigh处理下玉米产量分别降低了14.1%、18.0%和24.6%,但是FBlow处理下对玉米产量没有显著性的影响.与F处理相比,FS处理下土壤CO_2的年排放总量增加了60.2%,但是FBhigh处理下土壤CO_2的年排放总量减低了14.4%;生物质炭的施用降低了土壤N_2O的排放,与F处理相比,FBlow和FBhigh处理下分别减低了27.6%和38.7%,而秸秆的施用对N_2O的排放没有显著性的影响.总的来说,与F处理相比,FBlow和FBhigh处理下净增温潜势分别降低了24.13和58.44 t·hm-2,单位产量的净综合增温潜势分别降低了1.78和5.06 t·t-1.综上所述,对于小麦-玉米轮作体系而言,施用16 t·hm-2生物质炭可作为一种提高作物产量并降低净增温潜势的良好措施.     

The MONICA model: Testing predictability for crop growth, soil moisture and nitrogen dynamics

A fundamentally revised version of the HERMES agro-ecosystem model, released under the name of MONICA, was calibrated and tested to predict crop growth, soil moisture and nitrogen dynamics for various experimental crop rotations across Germany, including major cereals, sugar beet and maize. The calibration procedure also included crops grown experimentally under elevated atmospheric CO₂ concentration. The calibrated MONICA simulations yielded a median normalised mean absolute error (nMAE) of 0.20 across all observed target variables (n = 42) and a median Willmott's Index of Agreement (d) of 0.91 (median modelling efficiency (ME): 0.75). Although the crop biomass, habitus and soil moisture variables were all within an acceptable range, the model often underperformed for variables related to nitrogen. Uncalibrated MONICA simulations yielded a median nMAE of 0.27 across all observed target variables (n = 85) and a median d of 0.76 (median ME: 0.30), also showing predominantly acceptable results for the crop biomass, habitus and soil moisture variables. Based on the convincing performance of the model under uncalibrated conditions, MONICA can be regarded as a suitable simulation model for use in regional applications. Furthermore, its ability to reproduce the observed crop growth results in free-air carbon enrichment experiments makes it suited to predict agro-ecosystem behaviour under expected future climate conditions.     

黄河下游冲积平原轮作休耕农田土壤真菌群落结构与功能

通过明确不同轮作休耕方式对土壤真菌群落结构及功能的影响,探索农田土壤肥力对轮作休耕方式响应的微生态变化特性,为促进黄河下游冲积平原农田生态修复和耕地质量提升提供参考依据.以2018年开始的长期轮作休耕定位试验农田土壤为研究对象,采用Illumina MiSeq高通量测序技术,通过FUNGuild真菌功能预测工具,分析田间定位条件下不同轮作休耕方式［长期休耕(LF)、冬小麦-夏休耕(WF)、冬休耕-夏玉米(FM)和冬小麦-夏玉米周年轮作(WM)］,土壤真菌群落组成和功能的差异及其影响因素.结果表明,LF使耕层(0~20 cm)土壤真菌群落丰富度和多样性增加,而WF则使冬小麦收获后深层(20~40 cm)土壤的真菌丰富度和多样性增加;所有土壤样本中共获得2262 OTU,划分为14门、34纲、75目、169科、309属和523种,两个土层中共有的OTU分别包含420类(0~20 cm)和253类(20~40 cm);4种轮作休耕土壤真菌群落门水平上的结构组成相似,但相对丰度各异,优势菌门均为子囊菌门(Ascomycota)、担子菌门(Basidiomycota)和被孢菌门(Mortierellomycota),总丰度分别为91.69%~96.91%(0~20 cm)和91.67%~94.86%(20~40 cm);PCoA分析发现,PC1和PC2可以分别累计解释45.56%(0~20 cm)和46.20%(20~40 cm)的群落组成差异;LEfSe的LDA (阈值为4.0)结果可知,LF、FM、WF和WM中共有64个真菌进化枝在统计学上具有显著差异(P＜0.05);RDA分析表明,土壤有机碳(TOC)、全磷(TP)、碱解氮(AN)和含水率(SWC)同是显著影响0~40 cm土层真菌群落变化的主要环境因子(P＜0.05).通过FUNGuild功能比对发现,不同土层不同处理间的主要营养类型同为腐生营养型、腐生-共生营养型、病理-腐生-共生营养型和病理营养型,但其相对丰度存在差异;LF耕层土壤以病理-腐生-共生营养型真菌为主,深层土壤中则以病理营养型真菌相对丰度最高,而种植过小麦或玉米的处理(FM、WF和WM)两个土层都以腐生营养型为主.由此可见,不同轮作休耕方式改变了土壤真菌群落结构、多样性及营养类型,季节性休耕可用于调控集约化种植的农田土壤微生态环境,促进农田土壤生态系统健康和谐.