磷酸尿添加剂对乳牛骨营养代谢影响的X线监测

本文采用％线法监测磷酸尿添加剂对乳牛骨营养代谢的影响。试验结果表明，磷酸尿添加剂不仅能防治骨营养代谢性疾病而且对骨营养代谢无副作用。     

油炸南瓜饼的制作及其品质分析

[目的]研究油炸南瓜饼制作的最佳工艺及油炸前后南瓜饼的品质变化。[方法]以糯米粉和南瓜粉为材料,通过单因素和L9(34)正交试验研究了油炸温度、油炸时间、加水量、南瓜粉与糯米粉配比对油炸南瓜饼质构分析(Texture Profile Analysis,TPA)和感官评价的影响,并探究了油炸前后的南瓜饼含水量、吸油量和结晶度的变化。[结果]试验表明,油炸南瓜饼的最佳条件为:油炸温度150℃,油炸时间6 min,加水量80%,南瓜粉与糯米粉的比例为1∶4;随着油炸温度的升高、油炸时间的延长以及糯米粉比例的增加,油炸南瓜饼的脆性、硬度和黏性都呈现上升趋势,而随着水分含量增加,脆性、硬度和黏性呈现下降的趋势;随着油炸时间的增加,南瓜饼各部分吸油量先增加后趋于平缓;油炸后,南瓜饼外壳、中间和中心的结晶度分别为4.49%、3.86%和3.07%。[结论]在最佳条件下油炸的南瓜饼香脆可口,口感软硬适中,品质较优。     

基于NB-IoT技术的土壤重金属检测仪设计与验证

为解决土壤重金属检测准确度较低、实时性差以及数据分散的问题,该研究设计了一种基于窄带物联网(NarrowBand Internet of Things,NB-IoT)技术的土壤重金属检测仪.自主研发高准确度能量色散X射线荧光光谱仪,将测量得到的数据通过NB-IoT实时上传到数据集成云平台.设计试验探究了该设备的最佳测试...     

近三十年农田土壤磷分子形态的研究进展

农田土壤磷的赋存形态决定迁移、转化及归趋过程,单单通过全磷或有效磷含量并不能全面、准确、长效地评估土壤磷的养分供应能力和生态环境风险,探索可持续的农田磷素管理措施迫切需要能够科学表征、准确认识土壤磷形态。随着分析测试技术发展,农田土壤磷形态领域经历了以传统连续提取法为主的分级组分研究,到目前基于先进光谱技术的分子形态研究的发展历程。液相磷-31核磁共振技术(P-NMR)、基于同步辐射的X射线吸收近边结构谱技术(P-XANES)是当今土壤磷分子形态表征的主流技术,分别促进土壤多种有机磷和无机磷(铁磷/钙磷/铝磷)分子形态的有效识别。借助Histcite软件进行引文网络分析,梳理了近三十年(1990—2019年)土壤磷分子形态研究发展历程中具有重大借鉴意义的关键性成果,基于此综述了该领域的发展脉络,归纳发现农田土壤磷分子形态研究最初主要借助P-NMR技术侧重有机磷分子形态表征,而后过渡至与同步辐射XANES以及X射线微探针技术相结合,实现了土壤磷分子形态的全面认识。最后,对多谱学技术联用推动土壤磷分子形态研究的发展趋势进行了展望。     

A non-destructive method for the morphological assessment of earthworm burrow systems in three dimensions by X-ray computed tomography

Summary Earthworm burrows of endogeic species (Allolobophora caliginosa, Octolasium cyaneum) in artificially packed soil columns were examined using X-ray computed tomography. By means of digital image processing, it was possible to reconstruct and visualize the burrow system in three dimensions. The reconstruction revealed morphological features of the burrows which were not obvious from two-dimensional section images.     

高能重离子束和X射线辐射水稻幼苗的当代生物学效应研究

为探究高能重离子束和X射线辐射对水稻幼苗生长发育和生理特性的影响,使用5~40 Gy的高能碳离子束和10~80 Gy的X射线辐射处理粳稻Kitaake幼苗,测定根长、芽长、苗高、株高、分蘖数、结实率、千粒重、光合特性、抗氧化酶活性及遗传物质多态性指标。结果表明,高能重离子束或X射线辐射水稻幼苗后,其根长和芽长均呈现随辐射剂量增加而降低的趋势,但存活植株成熟期的株高与未辐射组相比差异不显著;M₁植株结实率及种子千粒重随剂量升高呈下降趋势,在较高剂量下表现为显著降低。辐射处理后相对根长约为69%时,两种辐射对幼苗的根及芽在较短时间内的抗氧化系统存在显著影响。与未辐射组相比高能碳离子束辐射组的叶绿素含量和F_v/F_m值均无显著差异,而X射线辐射处理组的叶绿素含量较高、F_v/F_m值降低。20 Gy高能碳离子束辐射处理水稻幼苗简单重复序列间扩增(ISSR)多态率为29.31%,40 Gy X射线辐射处理水稻幼苗ISSR多态率为37.76%。本研究结果为不同电离辐射处理水稻幼苗提供了推荐的诱变剂量区间:高能碳离子束20~30 Gy,X射线30~40 Gy。     

A neighborhood median weighted fuzzy c-means method for soil pore identification

Complex soil pore geometry and heterogeneity determines the ability of a soil to retain moisture and conduction. These soil properties are widely recognized as key factors of essential ecological functions and services. However, until recently, the existing pore identification methods have the problems of low identification accuracy and operating efficiency, which has restricted the development of soil science. The objective of this study was to propose a neighborhood median weighted fuzzy c-means method based on grayscale-gradient feature (NMFCM-G) to identify soil pore structure automatically and accurately. By combining three-dimensional (3D) printing technology with X-ray computed tomography technology, a 3D simulation model with known aperture (10-cm inner diameter) was adopted to evaluate the pore identification error rate of the NMFCM-G method quantitatively. Compared to the methods commonly applied in previous studies, the NMFCM-G method had the smallest average area relative error (2.98%), which was only 1/6 of that of the Image J method with the largest area relative error (18.46%). The NMFCM-G method also had the smallest average perimeter (5.46%), about 3/5 of that of the Image-Pro Plus method with the largest perimeter relative error (8.35%). Meanwhile, the NMFCM-G method was successfully tested on undisturbed cylindrical soil samples, providing encouraging results in terms of identifying irregular pore structure from the complex hierarchical organization of soil. The results show that the NMFCM-G method had the smallest distribution entropy (0.81), the smallest inter-class correlation (0.164 0), and the largest distribution coefficient (0.11), which proves that the NMFCM-G method performed the best in identifying different soil pore structures. Overall, the NMFCM-G method provides new insights into identifying pore structures and thus could provide an automatic and high-efficiency technique for studying the effects of tillage and freeze-thaw cycles on pore structure and soil quality in the future.     

Quantitative analysis of earthworm burrow systems with respect to biological soil-structure regeneration after soil compaction

 On arable land, tilled with conventional tillage (CT) and conservation tillage (CS) respectively, plots were compacted by wheeling them 6 times with a 5 Mg wheel load in spring 1995. Immediately after compaction, undisturbed soil monoliths were excavated from the compacted and uncompacted plots. The monoliths were defaunated and inoculated with either Lumbricus terrestris or Aporrectodea caliginosa. One monolith from each plot remained uninoculated as a control. After 6 months the monoliths were defaunated again and then scanned with X-ray helical computed tomography. The data were transformed, the void systems inside the monoliths were reconstructed and visualised, and the parameters total void length, total void volume, tortuosity and continuity were quantified. The parameters' values were generally lower in the controls than in the inoculated monoliths. Differences in burrow construction could be explained by the different life strategies of the two earthworm species. Changes in burrow morphology due to tillage system and soil compaction were minor. Only the continuity of the burrow systems clearly changed: decreasing for L. terrestris and increasing for A. caliginosa. This can be explained by a change in the earthworms' burrowing activity to minimise energy expenditure in compacted soil. By extrapolating field data, we concluded that earthworms have great potential for biologically regenerating the soil structure after a single compaction event. Due to higher earthworm abundances in soil managed by CS the regeneration of the soil structure is assumed to be better in these plots than those tilled by CT. Received: 17 December 1997     

X射线能谱和FTIR分析铜胁迫对玉米幼苗的影响

应用X射线能谱和傅里叶变换-衰减全反射红外光谱（FTIR-ATR）分析方法结合一些生理指标的变化及幼苗叶片下表皮扫描电镜观察,研究一定浓度（0、200、400、800、1000mg.kg-1）Cu2＋胁迫对玉米幼苗的影响。结果表明,随着Cu2＋浓度增高,叶绿素含量呈下降趋势,抗氧化酶（SOD、CAT、POD、APX）活...     

西藏拉屋和扎西康矿区土壤的黏粒矿物组成研究

采集西藏拉屋和扎西康两矿区代表性土壤样品,测定了土壤基本性状、黏土矿物和氧化铁含量。结果表明:拉屋矿区土壤呈酸性,扎西康矿区土壤呈碱性。拉屋矿区土壤有机质含量和CEC明显高于扎西康矿区的;两矿区的主要黏土矿物有水云母、高岭石、绿泥石、蛭石、1.4 nm过渡矿物和少量的混层矿物。拉屋矿区主要矿物是水云母和高岭石,扎西康矿区主要矿物是水云母;两矿区土壤的游离氧化铁均以晶形氧化铁为主,非晶形氧化铁所占比例很少。