基于希尔伯特-黄变换的覆土层厚度动态探测

准确揭示动态沉降过程中土层厚度及其变化情况对合理确定覆土层厚度,科学评价复垦土体稳定性具有重要意义。通过野外试验,结合探地雷达数据,基于希尔伯特-黄变换(Hilbert-Huang transform, HHT)进行信号处理,根据希尔伯特谱确定覆土层所在的时域范围;提取由HHT获取的多个固有模态函数(Intrinsic mode function, IMF)的时间-瞬时频率信息,建立IMF2分量与相对介电常数的关系模型,进而获取覆土层厚度;将所建立的关系模型进一步应用于时间序列上的覆土层厚度的探测之中,实现覆土层厚度的动态探测。研究结果表明：覆土层下沉会引起层状介质之间的介电常数差异,进而导致分界面处的振幅变化;瞬时频率平均值与相对介电常数之间存在较高相关性,其利用多项式回归的建模决定系数R²达到0.887 0;综合考虑时域下的振幅与瞬时频率变化的联合时频分析可有效探测覆土层厚度,随覆土层厚度的增加和时间的推移探测精度整体略有下降,探测结果的平均相对误差为3.65%。     

多约束条件下复垦土壤水分的微波探测及标定

探地雷达(GPR)是一个采用微波技术对地下目标进行无损探测的技术,试验旨在揭示复垦土壤在多盐分及多重金属污染条件下,不同水分系列对探地雷达的影响程度,试验采用中心频率为400 MHz的天线。GPR探测的体积水分含量与烘干法存在较大的误差,在体积水分含量达到40%左右,二者的测量值非常接近,随着水分含量的降低,误差增大。GPR探测的体积水分含量、复垦土壤电导率、复垦土壤孔隙度密切相关。通过拟合,建立了复垦土壤体积水分含量的数学模型。能够提供实时的大田规模土壤水分数据,解决了复垦田块有效灌溉管理关键技术。     

基于探地雷达的根系探测对土壤含水量的响应

在探地雷达对地下根系进行探测和识别的过程中,土壤含水量是影响根系探测效果的一个极为重要的因素.本文在2种质地土壤(砂质壤土和粘土)不同水分含量下,通过探地雷达对根进行模拟试验,测定了2种质地土壤的电磁波波速,同时测试了根的探测效果.结果表明:土壤含水量是影响电磁波波速的主要因素,电磁波波速不受天线频率的影响,但随着土壤...     

Impact of Temperature in Air-conditioned Room on Blood Rheological Characteristics

Based on the reversed cyclic loading tests of 21 nearly full-size interior joints in completed reinforced concrete frames,the law of bond deterioration of beam bars crossing the joint is tested and analyzed,which is influenced by the axial load ratio,shear-compression ratio,reinforced bar strength,concrete strength and the relative length of beam bars crossing the joint. By the nonlinear fitting method, the formula of the bond stress r between steel crossing interior joints and concrete under different loading step is obtained. According to the loading approach, the propositional formula of the relative length of beam bars crossing the joint hc/d is presented, which is influenced by axial load ratio, shear-compression ratio ,reinforced bar strength and concrete strength.     

利用GPR多频天线振幅包络平均值法估算滴灌棉田土壤盐分含量

土壤盐渍化问题严重制约着农业经济发展,快速准确地掌握农田土壤的盐渍化信息是盐渍化防治的前提.为准确快速地了解滴灌棉田土壤盐分含量情况,该研究采用探地雷达(Ground Penetrating Radar,GPR)多频天线(250 MHz和1000 MHz)对典型滴灌棉田土壤进行探测,通过GPR振幅包络平均值法(Aver...     

Evaluation of outcome associated with feline trauma: A Veterinary Committee on Trauma registry study

Objective

To evaluate outcome (survival to discharge) among trauma types (blunt, penetrating, both) in cats. Secondary objectives were to evaluate for associations between trauma type, injury severity, and the diagnostics and interventions selected by primary clinicians.

Design

Retrospective evaluation of veterinary trauma registry data.

Setting

Veterinary Committee on Trauma (VetCOT) veterinary trauma centers (VTCs).

Animals

A total of 3895 feline trauma patients entered in the VetCOT trauma registry from April 1, 2017 to December 31, 2019.

Interventions

Data collected included patient demographics, trauma type, Abdominal Fluid Score (AFS), Animal Trauma Triage (ATT) score, surgical intervention, glide sign on Thoracic Focused Assessment with Sonography for Trauma, Triage, and Tracking (TFAST), pleural effusion on TFAST, modified Glasgow Coma Scale (mGCS), and outcome (survival to discharge).

Measurements and Main Results

Data from 3895 cats were collected over a 30-month period. Incidence of trauma types was as follows: blunt, 58% (95% confidence interval [CI]: 56%–59%); penetrating, 35% (95% CI: 34%–37%); and combination, 7.4% (95% CI: 6.7%–8.3%). Differences in survival incidence among the trauma types were identified: blunt, 80% (95% CI: 78%–81%); penetrating, 90% (95% CI: 89%–92%); and combined, 68% (95% CI: 63%–74%) (P < 0.01). Cats in the penetrating trauma group had the lowest proportion of severe injuries (6%) and highest proportion of mGCS of 18 (89%); cats with combined trauma had the highest proportion of severe injuries (26%) and lowest proportion of mGCS of 18 (63%). Point-of-care ultrasound and surgery were not performed in the majority of cases. When surgery was performed, the majority of blunt cases’ procedures occurred in the operating room (79%), and the majority of penetrating cases’ procedures were performed in the emergency room (81%).

Conclusions

Cats suffering from penetrating trauma had the best outcome (survival), lower ATT scores, and higher mGCS overall. Cats that sustained a component of blunt trauma had a lower survival rate, higher ATT scores, and the highest proportion of mGCS <18.     

中兽药复方涂膜剂乳炎清体外透皮效果研究

目的：评价中兽药复方涂膜剂乳炎清于奶牛乳房皮肤的透皮效果。方法：以中兽药复方涂膜剂乳炎清中绿原酸成分为标记物，运用高效液相色谱法（HPLC）测定透过液中绿原酸的含量，评价中兽药复方涂膜剂乳炎清中绿原酸透过皮肤的动力学特征。结果：动力学曲线类似零级动力学，说明乳炎清涂膜剂具有维持恒定的血药浓度或药理效应、延长作用时间等优点。结论：中兽药复方涂膜剂乳炎清对奶牛乳房皮肤具有一定的透皮效果。     

探地雷达测定土壤含水率研究综述

准确快速测定土壤含水率,在理论研究与实际应用中都具有重要意义。在综合分析烘干法、中子法、时域反射法和遥感4种土壤含水率测定方法的优缺点基础上,指出探地雷达是一种适合于中尺度的土壤含水率测定的技术。对探地雷达以及探地雷达测定土壤含水率的技术原理与方法进行全面介绍,并以介电常数与土壤含水率的关系模型为主,对国内外这方面的研究工作以及存在的问题进行了总结。最后指出,探地雷达测定土壤含水率是一项非常有前景的技术,但目前国内在这方面的研究工作与国外相比远远不够,今后应加强这方面的研究工作。     

Effect of different penetrating and non‐penetrating cryoprotectants and media temperature on the cryosurvival of vitrified in vitro produced porcine blastocysts

The aim of this study was to determine the most efficient vitrification protocol for the cryopreservation of day 7 in vitro produced (IVP) porcine blastocysts. The post‐warm survival rate of blastocysts vitrified in control (17% dimethyl sulfoxide + 17% ethylene glycol [EG] + 0.4 mol/L sucrose) and commercial media did not differ, nor did the post‐warm survival rate of blastocysts vitrified in medium containing 1,2‐propandiol in place of EG. However, vitrifying embryos in EG alone decreased the cryosurvival rate (55.6% and 33.6%, respectively, p < .05). Furthermore, the post‐warm survival rates of blastocysts vitrified with either trehalose or sucrose as the non‐penetrating cryoprotectant did not differ. There was also no significant difference in post‐warm survival of blastocysts vitrified in control (38°C) media and room temperature (22°C) media with extended equilibration times, although when blastocysts were vitrified using control media at room temperature, the post‐warm survival rate increased (56.8%, 57.3%, 72.5%, respectively, p < .05). The findings show that most cryoprotectant combinations examined proved equally effective at supporting the post‐warm survival of IVP porcine blastocysts. The improved post‐warm survival rate of blastocysts vitrified using media held at room temperature suggests that the cryoprotectant toxicity exerted in 22°C media was reduced.