基于探地雷达的田块尺度下不同深度土壤含水量监测

为确定田块尺度下探地雷达对不同深度及相邻反射层间土壤含水量的反演精度、有效反演深度、最佳反演深度及最优反演模型,本研究采用1000 MHz中心频率探地雷达设备,分别在无降雨偏干旱土壤和降雨后湿润土壤两种条件下,在选定农田区域基于共中心点法采集雷达波数据,提取有效地表波与反射波数据,通过双曲线拟合法分别获取不同深度反射层...     

木材流体渗透理论与研究方法

为较全面系统地了解木材流体渗透理论研究现状,从流体在多孔介质内的主要类型与流动理论、流体在木材内的主要流通通道及木材流体渗透性研究的主要理论与试验方法等几方面进行综合概述,提出木材流体渗透性理论研究的主要发展方向.试验观察应采取更先进的手段,动态观察流体尤其是液体渗透木材的整个连续过程,并构筑更合理的木材流体简化结构渗透模型,以较少的参数反映更完整的流体渗透途径;理论研究应借鉴木材干燥过程中应用较成熟的传质传热模型,建筑多孔材料如水泥、石、砖等的渗透性研究,土壤流体渗透性及地下石油流体渗透性研究方面应用较成熟的理论和方法,并拓宽木材渗透性的研究对象,建立符合木材非稳态渗透实际过程的二维或三维理论模型,以更逼真地模拟木材流体渗透过程;2种方法结合起来,定性和定量完整描述木材流体渗透机制.     

探地雷达功率谱模型在砂壤含水率和紧实度探测中的应用

为了快速、高效地探测中国西部地区土地整治后砂壤的物理特性,该研究使用探地雷达对砂壤进行探测,利用自回归移动平均(auto regressive and moving average,ARMA)功率谱估计方法处理数据,建立砂壤物理模型,分析对比不同含水率和紧实度砂壤的功率谱分布特征,分别建立与含水率和紧实度具有最优拟合度的关系模型。结果表明:在频率670 MHz时,低频功率谱能量占全部功率谱能量比值(L/(H+L))与砂壤含水率相关性最强,相关系数达0.952;频率为1 000 MHz时,高频功率谱能量占全部功率谱能量比值(H/(H+L))与紧实度倒数的相关性最强,相关系数达到0.947。通过实际探测验证,该模型可以获得连续、准确、高效的砂壤含水率和紧实度数据,为土地整治工程的质量检测提供技术支持。     

Comparison of the pig and feline models for full thickness corneal transplantation

Purpose The goal of this study was to report on the advantages and limitations of the pig and feline models for experimental in vivo corneal transplantation. Methods Ten healthy domestic pigs and ten healthy cats were used. Full thickness penetrating keratoplasty was performed using autologous (eight cases), allogeneic (seven cases) or human xenogeneic (three cases) tissue. In two other cases, the inflammatory response to partial thickness trephination (without transplantation) was evaluated. Eyes were assessed daily before and after surgery by slit‐lamp, pachymetry, and tonometry. A transparency score ranging from 0 (opaque graft) to 4 (clear graft) was used, based on the slit‐lamp examination. Optical coherence tomography, histology, and electron microscopy were performed postmortem. Results In the pig, the mean (±SD) transparency score for the eight full thickness grafts was 0.88 ± 0.99, ranging from 0 to 3. In the feline model, the mean transparency score for the seven uncomplicated grafts was 3.93 ± 0.19, ranging from 3.5 to 4. Both negative controls without endothelium remained opaque at all time. Intraoperative tendency for iris incarceration into the wound, rapid corneal swelling, suture cheese wiring, and postoperative intraocular inflammation were the main factors jeopardizing the functional success of the corneal transplant in the pig model. Conclusion Suboptimal functional results were obtained after full thickness corneal transplantation in the pig model, while in the feline model, the same protocol yielded uneventful surgeries and clear transplants, with functional results similar to those achieved in human subjects.     

脲醛树脂在水曲柳刨切薄木湿贴工艺中的应用

扼要介绍了湿法棉秆中密度纤维板基材表面用以脲醛树脂为主要成分的混合胶,湿贴厚度为0.25mm和0.4mm水曲柳刨切薄木的工艺,并对基材、胶粘剂、贴面材、胶贴工艺等诸多因素优化研究,比较有效地解决了透胶和脱胶等问题,制得质量合格而又有明显经济效益和使用价值的棉秆中密度纤维板薄本装饰板。研究结果表明,湿贴工艺中采用以脲醛树脂为主要组分的混合胶是可行的,胶贴质量达到日本农林省JAS标准“装饰合板”中规定的指标。     

探地雷达树木根系定位与直径估算

针对树木根系的探地雷达(Ground Penetrating Radar,GPR)检测图像复杂、解译困难、自动化程度低且精度不高等问题,该研究提出了一种基于YOLOv3的树根自动识别和参数估计的方法.通过不同的根预埋试验分析了根直径、掩埋深度和朝向对根系识别和预测的影响,对比评估了在复杂现场环境下该方法与商业软件常用的...     

Validating the effectiveness of alternative euthanasia techniques using penetrating captive bolt guns in mature swine (Sus scrofa domesticus)

Euthanasia of mature swine is challenging. Temporal and behind-the-ear locations are two sites that have been identified as alternatives to the more commonly used frontal placement. In stage one, the effectiveness of two penetrating captive bolt gun styles (cylinder or pistol) was evaluated using frontal, temporal, and behind-the-ear placement in anesthetized mature swine (n = 36; weight: 267 ± 41 kg). For stage one, when evaluating treatment efficacy by sex, the cylinder-style equipment was 100% effective in achieving death when applied to all cranial locations (frontal, temporal, and behind-the-ear) for sows; however, the pistol-style equipment was only 100% effective when applied at the behind-the-ear location for sows. For boars, the cylinder-style equipment was 100% effective when applied to the frontal and behind-the-ear location, but the pistol-style equipment was not effective for any cranial location in boars. Therefore, the pistol–frontal, pistol–temporal, pistol–behind-the-ear, and cylinder–temporal were not included for boars, and pistol–frontal and pistol–temporal were not included for sows in stage two. In stage two, commercial, mixed-breed, mature swine (n = 42; weight: 292 +/− 56 kg) were randomly assigned to one of four treatments based on the inclusion criteria described in stage one. A three-point traumatic brain injury (TBI) score (0 = normal; 1 = some abnormalities; 2 = grossly abnormal, unrecognizable) was used to evaluate six neuroanatomical structures (cerebral cortex, cerebellum, hypothalamus, thalamus, pons, and brain stem), and the presence of hemorrhage was also noted. All treatments were 100% effective in stage two. A significant interaction between gun style and placement was determined on predicting total TBI as the cylinder style produced a higher total TBI score compared with the pistol type of the magnitude of +2.8 (P < 0.01). The cylinder style tended to produce a greater TBI score than the pistol in the temporal location (+1.2; P = 0.08). No difference was noted for TBI score behind-the-ear between the cylinder- and pistol-style gun (P > 0.05). TBI tended to be less in boars compared with sows (−0.6; P = 0.08). Hemorrhage was observed in frontal, parietal, occipital, and temporal lobes. This study demonstrated that the cylinder-style captive bolt gun more effectively resulted in brain trauma and death compared with a pistol-style gun and the behind-the-ear and temporal placement showed promise as an alternative placement site for euthanizing mature pigs on-farm.     

穿流转笼式烘干机设计研究

为了解决某些易碎颗粒物料的烘干问题,设计了穿流转笼式烘干机。物料装在转笼内,随着转笼的转动,在重力和内摩擦力的作用下,连续缓慢地交换内外层物料的位置。热风穿过物料层,使物料均匀烘干。比较了敞口式、三段式和栅栏式出风口对风速分布的影响。通过试验表明,栅栏式出风口的轴向风速分布较均匀。并用开口核桃的烘干进行了生产试验,用风温125℃,风量8 511 m³/h,在2 h内将开口核桃的含水率从30%降低到3%,且干湿均匀,品质好,基本无破碎,可满足生产需要。     

人参黑斑病的研究——Ⅰ.损失调查、病原菌及发病规律

人参黑斑病可使参根减产0.4～1.6倍;重者达10倍以上。人参黑斑病菌Alternaria panax whetz.原取名西洋参;经测定辽宁的分主孢子尺度明显偏大。接种和调查29种杂草,在参场内未见其它奇主.分生孢子萌发的起点温度为1℃±;最适为20～25℃。孢子以在人参叶汁、1％糖水、露水和饱和湿度下萌芽率最高:在蒸馏水、自来水中萌芽率最低;土壤对孢子萌发有强烈抑制作用。病害的侵染来源是分生孢子,以穿透方式侵入,潜育期24～48小时,接种3～6天产生孢子,且病部可反复多次产生,每平方厘米病叶可产孢4,107～51,120个;越冬病叶也可再次产生孢子和造成侵染。孢子没有休眠期,随时可以萌发侵染,但不能为害木质化的茎秆。黑斑病具有小区内局部流行特点。孢子体形大,浮动传播较差,田间菌源的多少与发病成正相关。据辽宁的气象条件,人参产区是黑斑病的长发区。