林区某工程本体取样检验C50混凝土强度的折算分析

针对本体取样法在检验结构混凝土强度的应用,采用了误差理论对取样强度值进行数据处理.由此计算修正系数和回归分析,探寻本体取样与标养试件混凝土强度之间的折算关系,并对两种修正结果进行了比较分析,得出回归方程更精确的结论.     

用禽流感H9SD株适时强免对提高蛋鸡生产性能的影响

为了防控低致病性禽流感引发的产蛋下降症,在用禽流感H9HL株免疫(对照组)的同时,再用H9SD696株强化免疫2次(试验组)。结果显示,不同时期抗体效价试验组比对照组平均高出0.66个滴度;平均周产蛋率高出1.25%;死淘率降低2.78%,生产性能和经济效益显著提高。用不同毒株的疫苗免疫鸡群在防控低致病性禽流感的实践中能发挥协同防患的作用,具有一定推广价值。     

Predicting the Stiffness of Sawn Products by X-ray Scanning of Norway Spruce Saw Logs

The aim of the study was to investigate the possibility of strength grading Norway spruce [Picea abies (L.) Karst.] saw logs on the basis of simulated X-ray LogScanner measurements and to evaluate the potential accuracy of X-ray LogScanner measurements of green heartwood density and percentage of heartwood. The study was based on 272 logs for strength grading and 29 logs for measurements of green heartwood density and percentage of heartwood. The logs were scanned using computed tomography (CT). After sawing, the modulus of elasticity (MOE) of the centre boards was measured using a strength-grading machine. The CT images were used for simulations of an X-ray LogScanner, resulting in simulated measurements of different variables such as diameter, taper, percentage of heartwood, density and density variations. Multivariate models for prediction of MOE were then calibrated using partial least squares (PLS) regression. The MOE of a log was defined as the mean value of the MOE of the two centre boards. The study showed that the simulated X-ray LogScanner measured the percentage of heartwood and green heartwood density with relatively high accuracy (R ² = 0.94 and R ² = 0.73, respectively, after removing two outliers) and that these and other variables measured by the simulated X-ray LogScanner could be used to predict the stiffness of the centre boards. These predictions were used to sort the logs according to the predicted MOE. When sorting out 50% of the logs (''high-strength'' logs), the percentage of C30 boards increased from 73% (all logs in the study) to 100% (only ''high-strength'' logs). The rest of the logs could then be divided into two groups, one of them with 100% C24 and C30 boards.     

阿克苏地区混凝土快速强度试验方法研究

主要利用实验所得早期强度或某些参与标准养护28天强度具有一定相关关系的特性，应用数理统计学中的回归理论，建立早期强度或某些参数与标准养护28天强度的关系式，根据要求的标志养护28天强度求得应有的早期强度或某些参数值，据以设计确定混凝土配合比或调整配合比。     

林区桥梁测强曲线的编制

为解决林区桥梁结构砼强度现场检测精度问题，按林区各地区常用原材料，配合比和工艺条件制备试块，并对其回弹法，超声法试验研究，利用数理统计方法确立相关数学关系式Ｒ＝ｆ（Ｎ，Ｌ），Ｒ＝ｆ（Ｖ，Ｎ），建立了林区桥梁测强曲线。     

拆装次数对螺钉连接的木塑构件机械性能的影响

螺钉连接是木塑复合材料构件的一种重要的连接方式,它在反复拆装后能否保持其原用强度尚有待于研究.笔者通过对L型和T型木塑构件,经不同拆装次数的结构强度和握钉力试验,得出了拆装次数与木塑构件强度的基本关系.     

海岛棉纤维含糖量、微观结构与比强度关系的研究

对海岛棉４０个品种（系）的纤维水溶性总糖量、水溶性糖组分、微观结构参数和纤维比强度的分析测试表明：从整体看，零式果枝类型海岛棉纤维总糖量、晶区取向参数均优于长果枝类型；纤维总糖量、晶区取向参数具有中段优势的空间分布特点；葡萄糖＋纤维二糖对晶区取向参数ψ、φ有较显著的正向作用；纤维总糖量通过３个晶区取向参数对纤维比强度有大的负向间接作用，从而抵消了它对纤维比强度的正向直接作用，使其总作用呈负效应；Ｌｅｎ、ψ角、纤维总糖量是影响海岛棉纤维比强度的重要性状指标。这对指导海岛棉高强育种和调控纤维发育以提高纤维比强度有重大意义。     

消除建筑结构中的强度隐患

本文对建筑结构设计与施工中容易被人们忽视的一些强度问题加以讨论，以求消除这些方面的强度隐患。     

A Comparison of the Accuracy and Efficiency of Two Ionic Strength Adjustment Buffers in Measuring Potassium Using an Ion-Selective Electrode

It is recommended to use ionic strength adjustment buffers to increase reading accuracy while measuring potassium (K⁺) concentrations in aqueous solutions by using ion-selective electrodes (ISEs). Three laboratory leachate column studies were conducted to evaluate the efficiency of two buffers, 2.5 M sodium perchlorate (NaClO₄) and 2.5 M sodium chloride (NaCl), in measuring K⁺ concentrations in three media types (peat moss, Oxisols, and Mollisols soils). Three algae species, KCl, and KNO₃ were applied to provide 112 and 336 kg K/ha. Leachate samples were collected to a total of 16 weeks and measured using a K-ISE. The K⁺ data from the three trials showed a highly significant (r ~ 0.99) correlation between the two buffers. T-Test results showed highly significant (P < 0.01) differences between unbuffered and the two buffered solutions. However, there were no significant differences between the two buffered solutions, under the peat moss, Oxisols, and Mollisols soils. The results suggest that the least expensive buffer of 2.5 M NaCl is as accurate as NaClO₄ in such aqueous solutions.     

黔北地区主要竹种的物理力学强度评价

参照木材的材性部分分级标准,对各竹材的物理力学性能评价表明：不同竹种的各项物理及力学强度存在一定的差异,分别属于不同的等级。由于对竹材目前还没有特定的分级规定标准,因此适当参照木材的评价标准对竹材的物理力学性能进行评价具有一定的实际参考意义。