Comparison study of two different topical lubricants on tear meniscus and tear osmolarity in dry eye

PurposeTo compare the effect of single-drop administration of two different ophthalmic solutions on tear meniscus and tear osmolarity in patients with mild to moderate dry eye disease.MethodsThis prospective study comprised of 122 patients with mild to moderate dry eye disease. These patients received a single dose of either unpreserved trehalose 3%, hyaluronic acid 0.15%, carbomer 0.25% (THHA, Thealoz Duo Gel) (Group 1) or hyaluronic acid 0.3% (HA) (Group 2) gel-based lubricants. Tear meniscus (height and depth) were measured using anterior segment optic coherence tomography (AS−OCT) at baseline and 10, 60, 120, and 240 min. after instillation. Tear osmolarity, Schirmer I test, tear break-up time (TBUT), gel properties, and patient comfort were evaluated 240 min. after instillation.ResultsTear meniscus height (TMH) and tear meniscus depth (TMD) showed a significant increase with both lubricants compared to the baseline (p < 0.001). This effect remained significant for up to 60 min. and 120 min. for the THHA and HA 0.3% solutions, respectively (p < 0.05, for both). Mean comfort duration was 115.1 ± 20.1 min. in Group 1 and 148.3 ± 49.0 min in Group 2 (p < 0.001). Tear osmolarity, Schirmer I test, and TBUT were similar between the baseline and 240 min. for each group.ConclusionsThe results of this study demonstrate that 0.3% HA remains on the ocular surface for longer than TH-HA. The longer ocular residency time also seems to correlate with a longer patient comfort duration.     

基于MODIS资料的陕西水云特征研究

陕西位于西北内陆地区,是中国气候的敏感区,为准确认识其上空的水云特征,利用MODIS的MYD06二级云产品数据,对陕西水云的概率分布、云顶高度、粒子有效半径、光学厚度进行了统计分析。结果表明:(1) 水云概率分布显示出单峰结构,峰值出现在11月, 5月出现概率最低。水云在秋季出现概率最高,春季出现概率最低。 (2) 7月和9月水云云顶高度的概率分布会产生显著的变化,7月和8月的分布形态与其余各月有显著差别。水云云顶高度平均最大值出现在春季的4~5月,最小值出现在冬季的12~2月。(3)水云的粒子有效半径在10月~次年5月, 分布形态相似,6~9月分布形态与之明显不同。水云粒子尺度平均最大值出现在夏季的6~8月, 最小值出现在秋季的11月。(4) 光学厚度在0~5之间的水云在10月~次年5月,出现概率最高, 峰值出现在12~2月; 6~9月光学厚度在5~10之间的水云出现概率最高, 峰值出现在7~8月。水云光学厚度最大值出现在秋季的9~11月,最小值出现在夏季的7~8月。     

浅谈水准仪测量的误差来源及控制方法

研究了勘察设计过程中水准测量的问题,结合水准测量的现状对水准测量的误差进行了分析,并提出了误差的控制方法,以提高水准仪测量的精度,可供相关技术人员参考。     

APPLICATION OF MAXIMUM ENTROPY PRINCIPLE METHOD TO THE STUDY OF WAVE CLIMATE STATISTICAL CHARACTERISTICS

The Maximum Entropy Principle (MEP) method is elaborated, and the corresponding probability density evaluation method for the random fluctuation system is introduced, the goal of the article is to find the best fitting method for the wave climate statistical distribution. For the first time, a kind of new maximum entropy probability distribution (MEP distribution) expression is deduced in accordance with the second order moment of a random process. Different from all the fitting methods in the past, the MEP distribution can describe the probability distribution of any random fluctuation system conveniently and reasonably. If the moments of the random signal is limited to the second order, that is, the ratio of the root-mean-square value to the mean value of the random variable is obtained from the random sample, the corresponding MEP distribution can be computed according to the deduced expression in this essay. The concept of the wave climate is introduced here, and the MEP distribution is applied to fit the probability density distributions of the significant wave height and spectral peak period. Take the Mexico Gulf as an example, three stations at different locations, depths and wind wave strengths are chosen in the half-closed gulf,the significant wave height and spectral peak period distributions at each station are fitted with the MEP distribution, the Weibull distribution and the Log-normal distribution respectively, the fitted results are compared with the field observations, the results show that the MEP distribution is the best fitting method, and the Weibull distribution is the worst one when applied to the significant wave height and spectral peak period distributions at different locations, water depths and wind wave strengths in the Gulf. The conclusion shows the feasibility and reasonability of fitting wave climate statistical distributions with the deduced MEP distributions in this essay, and furthermore proves the great potential of MEP method to the study of wave statistical properties.     

高速钢轧材耳子冷拉变形与折迭形成条件

介绍了带有耳子的高速工具钢热轧材在冷拔时的变形与折迭形成条件。结果表明：在冷拉变形时，耳子的顶部宽展大于根部宽展；宽展随压下率的增大及拉拔道次的增多而增大；当耳子的宽高比小于６．３０时，则产生折迭。     

FH1919(DD-800)多道脉冲分析系统

本文叙述了FH1919(DD-800)多道脉冲分析系统硬件和软件的功能及特点,对高速数据获取接口(DMA)的组成和工作过程作了描述,对支持谱仪系统的功能驱动软件(MCA)的逻辑结构、能谱曲线显示程序作了介绍。     

炉膛高度的选取对高温过热器工况影响的研究

文中从辐射换热的基本原理和简化了的辐射换热模型出发，定量分析了炉膛高度的变化对炉膛出口高温过热器辐射热强度的影响，其结果对在电站锅炉的设计和运行中研究及解决过热器起温问题有一定的参考价值。     

深凹露天矿高台阶开采新水平准备方法的探讨

以南芬露天矿现有的自然条件和装备水平为基础，提出了两种由１２ｍ台阶开采向上盘１８ｍ高台阶剥岩、下盘１２ｍ台阶采矿的开采过渡方案，两方案的平沟段高分别为１８ｍ和１２ｍ，通过新水平准备工程量和准备时间的计算比较，结果表明平沟段高为１８ｍ的方案较优。     

Effects of flying height deviations on glide height tests for manufacturing hard disks

In this study, theoretical analysis and experiments were carried out to investigate the effects of avalanche-point deviation and the deviation between the calibration and test-flying heights during the glide head calibration in the glide height tests for manufacturing hard disks. To obtain accurate glide height test results and improve the reproducibility of the test, flying height control should be carried out by limiting the acceptable deviation range of the flying heights of the glide heads. When the avalanche-point deviation is zero, the test results using different calibrated rails (or heads) are the same when they are used to detect the same defect. To avoid wrong test results due to avalanche-point deviation, the test-flying height should be the same as the calibration flying height because the difference of the output voltages of any two rails (or heads) is zero in this case. If these two deviations cannot be eliminated completely, the calibration and test-flying heights should be carefully selected because the error still can be minimised depending on the selection of the flying heights.     

似大地水准面精化成果在水利工程测量中的应用

结合广西某大型水利工程GPS控制网实际案例,对GPS大地高转为正常高的高程转换方法进行了介绍和分析,采用广西似大地水准面精化成果进行GPS高程转换,并进行了精度分析,提高了高程测量精度和效率。