Sensitivity Analysis on the Negative Degree of Difficulty Geometric Programming Problem

The range of optimal values in cost optimization models provides management with options for decision making. However, it can be quite challenging to achieve feasible range of optimality in Geometric programming (Gp) models having negative degrees of difficulty. In this paper, we conduct sensitivity analysis on the optimal solution of Geometric programming problem with negative degree of difficulty. Using imprest data, we determine the optimal objective function, dual decision variables, primal decision variables;the range of values, the cost coefficient and RHS constraint must lie for the solution to stay optimal. From the analysis, we established that incremental sensitivity analysis has the functional form .

Land Eco-sensitivity Assessment of Ecological Cities Based on LUCC

Land eco-sensitivity assessment is an important method in analyzing regional eco-environmental safety. This article is based on the studies of land use and coverage change (LUCC) with the interpretation result from Landsat images. It analyzes the land use degree of Shangluo City and gives the land eco-sensitivity classification, which includes soil and water conservation, disaster prevention and eco-environmental protection. Then an improved classification model is taken through the gray model and the variation coefficient. By comparing sensitivity in each level of land use degree change, the ecological recovery mode in study area is analyzed. The results show: the land use degree in Shangluo City has been declining from 1990 to 2009, with large area converted form cropland to forest, environment becomes better; the sensitivities of zoning based on the index level shows the medium sensitive area was largest. According to the variation coefficient gives the more reasonable proportion, the zoning was improved based on uncertainties. Because of the least amount of land use degradation area was taken in high sensitive region, it is considered that the ecological construction model in study area was still worth discussing. The healthy ecological development mode is proposed that low sensitive region should be protected while high sensitive region should receive high attention, so as to further improve the regional ecological security and improve the living environment efficiently.

Application of the Third Theory of Quantification in Screening Sensitive Geological Factors Influencing Coal and Gas Outburst

The principles of the third theory of quantification were discussed. The concept and calculation method of reaction degree were put forward, which have extended the applying range and scientificalness of the primary reaction. Taking the Zhongmacun mine as an example, the geological factors affecting coal and gas outburst were researched. Eight sensitive factors for the outburst of coal and gas were screened out from 11 geological factors using the method of unit classification and the third theory of quantification. On the basis of this, the Zhongmacun coal mine was classified into several divisions. The practice shows that it is feasible to apply the third theory of quantification to gas geology, which offers a new thought to screen the sensitive geological factors of gas outburst forecast.

Application of the third theory of quantification in coal and gas outburst forecast

The essential principles of the third theory of quantification are discussed, the concept and calculated method of reaction degree are put forward which extend the ap- plying range and scientificalness of the primary reaction. Taking the Zhongmacun Mine as example, on the base of analyzing the rules of gas geology synthetically and travers- ing the geological factors infecting coal and gas outburst, the paper adopts the method of combining carving up statistical units with the third theory of quantification, screens out 8 sensitive geological factors from 11 geological indexes and carries through the work of gas geology regionalism to the exploited area of Zhongmacun according to the researching result. The practice shows that it is feasible to apply the third theory of quantification to gas geology, which offers a new thought to screen the sensitive geo- logical factors of gas outburst forecast.

Separation of Comprehensive Geometrical Errors of a 3-DOF Parallel Manipulator Based on Jacobian Matrix and Its Sensitivity Analysis with Monte-Carlo Method

Parallel kinematic machines （PKMs） have the advantages of a compact structure,high stiffness,a low moving inertia,and a high load/weight ratio.PKMs have been intensively studied since the 1980s,and are still attracting much attention.Compared with extensive researches focus on their type/dimensional synthesis,kinematic/dynamic analyses,the error modeling and separation issues in PKMs are not studied adequately,which is one of the most important obstacles in its commercial applications widely.Taking a 3-PRS parallel manipulator as an example,this paper presents a separation method of source errors for 3-DOF parallel manipulator into the compensable and non-compensable errors effectively.The kinematic analysis of 3-PRS parallel manipulator leads to its six-dimension Jacobian matrix,which can be mapped into the Jacobian matrix of actuations and constraints,and then the compensable and non-compensable errors can be separated accordingly.The compensable errors can be compensated by the kinematic calibration,while the non-compensable errors may be adjusted by the manufacturing and assembling process.Followed by the influence of the latter,i.e.,the non-compensable errors,on the pose error of the moving platform through the sensitivity analysis with the aid of the Monte-Carlo method,meanwhile,the configurations of the manipulator are sought as the pose errors of the moving platform approaching their maximum.The compensable and non-compensable errors in limited-DOF parallel manipulators can be separated effectively by means of the Jacobian matrix of actuations and constraints,providing designers with an informative guideline to taking proper measures for enhancing the pose accuracy via component tolerancing and/or kinematic calibration,which can lay the foundation for the error distinguishment and compensation.

Model Simplification and Parameter Modification for Offshore Platforms Using Experiment Data

In this paper, a computation method has been developed so as to compare the finite element method (FEM) with the test results directly. The structure is divided into the 'master' and 'slave' degrees of freedom. The simplified model can be obtained with modal reduction. Then the design sensitivity analysis of the eigenvalues and eigenvectors has been carried out using the modal frequency and modal shape of the test. A two-story frame structure and a jacket model structure have been calculated. Meanwhile, the modified coefficient, the FEM computational and experimental values have been given. It has been shown that the FEM model modified using the test modal value is efficient.

连续管磨损程度及剩余抗内压强度敏感性分析

针对连续管在水平井中下入起出时与套管内壁产生摩擦磨损的问题,借鉴钻杆-套管磨损模型建立思路,采用“磨损-效率”模型,研究下入起出时连续管摩擦磨损,获得了连续管外壁磨损深度的计算方法与公式;利用ANSYS Workbench有限元软件分析了连续管外径、壁厚、钢级、磨损率等敏感性因素对磨损连续管剩余抗内压强度的影响规律。研究表明:磨损率不同,井下磨损连续管最先屈服的部位亦不同;Φ44.45mm×3.96mm的QT-900连续管磨损率从0%到25%时,剩余抗内压强度下降率为35%;磨损连续管剩余抗内压强度随壁厚和钢级的增加而非线性增大,随外径和磨损率的增大而非线性降低;磨损率对连续管剩余抗内压强度的影响最强。研究结果可为磨损后连续管施工参数提供指导。

多维平行六面体模型非概率可靠性灵敏度分析

可靠性灵敏度能够反映基本变量分布参数对可靠度的影响程度,为可靠性分析与优化设计提供指导。提出了一种基于多维平行六面体模型的非概率可靠性灵敏度分析方法。首先,给出基本变量域完全位于安全域时采用非概率可靠性指标,而基本变量域与安全域有交集时采用非概率失效度作为可靠性度量的原因。其次,推导结构线性系统的可靠性灵敏度解析式,并进一步探讨所提方法对结构非线性系统的适应性问题。最后,通过3个工程算例验证文中方法有效可行。

高洁净度超光滑非球面的自动化干涉检测方法

为了实现应用于高能激光等领域对表面洁净度有着极高要求的超光滑非球面检测,排除检测人员带来的洁净度与空气扰动的影响,研究了高洁净度超光滑非球面的自动化干涉检测方法。通过建立补偿干涉法非球面失调量与波前像差之间的灵敏度矩阵,实现利用波前像差求解被测非球面失调量。以理想干涉系统的离焦、彗差与像散为优化目标,进行反馈控制,实现被测非球面的自动化调整,进而实现高洁净度超光滑非球面的自动化干涉检测。实验结果表明,在干涉图可测范围内,利用灵敏度矩阵通过几步迭代即可实现非球面失调量的收敛。结合Stewart六自由度调整台,分别实现2μm精度的平移误差调整、2"精度的光轴自动化对准,最终完成被测非球面的精密调整,实现高洁净度超光滑非球面的自动化干涉检测。采用灵敏度矩阵与六自由度调整的非球面自动化干涉检测方法可实现被测非球面失调量的快速求解与自动调整,降低人员和环境带来的扰动影响,提高了非球面的检测速度,并实现了高洁净度超光滑非球面的自动化干涉检测。

Sensitivity Analysis of the Hydrodynamic Coefficients in 4 Degrees of Freedom Ship Manoeuvring Mathematical Model

The S-type test is simulated based on a ship manoeuvring mathematical model of 4 degrees of freedom(4-DOF);simultaneously,sensitivity analysis of the hydrodynamic coefficients in the mathematical model is implemented by using an indirect method.The mathematical model is simplified by omitting the coefficients of smaller sensitivity according to the results of sensitivity analysis.The 10°/10° zigzag test and 35° turning circle manoeuvre are simulated with the original and the simplified mathematical models.The comparison of the simulation results shows the effectiveness of the sensitivity analysis and the validity of the simplified model.

糖基化修饰对小麦面筋蛋白致敏性的影响

食物过敏是全球范围内广泛关注的食品安全问题之一。为探究一种有效的降低小麦致敏蛋白致敏性的方法,本研究采用单糖(葡萄糖、果糖、半乳糖)与小麦致敏蛋白进行糖基化反应制备复合物,并利用SDS-PAGE、Western blot、ELISA等方法对糖基化反应前后小麦致敏蛋白的致敏性差异进行分析。实验结果显示,糖基化修饰降低了小麦面筋蛋白的致敏性,对麦醇溶蛋白致敏性的影响效果强于麦谷蛋白。半乳糖作为糖基供体时降低致敏性的效果比葡萄糖、果糖的效果显著,葡萄糖和果糖效果相当。研究结果可为降低小麦致敏蛋白致敏性和研发低致敏性小麦制品提供一种新的参考方法。

热敏灸联合针刺治疗寒湿型颈肩部肌筋膜疼痛综合征临床研究

目的:观察热敏灸联合针刺治疗寒湿型颈肩部肌筋膜疼痛综合征的临床疗效。方法:将94例颈肩部肌筋膜疼痛综合征患者按照随机数字表法分为热敏灸联合针刺组和针刺组,每组47例。热敏灸联合针刺组给予热敏灸联合针刺治疗,针刺组给予针刺治疗。治疗前后检测两组患者β-内啡肽(β-endorphin,β-EP)、P物质(substance P,SP)、6-酮前列腺素E1α(6-keto-prostaglandin E1α,6-keto-PGE1α)、5-羟色胺(5-hydroxytryptamine,5-HT)、白细胞介素-1β(interleukin-1β,IL-1β)、环氧化酶-2(cyclooxygenase-2,COX-2)、肿瘤坏死因子-α(tumour necrosis factor-α,TNF-α)、25-羟基维生素D[25-dihydroxy vitamin D,25(OH)D]含量,检测筋膜厚度、组织弹性图评分、杨氏模量值、平均振幅值及平均频率斜率,观察患者疼痛视觉模拟评分(visual analogue scale,VAS)、颈部功能障碍指数(neck disability index,NDI)、生活质量综合评定问卷(generic quality of life inventory 74,GQOLI-7)变化情况及临床疗效。结果:热敏灸联合针刺组治疗后IL-1β、COX-2、TNF-α含量低于针刺组,25(OH)D含量高于针刺组,差异有统计学意义(P<0.05);热敏灸联合针刺组治疗后6-keto-PGE1α、SP、5-HT含量低于针刺组,β-EP含量高于针刺组,差异有统计学意义(P<0.05);热敏灸联合针刺组筋膜厚度、组织弹性图评分、杨氏模量值低于针刺组,差异有统计学意义(P<0.05);热敏灸联合针刺组治疗后平均振幅值、平均频率斜率高于针刺组,差异有统计学意义(P<0.05);热敏灸联合针刺组治疗后NDI评分、VAS评分低于针刺组,GQOLI-74评分高于针刺组,差异有统计学意义(P<0.05);热敏灸联合针刺组有效率为95.74%,针刺组有效率为82.98%,热敏灸联合针刺组有效率显著高于针刺组,差异有统计学意义(P<0.05)。结论:热敏灸联合针刺治疗寒湿型颈肩部肌筋膜疼痛综合征,可抑制患者炎性因子含量,降低疼痛介质指标,改善患者组织弹性、肌肉活动能力和疲劳程度,提高患者临床疗效及生活质量。

基于分段累计积分的电压暂降严重性程度评估

针对传统电压暂降评估方法中暂降波形均以矩形描述从而造成过度评估以及评估函数存在不合理的问题,提出一种基于分段累计积分的电压暂降严重性程度评估方法。对传统的电压特征量描述方法进行改进,分析传统电压暂降评估函数的局限性,针对其局限性提出一种结合常用设备电压耐受能力的权值函数法,得到电压暂降各特征量影响度函数,在这一基础上利用分段累计积分形式,结合改进电压暂降特征量描述方法对暂降事件进行评估。最后通过算例分析验证方法的科学性及客观性。

堆外核测量系统裂变电离室线性响应研究

为满足先进反应堆堆外核测量系统中间量程测量通道灵敏度高、探测器灵敏区长、反应堆线性响应好的需求,采用多支灵敏区长度具有一定比例关系、同时机械结构完全相同的裂变电离室,进行热中子灵敏度标定和反应堆线性响应研究,以为核电厂实际所需长灵敏区裂变电离室提供一种在现有试验堆条件下进行其核性能试验的方法。通过测量不同灵敏区长度的裂变电离室热中子灵敏度和反应堆高中字注量率下的线性响应,对其热中子灵敏度随灵敏区长度的线性变化和反应堆线性响应进行试验验证。测量结果表明,裂变电离室热中子灵敏度随灵敏区长度呈线性关系,且在反应堆热中子注量率1.23×10^(2)~3.10×10^(10)nv(1nv=1n·cm^(-2)·s^(-1))范围内进行计数率模式和MSV模式线性拟合,裂变电离室最大线性度为-1.23%。

基于PYTHON的城市人为热通量与温度关系分析及风险评估

针对全球城市热岛效应日趋严重而复杂形势,提出了一种运用SUEWS模型和Python进行数据分析的方法,探讨人为热通量影响城市热岛效应的重要性与形成机理,重点分析温度变化对制冷度日和人为热通量的影响程度。通过对城市气候大数据的分析研究,发现制冷度日和人为热通量之间存在一定相关性,人为热通量与温度变化之间有敏感响应关系;最后提出相应建议和措施。

聚合瓷修复体对前牙修复患者咀嚼功能、牙体敏感程度的作用效果及其影响因素分析

目的分析Ceramage聚合瓷修复体对前牙修复患者咀嚼功能、牙体敏感程度的作用效果及其影响因素。方法选取2020年5月~2022年4月于我院进行前牙修复的102例前牙冠折断患者为研究对象,均采用Ceramage聚合瓷修复体进行修复,观察患者咀嚼功能、牙体敏感程度变化。修复后1年对患牙进行评估,根据预后情况将患者分为预后良好组和预后不佳组,收集两组临床资料,分析影响聚合瓷修复体前牙修复预后的因素。结果Ceramage聚合瓷修复体颜色、形态、边缘密合度有效率均为100%。修复后,患者咀嚼效率和最大咬合力均明显增大(P<0.05),牙齿敏感程度明显改善(P<0.05)。单因素分析显示,预后不佳组吸烟、不良卫生习惯、牙冠台阶状断端、牙菌斑控制不佳与预后良好组均存在显著差异(P<0.05)。多因素Logistic回归分析显示,不良卫生习惯、台阶状断端、牙菌斑控制不佳是患者预后的影响因素(P<0.05)。结论Ceramage聚合瓷修复体可以有效改善前牙折冠患者咀嚼功能,减轻牙体敏感程度,患者预后与不良卫生习惯、牙冠折断状态、口腔环境有关,需针对性进行预防。

HPV检测联合TCT检查在宫颈上皮内瘤变诊断中的应用价值

目的 分析人乳头瘤病毒(human papillomavirus,HPV)检测与液基薄层细胞学(thinprep cytologic test,TCT)检查联合用于临床诊断宫颈上皮内瘤变(cervical intraepithelial neoplasia,CIN)的价值。方法 选择2021年1—12月在厦门医学院附属第二医院检验科进行CIN筛查的416例女性,均进行过HPV检测与TCT检查,其中150例经宫颈组织病理学诊断确诊为CIN,266例非CIN,以宫颈组织病理学诊断为“金标准”,分析HPV检测与TCT检查联合用于临床诊断CIN的价值。结果 联合诊断结果与宫颈组织病理学诊断结果的Kappa值为0.877,高于HPV检测与宫颈组织病理学诊断结果的Kappa值0.749,也高于TCT检查与宫颈组织病理学诊断结果的Kappa值0.694。HPV检测、TCT检查联合诊断宫颈癌的敏感度为96.00%(144/150)、特异度为93.23%(248/266)、准确度为94.23%(392/416)、阳性预测值为88.89%(144/162)、阴性预测值为97.64%(248/254),均高于HPV检测[87.33%(131/150)、88.72%(236/266)、88.22%(367/416)、81.37%(131/161)、92.55%(236/255)]、TCT检查[88.67%(133/150)、83.46%(222/266)、85.34%(355/416)、75.14%(133/177)、92.89%(222/239)],差异有统计学意义(P <0.05)。结论HPV检测与TCT检查在临床诊断CIN中均具有一定的应用价值,两者联合可提升诊断价值。

镁合金棒室温拉伸试验不确定度评定

依据GB/T 228.1—2021对镁合金进行拉伸试验,并对结果进行不确定度评定。结果表明:在包含概率为95%的区间内,镁合金的抗拉强度为(343±6)MPa,其中合成标准不确定度为2.95 N/mm^(2),自由度为35,包含因子为2.03;镁合金的规定塑性延伸强度为(236±10)MPa,其中合成标准不确定度为4.53 N/mm^(2),自由度为28,包含因子为2.05;镁合金的断后伸长率为(6.0±1.0)%,其中合成标准不确定度为0.510%,自由度为24,包含因子为2.06。

基于PSD的六自由度位移测量解耦方法研究

基于位置敏感探测器(Position Sensitive Detector,PSD)的六自由度(6 Degree of Freedom,6DOF)位移测量对紧凑空间内精密位移台初始位置和姿态的精密测量具有重要作用。精密位移台位移与PSD上光斑位移之间非线性关系的解耦是实现精密位移台亚微米及微弧度位移测量精度的关键。根据PSD与6DOF精密位移台上角锥棱镜之间的位置关系,构建了6DOF位移测量方案,建立了6DOF位移台位移与PSD上光斑位移之间的精确对应关系模型,采用数值计算法对该模型进行解耦求解,并与小角度近似法进行了对比分析。结果表明,当6DOF位移台单自由度位移范围为±10 mm和±10 mrad时,数值计算法引入的解算误差最大值为10^(-17)mm和10^(-15)~10^(-16)mrad量级,而小角度近似法引入的解算误差最大值为5.39μm和35.5μrad;在此基础上,采用蒙特卡洛法以随机均匀分布方式产生10000组六自由度位移进行分析,表明数值计算法引入的解算误差平均值为10^(-17)mm和10^(-17)mrad量级,而小角度近似法引入的解算误差平均值为10^(-3)~10^(-6)mm和10^(-5)mrad量级,其中z方向解算误差达到4.4μm,R_(x)和R_(y)方向解算误差达到28μrad,故小角度近似法无法满足上述位移测量精度要求。所提出的基于数值计算法的解耦方法对实现6DOF位移台的高精度位移测量具有重要意义。

基于层次分析法-模糊综合评价法的住宅舒适度评价体系研究

住宅舒适度受多种因素影响,然而目前的相关研究大多侧重于单个因素。本文通过查阅大量的文献并向专家咨询确定了17项住宅舒适度评价指标,基于层次分析法确定评价指标的权重后运用模糊综合评价法对住宅舒适度进行整体评价。通过单因素轮换法对影响住宅舒适度的关键指标进行权重敏感性分析,得到敏感性强的指标是光照时间,其次是公共交通站点距离、通风及光照强度,敏感性相对较弱的是公共交通网线密度。验证了运用层次分析法确定的各指标权重在住宅舒适度评价中是合理可靠的,最后形成一套可行的住宅舒适度评价体系,为后续的研究与应用打下坚实基础。