RAF near point rule for near point of convergence-a short review

RAF near point rule (RNPR) is a routinely used instrument in ophthalmology and optometry practice as well as for research purposes to measure the near point of convergence (NPC). The measurement of NPC is an important criterion for diagnosis and management of convergence insufficiency. The RNPR forms an important tool for ophthalmic clinicians however, only a very little is understood about it. This article tries to describe and review the designs, measurement techniques, merits and demerits of the RNPR and establish the need for its modification. It recommends that clinicians and researchers consider these findings while measuring NPC with the RNPR.

Receded near point of convergence as a predictor of mild cognitive impairment in the general geriatric population:results from a population-based study

AIM:To investigate the relationship between near point of convergence(NPC)and mild cognitive impairment(MCI)in the general elderly population.METHODS:The present report is a part of the Tehran Geriatric Eye Study(TGES):a population-based crosssectional study conducted on individuals 60 years of age and above living in Tehran,Iran using the multi-stage stratified random cluster sampling method.Cognitive status was assessed using the Persian version of the Mini-Mental State Examination(MMSE).All study participants underwent complete ocular examination including measurement of uncorrected and best-corrected visual acuity,objective and subjective refraction,cover testing,NPC measurement,and slit-lamp biomicroscopy.RESULTS:The data of 1190 individuals were analyzed for this report.The mean age of the participants analyzed was 66.82±5.42(60-92y)and 728(61.2%)of them were female.Patients with MCI had a significantly more receded NPC compared to subjects with normal cognitive status(10.89±3.58 vs 7.76±2.71 cm,P<0.001).In the multivariable logistic regression model and in the presence of confounding variables,a receded NPC was statistically significantly associated with an increased risk of MCI(odds ratio:1.334,95%confidence interval:1.263 to 1.410,P<0.001).According to receiver operating characteristic(ROC)analysis,a cut point NPC>8.5 cm(area under the curve:0.764,P<0.001)could predict the presence of MCI with a sensitivity and specificity of 70.9%and 69.5%,respectively.CONCLUSION:A receded NPC can be clinically proposed as a predictor of MCI in older adults.It is recommended that elderly with a receded NPC>8.50 cm undergo detailed cognitive screening for a definite diagnosis of MCI.In this case,the necessary interventions can be carried out to slow down MCI progression to dementia.

NEAR CRACK LINE ELASTIC－PLASTIC ANALYSIS FOR A CRACK LOADED BY ANTIPLANE POINT FORCES

In this paper, the improved near crack line analysis method proposed in Refs. [1]and [2] is used to investigate a mode Ⅲ crack loaded by antiplane point forces in aninfinite plate in an elastic-perfectly plastic solid. The solutions of this paper aresufficiently precise near the crack line region because. the assumptions of the smallscale yielding theory have not been used and no other assumptions have been taken.

NEAR CRACK LINE ELASTIC-PLASTIC ANALYSIS FOR A FINITE PLATE LOADED BY TWO PAIRS OF ANTIPLANE POINT FORCES

In this paper, the improved near crack line analysis method proposed in Refs. [1] and [2] is used to investigate a center crack loaded by two pairs of antiplane point forces in a finite plate in an elastic-perfectly plastic solid. And the analytical solutions are obtained, that is elastic-plastic stress fields near the crack line and the law that the length of the plastic zone along the crack line is varied with an external loads tr,ld the bearing capacity of a finite plate with a center crack. The results of this paper are sufficiently precise near the crack line, because the assumptions of the small scale yielding theory have not been used and no other assumptions have been taken.

Near-algebra和Banach代数上的特征值和不动点定理(英文)

在near-algebra和Banach代数中引入(p,q)-可加自映象f和正则可逆元的概念,得到如下的结果:在一定条件下,对于定义在near-algebra或Banach代数X中(p,q)-可加自映象f,X中的任意正则可逆元都具有公共的特征值λ=2q/(1+q),p=q≠-1.其特例就是当λ=2q/(1+q)=1时,X中的任意正则可逆元都是(p,q)-可加自映象f的不动点.

Simulation and analysis of point-source surface wave fields

The complexity of near surface intensifies the diversity of seismic wave fields, which makes study on near surface wavefields important in many aspects. The strong absorption of low velocity layer can affect the resolution of seismic data, and free boundary can cause surface wave. Considering the above problems, we focus on the Rayleigh wavefields simulation using finite-difference wave equation of higher-order staggered grids and PML boundary conditions. Free boundary, buried source and overlying low velocity layer are taken into consideration and point explosion source is adopted. Through some numerical simulation with different parameters, we quantitatively analyze relationship between wave intensity and source depth, as well as the energy variation with propagation and obtain some practical knowledge and conclusions.

Spin Supercurrent in Phenomena of Quantum Non-Locality (Quantum Correlations, Magnetic Vector Potential) and in Near-Field Antenna Effect

It is shown that such phenomena as quantum correlations (interaction of space-separated quantum entities), the action of magnetic vector potential on quantum entities in the absence of magnetic field, and near-field antenna effect (the existence of superluminally propagating electromagnetic fields) may be explained by action of spin supercurrents. In case of quantum correlations between quantum entities, spin supercurrent emerges between virtual particles pairs (virtual photons) created by those quantum entities. The explanation of magnetic vector potential and near-field antenna effect is based on contemporary principle of quantum mechanics: the physical vacuum is not an empty space but the ground state of the field consisting of quantum harmonic oscillators (QHOs) characterized by zero-point energy. Using the properties of the oscillators and spin supercurrent, it is proved that magnetic vector potential is proportional to the moment causing the orientation of spin of QHO along the direction of magnetic field. The near-field antenna effect is supposed to take place as a result of action of spin supercurrent causing secondary electromagnetic oscillations. In this way, the electromagnetic field may spread at the speed of spin supercurrent. As spin supercurrent is an inertia free process, its speed may be greater than that of light, which does not contradict postulates of special relativity that sets limits to the speed of inertial systems only.

ELASTIC-PLASTIC ANALYTICAL SOLUTIONS FOR AN ECCENTRIC CRACK LOADED BY TWO PAIRS OF ANTI-PLANE POINT FORCES

The improved near crack line analysis method was used to investigate an eccentric cracked plate loaded by two pairs of anti_plane point forces at the crack surface in an elastic_perfectly plastic solid. The analytical solutions of the elastic_plastic stress fields and displacements near the crack line have been found without the assumptions of the small scale yielding. The law that the length of the plastic zone along the crack line is varied with an external loads and the bearing capacity of an eccentric cracked plate are obtained.

Elastic-plastic analytical solution for centric crack loaded by two pairs of point shear forces in finite plate

The near crack line analysis method was used to investigate a centric crack loaded by two pairs of point shear forces in a finite plate, and the analytical solution was obtained. The solution includes the unit normal vector of the elastic-plastic boundary near the crack line, the elastic-plastic stress fields near the crack line, the variations of the length of the plastic zone along the crack line with an external load, and the bearing capacity of a finite plate with a centric crack loaded by two pairs of point shear forces. The results are sufficiently precise near the crack line because the assumptions of small scale yielding theory have not been made and no other assumptions are taken.

近冰温贮藏对西梅的采后品质及活性氧代谢的影响

该试验以新疆‘法兰西’西梅为试材,采用不同贮藏温度(近冰温、1~2℃和4~6℃)处理,定期测定西梅果实品质及活性氧代谢相关指标。结果表明,西梅果实冰点为-2.8℃,确定西梅果实近冰温的贮藏温度为-1~-1.5℃,与1~2℃和4~6℃贮藏相比,近冰温贮藏可以显著维持西梅果实的表面色泽、硬度、可溶性固形物、可滴定酸和抗坏血酸的含量,有效降低西梅果实的呼吸强度。同时近冰温贮藏有效提高了西梅果实的过氧化物酶、过氧化氢酶和超氧化物歧化酶的活性,显著减缓超氧阴离子的产生速率,抑制H_(2)O_(2)的生成,进一步影响丙二醛的积累与细胞膜透性的上升。综上,近冰温贮藏可有效调控采后西梅果实活性氧代谢的平衡,保持其采后贮藏品质,从而延长其采后贮藏时间。该试验旨在为西梅采后贮藏保鲜提供技术参考和理论依据。

自体荧光基点光谱分析联合免疫胶体金技术在继发性甲旁亢术中识别异位微型旁腺的临床探索

目的研究近红外自体荧光基点光谱分析(near-infrared autofluorescence point-spectral analysis,NIAPSA)联合免疫胶体金技术(immune colloidal gold technique,ICGT)在继发性甲状旁腺功能亢进(secondary hyperparathyroid,SHPT)术中识别异位微型旁腺组织并指导手术切除的效果。方法回顾性分析2021年10月至2022年9月手术治疗的34例SHPT患者的临床资料。术中于双侧颈中央区使用NIAPSA探测分析,结合肉眼辨认后以注射器针头穿刺取洗脱稀释液行ICGT检测。联合检测为阴性者仅全切正常解剖位置腺体,阳性者加行阳性侧颈中央区纤维脂肪组织廓清术。分析联合检测的识别效果、相关生化指标、术后临床症状转归、甲状腺功能与骨代谢情况。结果本组34例手术均成功,其中经NIAPSA联合ICGT检测后行甲状旁腺廓清术(clean parathyroidectomy,CPTX)8例,仅行甲状旁腺全切术(total parathyroidectomy,TPTX)26例;共切除甲状旁腺143枚,其中正常位置134枚(显著增生),异位9枚(4枚轻度增生,5枚未见明显增生)。本组颈中央区纤维脂肪组织内NIAPSA探测阳性共10例12处,联合ICGT识别阳性病例8例共9份样本,联合检测阳性的廓清样本经术后病理证实均为异位旁腺。NIAPSA阳性样本预测值为75.0%,阳性病例预测值为80.0%,NIAPSA联合ICGT阳性预测值为100%。术前、术后1 d、3 d、术后1周及1月、3月、6月甲状旁腺激素(parathyroid hormone,PTH)、血钙、血磷、钙磷乘积(calcium-phosphorus product,CPP)、碱性磷酸酶(alkaline phosphatase,ALP)比较均有统计学差异(P<0.001)。PTH、血钙、血磷及CPP术后各时段均较术前明显改善,ALP自术后1周始至术后6月较术前改善(P<0.05)。PTH、血钙和CPP于术后1 d降至最低,血磷于术后1月降至最低,此后逐渐升高趋于正常;ALP自围术期开始向中远期缓慢降低。术后患者关节骨痛、皮肤瘙痒、肌无力症状明显改善,且随着时间的延长,术后各时间段有症状患者持续减少(P<0.001),术后3月及末次随访所有患者症状消失。本组患者术前与术后1月游离三碘甲状腺原氨酸(free triiodothyronine,FT3)、游离甲状腺素(free thyroxine,FT4)、促甲状腺激素(thyroid stimulating hormone,TSH)甲状腺功能指标比较均无统计学差异(P>0.05);术后6月N端中段骨钙素(N-terminal mid-fragment of osteocalcin,N-MID)、Ⅰ型前胶原氨基末端前肽(procollagen typeⅠamino-terminal propeptide,P1NP)、β-胶原特殊序列(β-crosslaps,β-CTX)骨代谢功能指标较术前均明显降低(P<0.001)。结论NIAPSA联合ICGT技术识别并指导SHPT术中清除颈中央区增生状态不明确的微型甲状旁腺组织安全有效,术后可有效降低PTH水平,调节钙磷代谢,抑制骨代谢活性,改善临床预后。

不同年龄军事飞行人员对比敏感度与调节近点的比较与分析

目的比较不同年龄组军事飞行人员的对比敏感度、近视力和调节近点,探讨年龄对飞行视觉功能的影响。方法随机抽选某疗养中心的军事飞行人员81名,均为男性,按飞行人员年龄分为4组,即20~30岁组、>30~40岁组、>40~50岁组及>50~60岁组。采用Metrovision MonPackOne检测飞行人员对比敏感度和瞳孔大小,近视力检测采用标准对数近视力表,采用移近法测量调节近点。结果右眼中空间频率(4 c/d)及高空间频率(16 c/d)下,>50~60岁组对比敏感度明显低于其他各年龄组(P<0.05);左眼高空间频率(16 c/d)下,>40~50岁组及>50~60岁组对比敏感度明显低于>30~40岁组(P<0.05)。>40~50岁组右、左眼logMAR近视力和调节近点均显著高于20~30岁组及>30~40岁组(P<0.05);>50~60岁组右、左眼logMAR近视力和调节近点均显著高于其他各年龄组(P<0.05)。暗环境下,>40~50岁组及>50~60岁组右眼瞳孔大小显著小于20~30岁组(P<0.05);明环境下,>30~40岁组及>40~50岁组右、左眼瞳孔大小均显著小于20~30岁组(P<0.05);>50~60岁组右眼明暗瞳孔变化差值明显低于20~30岁组(P<0.05)。结论年长飞行人员存在轻度的视觉功能下降,主要体现在高空间频率对比敏感度、近视力的下降以及调节功能的不足。为合理延长其飞行年限,精准筛查及科学改善年龄相关的视觉功能降低是下一步的工作重点。

舞阳盐矿水平对接井近点反拉施工技术

由于单井矿盐开采存在生产效率低、成本高、安全风险高、卤水溶解度不确定、环境影响大等问题,近年来水平对接井钻井技术不断发展和完善。舞阳盐矿JSV005-JSV006井是部署在舞阳凹陷的一组水平对接井,本文从井身结构、钻具组合、钻进参数、钻井液性能、定向井眼轨迹控制及地质导向技术、预防井下故障措施等多方面对两井组的对接连通进行了系统的总结,重点阐述了采用近点反拉技术解决水平位移不足的问题,为今后矿盐的开采提供了技术支撑。

某矿山地表工业建筑下矿体开采工艺探讨

采场距离地表越近,对地表的沉降影响越大,因此近地表矿体开采极易引起上方地表过大的变形,破坏建筑物结构。为了解决地表建筑物下矿体开采难题,首先通过地质资料及开采技术条件分析确定合适的采矿工艺,房柱法嗣后充填法可有效地留设原生矿柱,改善顶板支撑效果;然后通过普氏压力拱理论、K.B.鲁别涅依特经验公式、结构力学法综合计算采场大小;最后根据采场跨度大小,确定荷载计算范围,采用许用承载强度计算法确定点柱荷载和点柱尺寸。在某矿山实践结果表明,房柱法嗣后充填能很好地控制地表变形。研究成果为类似矿山开采提供参考。

双重预防机制构建理论与实务探究

为明确双重预防机制基础理论,形成一套切实有效的构建方法与程序,采用文献分析、定性分析、思辨分析、模型构建等方法,辨析双重预防机制的关键概念(风险点、危险源、风险、事故隐患),分析其内在逻辑关系,并构建逻辑关系模型;在此基础上,总结出通用的双重预防机制构建方法与程序。分析结果显示:危险源分为根源危险源与状态危险源,险兆事件是潜在状态危险源的现实表现,风险管控的核心是防止潜在的状态危险源演变为现实的险兆事件;危险源辨识过程中根源与状态危险源分别细分为2种类型、5种表现形式,且事故隐患与控制措施存在一一对应关系;双重预防机制构建程序分为5个构建阶段,包含16项工作内容、13项输出成果。

近场爆炸荷载作用下盾构隧道损伤模式研究

为了研究近场爆炸荷载作用下盾构隧道的损伤机理,选用23 kg TNT,中心距离300 mm的爆炸工况,采用有限元手段对于拱顶、拱肩、拱腰、拱脚、拱底等五个位置的近场爆炸工况进行分析,总结盾构隧道损伤分布规律。通过LS-DYNA有限元分析发现,在近场爆炸作用下,盾构隧道管片出现显著损伤,其中内侧损伤最为显著,面积最小值达54 dm~2,其次是管片截面和背面,损伤面积最小值分别为38 dm~2和32 dm~2;当爆炸点位于拱肩和拱脚时,损害面积最大,因爆点靠近管片环缝和纵缝连接处,该区域的强度相对较低,冲击波反射现象增加;一字型接缝位置(环缝、纵缝)受到近场爆炸荷载时,损伤呈对称圆形分布;而接缝交点位置受到近场爆炸荷载时,损伤显著增加且分布不均。

丘陵地DEM建模精度受像控点空间分布影响研究

为了探究像控点空间分布对DEM建模精度的影响,利用无人机摄影测量技术对6.25 hm^(2)丘陵区域进行DEM建模实验。通过在刺点过程中采用多种像控点平面和高程布设方式来研究DEM建模精度与像控点空间分布之间的关系。结果表明,在同等实验条件下,“边缘+中心”的平面布设方式和“高程梯次组合”的高程布设方式可获得更高的建模精度。实际应用中可参考研究结果优化像控点的空间布设方案。

传统法与深度学习级联结合的近实时火点监测

针对山火监测精度和时效性不足的问题,提出一种级联传统法的多通道卷积神经网络(Multichannel Convolutional Neural Network,MCNN)近实时火点监测算法。首先,结合最大类间方差和空间上下文法,利用背景亮温空间信息差异筛选出潜在火点。然后,采用集成学习思想构建三个卷积神经网络通道,各通道分别输入光谱信息、空间上下文信息及时间地理信息特征的不同组合,同时,通过粒子群优化算法搜索各通道的最佳权重,获取三个通道的火点联合预测概率,实现火点准确识别。结果表明,相比于单通道卷积神经网络(Convolutional Neural Network,CNN)模型,MCNN精确度达到0.88,漏报率降低0.16,并且较日本气象厅官方产品漏报率降低0.06,且实验中模型运行平均耗时172 s。因此,文章提出的MCNN模型可实现较高精度的近实时火点监测,为火灾应急处理提供科学依据。

不同类型间歇性外斜视儿童调节集合功能研究

目的:通过观察集合不足型、基本型、分开过强型间歇性外斜视(IXT)儿童的调节幅度(AMP)、调节灵活度(AF)、集合近点(NPC)、调节性集合/调节(AC/A)及正相对集合(PRC)测量值,并与非斜视儿童对比,研究其调节与集合功能差异。方法:临床回顾性研究。收集2018-12/2020-06我院就诊的6~12岁IXT儿童40例,根据6m及33cm斜视度测量差值,将患者分为三组:集合不足型12例、基本型18例、分开过强型10例。同期就诊非斜视儿童20名作为对照组。采用改良移近法及±2D翻转法分别测量双眼AMP及AF,移近法测量NPC,梯度法测量AC/A值,底朝外(BO)的棱镜测量远PRC及近PRC。比较各组患者间调节及集合参数测量值的差别。结果:IXT儿童集合不足组、基本组、分开过强组与对照组双眼AMP、AF、NPC、AC/A、近PRC、远PRC比较有差异(P<0.05)。进一步两两比较,IXT各组AMP均低于对照组,集合不足组AMP低于其他IXT两组;集合不足组AF低于基本组和对照组;集合不足组NPC大于其他三组;集合不足组和基本组AC/A低于其他两组;IXT各组近PRC均低于对照组,集合不足组近PRC低于其他IXT两组;IXT各组远PRC均低于对照组(均P<0.05)。结论:IXT儿童不同类型之间存在调节及集合差异,集合不足型低于其他类型。IXT儿童双眼调节集合功能低于非斜视儿童。

垂直管内超临界水传热实验研究

在宽广的实验范围内对直径10mm垂直管内超临界水在不同工况下的传热特性进行了实验研究,分析了热流密度、质量流速及压力变化对内壁面温度及传热系数的影响规律。实验参数为:压力23、25、26MPa,质量流速450～1 200kg/(m2.s),热流密度200～1 200kW/m2。实验结果表明:随主流温度的升高,壁面温度逐渐上升,在拟临界点附近由于物性剧变存在传热强化现象;热流密度的增加以及质量流速的减小均会削弱传热强化现象,并导致传热恶化;压力的影响主要体现在传热恶化、强化的起始热流密度和起始主流温度的不同。