ASYMMETRIC VORTICES FLOW OVER SLENDER BODY AND ITS ACTIVE CONTROL AT HIGH ANGLE OF ATTACK

The studies of asymmetric vortices flow over slender body and its active control at high angles of attack have significant importance for both academic field and engineering area.This paper attempts to provide an update state of art to the investigations on the fields of forebody asymmetric vortices.This review emphasizes the correlation between micro-perturbation on the model nose and its response and evolution behaviors of the asymmetric vortices.The critical issues are discussed, which include the formation and evolution mechanism of asymmetric multi-vortices;main behaviors of asymmetric vortices flow including its deterministic feature and vortices flow structure;the evolution and development of asymmetric vortices under the perturbation on the model nose;forebody vortex active control especially discussed micro-perturbation active control concept and technique in more detail.However present understanding in this area is still very limited and this paper tries to identify the key unknown problems in the concluding remarks.

Ultrasound biomicroscopic imaging demonstrate thinner ciliary body thickness in eyes with angle closure

·AIM:To compare the ciliary body thickness between eyes with primary angle closure(PAC)and primary angle-closure glaucoma(PACG)with the normal eyes,and to investigate the association between ciliary body thickness and ciliary processes situation.·METHODS:In this cross-sectional study,57 patients with PAC/PACG were matched to 57 normal subjects after propensity score matching(PSM)adjusting for age and gender.All subjects underwent conventional ocular examinations and ultrasound biomicroscopy(UBM)examination,among which the patients with PAC/PACG performed the examinations one month after laser peripheral iridotomy(LPI).Quantitative parameters were measured,which included ciliary body thickness at the position of 1 mm posterior to the scleral spur(CBT1),trabecular-ciliary process distance(TCPD)and trabecularciliary process angle(TCA).·RESULTS:Eyes with PAC/PACG presented significantly thinner CBT1,shorter TCPD and smaller TCA(P<0.001)than the normal eyes,both in comparison of the means of four quadrants and in comparisons of each quadrant.After removing images with peripheral anterior synechia(PAS),the same results were also found in comparisons between the two groups.Significant correlations were found between TCPD(R~2=0.537,P<0.001)and TCA(R~2=0.517,P<0.001)with CBT1.·CONCLUSION:Eyes with PAC/PACG have thinner ciliary body thickness and more anteriorly situated ciliary processes.Thinner ciliary body thickness is associated with anterior situation of the ciliary processes.

Effect of body position on the pathogenesis of asymmetric primary open angle glaucoma

AIM： To explore the pathogenesis of asymmetric primary open angle glaucoma（POAG） in both eyes by comparing the intraocular pressure（IOP） of patients who sleep in different positions and to investigate the relationship between IOP variations and sleep positions.METHODS： One hundred and thirty-one patients with asymmetric POAG and forty-six healthy volunteers were enrolled. All participants completed a questionnaire that provided information about their sleep laterality. The cup disc ratio（C/D） and visual field defect established binocular asymmetry. The IOP of both eyes was measured using i Care parameters after the patients were asked to change body position. The ＂worse＂ and ＂better＂ eyes were identified according to the diagnosis, whereas the ＂dependent＂ and ＂independent＂ eyes were defined according to the lateral position. RESULTS： No significant difference in sleep laterality was observed between healthy people and patients with POAG（F=3.195, P=0.362）. Among the enrolled patients, the IOP of the dependent eye was always greater than that of the independent eye in the lateral position（P〈0.05）. In the patients with binocular asymmetric POAG, the questionnaire clearly showed that 85.7% of left side preferences were found their left eyes to be the worse eyes and the right eyes of 71.4% patients with a right side preference were the more serious. When the asymmetric C/D ratio was greater than or equal to 0.2, the worse eye of patients with POAG and a preferred sleeping position was the dependent eye（χ~2=16.762, P=0.001）.CONCLUSION： A higher IOP was measured in the dependent eye in the lateral position. The long-term tendency to choose a lateral sleeping position might lead the dependent eye to manifest more severe symptoms than the independent eye. Thus, the lateral sleeping position might be one cause of asymmetric POAG.

Removal of intraocular foreign body in anterior chamber angle with prism contact lens and 23-gauge foreign body forceps

AIM：To introduce a novel approach in removal of anterior chamber angle foreign body（ACFB） using a prism contact lens and 23-gauge foreign body forceps.METHODS：Data of 42 eyes of 42 patients who had undergone removal of ACFB using a prism contact lens and 23-gauge foreign body forceps from January 2008 to October 2013 were collected and analyzed. Twenty eyes in group A received the conventional approach by using toothed forceps through corneal limbus incision, and 22 eyes in group B underwent the novel method through the opposite corneal limbus incision. RESULTS：The success rate of ACFB once removal was 75%（15/20） in group A, and 100%（22/22） in group B. The average operation time of group A was significantly longer compared with group B（34.9±9.88 min vs 22.13±8.85min; P〈0.05）. The average size of corneal limbus incision in group A was significantly larger than that of group B（4.85±1.89 mm vs 3.95±1.17 mm; P〈0.05）. The corneal limbus incision suturing were conducted in all eyes in group A, and only 5 eyes in group B. CONCLUSION：Removal of ACFB using a prism contact lens and 23-gauge foreign body forceps is a safer, more effective, and convenient technique compared with the conventional approach.

Phase angle obtained by bioelectrical impedance analysis independently predicts mortality in patients with cirrhosis

AIM To evaluate the prognostic value of the phase angle(PA)obtained from bioelectrical impedance analysis(BIA) for mortality prediction in patients with cirrhosis. METHODS In total, 134 male cirrhotic patients prospectively completed clinical evaluations and nutritional assessment by BIA to obtain PAs during a 36-mo follow-up period. Mortality risk was analyzed by applying the PA cutoff point recently proposed as a malnutrition marker(PA ≤ 4.9°) in Kaplan-Meier curves and multivariate Cox regression models. RESULTS The patients were divided into two groups according to the PA cutoff value(PA > 4.9°, n = 73; PA ≤ 4.9°, n = 61). Weight, height, and body mass index were similar in both groups, but patients with PAs > 4.9° were younger and had higher mid-arm muscle circumference, albumin, and handgrip-strength values and lower severe ascites and encephalopathy incidences, interleukin(IL)-6/IL-10 ratios and C-reactive protein levels than did patients with PAs ≤ 4.9°(P ≤ 0.05). Forty-eight(35.80%) patients died due to cirrhosis, with a median of 18 mo(interquartile range, 3.3-25.6 mo) follow-up until death. Thirty-one(64.60%) of these patients were from the PA ≤ 4.9° group. PA ≤ 4.9° significantly and independently affected the mortality model adjusted for Model for End-Stage Liver Disease score and age(hazard ratio = 2.05, 95%CI: 1.11-3.77, P = 0.021). In addition, Kaplan-Meier curves showed that patients with PAs ≤ 4.9° were significantly more likely to die. CONCLUSION In male patients with cirrhosis, the PA ≤ 4.9° cutoff was associated independently with mortality and identified patients with worse metabolic, nutritional, and disease progression profiles. The PA may be a useful and reliable bedside tool to evaluate prognosis in cirrhosis.

Low Phase Angle Predicts Poor Survival in Patients with Hepatocellular Carcinoma:A Retrospective Study

Background The phase angle(PA)is an indicator of nutritional status derived from bioelectrical impedance analysis(BIA).Studies have shown that the PA is one of several factors related to the survival of cancer patients.However,the correlation between the PA and prognosis in patients with hepatocellular carcinoma(HCC)has not been reported.This study aimed to explore the relationship between the PA,nutrition-related indicators,and patient prognosis.Methods The data from 248 HCC patients who underwent BIA between January 2015 and December 2019 at the First Hospital of Jilin University were retrospectively analyzed.Patients were divided into two groups according to the median PA value,then the nutrition-related indicators and overall survival(OS)were compared between the two groups.The correlations between the PA and laboratory test nutrition-related indicators and the results of a body composition analysis were determined using Pearson correlation analysis.Independent predictors of the patient prognosis were identified using univariate and multivariate analyses.Results The median OS in the high and low PA groups were 70 and 54.6 months,respectively(P=0.004).The Pearson correlation analysis revealed that the PA was associated with both laboratory test nutrition-related indicators and the results of a body composition analysis.The multivariable Cox regression analysis identified the PA as an independent risk factor affecting the prognosis of patients with Barcelona Clinic Liver Cancer stage A or B.Conclusion The PA is a good biomarker for the nutritional status.We found that the PA was associated with the prognosis in patients with HCC,with a low PA indicating a poor nutritional status and worse prognosis.

Phase angle and non-alcoholic fatty liver disease before and after bariatric surgery

BACKGROUND Obesity is a global health problem that is continuing to increase in the young population.In Brazil,the frequency of obesity in 2018 was 19.8%.Several comorbidities are directly associated with obesity,such as non-alcoholic fatty liver disease(NAFLD),which is considered the most common liver disorder in Western countries and affects up to 46%of adults.Bariatric surgery is effective in treating obesity and can improve NAFLD;however,the effect of bariatric surgery on body composition,phase angle(PA),and improving NAFLD needs to be further studied.AIM To analyze the PA in the postoperative period of bariatric surgery and to correlate it with changes in body composition and liver disease.METHODS This study is a retrospective cohort study of the analysis of the medical records of patients undergoing bariatric surgery in a reference center of a teaching hospital in Porto Alegre over a 2-year period.Patients older than 18 years whose record contained all information relevant to the study were included.The data analyzed were body composition and PA through electrical bioimpedance and NAFLD through liver biopsy in the pre-and postoperative period.The level of significance adopted for the statistical analyses was 5%.RESULTS We evaluated 379 patients with preoperative data.Regarding PA,169 patients were analyzed,and 33 patients had liver biopsy pre-and postoperatively with NAFLD information.In total,79.4%were female,with a mean age of 39.1±10.6 years.The average body mass index(BMI)was 45.9±7.5 kg/m².The PA showed a mean of 5.8±0.62°in the preoperative period and a significant reduction in the postoperative period.A postoperative reduction in body composition data(skeletal muscle mass,fat percentage,fat mass,body cell mass,BMI and visceral fat area)was shown as well.Regarding liver disease,all patients presented a reduction in the degrees and stages of liver disease in the postoperative period,and some had no degree of liver disease at all.CONCLUSION PA decreased after bariatric surgery,with a direct correlation with weight loss and changes in body composition.The decrease in PA was not correlated with the improvement in NAFLD.

INFLUENCE OF NOSE PERTURBATIONS ON BEHAVIORS OF ASYMMETRIC VORTICES OVER SLENDER BODY

The influence of nose perturbations on the behaviors of asymmetric vortices over a slender body with a three-caliber ogive nose is studied in this paper. The tests of a nose-disturbed slender body with surface pressure measurement were conducted at a low speed wind tunnel with subcritical Reynolds number of 1×105 at angle of attack α=50°. The experiment results show that the behaviors and structure of asymmetric vortices over the slender body are mainly controlled by manual perturbation on the nose of body as compared with geometrical minute irregularities on the test model from the machining tolerances. The effect of the perturbation axial location on asymmetric vortices is the strongest if its location is near the model apex. There are four sensitive circumferential locations of manual perturbation at which bistable vortices over the slender body are switched by the perturbation. The flowfield near the reattachment line of lee side is more sensitive to the perturbation, because the saddle point to saddle point topological structure in this reattachment flowfield is unstable. Various types of perturbation do not change the perturbation effect on the behaviors of bistable asymmetric vortices.

Recent progress on the study of asymmetric vortex flow over slender bodies

The investigations of forebody vortex flow and its flow control have great importance in both academic field and engineering application areas. A large number of papers and many review papers have been published. However in this research field of forebody asymmetric vortices, three problems such as tip perturbation effect, Reynolds number effect and flow instability are less studied and thus not understood completely. So many researches are still working on the issues in recent years. The present paper attempts to provide a review of recent research progress on first two problems. The first problem is mainly concerned with how the vortex flow evolves after tip perturbation; how to solve the problem of repeatability and reproducibility of wind tunnel testing data; how to develop a conception of active flow control technique with tip perturbation based on the study of vortex flow response to tip perturbation. For the second problem one is mainly concerned that how the asymmetric vortices are developed with the increase of Reynolds number; how to classify the vortex flow patterns in different Reynolds number regimes; how to develop an appropriate boundary layer transition technique to simulate flows at high Reynolds number in the convention wind tunnels. Finally, some important ques- tions that deserve answers are proposed in the concluding remarks.

Rotation of the Earth as a Triaxial Rigid Body

The Earth is taken as a triaxial rigid body, which rotates freely in the Euclidian space. The starting equations are the Euler dynamic equations, with A smaller than B and B smaller than C. The Euler equations are solved, and the numerical results are provided. In the calculations, the following parameters are used: (C-B)/A=0.003 273 53; (B-A)/C=0.000 021 96; (C-A)/B=0.003 295 49, and the mean angular velocity of the Earth's rotation, ω =0.000 072 921 15 rad/s. Calculations show that, besides the self-rotation of the Earth and the free Euler procession of its rotation, there exists the free nutation: the nutation angle, or the angle between the Earth's momentary rotation axis and the mean axis that periodically change with time. The free nutation is investigated.

Effect of Resonance on the Motion of Two Cylindrical Rigid Bodies

The effect of resonance on the motion of two cylindrical rigid bodies has been studied in the light of Bhatnagar [1] [2] [3] and under some defined axiomatic restrictions. Here we have calculated variation in Eulerian angles due to resonance in terms of orbital elements and unperturbed Eulerian angles.

重型颅脑损伤患者营养状况及住院时间与相位角的关系

目的探讨重型颅脑损伤患者营养状况及住院时间(LOS)与相位角(PA)的关系。方法选取神经外科收治的患者100例[格拉斯哥昏迷量表(GCS)评分≤8分]作为研究对象。通过人体成分分析检测以及采血化验,获得患者细胞内外水分、骨骼肌、PA、预后营养指数(PNI)以及LOS指标。根据PA值将患者分为低PA组(n=42)和正常PA组(n=58)。比较2组人体成分相关指标、PNI和LOS,分析PA与各指标的相关性,分析患者发生营养不良的影响因素。结果低PA组患者细胞内水分、身体总水分、身体细胞含量、PNI低于正常PA组,LOS长于正常PA组,差异有统计学意义(P<0.05)。PA与细胞内水分、细胞外水分、身体总水分、骨骼肌、身体细胞含量、骨矿物质含量、基础代谢率、PNI呈正相关(P<0.05),PA与LOS呈负相关(P<0.05)。PA(OR=5.441,P=0.001,95%CI:2.011~14.719)和LOS(OR=8.373,P<0.001,95%CI:3.079~22.765)是患者发生营养不良的影响因素。结论PA与重型颅脑损伤患者营养状况以及LOS显著相关。

基于构造导向滤波技术的断层识别方法研究

断层是良好的导水通道,其严重威胁着煤矿的安全生产,查明地下断层的发育情况对煤矿防治水害有重要的意义。地震勘探方法是对地下断层解释的重要手段,地震解释工作使用的地震数据必须具有一定的信噪比,但目前所使用的去噪方法具有提高信噪比的同时破坏断层等非连续性信息的缺陷。文章以倾角相干数据为基础求解地层的倾角信息,在倾角信息约束下沿地层倾向进行去噪,提升去噪效果;利用多窗口自适应滤波技术,对断层等边缘信息进行检测,实现在去噪的同时保护非连续信号不被破坏。实际数据的应用效果表明,方法实现了在提高数据信噪比的同时提升对断层的识别能力。

塔腿主斜材夹角及塔身抗扭布置分析研究

研究了输电塔塔腿主斜材夹角对塔腿的影响并给出合适的主斜材布置角度,对比分析了输电塔塔身交叉型斜材和倒K型斜材2种不同斜材布置形式下的塔身抗扭刚度。结果表明,塔腿主斜材夹角的最优取值范围为30°~40°;倒K型斜材布置的塔身抗扭刚度要低于交叉型斜材布置的塔身抗扭刚度,扭转载荷较大时建议采用交叉型斜材塔身布置。

宽体飞机地面主轮协同转弯控制律设计

主轮协同转弯技术能有效提高飞机的地面机动性,降低主起落架在转弯过程中受到的附加侧向扭矩,减小重载飞机地面转弯半径,但目前实现此技术的前主轮转角控制律设计方法尚不明确。提出以主起落架受力为约束条件,计算不同滑行速度下的前主轮转角关系,在全速度范围内进行分段选择并离散化,据此设计前主轮协同转弯控制律,以原理样机为对象进行仿真分析,验证了该控制律能有效降低两侧主起落架扭矩和的峰值。提出的设计方法对多轮系地面运载装备的复合转弯控制律设计具有一定的理论指导意义。

下肢运动状态特征对裤装臀围的影响分析

为达成合体不束缚目标,探究裤装在不同运动状态下的臀围需求,综合分析人体特征参数、下肢动态参数的约束关系,基于单腿、双腿抬起为起点探讨臀围截面形态变化规律,构建了臀围与人体特征参数、下肢动态参数之间的数学模型,并进行趋势分析以及模型修正。研究结果表明:在单侧抬腿状态时,臀围会随着方向角度α的增加呈现先减小后增大的趋势;而在双侧抬腿状态时,其与臀围呈现负相关关系。抬起角度β与臀围呈正相关,在抬起角度β≤60°时,可按人体运动需求角度计算裤装臀围值;在β>60°时,需要使用坐宽参数代替臀围宽度参数。在下肢多种运动状态下选取臀围变化后的最大值作为不束缚人体的裤装臀围最小值。模型解决了下肢运动状态对裤装臀围的影响,可为裤装臀围制版提供理论依据,为服装定制提供理论参考。

人体成分分析在住院精神疾病患者营养诊断中的应用研究

目的探讨人体成分分析在住院精神疾病患者营养诊断中的作用。方法纳入住院精神疾病患者100例为病例组,同时招募与病例组年龄、性别等相匹配的健康者100例为对照组。利用生物电阻抗技术进行人体成分检测,并对比分析各组的检测结果。结果病例组男性与女性的身体质量指数(21.05 vs.24.30;18.40 vs.23.30)、蛋白质(9.40 vs.10.70;6.85 vs.7.95)、无机盐(3.02 vs.3.74;2.48 vs.2.94)、骨矿物质含量(2.46 vs.3.10;2.05 vs.2.47)、上臂围度(28.85 vs.31.10;25.05 vs.28.60)、相位角(4.95 vs.6.00;4.70 vs.5.19)、身体细胞量(24.65 vs.35.45;24.50 vs.26.45)、细胞内水分比率(0.61 vs.0.62;0.61 vs.0.62)、去脂体重(38.25 vs.53.95;38.05 vs.40.75)、骨骼肌质量(20.45 vs.30.30;20.30 vs.22.10)、无脂肪质量指数(14.39 vs.18.80;14.57 vs.15.70)、骨骼肌质量指数(7.58 vs.10.50;7.78 vs.8.55)及身体脂肪量(11.45 vs.15.60;12.60 vs.17.95)分别低于对照组(P<0.05),而细胞外水分比率(0.39 vs.0.38;0.39 vs.0.38)高于对照组(P<0.05);病例组与对照组中,男性与女性的相位角与细胞内水分、细胞内外水分比率、蛋白质、骨骼肌质量及身体细胞量均呈正相关(P<0.05)。结论病例组男性与女性的人体成分分析结果较对照组差,因此可用于住院精神疾病患者的营养诊断。

金属矿急倾斜矿体开采地表移动范围理论分析初探

为揭示金属矿急倾斜矿体开采地表移动规律,有效预测地表移动范围,以弓长岭铁矿急倾斜矿体开采上盘地表移动为例,考虑地形、废石回填、采深3个因素,建立了用于计算地表主应力分布与易开裂范围的力学模型。基于力学模型,将移动角与地表易开裂范围建立了力学联系,并对移动角进行了补充定义:由最深部开采层边缘向地表作直线,位移为0且使地表开裂范围最大的直线即为移动边界线,移动边界线与水平方向的夹角即为移动角。提出了借助力学模型计算移动角的试算法:预设不同的移动角,由力学模型计算得到的地表最大易开裂范围所对应的预设移动角即为真实移动角。在得到真实移动角后,由力学模型可确定地表易开裂范围与深度。同时,借助极限平衡原理将地表易开裂范围与块体滑移建立了力学联系,提出了地表潜在陷落范围的计算方法:对地表易开裂区内不同开裂点对应的潜在滑移块体列极限平衡方程,依次判别块体是否会发生剪切滑移,可确定地表潜在陷落范围。经计算,弓长岭铁矿下盘含铁带地下开采对上盘地表的移动角为60°,上盘地表具有初次滑移风险的位置距离初采位置的水平距离为130 m,潜在滑移角为55°。根据弓长岭铁矿露天与地下联合开采的现场经验,利用废石及时对地下采空区进行密实回填,并通过优化联合开采时空顺序与开采强度可有效控制地表移动,实现露天与地下安全联合开采。

高速条件下细长旋成体背风区流动特性试验研究

导弹全方向攻击时会产生由旋涡主导的复杂流动,发生转捩和流动分离,对导弹的机动性和控制能力具有重大影响。为探索攻角及马赫数对弹体流动形态的影响,针对某细长旋成体在FD-12风洞开展高速粒子图像测速及荧光油流试验,来流Ma分别为0.4、0.6、0.8,攻角范围α为0°~180°,获取了细长体背风区的流场特性演化规律。研究结果表明:当攻角α<90°时,随着攻角的增大,模型背风区流场从附着流变化为分离流,且分离涡从对称变为非对称,最终演化为非定常流动;当攻角α>90°时,情况有所不同,α=100°及α=120°时背风区存在非定常涡脱落现象,时均流场具有明显的非对称性;当攻角α=150°时,迎风面分离区出现不对称偏移,初始分离区下边界已越过模型端面,在模型中后部形成分离线;当攻角α=180°时,时均流场没有明显的特征,在模型头部位置出现了环形分离区及再附区,表明由于底部扰动的影响,该截面流场呈现局部的非定常、非线性流动状态;在攻角相同情况下,增大流场的来流Ma,不但会使分离涡的影响范围变大,也会导致分离涡的位置抬高。