A pressure-sensitive rheological origin of high friction angles of granular matter observed in NASA–MGM project

An abnormally high peak friction angle of Ottawa sand was observed in(National Aeronautics and Space Administration) NASA–(Mechanics of Granular Materials) MGM tests in microgravity conditions on the space shuttle. Previous investigations have been unsuccessful in providing a constitutive insight into this behavior of granular materials under extremely low effective stress conditions. Here, a recently proposed unified constitutive model for transient rheological behavior of sand and other granular materials is adopted for the analytical assessment of high peak friction angles. For the first time, this long-eluded behavior of sand is attributed to a hidden rheological transition mechanism, that is not only rate-sensitive, but also pressure-sensitive. The NASA–MGM microgravity conditions show that shear-tests of sand can be performed under abnormally low confining stress conditions. The pressure-sensitive behavior of granular shearing that is previously ignored is studied based on the μ(I) rheology and its variations. Comparisons between the model and the NASA microgravity tests demonstrate a high degree of agreement. The research is highly valid for pressure-sensitive and rate-dependent problems that occur during earthquakes, landslides, and space exploration.

Low-temperature characteristicsof rubbers and performance testsof type 120 emergencyvalve diaphragms

Purpose–The type 120 emergency valve is an essential braking component of railway freight trains,butcorresponding diaphragms consisting of natural rubber(NR)and chloroprene rubber(CR)exhibit insufficientaging resistance and low-temperature resistance,respectively.In order to develop type 120 emergency valverubber diaphragms with long-life and high-performance,low-temperatureresistant CR and NR were processed.Design/methodology/approach–The physical properties of the low-temperature-resistant CR and NRwere tested by low-temperature stretching,dynamic mechanical analysis,differential scanning calorimetryand thermogravimetric analysis.Single-valve and single-vehicle tests of type 120 emergency valves werecarried out for emergency diaphragms consisting of NR and CR.Findings–The low-temperature-resistant CR and NR exhibited excellent physical properties.The elasticityand low-temperature resistance of NR were superior to those of CR,whereas the mechanical properties of thetwo rubbers were similar in the temperature range of 0℃–150℃.The NR and CR emergency diaphragms metthe requirements of the single-valve test.In the low-temperature single-vehicle test,only the low-temperaturesensitivity test of the NR emergency diaphragm met the requirements.Originality/value–The innovation of this study is that it provides valuable data and experience for futuredevelopment of type 120 valve rubber diaphragms.

Traumatic Diaphragmatic Hernia in Children: A Case Report

Introduction: Traumatic diaphragmatic hernia is a rare condition in children complicating closed or penetrating trauma to the abdomen and thorax. We report the case of an 11-year-old girl with a traumatic diaphragmatic hernia. Case Presentation: An 11-year-old girl was seen in the paediatric surgery department for a thoracolumbar spine deformity and intermittent chest pain. These symptoms occurred after a domestic accident involving a fall from a low wall onto the thoracolumbar spine 5 months previously. The diagnosis was suggested by the presence of a left hemithoracic hydroaera and confirmed by a thoraco-abdominal CT scan. Surgical exploration revealed a linear rupture of the entire left hemi-diaphragm with herniation of the stomach, small intestine, cecum, transverse colon and omentum. We performed a double-layer suture of the diaphragmatic rupture with a non-absorbable suture without edge rejuvenation after the reduction of the hernia. The outcome was favourable with normal postoperative radiographs at one year follow-up. Conclusion: Traumatic diaphragmatic hernia, although uncommon and difficult to diagnose, is a condition that is relatively easy to manage surgically, even if it is discovered late. In all cases of trauma to the thoracolumbar spine, regular follow-up and repeat X-rays are necessary if pain persists.

Application Effect of External Diaphragm Pacemaker Combined with Active Respiratory Circulation Technology in Pulmonary Rehabilitation of Perioperative Lung Cancer Patients

Aim: To explore the application effect of external diaphragm pacemaker combined with active respiratory circulation technology in pulmonary rehabilitation of perioperative lung cancer patients. Methods: A total of 98 lung cancer patients admitted to our hospital from April 2020 to November 2021 were selected as the observation objects, and then divided into a control group and an observation group using the random number table method, with 49 cases in each group. The control group received routine admission guidance and active respiratory circulation training, while the observation group was supplemented with external diaphragm pacemaker on the basis of the control group. The intervention effect was evaluated by blood gas indicators, pulmonary function indicators, diaphragm function indicators, sputum comfort degree, and activity tolerance indicators before and after intervention. Results: Before intervention, there were no significant differences in blood gas analysis indicators, pulmonary function indicators, diaphragm function indicators, sputum comfort degree, and activity tolerance indicators between the two groups (P > 0.05). After intervention, the improvement degree of the above indicators in the observation group was higher than that in the control group (P < 0.05). Conclusions: The application of external diaphragm pacemaker combined with active respiratory circulation technology in pulmonary rehabilitation of perioperative lung cancer patients is significant, which can effectively improve the pulmonary function, blood gas function, and diaphragm function of lung cancer patients after surgery, and improve the activities of daily living and quality of life of patients.

Numerical Simulation of Liquid-Solid Coupling in Multi-Angle Fractures in Pressure-Sensitive Reservoirs

This study clarifies the seepage characteristics of complex fractured pressure-sensitive reservoirs,and addresses a common technological problem,that is the alteration of the permeability degree of the reservoir bed(known to be responsible for changes in the direction and velocity of fluid flows between wells).On the basis of a new pressuresensitive equation that considers the fracture directional pressure-sensitive effect,an oil-gas-water three-phase seepage mathematical model is introduced,which can be applied to pressure-sensitive,full-tensor permeability,ultralow-permeability reservoirs with fracture-induced anisotropy.Accordingly,numerical simulations are conducted to explore the seepage laws for ultralow-permeability reservoirs.The results show that element patterns have the highest recovery percentage under a fracture angle of 45°.Accounting for the pressure-sensitive effect produces a decrease in the recovery percentage.Several patterns are considered:inverted five-seven-and nine-spot patterns and a cross-row well pattern.Finally,two strategies are introduced to counteract the rotation of the direction of the principal permeability due to the fracture directional pressure-sensitive effect.

Pressure-sensitive plasticity of lithiated silicon in Li-ion batteries

Lithiation-induced plasticity is a key factor that enables Si electrodes to maintain long cycle life in Li-ion batteries. We study the plasticity of various lithiated sili-con phases based on first-principles calculations and iden-tify the linear dependence of the equivalent yield stress on the hydrostatic pressure. Such dependence may cause the compression-tension asymmetry in an amorphous Si thin film electrode from a lithiation to delithiation cycle, and leads to subsequent ratcheting of the electrode after cyclic lithiation. We propose a yield criterion of amorphous lithi-ated silicon that includes the effects of the hydrostatic stress and the lithiation reaction. We further examine the micro-scopic mechanism of deformation in lithiated silicon under mechanical load, which is attributed to the flow-defects mediated local bond switching and cavitation. Hydrostatic compression confines the flow defects thus effectively strength-ens the amorphous structure, and vice versa.

Element Analysis of Instrumented Sharp Indentations into Pressure-sensitive Materials

Finite element analysis was carried out to investigate the conical indentation response of elastic-plastic solids within the framework of the hydrostatic pressure dependence and the power law strain hardening. A large number of 40 difierent combinations of elasto-plastic properties with n ranging from 0 to 0.5 and σy/E ranging from 0.0014 to 0.03 were used in the computations. The loading curvature C and the average contact pressure Pave were considered within the concept of representative strains and the dimensional analysis.Dimensionless functions associated with these two parameters were formulated for each studied value of the pressure sensitivity. The results for pressure sensitive materials lie between those for Von Mises materials and the elastic model.

Roles of the ocular pressure, pressure-sensitive ion channel, and elasticity in pressure-induced retinal diseases

The intraocular pressure inside the human eye maintains 10–21 mmHg above the atmospheric pressure.Elevation of intraocular pressure is highly correlated with the retinopathy in glaucoma,and changes in the exterior pressure during mountain hiking,air traveling,and diving may also induce vision decline and retinopathy.The pathophysiological mechanism of these pressure-induced retinal disorders has not been completely clear.Retinal neurons express pressure-sensitive channels intrinsically sensitive to pressure and membrane stretch,such as the transient receptor potential channel(TRP)family permeable to Ca^2+and Na^+and the two-pore domain K channel family.Recent data have shown that pressure excites the primate retinal bipolar cell by opening TRP vanilloid 4 to mediate transient depolarizing currents,and TRP vanilloid 4 agonists enhance the membrane excitability of primate retinal ganglion cells.The eyeball wall is constructed primarily by the sclera and cornea of low elasticity,and the flow rate of the aqueous humor and intraocular pressure both fluctuate,but the mathematical relationship between the ocular elasticity,aqueous humor volume,and intraocular pressure has not been established.This review will briefly review recent literature on the pressure-related retinal pathophysiology in glaucoma and other pressure-induced retinal disorders,the elasticity of ocular tissues,and pressure-sensitive cation channels in retinal neurons.Emerging data support the global volume and the elasticity and thickness of the sclera and cornea as variables to affect the intraocular pressure level like the volume of the aqueous humor.Recent results also suggest some potential routes for TRPs to mediate retinal ganglion cell dysfunction:TRP opening upon intraocular pressure elevation and membrane stretch,enhancing glutamate release from bipolar cells,increasing intracellular Na^+,Ca^2+concentration in retinal ganglion cells and extracellular glutamate concentration,inactivating voltage-gated Na^+channels,and causing excitotoxicity and dysfunction of retinal ganglion cells.Further studies on these routes likely identify novel targets and therapeutic strategies for the treatment of pressure-induced retinal disorders.

超声在膈肌功能评估中的信度研究

目的:分析超声用于膈肌功能评估的一致性及可重复性。方法:采用PA12A型便携式彩色多普勒超声诊断系统。记录60例健康受试者平静呼吸和深呼吸时的膈肌数据,包括平静呼吸和深呼吸时的膈肌移动度、平静呼气和平静吸气时的膈肌厚度、最大呼气和最大吸气时的膈肌厚度,对以上指标的测试内信度、测试者间信度和重测信度分别进行分析。结果:测试内信度:平静呼吸时膈肌移动度、深呼吸时膈肌移动度、平静呼气时膈肌厚度、平静吸气时膈肌厚度、最大呼气时膈肌厚度和最大吸气时膈肌厚度的组内相关系数(intra-class correlation coefficient,ICC)值分别为0.99、0.99、0.99、0.99、0.99、0.99;测试者间信度方面6个指标的ICC值分别为0.84、0.80、0.82、0.82、0.83、0.77;重测信度:6个指标的相对信度ICC值分别为0.98、0.86、0.98、0.97、0.94、0.86;绝对信度6个指标的测量标准误(standard error of measurement,SEM)分别为0.09、0.39、0.01、0.02、0.02、0.03,SEM%分别为5.23%、8.40%、5.38%、5.7%、8.17%、8.77%,最小真正改变量(minimal detectable change,MDC)分别为0.26、1.08、0.03、0.04、0.04、0.09,MDC%分别为14.48%、23.28%、14.9%、15.8%、22.64%、24.31%;Bland-Altman图形分析显示无系统性误差。结论:超声在膈肌功能评估中具有良好信度。

床旁膈肌超声在预测胸腔镜肺叶切除术后肺部并发症中的应用价值

目的评估床旁膈肌超声在预测胸腔镜肺叶切除术后肺部并发症(PPCs)中的应用价值。方法收集河南省人民医院择期行胸腔镜肺叶切除术患者,记录一般资料、围术期相关指标;术前,术后1、3、5 d床旁超声检测膈肌活动度(DE1d、DE3d、DE5d)。根据是否发生PPCs将患者分为两组(PPCs组和非PPCs组)。将单变量分析中有统计学差异的参数纳入多变量logistic回归分析中,筛选PPCs的独立影响因素。绘制受试者工作曲线(ROC),并通过曲线下面积(AUC)评估膈肌超声预测PPCs的效能。结果共纳入患者934例,其中537例发生PPCs(57.5%)。单因素分析显示:与非PPCs组比较,PPCs组糖尿病患者占比、术后24 h活动VAS评分增加;胸管拔除时间、单肺通气时间、术后住院时间长;PPCs组患者术后DE1d、3d手术侧、健侧;DE5d手术侧DE值低(P<0.05)。多因素logistic回归分析显示:单肺通气时间延长、糖尿病、术后(DE1d、3d)手术侧、健侧和DE5d手术侧DE值降低是发生PPCs的独立危险因素。ROC曲线显示:术后DE1d、3d的手术侧、健侧预测PPCs的效能较高(AUC分别为0.797、0.821、0.933、0.929);术后DE5d手术侧、健测预测PPCs效能较弱(AUC分别为0.703、0.512)。结论术后相应时间DE降低、单肺通气时间延长、糖尿病是胸腔镜肺叶切除术后发生PPCs的独立危险因素,术后3 d应用床旁超声评价DE对PPCs具有较高的预测价值。

北京地铁薄壁地下连续墙基坑变形规律统计分析

[目的]地下连续墙(以下简称“地连墙”)厚度对基坑变形量与变形模式的影响较为明显,尤其是薄壁地连墙对于基坑开挖和坑边荷载十分敏感。因此,有必要对北京地铁不同壁厚的地连墙基坑变形规律进行研究。[方法]以北京地铁6座薄壁地连墙车站基坑工程为例,使用统计学方法对其地面竖向变形、地连墙墙顶竖向变形、地连墙水平位移及钢支撑轴力的监测数据进行统计分析。[结果及结论]薄壁地连墙基坑的地面变形可分为隆起-沉降型和沉降型两种,且地面变形中隆起变形的占比较高。土方开挖阶段,地连墙呈快速隆起趋势,开挖结束后墙顶隆起值产生小幅回落,并最终达到稳定值。根据地连墙变形特征,将其分为正常抛物线型、荷载抛物线A型、荷载抛物线B型3种类型。地连墙最大变形位置一般处于0.50H~0.85H(H为基坑深度),累计变形量集中于10~20 mm。第1道钢支撑轴力变化特征较为明显,其曲线可分为快速上升、快速下降、缓慢下降、快速上升4个阶段。

变光阑长波红外连续变焦光学系统设计

非制冷长波连续变焦光学系统由于相对孔径大导致小型化和无热化设计困难,本文采用可变光阑约束物镜尺寸压缩系统总长,实现长波640×512非制冷连续变焦光学系统轻小型化设计。通过材料合理配置及主动补偿实现5片透镜的8.5×连续变焦光学系统消热设计。该系统F#恒定1.2、工作波段为8~12μm、视场变焦范围为30°×24°~3.5°×2.8°、系统总长187.5 mm,该连续变焦光学系统重量轻、总长短、透过率高、在-40℃~+60℃温度范围全视场成像质量良好。

装配式地连墙接缝变形特性研究

为了研究接缝对装配式地连墙变形特性的影响并采取合理的改进措施,采用现场试验的方法将局部现浇地连墙替换为装配式地连墙,并对其实测的变形数据进行了对比分析;在实测数据分析的基础上,通过PLAXIS2D有限元软件模拟分析了不同深度横向接缝对装配式地连墙变形特性的影响规律;通过PLAXIS3D有限元软件对比了现浇墙与装配式地连墙水平方向及竖直方向变形形态,分析了竖向接缝对装配式地连墙变形特性的影响规律;最后,针对实测数据显示出的变形偏大问题,提出了改变冠梁刚度、围檩刚度、墙幅宽度、支撑位置4种改进措施,并通过PLAXIS3D有限元软件进行了验证。结果表明:装配式地连墙的接缝对墙体的刚度存在弱化作用,增大了其变形程度;位于坑底以上的横向接头失效时,墙体水平位移会显著增大,位于坑底以下的横向接头失效时,不会引起墙体水平位移的显著增大;竖向接头会显著减小装配式墙体的整体刚度,使其协同变形能力变差,变形更加难以控制;适当调节支撑位置可有效缓解墙幅间的错动和减小墙体变形。

开洞刚性墙后土体破坏模式运动单元上限分析

超载作用下开洞地下刚性连续墙后土体稳定性问题具有广泛的工程应用背景。考虑墙体矩形开洞宽度足够大,且刚性墙与土体完全光滑接触等条件,参考构造刚性多块体上限法思路,预设墙后土体极简破坏机构并转化为初始三角网格,提出交替循环式新增节点、单元缩减、对角互换及成层加密等网格更新措施,同步开展基于刚体平动运动单元上限方法的刚性墙后土体破坏分析,通过多层级非线性规划运算获得高精度临界超载系数σ_(s)/c上限解,界定墙后土体滑移线网破坏模式及其定量范围与扩展边界。进一步依前述流程计算获得多参数影响下的临界超载系数σ_(s)/c上限解图表,结果表明:1)刚性墙后土体典型破坏特征表现为土体上方和开洞处的整体下沉刚性区域,开洞前方核心区域以密集滑移线网区隔的刚性滑块群,以及外围主要滑动面;2)临界超载系数σ_(s)/c随土体内摩擦角ϕ增大而增大,且后续增幅显著增加;3)σ_(s)/c随开洞深度比C/D的增大呈现出近似线性增大的趋势;4)相较于ϕ和C/D,土体重度参数γD/c的变化对于σ_(s)/c的影响不甚明显,σ_(s)/c随γD/c增大呈现近似线性减小的趋势;5)σ_(s)/c受剪胀角参数ψ/ϕ的影响与ϕ的增大程度密切相关。本研究结果可为开洞地下刚性连续墙后土体失稳破坏模式定量分析、破坏机理研究及工程措施制定等工作提供有力的数据支持。

体外膈肌起搏器联合间歇式训练在慢性阻塞性肺疾病急性加重期患者肺康复中的应用

目的探讨体外膈肌起搏器联合间歇式训练在慢性阻塞性肺疾病急性加重期(AECOPD)患者肺康复中的应用价值。方法选取2019年2月至2022年2月南京市第一医院呼吸内科门诊或急诊收治的100例AECOPD患者,采用随机数字表法将其分为对照组和试验组,各50例。对照组采用间歇式训练干预,试验组采用体外膈肌起搏器联合间歇式训练,两组均持续接受干预到出院,出院时进行效果评价。对两组膈肌功能、肺功能进行比较。结果干预后,两组膈肌活动度、膈肌增厚分数高于干预前,且试验组高于对照组,差异有统计学意义(P<0.05)。干预后,两组第1秒用力呼气量(FEV_(1))、用力肺活量(FVC)、FEV_(1)/FVC水平高于干预前,且试验组高于对照组,差异有统计学意义(P<0.05)。结论采用体外膈肌起搏器联合间歇式训练干预AECOPD患者能显著改善膈肌功能,促进肺功能康复。

加强型翼缘-波纹腹板组合隔板贯通式节点抗震性能研究

为克服隔板贯通式节点易发生脆性断裂而导致结构破坏的不足,结合“加强”和“削弱”的措施,使塑性铰外移,提出了加强型翼缘-波纹腹板组合隔板贯通式梁柱新型节点,并利用有限元软件ABAQUS探究了该新型节点在低周往复荷载作用下的破坏模式、应力分布情况。研究波纹数量、波纹厚度、加强板厚度、加强板长度这4种参数对该新型节点的滞回曲线、骨架曲线、耗能能力的影响规律。结果表明:新型节点有较好的承载力,应力主要集中在梁翼缘上波纹腹板削弱处,破坏发生在远离削弱处一侧,且腹板未发生屈曲变形。随着波纹厚度、加强板长度的增大,新型节点的承载力增加,耗能能力下降;随着波纹数量的增多,新型节点承载力和耗能能力增加;随着加强板厚度的增大,承载力增加,耗能能力先减小后增大。

南京仙新路长江大桥主桥结构设计

南京仙新路长江大桥主桥为跨径1760 m的单跨钢箱梁悬索桥,主缆垂跨比1/9,边跨跨径580 m,边中跨比0.33。该桥上、下游各设1根主缆,单根主缆由169股127∅5.4 mm镀锌铝高强钢丝索股组成,采用PPWS法施工,钢丝标准抗拉强度2100 MPa。吊索与索夹采用销接式结构,跨中设置柔性中央扣索,短吊索设置关节轴承。主索鞍采用宽鞍槽单纵肋铸焊结合构造,散索鞍采用底座式全铸结构。加劲梁采用扁平流线型封闭整体钢箱梁,总宽31.5 m,梁高4 m,顶板与U肋之间采用双面埋弧全熔透焊接。桥塔采用门形混凝土结构,总高277.3 m,其上横梁为预应力混凝土结构,外包N字造型钢结构;桥塔基础采用直径2.8 m钻孔灌注桩。南锚碇采用外径65 m圆形地下连续墙基础;北锚碇采用沉井基础,平面尺寸70 m×50 m,高50 m。对结构进行静力分析及抗风性能理论和试验研究,结果表明:结构强度、刚度均满足规范要求;在加劲梁上设置0.67 m高中央稳定板、两侧风嘴处设置1 m宽水平稳定板后,大桥的颤振、涡振等抗风性能均满足要求,且具备一定的阻尼储备。

基于断裂力学的横隔板弧形切口CFRP加固参数研究

横隔板弧形切口疲劳开裂为正交异性钢桥面板的主要疲劳病害之一。为研究该部位的疲劳性能,分析碳纤维增强复合材料(carbon fiber reinforced polymer,CFRP)参数对加固效果的影响,首先,建立钢梁节段模型,在弧形切口应力幅最大处引入初始裂纹,基于断裂力学理论得到疲劳荷载作用下横隔板弧形切口处的开裂模式及疲劳寿命;然后,建立CFRP板加固模型,改变各加固参数,对比不同初始裂纹条件下裂纹扩展过程中的应力强度因子变化规律,探究CFRP板长度、宽度、厚度、弹性模量以及胶层剪切模量等参数对加固效果的影响;最后,给出推荐加固参数组合。研究结果表明:横隔板弧形切口处疲劳裂纹为I型裂纹,疲劳寿命约为576.42万次;CFRP板加固能有效降低裂纹尖端应力强度因子幅值,但是CFRP板长度与宽度存在加固的临界尺寸,当尺寸大于这一临界值时,其对加固效果影响极小;CFRP板厚度、胶层剪切模量对加固效果的影响随参数增大而逐渐减弱;采用长×宽×厚为45.0 mm×30.0 mm×2.0 mm、弹性模量为460 GPa的CFRP板进行加固后,裂纹将不再扩展,疲劳寿命显著提高。

变工况隔膜压缩机曲轴动力学仿真分析

隔膜压缩机通过活塞运动挤压膜片达到压缩气体的作用,而这一过程中产生的排油压力会导致各传动部件受到复杂的交变载荷,而像曲轴等重要部件上则会产生较大的应力应变,这些复杂的作用力会引发曲轴等部件的强烈振动。针对这一问题,采用理论分析与ADAMS刚柔耦合仿真方法,对一台排气压力为45MPa隔膜压缩机的往复运动机构进行分析,结果表明:在额定工况下,曲柄销径向最大受力约为70282.4N,切向最大受力约为72593.2N,曲轴上最大应力值为141.36MPa,最大变形量为0.108mm;而对不同工况的分析结果显示,排气压力升高、曲轴转速变大都会导致曲轴上的应力增大。其中,转速变大对应力值的影响较小,而排气压力升高则对应力值的影响较大。

床旁超声膈肌功能评估对慢性阻塞性肺疾病机械通气撤机的预测价值

目的:研究分析床旁超声膈肌功能评估对慢性阻塞性肺疾病(COPD)机械通气撤机的预测价值。方法:选取2022年4月—2023年6月凉山彝族自治州第一人民医院行机械通气的60例患者作为研究对象,在符合临床撤机条件后进行2 h自主呼吸试验(SBT)。试验结束后采用床旁超声对患者进行评估,按照撤机结果分为参照组(撤机失败,n=28)和试验组(撤机成功,n=32)。比较两组行SBT 30 min后吸气末膈肌厚度(DTei)、呼气末膈肌厚度(DTee)、膈肌增厚指数(DTF)、右侧膈肌移位距离(DD)、浅快呼吸指数(RSBI)及膈肌浅快呼吸指数(D-RSBI)等床旁超声膈肌功能评估相关参数,并应用受试者工作特征曲线(ROC)分析床旁超声功能评估相关参数在COPD机械通气患者撤机指导中应用效能。结果:两组行SBT 30 min后DTei、DTee比较,差异无统计学意义(P>0.05);试验组行SBT 30 min后DTF高于参照组,DD长于参照组,差异有统计学意义(P<0.05)。试验组行SBT 30 min后RSBI、D-RSBI低于参照组,差异有统计学意义(P<0.05)。曲线下面积(AUC)≥0.7时,表示预测价值良好,DTF、DD、RSBI、D-RSBI均对撤机有较好的预测价值,其AUC依次为0.840、0.749、0.876、0.804;同时,DTF敏感度高于DD、RSBI、D-RSBI。结论:床旁超声膈肌功能评估获取DTF、RSBI及D-RSBI等参数在COPD撤机指导中应用效能良好,可为临床成功撤机提供良好预测价值。