【正文】 ata are stored for later use in the data analysis part of the program.Lab View programs are called virtual instruments (VIs) because of their appearance and operations are analogous to measuring instruments. A VI that is called within another VI is called a subVI and is analogous to a subroutine in textbased languages.The data acquisition, analysis and presentation are prised of three main procedures:(1) Data acquisition card to interface the hardware to the PC.(2) Data acquisition program to acquire and store data in a spreadsheet file.(3) Data analysis to carry out digital signal processing, calculate PWV and present results.PWV Calculation 1. PWV calculation using peak detection. To calculate PWV using peaks, the location of the peaks must first be determined, so that the transit time of the wave between the peaks can be determined. It was found that the best method of peak detection is the derivative of the curve method. If the first derivative of a curve is zero, then an extreme value can exist—eithera peak or a turning point. It is necessary to take the second derivative at this point—if this is also zero, then an extreme value exists. The second VI used to determine the PWV is PWVcalc, using the time separation between the located peaks.2. PWV with pressure wave foot detection. The VI named PWV Foot determines the leading edge (foot) of the pressure wave at the upstream and downstream locations. The VI named PWVcalc is again used to pute the PWV from the time separation between the two leading edges (‘foottofoot’ APWV or FFAPWV).3. PWV with crosscorrelation. The PWV determination with crosscorrelation is done with the VI named CalcPWV. The VI is in two parts: a part for the initialization function and a part for the calculation of the CCAPWV.In all cases PWV values are assembled in an array and the mean value, standard deviation and variance are calculated. Sensor positioning 27 Sensor placement is critical to obtaining consistent measurements. A screw mechanism was first used to apply the sensors to the skin. But readings were very variable and so this technique was replaced by that in which the sensors are fixed to the skin by elastic strips. This led to better results.Arm position is another critical feature of measurement. Two positions, normal and dependent, were analyzed in detail, using one test subject. In the normal position, the subject sits with the arm resting on a table. All test subject measurements were made in this position. In the dependent position, the subject sits with the arm hanging straight down.The PWV values were smaller in this position and the variability was much greater, so this technique was discarded.A correction module, ‘Delete Incorrect’, was used to delete PWV values resulting from aberrant signals, caused monly by arm movement during the measurement. These unrealistic values were deleted before the PWV values were passed to the analysis VI.27外文譯文壓電傳感器測(cè)定動(dòng)脈脈搏波速度動(dòng)脈脈搏波速度(APWV)是一個(gè)測(cè)量的彈性(或剛度)的外周動(dòng)脈血管。這里指的脈沖將壓力脈沖,而不是流脈沖多普勒超聲測(cè)量。壓力脈沖速度變化范圍從12ms?1到15ms?1,而在正常動(dòng)脈有速度范圍,在7到9 ms?1。這個(gè)項(xiàng)目的目標(biāo)是開發(fā)一種快速和易于使用的系統(tǒng)測(cè)定外周動(dòng)脈脈搏波速度。測(cè)量?jī)x的原理是基于同時(shí)測(cè)量?jī)蓚€(gè)脈沖波在兩個(gè)不同的位置,比如橈動(dòng)脈在手腕和上臂肱動(dòng)脈略高于肘部。通過測(cè)定脈沖過境時(shí)間這些點(diǎn)之間和距離測(cè)量這兩個(gè)地點(diǎn),脈搏波速度可能會(huì)被計(jì)算。壓力脈沖檢測(cè)是通過使用兩個(gè)壓電傳感器產(chǎn)生一個(gè)可測(cè)量的電壓輸出聯(lián)系人如果他們是機(jī)械變形。變形產(chǎn)生電壓是第一放大和過濾,然后用數(shù)據(jù)采集卡數(shù)字化。分析中獲得的數(shù)據(jù)傳感器包括一個(gè)過濾過程中,計(jì)算有三種不同的方法——foottofoot APWV。 peaktopeak APWV 和 crosscorrelation APWV。傳感器技術(shù)用于這項(xiàng)工作涉及到壓電效應(yīng)在聚偏二氟乙烯(PVDF),它產(chǎn)生一個(gè)輸出電壓響應(yīng)機(jī)械壓力對(duì)材料。三種測(cè)定動(dòng)脈脈搏波速度的方法是: foottofoot APWV。 peaktopeak APWV and crosscorrelation APWV。FFAPWV和CCAPWV方法不敏感,壓力波反射在分支等在動(dòng)脈樹,比如PPAPWV方法。平均值和標(biāo)準(zhǔn)偏差是這三種方法分別要計(jì)算并比較的?！瓼oottofoot’APWV (FFAPWV)。 這是基于壓力脈沖波速度的“腳”,或前緣。腳的到達(dá)時(shí)間的脈沖波在兩個(gè)位置沿動(dòng)脈被記錄。Δt是到達(dá)時(shí)間之差和Δs是兩個(gè)記錄位置(近端和遠(yuǎn)端)之間的距離,FFAPWV是FFAPWV =Δs /Δt?！甈eaktopeak’APWV (PPAPWV)。 這是完全類似于FFAPWV，只是點(diǎn)的觀測(cè)是脈沖波的兩個(gè)(近端和遠(yuǎn)端)的山峰PPAPWV =Δs /Δt。Apparent pulse wave velocity (AAPWV)。壓力波可以表示為一個(gè)傅里葉級(jí)數(shù),P (t) = P0 +Pn (nωt +θn)P0是流體壓力,n是諧波數(shù),Pn是第n次諧波的振幅和相位角的θn是第n次諧波。空間變化速度的階段的一個(gè)諧波是沿著動(dòng)脈基于兩個(gè)同時(shí)壓力測(cè)量距離Δs,與明顯的動(dòng)脈脈搏波速度(AAPWV)由以下方程表示,AAPWVn = (Δs) n(f)(360 o)/(θx1—θx2)在AAPWVn是明顯的脈搏波速度的第n次諧波,f是心率、θx1是相角為近端諧波n和θx2是相角為遠(yuǎn)端諧波n。Crosscorrelation PWV.。如果動(dòng)脈脈沖在近端測(cè)量位置代表的壓力時(shí)間序列P(x1,t)、遠(yuǎn)端位置P(x2,t)和互關(guān)聯(lián)系數(shù)的Φx1,x2(τ),然后有一個(gè)最大值Φ將在某個(gè)時(shí)間滯后。相關(guān)函數(shù)可以表示為Φx1,x2(τ)=(1 / T) P(x1, τ)P(x2, τ)dt。τ的價(jià)值的最大相關(guān)性發(fā)生代表時(shí)間差(Δt)的壓力波從位置x1,x2位置沿動(dòng)脈段。從分離距離和時(shí)間數(shù)據(jù)相關(guān)動(dòng)脈脈搏波速度CCAPWV =(x2?x1)/Δt。在這個(gè)工作正常,年輕的測(cè)試對(duì)象被使用,而且它的主要目標(biāo)優(yōu)化測(cè)量程序和建立統(tǒng)計(jì)傳播和觀測(cè)到的PWVs平均值為一個(gè)特定的外周動(dòng)脈段。在此基礎(chǔ)上,它是計(jì)劃利用系統(tǒng)在臨床試驗(yàn)中涉及外周動(dòng)脈疾病患者(由于糖尿病、高血壓等)、前、中、后的治療(藥物或手術(shù))。模擬和數(shù)字電路模擬電荷放大器。壓電材料機(jī)械應(yīng)力或應(yīng)變轉(zhuǎn)換成適當(dāng)?shù)碾娔?通過產(chǎn)生一個(gè)電荷當(dāng)受到機(jī)械應(yīng)力。電荷轉(zhuǎn)換成電壓通過一個(gè)運(yùn)算放大器連接作為當(dāng)前積分器,稱為電荷放大器。信號(hào)輸出的放大器是大約30 mV。它增強(qiáng)了信號(hào)放大。模擬信號(hào)放大。 這是通過使用一個(gè)反相放大器。因?yàn)橐粋€(gè)直流信號(hào)出現(xiàn)在輸出的電荷放大器、直流偏移切除是必要的,是實(shí)現(xiàn)反相求和下一階段的模擬電路是一個(gè)低通濾波器來去除噪聲干擾的50赫茲。數(shù)字控制的數(shù)據(jù)采集和分析。一個(gè)數(shù)據(jù)采集板(DAQ)時(shí)需要傳感器信號(hào)需要用電腦連接。董事會(huì)包含12位加號(hào)和逐次逼近和自校準(zhǔn)模擬到數(shù)字轉(zhuǎn)換器(ADC)。ADC招致一個(gè)系統(tǒng)誤差稱為量化誤差。這是由于有限的決議和模擬輸入上限設(shè)定在?5 + 5 V,量化誤差的A / mV。數(shù)據(jù)采集和分析是通過使用虛擬儀器一個(gè)強(qiáng)大的儀器和分析編程語言對(duì)個(gè)人電腦。 數(shù)字?jǐn)?shù)據(jù)采集程序。 數(shù)據(jù)采集電路執(zhí)行所有的必要的操作與虛擬儀器的數(shù)據(jù)采集。電路的功能初始化數(shù)據(jù)采集和讀取的數(shù)據(jù)采集卡。這些數(shù)據(jù)是存儲(chǔ)供以后使用的數(shù)據(jù)分析程序的一部分。虛擬儀器程序被稱為虛擬儀器(VIs),因?yàn)樗麄兊耐獗砗筒僮黝愃朴跍y(cè)量?jī)x器。一個(gè)虛擬儀器,被稱為在另一個(gè)虛擬儀器是稱為子虛擬儀器和類似于在基于文本的語言子程序。數(shù)據(jù)采集、分析和表示包含三個(gè)主要過程:(1)數(shù)據(jù)采集卡的接口硬件到PC。(2)數(shù)據(jù)采集程序獲取和存儲(chǔ)數(shù)據(jù)在一個(gè)電子表格文件。(3)數(shù)據(jù)分析進(jìn)行數(shù)字信號(hào)處理,計(jì)算和現(xiàn)在的結(jié)果脈搏波速計(jì)算 。計(jì)算脈搏波速使用峰值，峰值的位置首先必須確定,以便運(yùn)輸時(shí)間的波形峰值之間可以確定。最好的方法就是微分峰值檢測(cè)的曲線求積法。 如果曲線的一階導(dǎo)數(shù)為零,那么一個(gè)極端值可以存在要么一個(gè)峰值或一個(gè)轉(zhuǎn)折點(diǎn)。有必要進(jìn)行二階導(dǎo)數(shù)在這一點(diǎn)如果這也是零,那么一個(gè)極端的價(jià)值存在。第二個(gè)脈搏波速測(cè)量?jī)x是用來確定PWVcalc,使用時(shí)間是被測(cè)波峰間時(shí)間差。VI命名儀確定了。腳前緣(腳)的壓力波在上游和下游位置。虛擬儀器命名PWVcalc 再次用于計(jì)算測(cè)量?jī)x兩個(gè)前緣從時(shí)間之間的分離 (“foottofoot” APWV或FFAPWV)。脈搏波速的測(cè)定與互相關(guān)完成與VI CalcPWV命名。 VI是兩個(gè)部分:一個(gè)部分是初始化函數(shù)和一個(gè)部分為計(jì)算CCAPWV。在所有情況下脈搏波速值聚集在一個(gè)數(shù)組和均值、標(biāo)準(zhǔn)偏差和方差計(jì)算。傳感器定位傳感器位置獲得一致的測(cè)量至關(guān)重要。一個(gè)螺絲機(jī)制是第一次使用的傳感器應(yīng)用到皮膚。但閱讀是非常變量,所以這種技術(shù)取而代之的是由從傳感器固定在皮膚彈性帶。這導(dǎo)致更好的結(jié)果。臂位置是另一個(gè)關(guān)鍵特性的測(cè)量。兩個(gè)位置,正常的和依賴,都進(jìn)行了詳細(xì)分析,使用一個(gè)測(cè)試主題。在正常位置,這個(gè)主題坐著手臂枕在一個(gè)表。所有測(cè)試主題數(shù)據(jù)均在這個(gè)位置。在相關(guān)位置,主體位于手臂垂直懸的。脈搏波速的價(jià)值觀在這個(gè)位置上,小的差異是大得多,所以這技術(shù)被丟棄。一個(gè)校正模塊,刪除不正確的,是用來刪除脈搏波速測(cè)量?jī)x產(chǎn)生的值異常的信號(hào),通常由臂運(yùn)動(dòng)引起的在測(cè)量。這些不現(xiàn)實(shí)的價(jià)值觀被刪除之前的值被傳遞給該脈搏波速分析虛擬儀器。附錄 C 主要參考文獻(xiàn)題錄及摘要[1] 程光，趙崇侃．指動(dòng)脈搏波光電傳感器的研制[J]．南京醫(yī)學(xué)院學(xué)報(bào)，1991年第11卷第4期，329—330．【原文】：通常人們把動(dòng)脈血壓波形或動(dòng)脈血液