下载掌阅APP，畅读海量书库
立即打开
书籍是一种财富，对书籍的拥有就是对财富的拥有。获取知识就是获取财富，这种财富也是可增值的。以获取专业知识为目的的阅读是一种精读，学习心得要随时记录，最方便的就是记录在书本上。不仅要字面读懂，而且要洞察其深刻的含义。不但要理解其精髓，更重要的是要发现可能存在的问题，以及需要进一步研究的问题。如果在阅读中遇到了困难，要“自己解放自己”，查阅别的同类书籍。下面给出一段阅读材料，读者读后可以总结一下获得了一些什么知识。
Figure 2.7 shows how an ECG is measured using electrodes attached to the body surface and connected to instrumentation(ECG)amplifier. For the points in time that the vector points toward the electrode connected to the positive terminal of the amplifier, the output ECG signal will be positive-going. If it points to the negative electrode, the ECG will be negative. Then time varying motion of the cardiac vector produces the body surface ECG for one heartbeat with its characteristic P and T waves and QRS complex. Figure 2.8 shows a lead Ⅱ recording for one heartbeat of a typical normal ECG.
以下是本段文字的译文，试将你的翻译与之对照，并进行讨论。
图 2.7 所示的是用附于体表的电极和与其相连的仪表放大器来测量ECG的示意图。在某时刻某点，当矢量指向仪表放大器的正端连接点时，ECG信号就向正方向变化。如果矢量指向负极，那么ECG就为负。时变的心脏矢量在一个心跳周期内将产生具有P波、T波和QRS复合波的ECG。图 2.8 所示的是导联Ⅱ记录的一次心跳的典型正常ECG。
Figure 2.7 Basic configuration for recording an electrocardiogram. Using electrodes attached to the body，the ECG is recorded with an instrumentation amplifier.（a）Transverse（top）view of a slice of the body showing the heart and lungs.（b）Frontal view showing electrodes connected in an approximate lead Ⅱ configuration.
［图 2.7 记录心电图的基本电路结构（组态）。将电极贴在体表，用仪表放大器记录ECG。（a）示出心和肺的人体的一片横断面（顶视图）。（b）示出连于近似导联Ⅱ组态的电极的正视图。］
Figure 2.8 Electrocardiogram（ECG）for one normal heartbeat showing typical amplitudes and time duration for the P，QRS，T waves.
［图 2.8 一个正常心搏的心电图，示出P，QRS，T波的典型幅度和时程。］
Figure 2.9 Relationship between the spread of cardiac electrical activation represented at various time instants by a summing vector（in the upper frames）and the genesis of the ECG（in the lower frames）.
［图 2.9 由各时刻合矢量表示的心电活动的传播（上部的一幅图形）与ECG的发生（下部的一幅图形）之间的关系。］
Figure 2.9 illustrates how the Cardiac spread of excitation represented by a vector at different points in time ［1］ relates to the genesis of the body surface ECG for an amplifier configuration like the one in Figure 2.8. In Figure 2.9(a), the slow moving depolarization of the atria ［3］ which begins at the sinoatrial(SA)node ［2］ produces the P wave. As Figure 2.9(b)shows, the signal is delayed in the atrioventricular(AV)node ［4］ resulting in an isoelectric region ［5］ after the P wave, and then as the Purkinje system starts delivering the stimulus to the ventricular muscle ［6］ , the onset of the Q wave occurs. In Figure 2.9(c), rapid depolarization of the ventricular muscle ［7］ is depicted as a large, fast-moving vector which begins producing the R wave. ［8］ Figure 2.9(d)illustrates that the maximal vector represents a point in time when most of the cells are depolarized, giving rise to the peak of the R wave. In Figure 2.9(e), the final phase ［10］ of ventricular ［9］ depolarization occurs as the excitation spreads toward the base of the ventricles ［11］ (to the top in the picture)giving rise to the S wave.
（摘自：Topkins W J. Biomedical Signal Processing . Prentice-Hall International，Inc. NJ USA，1993）
注：Topkins W J是University of Wisconsin-Madison教授，曾任美国EMBS主席。
以下是摘录的这段英文的译文，试将你的翻译与之对照，并进行讨论。
图 2.9 所示的是在 ［1］ 不同点不同时间用与体表ECG起因有关的矢量表示的激励的心电扩散图，ECG放大图如图 2.8 所示。图 2.9（a）所示的是起于 ［2］ SA节点的 ［3］ 前庭慢速去极化产生的P波，图 2.9（b）所示的是在 ［4］ AV节点信号被延迟并导至P波后的 ［5］ 电隔离区，Purkinje系统开始对 ［6］ 腹部肌肉提供刺激后，Q波就开始出现了。图 2.9（c）所示的是 ［7］ 腹部肌肉的快速去极化图，它被描绘为一个大而快的矢量，并产生R波。 ［8］ 图 2.9（e）所示的是 ［9］ 腹部去极化的最后一个 ［10］ 相位出现情况，激励向 ［11］ 腹部基准处（图的顶点）扩散并导致S波的出现。