【正文】 頻率的穿透能力最強(qiáng)，但是分辯率最低。 雷達(dá)掃描到的數(shù)據(jù)被記錄到 GSSISIR 系統(tǒng)中，這種系統(tǒng)與雷達(dá)發(fā)射脈沖和 記錄數(shù)據(jù)相對(duì)應(yīng)。雷達(dá)天線所收到的數(shù)據(jù)從模擬信號(hào)被轉(zhuǎn)換成了數(shù)字信號(hào)。這種轉(zhuǎn)換是使用一種 16 位的模擬信號(hào)變流器，它能使數(shù)據(jù)獲得相當(dāng)高的分辨率，以便用于后續(xù)的數(shù)據(jù)處理。這些數(shù)據(jù)被顯示 在一個(gè)高分辨率的彩色監(jiān)測(cè)器上。在可視化校對(duì)之后，將這些數(shù)據(jù)儲(chǔ)存在一個(gè) ，用于后面的分析和處理。首先通過(guò)磁帶記錄下數(shù)字化雷達(dá)所掃描到的原始數(shù)據(jù)，再通過(guò)相關(guān)的設(shè)置和處理程序轉(zhuǎn)化為精確和可靠的數(shù)據(jù)。 沿著軌跡做特別的標(biāo)記，再通過(guò)記錄元件或天線把這個(gè)軌跡描述下來(lái)。 在大學(xué)實(shí)驗(yàn)室里進(jìn)行非破壞性試驗(yàn)后，將所有的數(shù)字記錄從微機(jī)上拷貝下來(lái)，（原始數(shù)據(jù)資料處理將會(huì)消耗 35 兆字節(jié)的內(nèi)存。）后張法分析需要運(yùn)用特殊的處理軟件。這種分析是通過(guò)變換的顏色和線形來(lái)顯示出特征點(diǎn)，也可以通過(guò)顏色的變換顯示相位的變化。除了 這些能變換顏色的設(shè)備外，還可能使用用來(lái)過(guò)濾水平線和豎直線的特殊程序。用一個(gè)大型熒屏測(cè)試器同時(shí)顯示原始數(shù)據(jù)和處理過(guò)的數(shù)據(jù)，從而就能很清晰地看到被處理過(guò)數(shù)據(jù)是在那些地方做過(guò)修改的，同時(shí)電腦顯示器將把反饋信息標(biāo)注到縱坐標(biāo)上。 一個(gè)更為先進(jìn)的軟件能夠顯示專(zhuān)用雷達(dá)脈沖掃描的區(qū)域，在單獨(dú)檢測(cè)錨索周?chē)鸂顩r時(shí)，它是一種特別有價(jià)值元件。 調(diào)查研究 結(jié)果的分析 在別處已經(jīng)有對(duì)調(diào)查結(jié)果非常充分的研究，數(shù)字化雷達(dá)繪圖的本質(zhì)就是將掃描到的被確認(rèn)有雙重相位位移的節(jié)點(diǎn)轉(zhuǎn)化為著色線條，從而缺陷部位即被診斷出來(lái)。 結(jié)論 一個(gè)關(guān)于橋梁研究平 臺(tái)的雛形已經(jīng)在歐洲誕生。 雷達(dá)脈沖波檢測(cè)技術(shù)的運(yùn)用大大增加了對(duì) Besses o’ th’ Barn鐵路 橋評(píng)估結(jié)論的可信度。 雷達(dá)勘察可以顯示后張法鋼絞線孔道內(nèi)部的大部分缺陷區(qū)域。然而，即使運(yùn)用了極其一流的研究手段，也沒(méi)有跡象表明已發(fā)現(xiàn)受拉鋼絲的腐蝕原因。 Bridge research in Europe A brief outline is given of the development of the European Union, together with the research platform in Europe. The special case of posttensioned bridges in the UK is discussed. In order to illustrate the type of European research being undertaken, an example is given from the University of Edinburgh portfolio: relating to the identification of voids in posttensioned concrete bridges using digital impulse radar. Introduction The challenge in any research arena is to harness the findings of different research groups to identify a coherent mass of data, which enables research and practice to be better focused. A particular challenge exists with respect to Europe where language barriers are inevitably very significant. The European Community was formed in the 1960s based upon a political will within continental Europe to avoid the European civil wars, which developed into World War 2 from 1939 to 1945. The strong political motivation formed the original munity of which Britain was not a member. Many of the continental countries saw Britain’s interest as being purely economic. The 1970s saw Britain joining what was then the European Economic Community (EEC) and the 1990s has seen the widening of the munity to a European Union, EU, with certain political goals together with the objective of a mon European currency. Notwithstanding these financial and political developments, civil engineering and bridge engineering in particular have found great difficulty in forming any kind of mon thread. Indeed the educational systems for University training are quite different between Britain and the European continental countries. The formation of the EU funding schemes —. Socrates, Brite Euram and other programs have helped significantly. The Socrates scheme is based upon the exchange of students between Universities in different member states. The Brite Euram scheme has involved technical research grants given to consortia of academics and industrial partners within a number of the states— a Brite Euram bid would normally be led by an industrialist. In terms of dissemination of knowledge, two quite different strands appear to have emerged. The UK and the USA have concentrated primarily upon disseminating basic research in refereed journal publications: ASCE, ICE and other journals. Whereas the continental Europeans have frequently disseminated basic research at conferences where the circulation of the proceedings is restricted. Additionally, language barriers have proved to be very difficult to break down. In countries where English is a strong second language there has been enthusiastic participation in international conferences based within continental Europe —. Germany, Italy, Belgium, The Netherlands and Switzerland. However, countries where English is not a strong second language have been hesitant participants }—. France. European research Examples of research relating to bridges in Europe can be divided into three types of structure: Masonry arch bridges Britain has the largest stock of masonry arch bridges. In certain regions of the UK up to 60% of the road bridges are historic sto