Building on the success of previous editions, Focus on Grammar continues to provide an integrated-skills approach to engage students and help them accomplish their goals of communicating confidently, accurately, and fluently. With comprehensive grammar coverage, abundant practice, and ongoing assessment Focus on Grammar delivers immediate and visible progress through its unique and proven pedagogy that takes learners from comprehension to communication.
NEW to This Edition
?New and updated content engages, motivates, and appeals to learners from various cultural backgrounds. Many new readings and activities include topics of high interest to today learners.
?Updated charts and redesigned notes offer clear, corpus-informed grammar presentations that reflect real and natural language usage. Clear signposting draws attention to most common usage, the difference between spoken and written registers, and common errors.
?Additional communicative activities encourage collaboration and the application of the target grammar in a variety of settings.
?Expanded writing practice helps students to confidently apply each unit grammar to their own writing.
?New comprehensive assessment program with a variety of new assessment tools informs instruction and ensures that progress is measurable.
?Revised MyEnglishLab delivers rich online content and video media to engage and motivate students.
現今科技進步帶動 LED 應用更為多元，從傳統的顯示訊號燈發展、至隨處可見的一般室內照明，路燈照明，商業工業應用照明等。以節能減碳為前提下，尋找高效率光源一直都是各國努力之目標。直到 LED 光源的出現，大量地取代過去發光效率較低的傳統光源，並確實運用在各式各樣的產業。LED 發光效率提升，製造成本與 LED 燈具價格下滑，使得 LED 應用於照明對消費者而言不再是高不可攀的一項選擇。
本書著重於 LED 的製作和產業發展環境介紹，儘量避免提及艱深理論，並由LED產業概況、光電半導體元件、LED 照明產品設計與應用與產品發展趨勢作通盤解析，使讀者能從中掌握產業動向。各單元文末皆附 LED 工程師鑑定考題，讓讀者從中順利掌握命題趨勢。
本書特色
對於 LED 的產業發展而言，LED 的未來取決於下列幾點：
1. LED 發光效率提升 LED 元件技術發展速度快，短短幾年已成為最受期待的下一世代光源。高發光效率為 LED 元件擴張應用市場的重要切入點，LED元件發光效率持續快速提升中。當 LED 元件技術增進，產品更迭速度將更為快速，技術落後即被市場淘汰。
元件成本下滑，將帶動 LED 照明燈具終端價格降低，在 LED 照明走向終端通路且面臨市場上價格競爭激烈挑戰下，LED 照明燈具市場滲透率可望持續提升。
2. LED 技術研發方向由高效率化轉為低成本化 LED 元件發光效率提升，帶動每千流明價格下滑。參考美國 DOE於 2011 年 5 月公佈之固態照明發展年度計劃，如圖 12 所示，DOE 擬定 2015 年冷白光 LED 元件發光效率提升至 224 lm/w，價格下滑至每千流明 2 美元，暖白光則為發光效率提升至 202 lm/w，價格下滑至每千流明 2.2 美元。未來 LED 照明產品除了發光效率持續的提升，將更著重在低成本化的技術研發。
3. 模組化晶片的開發 為了配合高光通量的要求，2000 年推出第一代的 LED 功率晶片面積為 40 mil×40 mil，由於面積大的緣故，其光通量雖然高，但是發光效率卻不佳。2003 年，有業者開發出串聯式 LED 功率晶片，其優點為發光效率佳，而且由於 LED 是串聯的，所以其驅動電壓為所有 LED 驅動電壓的總合，其缺點為製程較複雜。另一方面，為了讓 LED 功率晶 片可以在 AC 的供電環境下使用，也有幾個研發團隊提出 AC LED 功率晶片的構想和作法。
4. 高演色性 LED 無論是照明用的 LED 燈還是 LCD 顯示器用的 LED 背光模組，都需要良好演色性的光源以呈現豐富的色彩。LED 光源的 CRI 值要大於90%才比較理想。RGB LED 光源的 CRI 雖然可以達到 90%，但是並不適用於照明用的 LED 燈。因此，未來必須開發高 CRI 值之照明 LED燈，在此其中，螢光粉和 UV LED（紫外光 LED）就會扮演重要的角色。
5. 高等 LED 製程技術的成熟和普及 此處所指之高等 LED 製程技術包含: (1) 覆晶（flip-chip）技術 (2) 雷射剝離（laser liftoff）技術 (3) 電鍍（electroplating）技術
這 3 種技術為目前製作 LED 功率晶片常用的製程技術，具有高光通量和高導熱係數，操作穩定性高。隨著製程技術的成熟，利用該技術製作之 LED 功率晶片會愈來愈普及。本書將針對上述特點一一進行討論，以期讓讀者對未來產業發展更有通盤性了解。
21st Century Communication is a four-level series that uses powerful ideas from TED Talks to teach learners to think critically and communicate effectively. Through authentic models of effective communication, students build fluency in the listening and speaking skills needed to achieve academic and personal success.
?TED Talks are used to develop essential 21st century skills, including critical thinking, collaboration, and visual literacy.
?Speaking, pronunciation, and presentation skills, inspired by TED speakers, prepare learners to speak confidently in any situation.
?Extended listening based on real-world situations and TED Talks provide listening and note-taking practice.
?Fully-blended Online Workbooks include the entire audio and video program, and automatically graded language practice activities
