【正文】 s Liaoning province, decades ago. The solider gave the old man a handmade saddle when they bid farewell. The story inspired Nasun to write Carved Saddle, a song that later became one of his most popular numbers. Now, every year, Nasun recruits young singers and dancers for the troupe. The troupe has also designed a new repertoire, which is mostly based on the daily lives of Mongolian people, especially the lives of nomadic families, and has bined contemporary musical elements with folk songs of the region. Haimu, a 25yearold khoomei (a local variant of overtone singing) singer, joined the troupe three years ago. Along with a sixmember band, he performs fast songs and soft ones that he writes－ all while playing the horsehead fiddle.Although I learned the piano since childhood and grew up listening to various kinds of music, to me, the folk music of Inner Mongolia is the root, he says. Performing in remote villages is pleasant. I feel at home on the boundless grasslands, and the warm people there make me feel fulfilled. The first round of spring auction season in Beijing ended last week, but it failed to create much spring in the art market. Although two pieces of Chinese painting fetched more than 100 million yuan, the decline in trading volume and sa le rate showed a downturn this year. In the ―Grand View: Chinese Painting Highlight‖ session at China Guardian 2022 spring auctions, Pan Tianshou’s representative work Eagle, Rock and Flora hit a record auction price of 279 million yuan, while Li Keran’s masterwork Jinggang Mountain fetched million yuan, an unexpected high in recent years. However, the trading volume fells to billion yuan from billion yuan in the same period the year before. The Huangchen 2022 Spring Auctions, which recorded million yuan in total sales, experienced the same. The section number went down to 5 from 12 pared to last year. According to expert Shao Jianwu, the art market did not attract much excitement this year due to the booming stock market and the persistent problems of fery and fake deals. The two pieces of Chinese painting notched up high price this spring due to their own value not due to a revival in the market. The successful transaction of two works with a hammer price of more than 100 million yuan once again confirms that valuable and rare works of high quality always earn the longlasting high price. Chinese painting and calligraphy is still the pillar of the market. However, the overall sales rate has dropped slightly, which reflects the demand for the ordinary auction goods has weakened,‖ said the president of China Guardian’s Hu Yanyan. Besides, the entry of new buyers also makes certain changes to the direction of purchasing. In a word, the overall market trend is very unpredictable. Although China Guardian 2022 Spring Auctions has achieved remarkable results, it does not mean that the market has walked out of the predicament. We still have to wait for the big economic boom to invigorate the art market.‖ Even so, the hot pursuit of some special items appeared this spring. A special session of China Guardian Spring Auctions titled ―Fine Gilt—Bronze Buddhist Images‖ achieved a great deal with total sales volume of million yuan and 92 percent sale rate. The 5th Shamar Rinpoche Statue from 1617th century of Tibet was sold for million yuan. The Beijing Chengxuan Auctions featured almost 2,800 items of coins and stamps in three sessions with good sale rate. The Huachen Auctions also set 。s Poly Theater. Their show, titled Ulan Muqir on the Grassland, depicted the history and development of the art troupe. Being from the region allowed me to embrace the culture of Inner Mongolia and being a member of the troupe showed me where I belonged, Nasun, the art troupe39。s performers of the troupe still tour the region39。t have a formal stage. The audience just sat on the grass. Usually, the performances became a big party with local people joining in. For him, the rewarding part about touring isn39。80s. We sat on the back of pickup trucks for hours. The sky was blue, and we couldn39。s Shaanxi province pass through a stop on the ancient Silk Road, Gansu39。 第 24 頁 共 25 頁 參 考 文 獻(xiàn) [1] 和軍平 , 陳為 , 姜 建 國(guó) . 開 關(guān) 電 源 共 模 傳 導(dǎo) 干 擾 模 型 的 研 究 [J]. 中 國(guó) 電 機(jī) 工 程 學(xué)報(bào) ,2022,25(8):50～ 54 [2] 劉濤 .LED 恒流驅(qū)動(dòng)開關(guān)電源的研制 [D].成都 .電子科技大學(xué) ， 2022 [3] 趙軍 .開關(guān)電源技術(shù)的發(fā)展 [J].船電技術(shù) ， 2022，（ 5）： 13～ 15 [4] 脫立芳 .降壓型 PWM DCDC 開關(guān)電源技術(shù)研究 [D].西安 .西安電子科技大學(xué) ， 2022 [5] 楊曉靜 .高頻開關(guān)電源的研究與設(shè)計(jì) [D].武漢 .武漢理工大學(xué) ,2022 [6] 張維 .單端反激式開關(guān)電源研究與設(shè)計(jì) [D].西安 .西安電子科技大學(xué) ,2022 [7] 余明楊等 .開關(guān)電源的建模與優(yōu)化設(shè)計(jì)研究 [J].中國(guó)電機(jī)工程學(xué)報(bào) ,2022,26(2):165～ 168 [8] 閆福軍 .寬電壓輸入反激式開關(guān)電源的研究 [D].成都 .電子科技大學(xué) ,2022 [9] 王蓉 .高頻高壓開關(guān)電源的設(shè)計(jì) [D].南昌 .南昌大學(xué) ， 2022 [10] 許幸 .高效率同步整流型 DCDC 開關(guān)電源的研究與設(shè)計(jì) [D].杭州 .浙江大學(xué) ， 2022 [11] 岳鵬 .大功率開關(guān)電源主電路研究 [D].廣州 .華南理工大學(xué) ,2022 [12] 張厚升 ,趙艷雷 .新型多功能反激式開關(guān)電源設(shè)計(jì) [J].電力自動(dòng)化設(shè)備 ， 2022， 31（ 1）： 113～ 117 [13] 鄒懷安 .寬輸入電壓高頻開關(guān)電源的研究與實(shí)現(xiàn) [D].武漢 .武漢理工大學(xué) ,2022 [14] 任學(xué)峰 .一種電流模式控制 PWM 開關(guān)電源的設(shè)計(jì) [D].西安 .西安電子科技大學(xué) ,2022 [15] 張敏娟 .48V/25A 通信用高頻開關(guān)電源的研究與開發(fā) [D].南京 .河海大學(xué) ,2022 [16] L. Asnin and V. acquisition in power systems and its digital processing for measurement and automation Computer Standards amp。 我還要感謝我的爸爸媽媽，因?yàn)樗麄兊母冻觯也拍苡薪裉臁? 在大學(xué)的四年里，接觸最多的是室友，對(duì)我?guī)椭疃嗟囊彩鞘矣选Ｎ乙钌畹馗兄x指導(dǎo)老師。在資料的準(zhǔn)備中，我過于依賴網(wǎng)絡(luò)，很多資料找的不是很全面，老師教我如何利用好學(xué)校圖書館的資源，而且鼓勵(lì)我到圖書館去多看看。 致 謝 畢業(yè)設(shè)計(jì)已經(jīng)完成了，雖然畢業(yè)設(shè)計(jì)是我的，但是是在很多人的幫助下才完成的。在網(wǎng)上 以及 圖 書館借的 multisim 教程里 第 23 頁 共 25 頁 也找了很多解決方法，最后都未能成功新建所需元件。 圖 41（ a） 第 21 頁 共 25 頁 圖 41 (b) 圖 42 是經(jīng)濾波 整流后的輸出電壓 約為 310V 圖 42 圖 43 是輸 出電壓 約為 12V 第 22 頁 共 25 頁 圖 43 圖 44 是輸 出波 形 圖 44 本課題仿真因 multisim 元件庫里有很多元件沒有，如反激式變壓器， PC817 光電耦合器等原因，不能完整正確的仿真出本課題的要求。 NI Multisim 10 具有較為詳細(xì)的電路分析功能，可以完成電路的瞬態(tài)分析和穩(wěn)態(tài)分析、時(shí)域和頻域分析、器件的線性和非 線性分析、電路的噪聲分析和失真分析、離散傅里葉分析、電路零極點(diǎn)分析、交直流靈敏度分析等電路分析方法，以幫助設(shè)計(jì)人員分析