似穩(wěn)條件下磁通量計(jì)算與中空螺旋管式無(wú)極燈

似穩(wěn)條件下磁通量計(jì)算與中空螺旋管式無(wú)極燈

陽(yáng)賓1陳奮策2

(1.廈門大學(xué)嘉庚學(xué)院機(jī)電工程系，福建漳州363105；2.福建教育學(xué)院理科研修部，福建福州350025)

摘要：在似穩(wěn)狀態(tài)下，從電磁理論出發(fā)，討論通過(guò)某一回路曲面的磁通量的計(jì)算、法拉第電磁感應(yīng)定律；并應(yīng)用于中空螺旋管式線圈無(wú)極燈能量耦合機(jī)制和結(jié)構(gòu)的探究，以使增大其有效磁通量，提高對(duì)電子有效加速，最終提高其發(fā)光效率的有效途徑。

關(guān)鍵詞：似穩(wěn)狀態(tài)；磁通量；法拉第電磁感應(yīng)定律

作者簡(jiǎn)介：陽(yáng)賓(1983-)，男，廣西桂林人，廈門大學(xué)嘉庚學(xué)院機(jī)電工程系助理工程師。

中圖分類號(hào)：O441.3文獻(xiàn)標(biāo)識(shí)碼：A

1引言

電磁學(xué)中似穩(wěn)電路的必要條件[1，2]

λ>>l，T>>l/c,ω=wπf<<2πc/l

①

其中f是電源的頻率，T周期，l電路(電子儀器)的尺寸，λ電磁波的波長(zhǎng)；似穩(wěn)電路還需滿足充分條件，即似穩(wěn)交流電路中的元件把電磁場(chǎng)集中在自己內(nèi)部小范圍內(nèi)。

似穩(wěn)電路中，以電源的圓頻率變化的電流通過(guò)導(dǎo)體，在導(dǎo)體周圍會(huì)形成交變的電磁場(chǎng)，即電磁波；在此以光速c傳播的電磁波及其變化傳遍整個(gè)電路所需要的l/c時(shí)間內(nèi)，電磁波的位相近似不變；每一時(shí)刻電磁場(chǎng)的分布與同一時(shí)刻的電流、電荷的分布的關(guān)系，近似和穩(wěn)恒電路一樣，一起同步地做緩慢的變化。

文章在似穩(wěn)近似下，以工作頻率在230KHz左右一種最近實(shí)用新型專利[3]提出的中空螺旋管式線圈無(wú)極燈為例，從電磁理論高度討論無(wú)極燈螺旋管產(chǎn)生的磁通量分布與計(jì)算，以及對(duì)燈泡內(nèi)電子有效加速情況。

2似穩(wěn)條件下磁通量計(jì)算

2.1磁通量的物理圖像

②

在經(jīng)典物理中[2，4]，法拉第電磁感應(yīng)定律表述了產(chǎn)生的感應(yīng)電動(dòng)勢(shì)與磁通量的關(guān)系。磁通量Φ的定義為覆蓋某面積的磁場(chǎng)的積分：

③

④

2.2.1似穩(wěn)狀態(tài)下交流電流產(chǎn)生的磁場(chǎng)

⑤

例如，圖1示意通以似穩(wěn)交流電流的螺繞線圈和其產(chǎn)生的磁場(chǎng)。

圖1

2.2.2似穩(wěn)條件下磁通量的計(jì)算

相似于似穩(wěn)狀態(tài)下交流電流產(chǎn)生的磁場(chǎng)的討論，公式③④⑤在似穩(wěn)條件①下都成立，似穩(wěn)狀態(tài)下磁通量的計(jì)算可以延用公式③，即：

③

3似穩(wěn)條件下磁通量的計(jì)算與應(yīng)用

3.1外置型中空螺旋管式線圈產(chǎn)生的磁場(chǎng)分布

現(xiàn)以磁環(huán)外置型中空螺旋管式無(wú)極燈為例，如圖2所示，實(shí)用新型專利[3]一種新型節(jié)能無(wú)極燈，在燈座1上設(shè)置一射頻功率源2；射頻功率源上設(shè)置有兩端非封閉的燈殼3、中空玻璃管4，中空玻璃管內(nèi)設(shè)置有中空鐵磁芯5，中空鐵磁芯纏繞有通電線圈6；中空玻璃管兩端與燈殼密閉連接形成燈管7；中空鐵磁芯中心兩端連通空氣。圖2是實(shí)用新型實(shí)施例結(jié)構(gòu)示意圖。

圖2

一般實(shí)驗(yàn)室電子儀器的尺寸或用電器如無(wú)極燈)的尺寸l為幾厘米到幾十厘米的量級(jí)，例如80瓦無(wú)極燈電源頻率f=230kHz<

B=μnl0

⑥

圖3是螺繞管式線圈在磁棒內(nèi)外的交變磁場(chǎng)線分布(理想化)與磁棒四周的環(huán)路示意圖。

圖3

3.2穿過(guò)螺繞管式線圈-磁棒四周環(huán)路的磁通量

3.3提高有效磁通量的途徑與作用

我們知道，無(wú)極燈主要由頻率發(fā)生器、功率耦合器和玻璃泡殼三部分組成，通過(guò)電磁感應(yīng)方式將能量耦合到燈泡內(nèi)；燈泡內(nèi)充有適量的特種氣體，耦合到燈泡內(nèi)的高頻能量使之電離或激發(fā)，激發(fā)后的原子從較高能級(jí)返回基態(tài)時(shí)，發(fā)出紫外光子，紫外光子激發(fā)泡殼內(nèi)壁的熒光粉產(chǎn)生可見(jiàn)光。

根據(jù)前面的討論，穿過(guò)環(huán)路的磁通量不同，在環(huán)路上產(chǎn)生的交變電場(chǎng)也不同，對(duì)燈泡內(nèi)電子的加速效果也不同，導(dǎo)致熒光粉產(chǎn)生可見(jiàn)光的效果也不同。改變燈的結(jié)構(gòu)和形狀，可以使回路中有最佳的有效磁通量，從而得到最近的交變電場(chǎng)，提高對(duì)電子的加速效果(減少電子無(wú)效的熱運(yùn)動(dòng))，最終提高發(fā)光效率。實(shí)用新型專利[3]中空螺旋管式無(wú)極燈的結(jié)構(gòu)設(shè)計(jì)正是為了克服市面上燈泡型無(wú)極燈存在的缺點(diǎn)：通電線圈外磁力線分布不合理，降低了燈殼內(nèi)有效的磁通量和有效交變電場(chǎng)，導(dǎo)致降低對(duì)燈殼內(nèi)電子的有效加速效果，因而降低燈的發(fā)光效率。

另外，該實(shí)用新型中空的鐵磁芯直接連通空氣，對(duì)磁芯的散熱快，及時(shí)降低磁芯的溫度，提高磁芯的耦合效率，從而提高發(fā)光效率；另外還可降低成本。

以上從電磁理論高度，在似穩(wěn)近似下，探究似穩(wěn)交變電流產(chǎn)生的磁通量計(jì)算原則，探究法拉第電磁感應(yīng)定律的形式；并應(yīng)用于中空螺旋管式無(wú)極燈的結(jié)構(gòu)設(shè)計(jì)，提出提高有效磁通量，以提高其發(fā)光效率的有效途徑。

參考文獻(xiàn)：

[1]陳奮策.似穩(wěn)條件與無(wú)極燈工作原理[J].福建教育學(xué)院學(xué)報(bào)，2014(6).

[2]趙凱華，陳熙謀.電磁學(xué)[M].北京:人民教育出版社,1978.

[3]陳奮策.實(shí)用新型專利“中空螺旋管式線圈新型節(jié)能無(wú)極燈”(專利號(hào)：中國(guó),ZL201420220738.4)[P].

[4]郭碩鴻.電動(dòng)力學(xué)[M].北京:高等教育出版社,1997.

On Approaches to Constructing New Ideological and Political Modes in Vocational Colleges Centering on Professional Quality Culture

LIN Bing-zhiLIN Hai-rongCHEN Shu-fang

(Fuzhou Polytechnic，F(xiàn)uzhou 350108，China)

Abstract：Based on actual situations, this paper proposes the necessity of constructing vocational colleges’ new ideological and political education modes centering on professional quality culture and approaches to their construction. It also puts forward the strengthening of the building of the teaching forces to improve the level of education; the enriching of the content of ideological and political education combining professional quality culture; the enhancing of mental health education to improve the students’ psychological quality; the using of campus culture as the basis to strengthen the training of professional quality; and the strengthening of social practice to enhance the education of the students.

Key words：higher vocational colleges; professional quality culture; ideological and political education; approach

Changes of the Creation of Female Novels Since the Late 70s of the 20th Century

LIN Shan

(Fujian Open University, Fuzhou 350003, China)

Abstract：Since the late 70s of the 20th century, the creation of female novels has gone through the four stages of renaissance, development, change, and expansion. Respectively, they expressed enlightenment narrative full of humanity feelings, gender narrative full of female consciousness, physical narrative full of “private” characteristics, underclass narrative and historical narrative full of femininity.

Key words：enlightenment narrative; gender narrative; physical narrative; underclass narrative; historical narrative

The Culture of Pleurotus Liquid and the Analysis of Extracellular Polymeric Substances

YI Jun1CHEN Ti-qiang2

(1. Department of Science Research and Training，F(xiàn)ujian Institute of Education，F(xiàn)uzhou 350025，China；

2. Edible Fungi Institute, Fujian Academy of Agricultural Sciences, Fuzhou 350013, China)

Abstract：To ascertain the effect of different carbon and nitrogen sources on the mycelial growth of Pleurotus tuber-regium (Fr.) Singer, the exo-polymers dynamic accumulation and its chemical composition. By liquid fermentation, the results showed that the mycelial growth was better in the medium of fructose as the carbon source than that of glucose as the carbon source, with biotransformation rate of 37.18～48.53%, and mycelium (lyophilized) yield 12.64±0.41～16.50±0.51 g / L; the mycelial growth in the medium of yeast powder as nitrogen source was better than that of peptone as nitrogen source, with biotransformation rate 28.06～33.68%, mycelium yield 9.54±0.79～11.45±0.73g / L. After 6～14d or 6～20 d inoculation, the exo-polymer has a smooth high level contents. The exo-polymer content (0.12～0.16g / L) in Gpy (glucose-yeast) medium was significantly higher than that in Fpy (fructose-yeast) medium (0.11～0.12g / L).GC was used to analyze the monosaccharide in the exo-polymer. The results showed that the exo-polymer was a heteropolysaccharide, and its monosaccharide composition included glucose, mannose and galactose. The exo-polymer yield was higher than the total weights of its monosaccharide. In this study, Fpy medium can be used to increase the mycelia yield, and Gpy medium to increase the exo-polymer yield.

Key words：Pleurotus tuber-regium; liquid culture; mycelium yield; exo-polymer; component analysis