The document provides background information about epic poems such as the works of Homer, Apollonius of Rhodes, and John Gardner's retelling of the myth of Jason and Medea. It discusses the characteristics of epic poems, including that they feature heroes on quests, supernatural elements, and elevated language. It also explains the dactylic hexameter structure used in classical epics, providing examples to illustrate how this poetic meter works.
A credit score is a number that summarizes a person's credit history and predicts their likelihood of repaying future loans. The three main credit reporting agencies are Equifax, Experian, and TransUnion. VantageScore is a generic credit score that ranges from 501-990, with higher numbers indicating better credit risk. A credit score considers information from a person's account history, public records, and credit inquiries.
The document provides announcements and updates for a real estate company. It recognizes top performers for GCI and PREA awards. It includes market updates and statistics on mortgage capture, title capture, and AHS capture by office. It lists upcoming events like an expo, marketing plan meeting, and appreciation party. It promotes an AHS lunch and learn on a new warranty plan and encourages agents to use free marketing materials from AHS.
The document provides background information about epic poems such as the works of Homer, Apollonius of Rhodes, and John Gardner's retelling of the myth of Jason and Medea. It discusses the characteristics of epic poems, including that they feature heroes on quests, supernatural elements, and elevated language. It also explains the dactylic hexameter structure used in classical epics, providing examples to illustrate how this poetic meter works.
A credit score is a number that summarizes a person's credit history and predicts their likelihood of repaying future loans. The three main credit reporting agencies are Equifax, Experian, and TransUnion. VantageScore is a generic credit score that ranges from 501-990, with higher numbers indicating better credit risk. A credit score considers information from a person's account history, public records, and credit inquiries.
The document provides announcements and updates for a real estate company. It recognizes top performers for GCI and PREA awards. It includes market updates and statistics on mortgage capture, title capture, and AHS capture by office. It lists upcoming events like an expo, marketing plan meeting, and appreciation party. It promotes an AHS lunch and learn on a new warranty plan and encourages agents to use free marketing materials from AHS.
The Grady Rd. Landfill receives around 1200 tons of waste per day from various sources like restaurants, schools, and construction sites. The waste consists primarily of municipal solid waste (85%) along with some construction and demolition debris (10%) and special wastes (5%). At this landfill, the waste is not separated and is processed using equipment like evacuators, compactors, and bulldozers. The landfill structure involves filling the site in phases with double covers to prevent erosion and contamination of the surrounding area. Water monitoring of the leachate is conducted through groundwater wells and testing every 3 months.
El documento describe el yate de lujo de Greg Norman llamado "Aussie Rules" que mide 69.5 metros de largo. Incluye varios botes más pequeños como lanchas de pesca, botes para buceo y balsas salvavidas. También describe otros yates de lujo como el del Sultán de Brunei que incluye helicópteros y el de Roman Abramovich que tiene estaciones de mando y un helipuerto.
O fotógrafo Carl Warner cria cenários utilizando apenas alimentos, chamados de "foodscapes". Ele usa frutas, legumes e outros itens para representar paisagens como florestas, praias e cachoeiras. Warner passa horas procurando os alimentos perfeitos e faz fotos em mesas grandes para dar profundidade às cenas.
The document provides background information about epic poems such as those written by Homer, Apollonius, and John Gardner. It discusses the characteristics of epic poems, including that they tell stories of heroes' journeys, invoke the Muses, use elevated language, and follow certain conventions. The document also explains that Gardner's retelling of the myth of Jason and Medea uses dactylic hexameter, the meter of classical epics.
18. 电流放大系数 β 与 f 的关系: 故可以粗略计算在某工作频率下的电流放大系数。 3 ) 最高振荡频率 fmax f max 表示晶体管所能够适应的最高极限频率。在此工作频率 时晶体管已经不能得到功率放大,当 f>f max 时 , 无论使用什么 方法都不能使晶体管产生振荡。 晶体管的功率增益 时的工作频率 可以证明 :
19. R 1 、 R 2 、 R 3 为 偏置电阻,决定工作点, L F 、 C F 为滤波电路,负压供电 C 4 、 L 组成 L 、 C 谐振回路 R 4 是加宽回路通频带用 R p 是并联回路本身的损耗 所谓单调谐回路共发放大器就是晶体管共发电路和并联回路的组合。所以前面分析的晶体管等效电路和并联回路的结论均可应用。 3. 3 单调谐回路谐振放大器
36. 3. 5 谐振放大器的稳定性 一、自激产生的原因 g F 改变了回路的 Q L 值 , bF 引起回路失谐。
37. g F 是频率的函数,在某些频率上可能为负值,即呈负电导性,使回路的总电导减小, Q L 增加,通频带减小,增益也因损耗的减少而增加,即负电导 g F 供给回路能量,出现正反馈。当 g F = g s + g ie (回路原有电导)则回路总电导 g = 0 , Q L ,放大器失去放大性能,处于自激振荡工作状态。
38. 二、放大器产生自激的条件 当 Y s + Y z = 0 回路总电导 g = 0 放大器产生自激。 此时放大器的反馈能量抵消了回路损耗能量,且电纳部分 也恰好抵消。表明放大器反馈的能量抵消回路损耗的能量,且 电纳部分也切好得到抵消。
42. 讨论: ① ( A vo ) s 与 f 有关, f ( A vo ) s , f y re 内反馈厉害。 ② 选管应选 大些的为好 ③ ( A vo ) s 只考虑内部反馈,未考虑外部反馈。 当 S = 5 时, ( A vo)s 是保持放大器稳定工作所允许的电压增益,称为稳定 电压增益,为保证放大器稳定工作, A vo 不允许超过 ( A vo)s 。
43. 由于 y re 的存在,晶体管是一个双向的器件,增强放大器 的稳定性可以考虑晶体管的单向化。 单向化的方法有: ⑴ 中和法 消除 y re 的反馈 ⑵ 失配法 使 G L 或 g s 的数值增大,因而使输入和输出回路 与晶体管匹配。 在实际运用中,中和法是外加一个电容抵消正反馈电容的作用 失配法: 信号源内阻不与晶体管输入阻抗匹配; 晶体管输出端负载不与晶体管的输出阻抗匹配。 即以牺牲电压增益来换取放大器的稳定性 四、克服自激的方法
44. (1) 中和法: 在放大器线路中插入一个外加的反馈电路,使它的作用 恰好和晶体管的内反馈互相抵消。 具体线路: 电桥平衡时, CD 两端的回路电压 不会反映到 AB 两端 , 即对应两边阻抗之比相等。
45. ((2) 失配法 原 晶 信号源内阻不与晶体管输入阻抗匹配,晶体管输出端 负载阻抗不与本级晶体管的输出阻抗匹配。 原理:由于阻抗不匹配,输出电压减小,反馈到输入 电路的影响也随之减小。使增益下降,提高稳定性。 使 Y i = y ie ,即使后项 0 ,则必须加大 Y L 晶体管实现单向比,只与管子本身参数有关,失配法 一般采用共发一共基级联放大 . 则
46. 3. 中和法与失配法比较 中和法: 优点:简单,增益高 缺点:① 只能在一个频率上完全中和,不适合宽带 ② 因为晶体管离散性大,实际调整麻烦,不适于 批量生产。 ③ 采用中和对放大器由于温度等原因引起各种参 数变化没有改善效果。 失配法: 优点:①性能稳定,能改善各种参数变化的影响; ② 频带宽,适合宽带放大,适于波段工作; ③ 生产过程中无需调整,适于大量生产。 缺点:增益低。