同步发电机维持静态稳定的判据是().A、P随着功角δ的增大而增大,随着功角δ的减小而

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问题:

同步发电机维持静态稳定的判据是().

A、P随着功角δ的增大而增大,随着功角δ的减小而减小

B、P随着功角δ的增大而减小,随着功角δ的减小而增大

C、Q随着功角δ的增大而增大,随着功角δ的减小而减小

D、Q随着功角δ的增大而减小,随着功角δ的减小而增大

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As Philadelphia grew from a small town into a city in the first half of the eighteenth century, it became an increasingly important marketing center for a vast agricultural hinterland. Market days (1) the crowded city even more crowded, as farmers from within a (2) of 24 or more kilometers brought their sheep, vegetables, cider and other products for direct sale to the (3) . The High Street Market was continuously (4) throughout the period until 1736, (5) it (6) from Front Street to Third. By 1745 New Market was opened on Second Street. The next year the Callow Hill Market began (7) .

Along with market days, the (8) of twice-yearly fairs persisted in Philadelphia (9) after similar trading days had been discontinued in other colonial cities. The (10) provided a means of bringing handmade goods from (11) places to would-be buyers in the city. Linens and stockings from Germantown, (12) , were popular items.

Auctions were another popular (13) of trade. Because of the competition, retail (14) opposed these as well as the fairs. (15) governmental attempts to eradicate fairs and auctions were less than successful, the ordinary (16) of economic development was on the merchants’side, as increasing business specialization became the (17) of the day. Export merchants became differentiated from their importing counterparts, and specialty shops began to appear (18) general stores selling a variety of goods.

One of the reasons Philadelphia’s merchants prospered was because the surrounding area was undergoing tremendous economic and demographic growth. They did their business, (19) , in the capital city of the province, (20) to not only the governor and his circle, but citizens from all over the colony.

4()

A.envisioned

B.endangered

C.enriched

D.enlarged

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我国化工专家侯德榜发明的侯氏制碱法的化学原理是将二氧化碳通入氨水的氯化钠饱和溶液中,其化学反应方程式为:NaCl+NH3+CO2+H2O=NaHCO3↓+NH4Cl。

(1)在实验室中利用上述原理从反应所得溶液中分离出碳酸氢钠晶体,应选用下列装置中的            

(2)实验所得碳酸氢钠晶体中,可能含有的杂质离子有Cl和NH4+,实验室鉴定Cl所选用的试剂是、,鉴定另一种杂质离子的方法是  (填序号)。

A.加水,将湿润的红色石蕊试纸放在试管口

B.加氢氧化钠溶液,加热,将湿润的红色石蕊试纸放在试管口

C.加氢氧化钠溶液,加热,滴入酚酞试剂

D.加氢氧化钠溶液,加热,滴入紫色石蕊试剂(3)碳酸氢钠晶体受热分解可得到纯碱,其化学反应方程式为

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患者女性,40岁。双侧腮腺区反复肿 大,伴双眼异物感、无泪、口干,饮水量增加。 检查发现双侧腮腺肿大,质软,无压痛;张口 度正常,口腔黏膜干燥,发红。腮腺导管口无 红肿,分泌液清,但量少

为明确诊断,需进一步作一系列检查, 其中对诊断帮助不大的是

A.Schirmer试验

B.腮腺平片

C.腮腺造影

D.唇腺活检

E.空腹血糖

题型:单项选择题

GNSS所有增强系统()。

A.必须包含故障检测(FD)及故障检测、排除(FDE)功能。

B.可以包含故障检测(FD)或故障检测、排除(FDE)功能

C.只能包含故障检测(FD)功能。

D.只能包含故障检测、排除(FDE)功能。

题型:单项选择题

某患者,人工流产术后,不规则流血15天,药物治疗无效,子宫稍大,软,宫口开大,应考虑

A.子宫内膜炎
B.吸宫不全
C.功血
D.宫颈粘连
E.子宫复旧不全

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