对噪声的理解,正确的是 A.提高X线剂量,可减小噪声 B.X线剂量增加1倍,噪声减半

题型:多项选择题

问题:

对噪声的理解,正确的是

A.提高X线剂量,可减小噪声

B.X线剂量增加1倍,噪声减半

C.扫描层厚加厚,噪声减小

D.检测器的灵敏度高,噪声减小

E.骨算法较软组织算法噪声提高

考点:医技考试放射技士专业实践能力初级放射医学技士专业实践能力
题型:多项选择题

设f(x)是定义在R上的奇函数,当x≤0时,f(x)=2x2-x,则f(1)=(    )。

题型:多项选择题

C

If you are a fruit grower—or would like to become one—take advantage of Apple Day to see what’s around. It’s called Apple Day but in practice it’s more like Apple Month. The day itself is on October 21, but since it has caught on, events now spread out over most of October around Britain.

Visiting an apple event is a good chance to see, and often taste, a wide variety of apples. To people who are used to the limited choice of apples such as Golden Delicious and Royal Gala in supermarkets, it can be quite an eye opener to see the range of classical apples still in existence, such as Decio which was grown by the Romans. Although it doesn’t taste of anything special, it’s still worth a try, as is the knobbly(多疙瘩的) Cat’s Head which is more of a curiosity than anything else.

There are also varieties developed to suit specific local conditions. One of the very best varieties for eating quality is Orleans Reinette, but you’ll need a warm, sheltered place with perfect soil to grow it, so it’s a pipe dream for most apple lovers who fall for it.

At the events, you can meet expert growers and discuss which ones will best suit your conditions, and because these are family affairs, children are well catered for with apple-themed fun and games.

Apple Days are being held at all sorts of places with an interest in fruit, including stately gardens and commercial orchards(果园).If you want to have a real orchard experience, try visiting the National Fruit Collection at Brogdale, near Faversham in Kent.

What can people do at the apple events?()

A. Attend experts’ lectures.

B. Visit fruit-loving families.

C. Plant fruit trees in an orchard.

D. Taste many kinds of apples.

题型:多项选择题

某热力发电厂主要生产工艺单元有:储煤场、煤粉制备与输煤系统、燃烧系统、汽水系统、凝结水系统、化学水系统、循环水系统、除灰渣与除尘脱硫系统、制氢系统、配电与送电系统、车库等。大型设备主要有:锅炉、汽轮机、发电机、磨煤机、制氢装置、水处理装置、除尘装置等。发电用燃煤,由汽车直接运往储煤场,在储煤场用滚轴筛将煤破碎后送进燃煤锅炉。制氢系统包括制氢装置和氢气储罐,制氢装置为配套电解制氢设备及其管路等。运行时装置中存有的氢气为50kg,与制氢装置边缘距离为30 m处,有6个24 m3额定工作压力为3.2 MPa,额定工作温度为20℃的卧式储罐,作为生产成品的周转储罐。制氢装置与氢气储罐用管道连接。锅炉点火助燃为柴油。厂内有两个2000 m3的固定储罐存储了柴油。罐的设计充装系数为0.85,两柴油罐在同一围堰内,在距制氢系统外部边界550 m处有一个汽油储罐区,有两个20 m3的卧式汽油储罐,储罐的设计充装系数为0.85,两个汽油储罐在同一围堰内。

相关资料:氢气在0℃、0.1 MPa环境中的密度为0.09 kg/m3,所用汽油的密度为750 kg/m3,所用柴油的密度830kg/m3。标准《危险化学品重大危险源辨识》(GB18218—2009)中给出:氢气在生产场所的临界量为1t,在储存区临界量为10 t:汽油在生产场所的临界量为2 t,在储存区的临界量为20 t。

题目

按照《危险化学品重大危险源辨识》(GB18218—2009)给出的危险物质及其临界量,选做以下两题中任一个:
①找出该电厂两处危险源及名称;
②计算出两处危险源中任一处的储量。

题型:多项选择题

工程竣工决算时,对其他费用的处理正确的是().

A.工程其他费用形成的资产属出资人所有

B.工程其他费用形成的资产属建设者所有

C.及时办理土地、房产等权属证明

D.确保资产权属完整、清晰

题型:多项选择题

一般液压泥炮的转炮、压炮、打泥装置是靠()来实现的。

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