什么是小提琴
弓弦乐器家族包含小提琴、中提琴、大提琴、低音大提琴。称为小提琴的乐器是家族中音调最高的成员。指板没有浮纹,四弦,木制琴体形状独特,其“腰身”造就了弓法的自由。被置於肩上,由右手拉弓。有极广的4个八度。16世纪在义大利演化而成,源於中世纪的提琴及其他乐器。它的平均比例在17世纪确立,但18~19世纪的改革增加了本身的音色能力。小提琴音色灿烂、灵活而具有歌唱性,在西方艺术音乐中一直是非常重要的,在所有弦乐器中拥有最大而最着名的曲目,包括数以千计的协奏曲。从17世纪中期以来,它一直是管弦乐团的基础,如今管弦乐团通常包括20~26支小提琴;小提琴也广用於室内乐,或作为独奏乐器。它在许多国家以民俗乐器的形式演奏,民俗小提琴常被称为提琴。
violin
Family of bowed stringed instruments consisting of the violin, viola, cello, and double bass. The instrument called the violin is the family's highest-pitched member. It has a fretless fingerboard, four strings, and a distinctively shaped wooden body whose “waist” permits freedom of bowing. It is held on the shoulder and bowed with the right hand. It has a wide range of over four octaves. It evolved in Italy in the 16th century from the medieval fiddle and other instruments. Its average proportions were settled by the 17th century, but innovations in the 18th-19th century increased its tonal power. With its brilliance, agility, and singing tone, the violin has been immensely important in Western art music, and it has the largest and most distinguished repertoire of any stringed instrument, including thousands of concertos. From the mid-17th century it has been the foundation of the symphony orchestra, which today usually includes 20-26 violins, and is also widely used in chamber music and as a solo instrument. It is played as a folk instrument in many countries, folk violins being often called fiddles.
-
什么是洪水预报
根据洪水形成和运动的规律,利用过去和现时水文气象资料,预测未来一定时段内的洪水情况。是水文预报中最重要的内容。一次洪水过程约数小时至数天,预见期较短,故常称短期洪水预报。洪水预报包括河道洪水预报、流域洪水预报、水库洪水预报等。主要预报项目有最高洪水...
-
什么是组织水平决策
根据一定的组织目标判断和选择组织管理方案的过程。它是管理工作的重要方面,是包含个体、群体和组织等各种因素的复杂过程。它包括4个主要阶段:搜索环境条件;创造、制定和分析可能采取的行动方案;选择特定的行动方案;对已作的选择进行评价。对于组织水平决策的研究...
-
什么是土壤地带性学说
认为土壤的发生、发展和分布,在生物因素为主导的诸成土因素综合影响下,呈现与气候带相适应的地带性现象。表现为成土过程、土壤性状与各自然地理要素之间存在着相互联系和制约。不论风化壳类型,矿物质的迁移和转化,有机质的分解、合成和累积,以及物质的淋溶和淀积等...
-
什么是岩体人工改造
改变岩体的组成成分或岩体结构、岩体赋存环境,以达到工程活动目的的措施。岩体改造的目标有两个方面:其一是强化或加固岩体,增强岩体的自稳能力。如为了提高隧道稳定性而用锚固、灌浆或卸载环等技术对岩体结构或围岩中应力状态进行的改造。其二是弱化岩体,增加岩...