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Run Time: 0.000602
Select Type | Table | Type | Possible Keys | Key | Key Len | Ref | Rows | Extra |
---|
SIMPLE | xf_data_registry | range | PRIMARY | PRIMARY | 27 | | 26 | Using where |
SELECT data_key, data_value
FROM xf_data_registry
WHERE data_key IN ('brListenerClasses', 'brBriviumAddOns')
Run Time: 0.000161
Select Type | Table | Type | Possible Keys | Key | Key Len | Ref | Rows | Extra |
---|
SIMPLE | xf_data_registry | range | PRIMARY | PRIMARY | 27 | | 2 | Using where |
SELECT *
FROM xf_brivium_addon
ORDER BY addon_id
Run Time: 0.000142
Select Type | Table | Type | Possible Keys | Key | Key Len | Ref | Rows | Extra |
---|
SIMPLE | xf_brivium_addon | index | | PRIMARY | 77 | | 1 | |
INSERT INTO xf_data_registry
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VALUES
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ON DUPLICATE KEY UPDATE
data_value = VALUES(data_value)
Params: brBriviumAddOns, a:0:{}
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Params: 1
Run Time: 0.000142
Select Type | Table | Type | Possible Keys | Key | Key Len | Ref | Rows | Extra |
---|
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SELECT thread.*
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user.gender, user.avatar_date, user.gravatar,
NULL AS thread_read_date,
0 AS thread_reply_banned,
0 AS thread_is_watched,
'' AS draft_message, NULL AS draft_extra
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Params: 145521
Run Time: 0.000331
Select Type | Table | Type | Possible Keys | Key | Key Len | Ref | Rows | Extra |
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SIMPLE | user | const | PRIMARY | PRIMARY | 4 | const | 1 | |
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permission.cache_value AS node_permission_cache,
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SIMPLE | node | const | PRIMARY | PRIMARY | 4 | const | 1 | |
SIMPLE | permission | const | PRIMARY | PRIMARY | 35 | const,const,const | 1 | |
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post.user_id, post.username, post.post_date,
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SIMPLE | user_profile | eq_ref | PRIMARY | PRIMARY | 4 | xenforo.cc.post.user_id | 1 | |
SIMPLE | user_privacy | eq_ref | PRIMARY | PRIMARY | 4 | xenforo.cc.post.user_id | 1 | |
SIMPLE | signature_parse_cache | eq_ref | content_type_id | content_type_id | 31 | const,xenforo.cc.post.user_id | 1 | Using where |
SIMPLE | session_activity | eq_ref | PRIMARY | PRIMARY | 22 | xenforo.cc.post.user_id,func | 1 | Using where |
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Params: post, 149612, a:10:{i:0;a:4:{s:3:"tag";s:1:"b";s:6:"option";N;s:8:"original";a:2:{i:0;s:3:"[B]";i:1;s:4:"[/B]";}s:8:"children";a:1:{i:0;s:201:"由麻省理工声学与流体力学专家组成的一支团队,已经与波士顿小提琴制造商达成了合作,旨在精心分析出数百把制作于“黄金时代”的小提琴的参数。";}}i:1;s:186:"这项研究不仅发现了设计上的几个关键点,还为我们揭示了这些“神器”的产生究竟是源自于一时的人为失误、还是工匠们的有意而为之。
";i:2;a:4:{s:3:"tag";s:6:"center";s:6:"option";N;s:8:"original";a:2:{i:0;s:8:"[CENTER]";i:1;s:9:"[/CENTER]";}s:8:"children";a:1:{i:0;a:4:{s:3:"tag";s:3:"img";s:6:"option";N;s:8:"original";a:2:{i:0;s:5:"[IMG]";i:1;s:6:"[/IMG]";}s:8:"children";a:1:{i:0;s:65:"http://static.cnbetacdn.com/article/2015/0212/0e6ec64e4f32b8c.jpg";}}}}i:3;s:803:"
这支团队将重心放在了出产于17到18世纪的数百把小提琴,其中包括了来自阿玛蒂(Amati)、斯特拉迪瓦里(Stradivari)、以及瓜耐里(Guarneri)等名家的作品。
除了使用X射线和CAT扫描,他们还购买了来自博物馆、收藏家、以及其它数据库的技术图纸,并且在多个维度上对乐器进行尺寸上的比较、以及声学共振上的测量。
这项研究鉴定了小提琴F孔上的形状和长度,此种波状外形开孔可以让空气从这里逃脱,并且会对声音的力度和饱满度产生重要的影响。
具体说来就是,研究人员们发现,大部分声音都是流过该孔周界(perimeter)而产生的,而不是孔的内部。因此更细长的音孔就意味着能够产生更有力道的声音。
";i:4;a:4:{s:3:"tag";s:6:"center";s:6:"option";N;s:8:"original";a:2:{i:0;s:8:"[CENTER]";i:1;s:9:"[/CENTER]";}s:8:"children";a:1:{i:0;a:4:{s:3:"tag";s:3:"img";s:6:"option";N;s:8:"original";a:2:{i:0;s:5:"[IMG]";i:1;s:6:"[/IMG]";}s:8:"children";a:1:{i:0;s:65:"http://static.cnbetacdn.com/article/2015/0212/cff5cf5a927bf29.jpg";}}}}i:5;s:753:"
此外,背板的厚度也会对声音的功率产生显著的影响。木结构的弹性,可以针对空气的震动给以细腻的反馈(扩张或收缩)。研究发现,乐器背板越厚,其对小提琴声音的推动力就越大。
最后,研究人员们还揭开了乐器发展背后的秘密。因为随着时间的推移,小提琴的背板厚度和F孔的长度也都有所增加。显然,这并不是偶然的失误而导致,而是制琴师们的有意而为之。
这项研究由麻省理工大学机械与海洋工程学院的Nicholas Makris教授所带领,作为“弦乐器声音动态扩展检查”的一部分,其成果有助于帮助现代乐器制造商们生产出声场更加强劲的小提琴。
[编译自:";i:6;a:4:{s:3:"tag";s:3:"url";s:6:"option";s:56:"http://www.gizmag.com/mit-scans-cremonese-violins/36039/";s:8:"original";a:2:{i:0;s:64:"[URL='http://www.gizmag.com/mit-scans-cremonese-violins/36039/']";i:1;s:6:"[/URL]";}s:8:"children";a:1:{i:0;s:6:"Gizmag";}}i:7;s:11:", 来源:";i:8;a:4:{s:3:"tag";s:3:"url";s:6:"option";s:58:"https://newsoffice.mit.edu/2015/violin-acoustic-power-0210";s:8:"original";a:2:{i:0;s:66:"[URL='https://newsoffice.mit.edu/2015/violin-acoustic-power-0210']";i:1;s:6:"[/URL]";}s:8:"children";a:1:{i:0;s:3:"MIT";}}i:9;s:1:"]";}, 1621686945, 1714393644
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