SELECT data_key, data_value
FROM xf_data_registry
WHERE data_key IN ('options', 'languages', 'contentTypes', 'codeEventListeners', 'deferredRun', 'simpleCache', 'addOns', 'defaultStyleProperties', 'routeFiltersIn', 'routeFiltersOut', 'routesPublic', 'nodeTypes', 'bannedIps', 'discouragedIps', 'styles', 'displayStyles', 'userBanners', 'smilies', 'bbCode', 'threadPrefixes', 'userTitleLadder', 'reportCounts', 'moderationCounts', 'userModerationCounts', 'notices', 'userFieldsInfo')
Run Time: 0.000541
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: 0.000146
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: 0.000144
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
(data_key, data_value)
VALUES
(?, ?)
ON DUPLICATE KEY UPDATE
data_value = VALUES(data_value)
Params: brBriviumAddOns, a:0:{}
Run Time: 0.000130
SELECT cache_value
FROM xf_permission_combination
WHERE permission_combination_id = ?
Params: 1
Run Time: 0.000145
Select Type | Table | Type | Possible Keys | Key | Key Len | Ref | Rows | Extra |
---|
SIMPLE | xf_permission_combination | const | PRIMARY | PRIMARY | 4 | const | 1 | |
SELECT thread.*
,
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
FROM xf_thread AS thread
LEFT JOIN xf_user AS user ON
(user.user_id = thread.user_id)
WHERE thread.thread_id = ?
Params: 297267
Run Time: 0.000394
Select Type | Table | Type | Possible Keys | Key | Key Len | Ref | Rows | Extra |
---|
SIMPLE | thread | const | PRIMARY | PRIMARY | 4 | const | 1 | |
SIMPLE | user | const | PRIMARY | PRIMARY | 4 | const | 1 | |
SELECT node.*, forum.*
,
permission.cache_value AS node_permission_cache,
NULL AS forum_read_date
FROM xf_forum AS forum
INNER JOIN xf_node AS node ON (node.node_id = forum.node_id)
LEFT JOIN xf_permission_cache_content AS permission
ON (permission.permission_combination_id = 1
AND permission.content_type = 'node'
AND permission.content_id = forum.node_id)
WHERE node.node_id = ?
Params: 38
Run Time: 0.000434
Select Type | Table | Type | Possible Keys | Key | Key Len | Ref | Rows | Extra |
---|
SIMPLE | forum | const | PRIMARY | PRIMARY | 4 | const | 1 | |
SIMPLE | node | const | PRIMARY | PRIMARY | 4 | const | 1 | |
SIMPLE | permission | const | PRIMARY | PRIMARY | 35 | const,const,const | 1 | |
SELECT post.*
,
thread.*, thread.user_id AS thread_user_id, thread.username AS thread_username,
thread.post_date AS thread_post_date,
post.user_id, post.username, post.post_date,
bb_code_parse_cache.parse_tree AS message_parsed, bb_code_parse_cache.cache_version AS message_cache_version,
user.*, IF(user.username IS NULL, post.username, user.username) AS username,
user_profile.*,
user_privacy.*,
signature_parse_cache.parse_tree AS signature_parsed, bb_code_parse_cache.cache_version AS signature_cache_version,
session_activity.view_date AS last_view_date,
0 AS like_date
FROM xf_post AS post
INNER JOIN xf_thread AS thread ON
(thread.thread_id = post.thread_id)
LEFT JOIN xf_bb_code_parse_cache AS bb_code_parse_cache ON
(bb_code_parse_cache.content_type = 'post' AND bb_code_parse_cache.content_id = post.post_id)
LEFT JOIN xf_user AS user ON
(user.user_id = post.user_id)
LEFT JOIN xf_user_profile AS user_profile ON
(user_profile.user_id = post.user_id)
LEFT JOIN xf_user_privacy AS user_privacy ON
(user_privacy.user_id = post.user_id)
LEFT JOIN xf_bb_code_parse_cache AS signature_parse_cache ON
(signature_parse_cache.content_type = 'signature' AND signature_parse_cache.content_id = post.user_id)
LEFT JOIN xf_session_activity AS session_activity ON
(post.user_id > 0 AND session_activity.user_id = post.user_id AND session_activity.unique_key = CAST(post.user_id AS BINARY))
WHERE (
(post.thread_id = ? AND (post.position >= 0 AND post.position < 10) )
)
AND (post.message_state IN ('visible'))
ORDER BY post.position ASC, post.post_date ASC
Params: 297267
Run Time: 0.001656
Select Type | Table | Type | Possible Keys | Key | Key Len | Ref | Rows | Extra |
---|
SIMPLE | thread | const | PRIMARY | PRIMARY | 4 | const | 1 | Using filesort |
SIMPLE | post | ref | thread_id_post_date,thread_id_position | thread_id_post_date | 4 | const | 1 | Using index condition; Using where |
SIMPLE | bb_code_parse_cache | eq_ref | content_type_id | content_type_id | 31 | const,xenforo.cc.post.post_id | 1 | Using where |
SIMPLE | user | eq_ref | PRIMARY | PRIMARY | 4 | xenforo.cc.post.user_id | 1 | |
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 |
INSERT INTO xf_thread_view
(thread_id)
VALUES
(?)
Params: 297267
Run Time: 0.000087
INSERT INTO `xf_session` (`session_id`, `session_data`, `expiry_date`) VALUES (?, ?, ?)
Params: fc53831a7076c91fbb92e9b1b995a101, , 1714285179
Run Time: 0.000745
INSERT INTO xf_session_activity
(user_id, unique_key, ip, controller_name, controller_action, view_state, params, view_date, robot_key)
VALUES
(?, ?, ?, ?, ?, ?, ?, ?, ?)
ON DUPLICATE KEY UPDATE
ip = VALUES(ip),
controller_name = VALUES(controller_name),
controller_action = VALUES(controller_action),
view_state = VALUES(view_state),
params = VALUES(params),
view_date = VALUES(view_date),
robot_key = VALUES(robot_key)
Params: 0, , , XenForo_ControllerPublic_Thread, Index, valid, thread_id=297267, 1714281579,
Run Time: 0.000104
INSERT INTO xf_bb_code_parse_cache
(content_type, content_id, parse_tree, cache_version, cache_date)
VALUES (?, ?, ?, ?, ?)
ON DUPLICATE KEY UPDATE parse_tree = VALUES(parse_tree),
cache_version = VALUES(cache_version),
cache_date = VALUES(cache_date)
Params: post, 303888, a:42:{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:38:"http://pic1.zhimg.com/da8e974dc_is.jpg";}}i:1;s:12:" pan seaeye ";i:2;a:4:{s:3:"tag";s:3:"url";s:6:"option";s:58:"https://www.zhihu.com/question/373545770/answer/1045662241";s:8:"original";a:2:{i:0;s:66:"[URL='https://www.zhihu.com/question/373545770/answer/1045662241']";i:1;s:6:"[/URL]";}s:8:"children";a:1:{i:0;s:12:"阅读原文";}}i:3;s:2:"
";i:4;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:78:"飞机不需要比射出的子弹更快,也能接回自己发射的子弹。";}}i:5;s:271:"
最近一次类似意外是 2019 年 1 月 21 日,荷兰空军一架 F-16 撞上了自己发射的 20mm 炮弹。(不过这一次炮弹是被地面反弹,刚好撞上,感谢评论区 @茶海 的指正)
空中接回子弹的案例请参考 kekE 的答案。
";i:6;a:4:{s:3:"tag";s:3:"url";s:6:"option";s:102:"https://theaviationist.com/2019/04/09/dutch-f-16-hit-by-own-bullet-during-mission-at-the-firing-range/";s:8:"original";a:2:{i:0;s:110:"[URL='https://theaviationist.com/2019/04/09/dutch-f-16-hit-by-own-bullet-during-mission-at-the-firing-range/']";i:1;s:6:"[/URL]";}s:8:"children";a:1:{i:0;s:64:"Dutch F-16 Hit By Own Bullet During Mission At The Firing Range.";}}i:7;a:4:{s:3:"tag";s:3:"url";s:6:"option";s:51:"https://new.qq.com/omn/20190407/20190407A030PR.html";s:8:"original";a:2:{i:0;s:59:"[URL='https://new.qq.com/omn/20190407/20190407A030PR.html']";i:1;s:6:"[/URL]";}s:8:"children";a:1:{i:0;s:54:"荷兰空军闹乌龙,战机开炮差点击落自已";}}i:8;s:2:"
";i:9;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:66:"http://pic1.zhimg.com/70/v2-ecd3f4b16eccb7d940d85f7352f2f2bc_b.jpg";}}i:10;s:80:"
假设飞机是 4000 米高度,0.8 马赫飞行(即 0.8 x 324.6 = 260m/s
";i:11;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:84:"由于空气阻力的影响,射出的子弹会很快减速,速度低于飞机。";}}i:12;s:535:"
假设是 7.62mm 口径的 NATO Ball M80 子弹,0 发射角度,膛口速度 855 m/s(加上飞机速度 = 1115 m/s。
那么这颗子弹的弹道是这样的:
它的落地时间是 40 秒,落地速度 152m/s,距离发射点的水平距离是 6109 米。
它通过下述水平距离的时间是
1000 米 1.21 秒,高度 3994 米
2000 米 2.75 秒,高度 3954 米
3000 米 7.89 秒,高度 3797 米
4000 米 13.55 秒,高度 3405 米
5000 米 21.78 秒,高度 2549 米
6000 米 37.04 秒,高度 440 米
";i:13;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:66:"http://pic1.zhimg.com/70/v2-92573e2507e9017f65ba1c72f1e8fc20_b.jpg";}}i:14;s:246:"
假设飞机追上子弹的位置是 5000 米水平距离,即 21.78 秒,2549 米高度。
飞机需要飞过的距离是 根号[ (4000 - 2549 )^2 + 5000^2 ] = 5206 米。
而飞机的速度是 260m/s,飞过 5206 米只需要 20 秒。
";i:15;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:46:"所以飞机可以在 20 秒内追上子弹。";}}i:16;s:258:"
表格计算采用下图的阻力系数曲线(来源:弹道研究实验室 MR-1833 文档)
考虑不同高度下的音速,空气密度,重力加速度的变化。
子弹重量 9.46 克,直径 7.83 毫米,截面积 0.000048152 平方米。
";i:17;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:66:"http://pic3.zhimg.com/70/v2-279e24d201c04def36e9e5922045f702_b.jpg";}}i:18;s:278:"
补充: 12.7mm Ball M33 的弹道图。
重量 42.83 克,直径 12.9500 毫米,截面积 0.000131713 平方米,初速度 1153 米 / 秒(子弹速度 893+ 飞机速度 260)
蓝色是子弹高度,橙色是速度,灰色是时间。
12.7mm 子弹初速度高,";i:19;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:18:"存速能力更强";}}i:20;s:124:",飞机如果保持 260m/s 就追不上子弹,要追上子弹飞机必须加速,或者以正发射角射出子弹。
";i:21;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:66:"http://pic4.zhimg.com/70/v2-0a43dc0b67b3935624e2389727982bab_b.jpg";}}i:22;s:2:"
";i:23;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:66:"http://pic4.zhimg.com/70/v2-747c030914e7c6b7920396f19a0e0e6b_b.jpg";}}i:24;s:345:"
再补充 20x102mm M56 HEI 炮弹的弹道图,这是美军现役战斗机 20 毫米机炮的炮弹。
飞机高度 4000 米,速度 1.4 马赫(454m/s),炮弹出膛速度 1038m/s(相对于空气的速度是 1493m/s。炮弹重量 98.16 克,直径 19.9136 毫米,截面积 0.000311451 平方米。
飞机只需在发射炮弹后";i:25;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:12:"稍微加速";}}i:26;s:39:",就可以在 4000 米水平距离,";i:27;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:40:"8.7 秒左右,接回射出的炮弹。";}}i:28;s:351:"
可以看出炮弹射出后,飞行大约 2300 米就比飞机更慢了,此时飞机也飞了 1230 米,炮弹距离发射的飞机只有 1070 米。
显然,如果 以 1.4 马赫尾追同样速度的敌机,机炮的有效射程不到 1070 米。如果考虑炮弹还需要一定的速度撞上敌机,那么有效射程只有几百米。
";i:29;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:66:"http://pic3.zhimg.com/70/v2-0964faa9daca211e30eeee8d7a0281c6_b.jpg";}}i:30;s:218:"
20mm M56 炮弹的阻力系数曲线来自《Comparison Of Aerodynamic Characteristics Of 20MM, HEI, T282EI Shell With Fuze M505 And 20MM, HEI, T282EI Shell With Fuze T321》,注意坐标轴的交点不是 0-0。
";i:31;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:66:"http://pic4.zhimg.com/70/v2-290bf954887a870c2c51cafe25f26007_b.jpg";}}i:32;s:389:"
如果一定要飞机速度超过炮弹出膛速度(其实这个条件毫无意义。。。)
那么假设 4000 米高度,飞机速度 3 马赫(974m/s),炮弹出膛速度 950m/s。
此时可以在 2800 米,2.9 秒内追回炮弹。(目前没有飞机能够在 4000 米高度飞出 3 马赫。)
此时机炮尾追射击 3 马赫敌机的有效射程小于 440 米。
";i:33;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:66:"http://pic1.zhimg.com/70/v2-a173ebe77ba0d744ada637673c95f5b8_b.jpg";}}i:34;s:234:"
到了这里,下面的 机炮命中率 - 距离 曲线图就很容易理解了。
机炮射击同高度,同速度的敌机,命中率随着距离增加,急速下降。如果敌机没有机动,那么命中率不到 0.2。
";i:35;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:24:"敌机有做机动躲闪";}}i:36;s:3:",";i:37;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:51:"3000 英尺(914 米)的机炮命中率就是零";}}i:38;s:5:"。
";i:39;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:66:"http://pic1.zhimg.com/70/v2-57ff17e2918f11c78ecd315c4ae57d2c_b.jpg";}}i:40;s:2:"
";i:41;a:4:{s:3:"tag";s:3:"url";s:6:"option";s:39:"http://www.zhihu.com/question/373545770";s:8:"original";a:2:{i:0;s:47:"[URL='http://www.zhihu.com/question/373545770']";i:1;s:6:"[/URL]";}s:8:"children";a:1:{i:0;s:12:"阅读原文";}}}, 1621686945, 1714281579
Run Time: 0.000797