agid])) { foreach ($g_flag_thread[$flagid] as &$val) { flag_thread_filter($val); } flag_thread_set($flagid, $g_flag_thread[$flagid]); } } return $g_flag_thread[$flagid]; } // 设置缓存 $key = flagid / $val = flagid下tid数组 function flag_thread_set($key, $val) { global $g_flag_thread; FALSE === $g_flag_thread and $g_flag_thread = website_get('flag_thread'); empty($g_flag_thread) and $g_flag_thread = array(); $g_flag_thread[$key] = $val; return website_set('flag_thread', $g_flag_thread); } // 删除flag下tid缓存 function flag_thread_delete_cache($flagid) { global $g_flag_thread; FALSE === $g_flag_thread and $g_flag_thread = website_get('flag_thread'); empty($g_flag_thread) and $g_flag_thread = array(); if (isset($g_flag_thread[$flagid])) { unset($g_flag_thread[$flagid]); website_set('flag_thread', $g_flag_thread); } return TRUE; } // Delete by tid / 通过tid删除flag下的主题和对应flagid缓存 function flag_thread_delete_by_tid($tid) { global $g_flag_thread; FALSE === $g_flag_thread and $g_flag_thread = website_get('flag_thread'); if (empty($g_flag_thread)) { $g_flag_thread = array(); } else { $thread = well_thread_read_cache($tid); $arrlist = flag_thread_find($tid, 1, $thread['flags']); $flagarr = $ids = array(); foreach ($arrlist as $val) { $flagarr[] = $val['flagid']; $ids[] = $val['id']; if (isset($g_flag_thread[$val['flagid']])) unset($g_flag_thread[$val['flagid']]); } website_set('flag_thread', $g_flag_thread); // 主键更新 flag_update($flagarr, array('count-' => 1)); // 主键删除 flag_thread_delete($ids); } return TRUE; } // 主键删除 通过$flagid删除flag下的主题和对应flagid缓存 function flag_thread_delete_by_flagid($flagid) { global $g_flag_thread; FALSE === $g_flag_thread and $g_flag_thread = website_get('flag_thread'); $read = flag_read_cache($flagid); if (empty($read)) return TRUE; $arrlist = flag_thread_find_by_flagid($flagid, 1, $read['count']); if (empty($arrlist)) return TRUE; $flagarr = $ids = array(); $n = 0; foreach ($arrlist as $val) { ++$n; $flagarr[] = $val['flagid']; $ids[] = $val['id']; if (isset($g_flag_thread[$flagid])) unset($g_flag_thread[$flagid]); } website_set('flag_thread', $g_flag_thread); // 主键更新 flag_update($flagarr, array('count-' => $n)); // 主键删除 $r = flag_thread_delete($ids); return $r; } ?>组保留的标签 余下为需要删除的标签 unset($oldtag[$key]); } } } if (!empty($oldtag)) { $tagids = array(); foreach ($oldtag as $tagid => $tagname) { $tagids[] = $tagid; } well_oldtag_delete($tagids, $tid); } $r = well_tag_process($tid, $fid, $create_tag, $tagarr); return $r; } // 删除标签和绑定的主题 function well_oldtag_delete($tagids, $tid) { $pagesize = count($tagids); $arrlist = well_tag_find_by_tagids($tagids, 1, $pagesize); $delete_tagids = array(); // 删除 $tagids = array(); $n = 0; foreach ($arrlist as $val) { ++$n; if (1 == $val['count']) { // 只有一个主题 $delete_tagids[] = $val['tagid']; } else { $tagids[] = $val['tagid']; } } !empty($delete_tagids) and well_tag_delete($delete_tagids); $arlist = well_tag_thread_find_by_tid($tid, 1, $n); if ($arlist) { $ids = array(); foreach ($arlist as $val) $ids[] = $val['id']; well_tag_thread_delete($ids); } !empty($tagids) and well_tag_update($tagids, array('count-' => 1)); } // 标签数据处理 $arr=新提交的数组 $tagarr=保留的旧标签 function well_tag_process($tid, $fid, $new_tags = array(), $tagarr = array()) { if (empty($tid)) return ''; // 新标签处理入库 if ($new_tags) { $threadarr = array(); $tagids = array(); $i = 0; $size = 5; $n = count($tagarr); $n = $n > $size ? $size : $size - $n; foreach ($new_tags as $name) { ++$i; $name = trim($name); $name = stripslashes($name); $name = strip_tags($name); $name = str_replace(array(' ', '#', "@", "$", "%", "^", '&', '·', '<', '>', '；', '`', '~', '!', '￥', '……', ';', '?', '？', '-', '—', '_', '=', '+', '.', '{', '}', '|', ':', '：', '、', '/', '。', '[', ']', '【', '】', '‘', ' ', ' ', ' ', ' ', ' '), '', $name); $name = htmlspecialchars($name, ENT_QUOTES); if ($name && $i <= $n) { // 查询标签 $read = well_tag_read_name($name); if ($read) { // 存在 count+1 $tagids[] = $read['tagid']; } else { // 入库 $arr = array('name' => $name, 'count' => 1); $tagid = well_tag_create($arr); FALSE === $tagid and message(-1, lang('create_failed')); $read = array('tagid' => $tagid, 'name' => $name); } $tag_thread = array('tagid' => $read['tagid'], 'tid' => $tid); $threadarr[] = $tag_thread; $tagarr[$read['tagid']] = $read['name']; } } !empty($threadarr) and tag_thread_big_insert($threadarr); !empty($tagids) and well_tag_update($tagids, array('count+' => 1)); } $json = empty($tagarr) ? '' : xn_json_encode($tagarr); return $json; } ?>内容的栏目 * @param int $category 0列表 1频道 2单页 3外链 * @return array */ function category_list($forumlist, $model = 0, $display = 0, $category = 0) { if (empty($forumlist)) return NULL; static $cache = array(); $key = $model . '-' . $display . '-' . $category; if (isset($cache[$key])) return $cache[$key]; if ($display) { foreach ($forumlist as $k => $val) { if (1 == $val['display'] && 1 == $val['type'] && $val['category'] == $category) { $cache[$key][$k] = $val; } } } else { foreach ($forumlist as $k => $val) { if (1 == $val['type'] && $val['category'] == $category) { $cache[$key][$k] = $val; } } } return empty($cache[$key]) ? NULL : $cache[$key]; } /** * @param $forumlist 所有版块列表 不分模型 * @param int $display 0全部CMS栏目 1在首页和频道显示内容的栏目 * @param int $category 0列表 1频道 2单页 3外链 * @return array */ function category_list_show($forumlist, $display = 0, $category = 0) { if (empty($forumlist)) return NULL; static $cache = array(); $key = $display . '-' . $category; if (isset($cache[$key])) return $cache[$key]; if ($display) { foreach ($forumlist as $k => $val) { if (1 == $val['display'] && 1 == $val['type'] && $val['category'] == $category) { $cache[$key][$k] = $val; } } } else { foreach ($forumlist as $k => $val) { if (1 == $val['type'] && $val['category'] == $category) { $cache[$key][$k] = $val; } } } return empty($cache[$key]) ? NULL : $cache[$key]; } /** * @param $forumlist 所有版块列表 * @return mixed BBS栏目数据(仅列表) 尚未开放bbs频道功能 */ function forum_list($forumlist) { if (empty($forumlist)) return array(); static $cache = array(); if (isset($cache['bbs_forum_list'])) return $cache['bbs_forum_list']; $cache['bbs_forum_list'] = array(); foreach ($forumlist as $_fid => $_forum) { if ($_forum['type']) continue; $cache['bbs_forum_list'][$_fid] = $_forum; } return $cache['bbs_forum_list']; } // 导航显示的版块 function nav_list($forumlist) { if (empty($forumlist)) return NULL; static $cache = array(); if (isset($cache['nav_list'])) return $cache['nav_list']; foreach ($forumlist as $fid => $forum) { if (0 == $forum['nav_display']) { unset($forumlist[$fid]); } } return $cache['nav_list'] = $forumlist; } ?>狗眼睛为什么是绿色
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狗眼睛为什么是绿色

2025-05-26 22:54:33   0次

狗眼睛为什么是绿色

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狗眼睛呈现绿色主要有三种原因：一是眼球对光线的反射作用，二是年龄增长导致的色素变化，三是某些眼部疾病引发的异常现象。其中最常见的是光线反射现象，这是犬科动物眼球结构的正常生理特征。

犬科动物眼睛呈现绿色主要与其特殊的视网膜结构有关。在光线较暗的环境下，狗眼睛底部特殊的晶点结构能够将周围微弱的光线收拢并集中反射，这种反射光在黑暗中会呈现出绿色。这种现象源于动物进化形成的特殊视觉系统，被称为"照膜"（Tapetum Lucidum）。照膜位于视网膜后方，由多层反光细胞组成，能够将未被视网膜吸收的光线二次反射回感光细胞，显著提升夜视能力。研究显示，犬科动物照膜的反光效率可达入射光的130%，这是其夜间的重要生理基础。

从生物化学角度看，狗眼睛颜色变化与沙丁胺酸这种特殊色素含量相关。随着年龄增长，狗狗眼睛内的沙丁胺酸含量会自然增加，可能导致眼睛颜色变深，甚至呈现绿色。临床数据表明，7岁以上的犬只中有约23%会出现不同程度的虹膜色素沉着变化。但需要区分的是，若发现狗狗眼睛突然变绿或伴随分泌物增多，则可能是青光眼、结膜炎等疾病的征兆。据统计，犬青光眼发病率约0.89%，其中约17%的病例会出现瞳孔区青绿色反光的典型症状。

在光学特性方面，狗狗眼睛的绿色反光现象与液晶膜的压电效应密切相关。当狗狗通过眼部肌肉对液晶膜施加压力时，会产生负电荷，使液晶分子维持在激发态。此时照射到眼睛的红外线会发生蓝移，转化为可见的绿光。这种机制解释了为何在完全黑暗环境中用手电筒照射狗眼时，仍能看到明显的绿色反光。实验测量显示，犬眼反射光的波长集中在500-550nm区间，正好对应人眼感知的绿色光谱范围。

值得关注的是，不同品种的狗狗眼睛反光颜色存在差异。例如哈士奇常见蓝色反光，而拉布拉多多为黄绿色。这与虹膜色素含量、照膜结构差异有关。专业摄影时，要避免狗眼绿光现象可使用偏离镜头光轴的补光方式，或选择特定波长的滤镜。若发现狗狗眼睛持续异常发绿并伴随视力下降、流泪等症状，建议及时就医排查青光眼、白内障等疾病。定期眼部检查对老年犬尤其重要，可及早发现83%的可治疗性眼疾。

本题链接：

狗眼睛变绿光线反射视网膜结构