°ç»„ä¿�留的标签 余下为需è¦�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']) {
            // �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�处� $arr=新�交的数组 $tagarr=�留的旧标签
function well_tag_process($tid, $fid, $new_tags = array(), $tagarr = array())
{
    if (empty($tid)) return '';

    

    // 新标签处�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);
            $name = str_replace(array('&nbsp;', '#', "@", "$", "%", "^", '&', '·', '<', '>', '；', '`', '~', '!', '￥', '……', ';', '?', '？', '-', '—', '_', '=', '+', '.', '{', '}', '|', ':', '：', '�', '/', '。', '[', ']', '�', '】', '‘', '	', '    ', '  ', '   ', '    '), '', $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;
}




?>    
    $cache[$key] = empty($arr) ? NULL : $arr;
    
    return $cache[$key];
}

// 门户 获�需�在频�显示的�目主题数�
function portal_channel_thread($fid)
{
    global $forumlist;
    if (empty($fid)) return NULL;

    

    $orderby = array('tid' => 1);
    $page = 1;

    

    // �历所有在频�显示内容的�目
    $category_forumlist = channel_category($fid);

    $arrlist = array();
    $forum_tids = array();
    $tidlist = array();

    

    if ($category_forumlist) {
        foreach ($category_forumlist as &$_forum) {

            

            // 频�显示数�
            $arrlist['list'][$_forum['fid']] = array(
                'fid' => $_forum['fid'],
                'name' => $_forum['name'],
                'rank' => $_forum['rank'],
                'type' => $_forum['type'],
                'url' => $_forum['url'],
                'channel_new' => $_forum['channel_new'],
                
            );

            

            $forum_thread = thread_tid__find(array('fid' => $_forum['fid']), $orderby, $page, $_forum['channel_new'], 'tid', array('tid'));
            // 最新信�按�目分组
            foreach ($forum_thread as $key => $_thread) {
                $forum_tids[$key] = $_thread;
            }

            

            unset($forum_thread);
        }
        $tidlist += $forum_tids;
    }

    

    unset($category_forumlist);

    

    // 获�属性对应的tid集�
    list($flaglist, $flagtids) = flag_thread_by_fid($fid);
    empty($flagtids) || $tidlist += $flagtids;

    

    unset($flagtids);

    

    // 频�置顶
    $stickylist = sticky_list_thread($fid);
    empty($stickylist) || $tidlist += $stickylist;

    

    // 在这之��并所有二维数组 tid值为键/array('tid值' => tid值)
    $tidarr = arrlist_values($tidlist, 'tid');

    // 在这之�使用$tidarr = array_merge($tidarr, $arr)��并所有一维数组 tid/array(1,2,3)
    

    if (empty($tidarr)) {
        $arrlist['list'] = isset($arrlist['list']) ? array_multisort_key($arrlist['list'], 'rank', FALSE, 'fid') : array();
        return $arrlist;
    }

    $tidarr = array_unique($tidarr);

    

    $pagesize = count($tidarr);

    

    // �历获�的所有tid主题
    $threadlist = well_thread_find_asc($tidarr, $pagesize);

    

    // �历时为��，翻转为��
    $threadlist = array_reverse($threadlist);

    

    foreach ($threadlist as &$_thread) {

        

        // ��目最新内容
        isset($forum_tids[$_thread['tid']]) AND $arrlist['list'][$_thread['fid']]['news'][$_thread['tid']] = $_thread;

        // 全站置顶内容
        isset($stickylist[$_thread['tid']]) AND $arrlist['sticky'][$_thread['tid']] = $_thread;

        // 首页属性主题
        if (!empty($flaglist)) {
            foreach ($flaglist as $key => $val) {

                if (isset($val['tids']) && in_array($_thread['tid'], $val['tids'])) {

                    $arrlist['flaglist'][$key][array_search($_thread['tid'], $val['tids'])] = $_thread;
                    ksort($arrlist['flaglist'][$key]);

                    $arrlist['flag'][$_thread['tid']] = $_thread;
                }
            }
        }

        
    }

    unset($threadlist);

    if (isset($arrlist['sticky'])) {
        $i = 0;
        foreach ($arrlist['sticky'] as &$val) {
            ++$i;
            $val['i'] = $i;
        }
    }

    if (isset($arrlist['flag'])) {
        $i = 0;
        foreach ($arrlist['flag'] as &$val) {
            ++$i;
            $val['i'] = $i;
        }
    }

    if (isset($arrlist['flaglist'])) {
        foreach ($arrlist['flaglist'] as &$val) {
            $i = 0;
            foreach ($val as &$v) {
                ++$i;
                $v['i'] = $i;
            }
        }
    }

    

    isset($arrlist['list']) AND $arrlist['list'] = array_multisort_key($arrlist['list'], 'rank', FALSE, 'fid');

    

    return $arrlist;
}




?>   $v = implode(",", $v);
        $temp[] = $v;
    }
    // 去掉��的字符串,也就是��的一维数组
    $temp = array_unique($temp);
    // �将拆开的数组�新组装
    $output = array();
    foreach ($temp as $k => $v) {
        if ($stkeep) $k = $starr[$k];
        if ($ndformat) {
            $temparr = explode(",", $v);
            foreach ($temparr as $ndkey => $ndval) $output[$k][$ndarr[$ndkey]] = $ndval;
        } else $output[$k] = explode(",", $v);
    }
    return $output;
}

// �并二维数组 如�� 值以第一个数组值为准
function array2_merge($array1, $array2, $key = '')
{
    if (empty($array1) || empty($array2)) return NULL;
    $arr = array();
    foreach ($array1 as $k => $v) {
        isset($v[$key]) ? $arr[$v[$key]] = array_merge($v, $array2[$k]) : $arr[] = array_merge($v, $array2[$k]);
    }
    return $arr;
}

/*
 * 对二维数组排� 两个数组必须有一个相�的键值
 * $array1 需�排�数组
 * $array2 按照该数组key排�
 * */
function array2_sort_key($array1, $array2, $key = '')
{
    if (empty($array1) || empty($array2)) return NULL;
    $arr = array();
    foreach ($array2 as $k => $v) {
        if (isset($v[$key]) && $v[$key] == $array1[$v[$key]][$key]) {
            $arr[$v[$key]] = $array1[$v[$key]];
        } else {
            $arr[] = $v;
        }
    }

    return $arr;
}




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<a href="/xitong">系统教程</a><a href="/xitong/1710555972a335808.html" title="首页">��能�什么中�科学教案</a></div></div></div><div class="fzithome-com main container-w cl"><div class="fzithome-com mainl"><div class="fzithome-com art-post"><div class="fzithome-com title"><h1>��能�什么中�科学教案</h1><div class="fzithome-com info"><span><a href="/xitong"><i class="iconfont icon-crossborder-fill"></i>系统教程</a></span><span><i class="iconfont icon-browse"></i>84</span><span><i class="iconfont icon-message-fill"></i>0</span><span>
                        更新时间：2026-04-06 20:49:04</span></div></div><div class="fzithome-com art-content"><article class="single-post"><div class="fzithome-com entry"><p>2024年3月16日�(作者：)</p><p><h2></h2></p><p></img></p><p style="text-indent: 2em;font-size:18px;"></p><p style="text-indent: 2em;font-size:18px;">��能�什么中�科学教案</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">��是我们生活中常�的物�之一，具有�附金属的特性。在中�</p><p style="text-indent: 2em;font-size:18px;">科学教案中，我们�以通过实验和活动，帮助孩�们了解��的特性</p><p style="text-indent: 2em;font-size:18px;">以�它能�附的物体�类，培养孩�们的科学观察和实验能力。</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">一�目标</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">通过本节课的学习，孩�们将能够：</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">1. �解��的特性和工作原�；</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">2. 观察并记录���以�附的物体�类；</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">3. 培养科学实验和观察能力。</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">二�准备工作</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">1. 准备��，�以是常�的���；</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">2. 准备���类的物体，如纸夹��钥匙��箔�木棒�塑料�等。</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">三�学习活动</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">1. 引入（5分钟）</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">�师�孩�们展示一���，问孩�们是�知�这是什么。如果孩</p><p style="text-indent: 2em;font-size:18px;">�们�知�，�以解释��是一�能够�附金属的物体，并且它有两</p><p style="text-indent: 2em;font-size:18px;">端，一端�引，一端排斥。然�让孩�们观察��的特性，并比较�</p><p style="text-indent: 2em;font-size:18px;">�的物体是��以被���附。</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">2. 实验（20分钟）</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">将���类的物体一个一个地放在桌�上，让孩�们使用��测试</p><p style="text-indent: 2em;font-size:18px;">并观察物体是�被�附。让孩�们�个记录实验结果，并画出实验记</p><p style="text-indent: 2em;font-size:18px;">录表格。鼓励孩�们通过实验�验�他们的想法和观察。</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">3. 分享和讨论（15分钟）</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">让孩�们将自己的实验结果和观察记录分享给其他�学，并��他</p><p style="text-indent: 2em;font-size:18px;">们�考为什么���能�附一些物体而�能�附其他物体。引导孩�</p><p style="text-indent: 2em;font-size:18px;">们明白，���能�附那些�有�元素的物体，比如�钥匙和纸夹。</p><p style="text-indent: 2em;font-size:18px;">其他��有�元素的物体，如木棒和塑料�，由于它们�具备�性，</p><p style="text-indent: 2em;font-size:18px;">所以无法被���附。</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">4. 以�组�作形�进行进一步探索（20分钟）</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">让孩�们分��组，讨论并�试找到更多能被���附的物体。�</p><p style="text-indent: 2em;font-size:18px;">个�组选择���类的物体，通过实验记录和讨论�记录他们的观察</p><p style="text-indent: 2em;font-size:18px;">结果。鼓励孩�们�出�设并进行实验验�。</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">5. 实际应用和总结（15分钟）</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">通过讨论和分享�组的实验结果，引导孩�们认识到��的特性和</p><p style="text-indent: 2em;font-size:18px;">应用。�以�问孩�们在现实生活中�以找到哪些使用了��原�的</p><p style="text-indent: 2em;font-size:18px;">物�。比如，冰箱门的��密���性画�上的�贴等。最�，总结</p><p style="text-indent: 2em;font-size:18px;">本节课的学习内容，并鼓励孩�们�散�维，�考更多与��相关的</p><p style="text-indent: 2em;font-size:18px;">问题。</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">四�扩展活动</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">1. 制作�性画�</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">让孩�们亲自动手制作一个�性画�，并用���附在画�上的�</p><p style="text-indent: 2em;font-size:18px;">贴。让他们在画�上�挥想象力，创作自己的作�。</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">2. 家庭实践</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">鼓励家长和孩�们一起在家中进行��实验，探索更多能被���</p><p style="text-indent: 2em;font-size:18px;">附的物体，并记录实验过程和结果。</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">五�教学��</p><p style="text-indent: 2em;font-size:18px;"> </p><p style="text-indent: 2em;font-size:18px;">本节课通过实验和�组�作的形�，让孩�们亲自观察和实践，帮</p><p style="text-indent: 2em;font-size:18px;">助他们更好地�解��的特性和工作原�。通过引导和讨论，培养了</p><p style="text-indent: 2em;font-size:18px;">孩�们的实验和观察能力，增强了他们对科学知识的学习兴趣。此外，</p><p style="text-indent: 2em;font-size:18px;">通过扩展活动和家庭实践的推�，进一步激�了孩�们�散�维和探</p><p style="text-indent: 2em;font-size:18px;">索科学的热情。</p><p style="text-indent: 2em;font-size:18px;"> </p><p><p><h2></h2></p></img></p></div></article></div><div class="fzithome-com info"><div><span>本文�布于:2024-03-16，感谢您对本站的认��</span></div><div><span>本文链接:</span><a href="https://www.fzithome.com/xitong/1710555972a335808.html" title="��能�什么中�科学教案">https://www.fzithome.com/xitong/1710555972a335808.html</a></div><div><span>版�声明:本站内容��自互�网，仅供演示用，请勿用于商业和其他�法用途。如果侵犯了您的�益请与我们�系，我们将在24�时内删除。</span></div></div><span class="tag"><i class="iconfont icon-discount" style="font-size:12px;font-weight:bold;opacity:.7;">本文标签：</i><a href="/tag/9272.html" target="_blank">��</a><a href="/tag/639.html" target="_blank">孩�</a><a href="/tag/2041.html" target="_blank">物体</a></span></div><div class="fzithome-com post_comments" id="comments"><div id="comt-respond" 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