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7:57:00 PM
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7:14:00 PM
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我和马加爵的大学岁月(绝密档案)
[业内传闻]方兴东:Google应卖给百度
〖天涯头条〗 活在硅谷
〖天涯头条〗 我和老婆的建房记录
〖天涯头条〗南非一年半(图文连载)
我在美国混日子
我的瑞士生活
[生活札记]老孙在非洲 乱写之一
[生活札记]这个城市不太冷
我认识了穆斯林阿拉伯人
拥抱太阳的清凉(原<爱情能够走多远>)
我看韩国
我的旅欧生活之法国篇---画像的朋友系列(照片)
世界上最卑劣的国家----新加坡
男友在国外读书我已等4年
我爱上了爱尔兰的男生
苏格兰格拉斯哥(Glasgow)风光!
[生活札记]一个陌生女孩的来信
我眼中的韩国——大学(补发照片)
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4:30:00 AM
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牛朝阳,创作了华语歌曲历史上最赚钱歌曲《两只蝴蝶》的音乐人。在此之前,如何创作一首众口流传的歌曲,牛朝阳已经足足练习了二十年,有《窗外》、《两只蝴蝶》、《杯水情歌》、《心醉》等作品获得火爆成功。十年前就签约于北京鸟人公司的牛朝阳本人因为种种原因转行去做了编剧导演,今年,昔日的老东家鸟人艺术老总周亚平又将这位音乐奇才重新招至麾下,重金打造,再战歌坛。
爱情可以企求吗?那样,宁愿不要。
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9:17:00 PM
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Folks,Yesterday we were The Venice Project... today we are Joost!
While we're still in beta, we hope that Joost will become synonymous with the best of TV and the best of the Web.
We're working on putting more content on the platform and creating moreand more applications and functionality. For those of you who've already been on the client, you can expect to see some of these updates in the0.8 release - which is not far away at all.
Now that we're Joost, we're going to be sending out many more betainvitations. I know some of you have been waiting quite some timefor your invitation and I appreciate your patience. We've been somewhat conservative about expanding our beta - but that'sgoing to change pretty rapidly now. So please keep a lookoutfor your invitation if you haven't gotten one already. And when you do receive it - please tell us what you think.
I have to say, we have an absolutely amazing team at Joost, andI include our beta testers as part of that team. Beta tester feedback on the platform has been so incredibly valuable. We've incorporated a lot of it into the platform - making it thatmuch better. So please, keep it coming!
Stay tuned.BR,Fredrik
--You are receiving this email because you are a beta tester ofJoost (The Venice Project). To remove yourself contact support@joost.comor log into http://www.joost.com/betatest/
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5:39:00 PM
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从前台做起 - 我的六年行政管理经历及经验
1.〖天涯头条〗男儿有泪莫轻弹--职场与情感心路历程 项目销售实用技巧(完整版)
2. 别了,富士康!虽有憾,但无悔。暨回顾我面试过的深圳部分知名公司
3. 〖首页推荐〗我的职场日记
4.〖首页推荐〗找工作并不难,难的是找到合适的工作
5.一个普通06毕业生从毕业到进入外企的一点小小体会
6.想在深圳从事物流行业的应届毕业生看过来(经验之谈)
7.如果你没找到生活里的“魔豆”呢?——失业两个月来的感悟
8. 游离在得失之间的时光------海尔五年
9.〖首页推荐〗第一次做"走鬼"
10.你害了多少???I生?--我在神舟???X有限公司的???v
11.做为一个hr经理,其实面试是这样的
12.乙肝病人跪求怎样在入职体检中作弊,实在是没有办法
13.我真的想打新来女大学生几个耳光
14.〖首页推荐〗浅谈我在职场中与人相处的技巧
15.伟创力(FLEXTRONICS)珠海,有人了解吗?
16. 〖首页推荐〗年终个人盘点:2006年账本大公开
17.〖首页推荐〗一个HR人给应届生的面试建议
18.〖首页推荐〗国企,外企,民企经历谈
19.做一个快乐的技术型销售--点滴心得分享续写
20.做销售丢脸吗--我的销售之路
21. 圈套玄机—《圈子圈套》中的职场案例分析
22.忧伤的时候抬头微笑(我毕业这四年的职场及情感经历)
23.〖首页推荐〗毕业以后—涅磐人生
24.与你分享五年HR招聘与面试的体会(天涯头条推荐)
25.我想招个应届生做助理,有合格的吗?
26. 学会和同事相处的30个原则
27.如果在三个月内获得三年的工作经验
28.美女们大学生们,千万别把贞操给了你那些穷光蛋同学!
29.七年职场人生,中专生的我由产线员工到工程师/研发主管
30. 西门子电力面试过程,大家可以借鉴。
31. 小学毕业的我面试一堆本科生`呵呵。
32. 81年MM觉醒篇之漫漫买房路
33.从客户角度看SALES
34.亮出自己的简历,凭此我打败了400名竞争对手!
35. 犹豫不决——上海,月薪1.6万值得去吗?
36. 大家心目中全国最适合养老的城市是哪个啊?
37.职场小说《圈子圈套》续集—《圈子圈套2》连载中
38.五年it经历:从销售到管理太容易 (原创连载)
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5:08:00 PM
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1.无/有线路由器安装、设置指南(贴图)
2.[手机][其他]iphone苹果手机终于出炉
3.[佳能]想买数码相机的请进,在线解答
4.[其他]大多数手机故障在线解答(六年从业经验)
5.[IBM]笔记本行情.有问必答.
6.看携程是怎么利用春节投机的
7.我看拉斯维加斯消费电子大展
8.[富士]扫盲 关于如何选购数码相机~
9.[手机][其他]俺的手机使用记录(1999-2006)
10.[笔记本][惠普]揭露奸商的丑恶嘴脸
11.[诺基亚]如何消除屏幕上的“中国移动”字样啊,有分分送
12.[三星]大家来看看~~我被三星售后整的全过程~~~~做好心理准备同志们
13.[其他]原创!对网上DC商家的一些个人评价,供要网购的兄弟们参考一下。
14.[随身听]垃圾MP3名单(欢迎添加)
15.[索爱]谈谈索爱和日货的关系!
16.[手机]手机通讯资讯站! (二)
17.[佳能]广州天河买sonyT9的受骗经历~~~血的教训
18.[诺基亚]我在易趣崽崽数码的购物经历—如此超级大卖家
19.[西门子]祭奠离去的最爱
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4:45:00 PM
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By being authentic in the face of a challenging situation, one can move through the experience in a more healthy fashion and thereby uncover more of one’s true self. There are many situations we face that can feel overwhelming. These can range from losing a job, to relationship problems, to health problems, to not knowing what to do with one’s life. Any one of these can bring up strong emotions and feel like a tremendous burden. In my own personal experience, there was a time when my entire future felt like it had been shattered. At that time I felt completely lost and fearful of the unknown.
We may choose to work with these life changing events in any number of ways, or we may choose to not work with the situation at all. We may talk things over with friends and/or family. We may choose to go to a workshop or we may decide to see a counselor. There are numerous possibilities of how we may work with a challenge. What I discovered is that many of the methods I used to work through tough situations were very analytical; very head oriented. In fact, I’ve invested hours and hours in analyzing and re-analyzing my past, my present and any tough situation I may have been experiencing. At times it felt like my mind was a hamster on a hamster wheel - running full out, but getting terribly tired. While this orientation provided some help, I didn’t seem to be able to move beyond the challenges I faced, or when I thought I had moved on, the challenge would return.
Years later a teacher and friend shared a method of working with challenges, a tool if you will, that has been profoundly useful. Its a simple tool. In fact, its so simple I doubted its ability to work. I wanted something more complicated… something like the analyzing I had done in the past. But that would have led me down the same path with the same results I had had in the past. Here is the new process I began using: When you are in the midst of a painful experience, pause, center yourself, and focus your attention on the emotions that are coming up and NOT on the story that is coming up. The story is what our "thinking" mind gives us. Here are several examples in the form of questions of how the story might be generated by an individual: why am I in this situation, what can I do about it, how is it going to impact me, what will other people think, and on and on. Instead of going with the story, sit with the emotions. One of the best ways to explain this is with a hypothetical example.
Lets say I’m involved in a highly emotional discussion with my wife. Afterward I’m distraught and my imagination starts to make up all kinds of stories: she doesn’t love me, we’re going to get a divorce, I’ll be alone, I’ll have to move, will I be alone for the rest of my life.. and so on. In essence, my mind takes over and goes nuts. This type of "processing" is agonizing. Instead, here is how the other method can work. I find a safe quite spot where I can be alone without interruption. I sit and focus on the emotion that is coming up. Sometimes it might be one emotion, such as fear, often times a number of emotions will come up. If its fear, I just sit with the fear. If its anger, I just sit with the anger. This can feel overwhelming. When I first started using this process, often my first reaction was to move away from the pain again. But when I just sat with the emotions, I benefited greatly. Feel the emotions. Acknowledge them. Accept them. If I commit to this, eventually I feel the emotion dissolve. Sometimes its replaced with another emotion. Maybe anger. The process again: sit with the anger, feel it, acknowledge it, accept it, and it too dissolves. Then FEAR come up. Once again, just sit and be with the fear. Don’t get caught up in the story. This process may last only a few moments or it may last for a much longer period of time. One time in my life I sat with emotions coming at me in giant waves. Wave after wave hit me, until finally, I was left feeling clean, clear and at peace. It felt tremendously healthy. Initially, it was easier for me to use this method after a particular situation was over and I had been able to find a quiet spot to sit with the emotions. Now I can sometimes be in the middle of a situation and do some of the work. As I practice, the process gets easier and easier. Without a doubt, one way I have been able to improve my ability to use this tool is by maintaining a regular meditation practice.
The benefits have been a sense of stability, flexibility and openness in my life after consistently using this process. While I’ve always been a big believer in therapy, I have progressed much further on my journey utilizing this simple tool as opposed to analyzing and re-analyzing the story. I have spent countless hours trying to figure out why something is "wrong" and what I needed to do to fix it. While there is definitely a place for this problem solving approach, allowing myself to fully sit and experience the emotions has propelled me forward more effectively than analysis ever has.
Good Luck!
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9:02:00 PM
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i used to be really shy, but i realized that being shy is not really beneficial in any way, so i decided to change.i also realized people tend to see you as you see yourself. so i say you should always be lifting yourself up in your own mind… don’t ever, ever, never ever put yourself down in your head! if you do, people will start looking down on you too…it’s weird but it really happens.if you act like a confident person, people will treat you like a confident person, and you will get more confidence as a result. i know it sounds strange but try it! it works!!~
I seem to have issues where I can never initiate anything. I could like someone but they always have to be the one to make the first move, to be the one to invite me to do something. I have an anxiety problem or something where the thought of calling someone and inviting them to do something makes me really nervous. I think I’d be alot happier if I could get over this but I seem to have this deep rooted fear of rejection.
Confidence is about having belief in oneself, but how can we believe in ourselves without really knowing ourselves?
Often, there are aspects of our personality that are underdeveloped or that we deny, ignore or even fear. Once we know and accept who we are, we can uncover our true gold and move more quickly toward confidence.goog luck!
It often seems hard to feel confident around people who know so much more than I do. For awhile now, though, I have felt more confident in what I do know, and in my ability to ask questions and learn from others. It’s fun to go to others and ask them to teach me things, especially when laughter is shared over the endeavor. It takes a bit of effort to get away from the “you really have no clue, do you?” mantra I was raised with at times – but being older, I feel better that I can say – no, those who told me that were wrong – I do have a clue, and what I don’t know, I can ask about and learn more about from those who do. I am becoming convinced that confidence is a kind of grace that comes with accepting one’s own limitations, yet not feeling restrained by them – because they are only permanent if one wishes them to be; confidence is also a silent strength, that comes from victories in accomplishing the goals one sets for oneself.
Steps to get there.
1. for one month write down one or more things I did well that
day.
2. Review that list at the end. Identify strengths.
i just need to be less shy. i am condfident with my close frieds and bf but i am hopeless in groups of people i dont know. i go to this posh girls school where all the girls think they are victoria beckham and it is hard to keep up with them. i feel more comfortable with guys than girls as i can use my considerable flirting skills to get on with them but i am hpeless with other girls. GRRRR
i felt better telling my boss about my POS colleague who is being groomed for my boss’s position (or so it seems). He is dishonest & demeaning. i can’t stand him.
i have put up with him and his ignorant but pompous sidekick for a long time now. finally i’m glad i had an opportunity to tell my boss about him today.
nothing may come of it but i feel better about having gotten it off my chest.
Getting a little more confident at work, been there 3 months now, am really trying to make my presence more known! Is hard though and people commenting on my quietness doesn’t encourage me to suddenly be loud! What are you supposed to say when someone says ‘you’re very quiet aren’t you’, am I supposed to scream at them?!
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8:51:00 PM
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1.[职场人生]痛快的堕落(广州IT销售生活实录)
2.[大话IT]~~~~闲话操作系统 (连载中......)
3.[职场人生]打算转行做IT---向IT界的兄弟姐妹们请教
4.[互联网]请教无线路由器的功率及辐射问题?
5.[职场人生][原创]营销之路(连载)
6.[职场人生]30岁的软件开发员走出的第一次跳槽经历
7.淘宝、腾讯“口水战”升级背后:马云、马化腾两大商业版图的碰撞
8.[业内传闻]一个“IT精英”与“一群IT精英”
9.中国血汗工厂排行榜,欢迎补充
10.[互联网]GOOGLE和百度比起来太垃圾了
11.[厂商]海尔洗衣机不用洗衣粉的秘密
12.[职场人生]软战记--一个对日软件开发项目的战斗历程
13.[大话IT]《圈子圈套2》连载中—描述IT业的职场与商战小说《圈子圈套》续集
14.学术腐败要从娃娃抓起——21岁外企美女副总吴莹莹真相
15.[业内传闻]IBM工资揭密
16.[原创评论]飞信,QQ王朝的终结者
17.[大话IT]程序员的唯一出路:做dsp软件
18.[大话IT]愤怒!IT界个人自私主义盛行
19.[软件]中国软件行业的恶性循环
20.[热讯快报]2006年“软件流氓”TOP10颁奖礼
21.[原创评论]就算C语言真的死了,也永远活在我心里
22.[职场人生]外企就真的那么好吗?
23.[大话IT]双核的意义有多大?
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8:04:00 PM
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6:24:00 PM
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首先:PCB(印刷电路板)的原料是什么呢?大家知道有种东西叫"玻璃纤维"吧,这种材料我们在日常生活中出处可见,比如防火布、防火毡的核心就是玻璃纤维,玻璃纤维很容易和树脂相结合,我们把结构紧密、强度高的玻纤布浸入树脂中,硬化就得到了隔热绝缘、不易弯曲的PCB 基板了--如果把PCB板折断,边缘是发白分层,足以证明材质为树脂玻纤。
然后呢?光是绝缘板我们可不能传递电信号,于是需要在表面覆铜。所以我们把PCB板也称之为覆铜基板。在工厂里,常见覆铜基板的代号是FR-4,这个在各家板卡厂商里面一般没有区别,所以我们可以认为大家都处于同一起跑线上,当然,如果是高频板卡,最好用成本较高的覆铜箔聚四氟乙烯玻璃布层压板。覆铜工艺很简单,一般可以用压延与电解的办法制造,所谓压延就是将高纯度(>99.98%)的铜用碾压法贴在PCB基板上--因为环氧树脂与铜箔有极好的粘合性,铜箔的附着强度和工作温度较高,可以在260℃的熔锡中浸焊而无起泡。这个过程颇像擀饺子皮,不过饺子皮可是很薄很薄的喔,最薄可以小于 1mil(工业单位:密耳,即千分之一英寸,相当于0.0254mm)呢!如果饺子皮这么薄的话,下锅肯定漏馅!所谓电解铜个在初中化学已经学过, CuSo4电解液能不断制造一层层的"铜箔",这个更容易控制厚度,时间越长铜箔越厚!通常厂里对铜箔的厚度有很严格的要求,一般在0.3mil和 3mil之间,有专用的铜箔厚度测试仪检验其品质。像古老的收音机和业余爱好者用的PCB上覆铜特别厚,比起电脑板卡工厂里品质差了很远。
为什么要让铜箔这么薄呢?主要是基于两个理由:一个是均匀的铜箔可以有非常均匀的电阻温度系数,介电常数低,这样能让信号传输损失更小,这和电容要求不同,电容要求介电常数高,这样才能在有限体积下容纳更高的容量,电容为什么比铝电容个头要小,归根结底是介电常数高啊!其次,薄铜箔通过大电流情况下温升较小,这对于散热和元件寿命都是有很大好处的,数字集成电路中铜线宽度最好小于0.3cm也是这个道理。制作精良的PCB成品板非常均匀,光泽柔和(因为表面刷上阻焊剂),这个用肉眼能看出来,不过老实说光看覆铜基板能看出好坏的人还真不多,除非你是厂里经验丰富的品检。有朋友问了,对于一块全身包裹了铜箔的PCB基板,我们如何才能在上面安放元件,实现元件--元件间的信号导通而非整块板的导通呢?那我要问一句了,你有没有看到一块主板表面都是铜的--回答当然是:没有!!板上都是弯弯绕绕的铜线,电信号就是通过铜线来传递的,那么答案很简单,把铜箔蚀掉不用的部分,留下铜线部分不就OK了?
好,那么这一步是如何完成的呢?好的,我们需要涉及一个概念:那就是"线路底片"或者称之为"线路菲林",我们将板卡的线路设计用光刻机印成胶片,然后把一种主要成分对特定光谱敏感而发生化学反应的感光干膜覆盖在基板上,干膜分两种,光聚合型和光分解型,光聚合型干膜在特定光谱的光照射下会硬化,从水溶性物质变成水不溶性而光分解型则正好相反。好,这里我们就用光聚合型感光干膜先盖在基板上,上面再盖一层线路胶片让其曝光,曝光的地方呈黑色不透光,反之则是透明的(线路部分)。光线通过胶片照射到感光干膜上--结果怎么样了?凡是胶片上透明通光的地方干膜颜色变深开始硬化,紧紧包裹住基板表面的铜箔,就像把线路图印在基板上一样,接下来我们经过显影步骤(使用碳酸钠溶液洗去未硬化干膜),让不需要干膜保护的铜箔露出来,这称作脱膜(Stripping)工序。
接下来我们再使用蚀铜液(腐蚀铜的化学药品)对基板进行蚀刻,没有干膜保护的铜全军覆没,硬化干膜下的线路图就这么在基板上呈现出来。这整个过程有个叫法叫"影像转移",它在PCB制造过程中占非常重要的地位。接下来自然是制作多层板啦!按照上述步骤制作只是单面板,即使两面加工也是双面板而已,但是我们常常可以发现自己手中的板卡是四层板或者六层板(甚至有8 层板),这究竟是怎么制造出来的呢? 有了上面的基础,我们明白其实不难,做两块双面板然后"粘"起来就行啦!比如我们做一块典型的四层板(按照顺序分1~4层,其中1/4是外层,信号层, 2/3是内层,接地和电源层),先呢分别做好1/2和3/4(同一块基板),然后把两块基板粘一块不就OK了?不过这个粘结剂可不是普通的胶水,而是软化状态下的树脂材料,它首先是绝缘的,其次很薄,与基板粘合性良好。我们称之为PP材料,它的规格是厚度与含胶(树脂)量。当然,一般四层板和六层板我们是看不出来的,因为六层板的基板厚度比较薄,即使要用两层PP三块双面基板,也未见得比一层PP两块双面基板的四层板能增加多少厚度--板卡的厚度都有一定规范,否则就插不进各种卡槽中了。说到这里,读者又会产生疑问,那个多层板之间信号不是要导通吗?现在PP是绝缘材料,如何实现层与层之间的互联?别急,我们在粘结多层板之前还需要钻孔!钻了孔可以将电路板上下位置相应铜线对起来,然后让孔壁带铜,那么不是相当于导线将电路串联起来了吗?这种孔我们称之为导通孔(Plating hole,简称PT孔,我喜欢叫扑通孔,呵呵)。这些孔需要钻孔机钻出来,现代钻孔机能钻出很小很小的孔和很浅的孔,一块主板上有成百上千个大小迥异深浅不一的孔,我们用高速钻孔机起码要钻一个多小时才能钻完。钻完孔后,我们再进行孔电镀(该技术称之为镀通孔技术,Plated-Through-Hole technology,PTH),让孔导通。
孔也钻了,里外层都通了,多层板粘好了,是不是完事了呢?我们的回答是No,因为主板生产需要大量进行焊接,如果直接焊接,会产生两个严重后果:一、板卡表面铜线氧化,焊不上;二、搭焊现象严重--因为线与线之间的间距实在太小了啊!所以我们必须在整个PCB基板外面再包上一层装甲--这就是防焊漆,也就是俗称阻焊剂的的东东,它对液态的焊锡不具有亲和力,并且在特定光谱的光照射下会发生变化而硬化,这个特性和干膜类似,我们看到的板卡颜色,其实就是防焊漆的颜色,如果防焊漆是绿色,那么板卡就是绿色,相应五颜六色怎么来的大家都清楚了吧?最后大家不要忘了网印、金手指镀金(对于显卡或者PCI等插卡来说)和质检,测试PCB是否有短路或是断路的状况,可以使用光学或电子方式测试。光学方式采用扫描以找出各层的缺陷,电子测试则通常用飞针探测仪(Flying-Probe)来检查所有连接。电子测试在寻找短路或断路比较准确,不过光学测试可以更容易侦测到导体间不正确空隙的问题。总结一下,一家典型的PCB工厂其生产流程如下所示: 下料→内层制作→压合→钻孔→镀铜→外层制作→防焊漆印刷→文字印刷→表面处理→外形加工。至此,整个PCB制造流程已经全面介绍完毕,下面我们就结合图片来参观精英鑫华宝讯厂--迄今为止国内最大的PCB板制造基地之一。
这是对PCB做中检,如果不合格可是要返工的哦!看工人一丝不苟的样子,要经过目检和工具检测两大关,结合探针,能检查出线路板的通断。 室内温度必须保持在24±2℃、相对湿度40%~65%,这是为了保证PCB基板和底片的尺寸稳定。因为板子和底片的组成材料都是有机高分子材料,对温湿度十分敏感。只有整个生产过程中都在相同的温湿度下,才能保证板子和底片不会发生涨缩现象,所以现在的PCB工厂中生产区都装有中央空调控制温湿度。如果超过温度极限,这个东东兼起报警器的作用。
这个仪器叫AOI(Automatic Optical Inspection,自动光学检验),比较高级,除了高倍放大外,AOI能进行裸板外观品质测试。AOI是集光学、计算机图形识别、自动控制多学科于一身的高技术产品,它的内部存有上百种板面缺陷的图样特征。工作时操作人员先将待检板固定在机台上,AOI会用激光定位器精确定位CCD镜头来扫描全板面。将得到的图样抽象出来与缺欠图样比对,以此来判断PCB的线路制作是否有问题。像常见的线路缺口、短断路、蚀刻不全等都可以凭借AOI找出来。AOI可以指出问题类型以及在板子上的位置。核心是它的分析软件。AOI技术的世界领跑者是以色列人,之所以这样据说是因为以色列处于阿拉伯各国环视之中,戒备心理极强,所以其雷达图像识别技术首屈一指(怕人家偷袭嘛),在20世纪70~80年代微电子技术大发展时,电子工业越来越需要一种高精度的外观检验装置,以色列抓住机遇军品转民品大大地赚了一票。这种单价在30万美元以上的设备早期被认为是PCB工厂品管严格的象征,由于采用AOI后可有效地提高成品率,防止产品报废,对于多层板生产还是十分合算的,所以现在AOI设备也是PCB厂的必备装置了。
压膜和对片,这张照片不大清楚,内部用UV紫外线爆光 这就是专门用来曝光的万级无尘室,曝光机完成影像转移工作,为什么要在无尘室内进行呢?原因是灰尘会折射光线,这必然会导致转移到干膜上的线路图失真。更为严重的是灰尘颗粒会粘在板面上阻挡光照造成杂质断路或短路。那么无尘室的灯光是黄色的,这又是为了什么?原来感光干膜对黄光不敏感,不会曝光,这和照相底片不能暴露在阳光下而在暗室的小绿灯下却没事是一个道理 这是在第二道成检,必须把表面清理干净,检查是否脱膜和线路过分细,如果PCB出厂就来不及了。
这就是多钻头精密数控钻床,一排排整齐列兵演出非常有气势。平面精度高达±3mil左右,这个东东国内售价单台就价值百万人民币!看PCB厂有没有实力主要就看有多少台钻床了,一般称得上大厂的起码有百台以上。这个“小小”车间就拥挤着46台,但这只是宝讯的一小部分而已! 每块主板根据孔的多少在钻孔,越精细的孔所花时间越多,通常有数百孔的主板要加工足一个小时!所以孔径是个个兼辛苦啊!
看看显示器上加工精度,三维座标精确到小数点后三位(单位mm),数控机床精度非常高,工人采用了人工装夹的方法,自然有一定误差,但机床完全数控,误差取决于机器本身的精度,在设计时PCB布线需要考虑到这一点。
钻头使用不久就需检测(是几次我需要再做进一步了解),因为磨损的钻头严重影响其寿命和钻孔精度,使用程度都用不同颜色表示。很科学合理。
提到pcb板,不得不提华通电脑(惠州)有限公司,此公司在PCB板业内也能够排个六七位,据说是一年不如一年,听在里面上过板的同仁说,大学生流水率达到90%以上。去过两次那,第二次去复试,因为第一次去恰巧07年旦的最后一个周末,所以厂长(怎么还有个厂长个说法?)提前下班了,要我过几天来复试,初试也就是做了下题目,50道重复的1+1=2的题目/25道逻辑推理理/一篇英翻汉,也就是感觉做逻辑推理理有点难度,做完后就在办公室傻等了三个来小时,快到四点半的样子,应聘的那个部门的科长才来跟我们面谈,最后五个人就要我一个人来复试,其余的等电话通知。
07年02号,我果然去复试了,年底到啦工作可不好找啊。下午两点到华通,那个真的叫偏僻啊,就是前面有条与广东经济严重不对称的国道,都是给罗浮山包围了,而且来回一躺要个100RMB。谁知道,那个厂长忙啊,开会就一直开到他们下班,结果我又是傻等了三四个小时,而且人力资源的根本只是到问了两次来了没?这哪像台资企业的风格啊?想当年在中山广盛可不是这样的哦,面试可是一伦一伦地来噢,最后不管到多晚总(副)经理都要坚持到最后的。既然厂长开会忙,最后还是初试那科长问我带了行李来了没?早说了!就这样说好,叫我3号去上班。
最后我还是决定不去:台资企业都是没什么技术含量的/PCB板行业工作条件好不到哪儿去/华通在走下坡路/华通地理位置太偏/华通的工资也不高...反正不去的理由是一大推的!又因为跟人力资源的缓了几天,弄的她老人家那天用几个号码打了六七个电话过来,最后还用她自己的手机给我发了短信。
后来我还是给她提了几天意见:给每个前来面试的同学至少报销单程车费。那天在人才市场可是很多人投递了简历而且都有机会来面试的,可是面试那天才去了几个,华通为什么不把网撒大点呢,可以多捞些鱼啊;合理地安排好面试管,比如不要再出现让同学傻等几个小时的事件,那天的几个同学也是这样;适当地介绍公司的待遇方面,我到现在还不是很清楚华通能给多少M我,因为人力资源根本没时间来和你沟通交流;有必要带面试的同学去车间看看,即使是走马观花也是很有必要的,这方面还是以前的中山广胜运动器材有限公司做的好,可是那个人力资源的MM贼,把我们都带了环境最好的车间去看,每个公司都要思考为什么职员流失率那么高,以前在广盛时有个同仁上了一天课恰巧明天又是周末坚决对跟公司say googbye了,当然这里头有个人因素,但公司的原因还是很大的,你让新进员工感到极大的失望,所以不得不赶紧撤!
后来那个人力女人短信也没回,估计是被我弄得不高兴了。
p.s华通的小mm特别多,都说男生在那是个宝!
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BEIJING, Jan 9 (Reuters) - China said on Tuesday that the hunt was still on for terrorists at large, adding they had links to international forces, a day after it disclosed details of a massive raid in its Central Asian border region of Xinjiang.
Police killed 18 people the government described as terrorists and captured another 17 in the raid on a training camp in the Pamirs plateau in southern Xinjiang that it said was run by the East Turkestan Islamic Movement.
"At present, some terrorists are still at large. The Public Security department is pursuing them," Foreign Ministry spokesman Liu Jianchao told a regular news conference.
"We have evidence that East Turkestan groups are connecting with international terrorist forces and plan to conduct terrorist activities," he said.
Oil-rich Xinjiang is home to 8 million Uighurs, a Turkic, largely Islamic people, many of whom resent the growing Han Chinese presence in the region and government controls on their religion and culture.
China has accused Uighurs in the region of using violence to agitate for an independent East Turkestan state, but human rights groups say it has used its support for the U.S.-led war on terror to justify a crackdown on Uighurs characterised by arbitrary arrests and closed-door trials.
Liu did not disclose the ethnicity of those in the camp, but said the raid was made "in accordance with the law".
Authorities were still investigating whether the suspects had links to al Qaeda, Liu said, adding that a stash of hand grenades were found at the site, in a remote part of Xinjiang, near the Pakistan and Afghanistan borders.
Police spokesman Wu Heping pledged that authorities would take tough measures to deal with terror attacks, indicating that there may be more raids in Xinjiang.
"In order to protect the stability of our border regions and the safety of people and property, the police will keep a close watch on this issue and continue to take strong measures ... to strike against all criminal activities of terrorist groups," Wu told a news conference.
China has also taken a leading role in the Shanghai Cooperation Organisation, a regional grouping of China, Russia and Central Asian nations that takes the fight against "extremism, separatism and terrorism" as one of its main tasks.
Liu said China would work with Central Asian border countries in the interest of safeguarding peace and stability in the region.
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高磁导率材料一直是国内外软磁材料研究的重点,它有着广阔的市场应用前景,因而,高磁导率材料的研发正方兴未艾。
回顾高磁导率Mn-Zn铁氧体研究历史,早在上世纪四五十年代,国外就已确定了锰锌铁氧体的基本配方(Fe2O3:MnO:ZnO)的摩尔比为:51.5-52.5:25.0-27.0:21.5-23。六七十年代国外对锰锌铁氧体制备工艺、相组成及显微结构进行了研究。八九十年代对三元系材料性能与成分的关系及添加物影响进行了系统研究。八十年代则已出现了溶胶-凝胶的湿法制粉工艺,由于原料性能均匀,粒度分布窄,团聚性小,从而明显减少材料的涡流损耗和磁滞损耗。这一阶段的材料居里温度也以从40℃提高到130℃以上,但温度稳定性还较差。而今,高磁导率Mn-Zn铁氧体材料基础理论已经相当成熟了,提高磁导率一般从配方和工艺上着手,进一步改进其工艺和调整配方进行掺杂。
我国高磁导率Mn-Zn铁氧体材料的研发起步相对较晚,五十年代才有专业的铁氧体生产工厂;七八十年代,随着家电的普及及需求量巨增,国内开始引进国外先进工艺设备和技术着手开展Mn-Zn铁氧体材料的研究,从而使生产规模和产品质量有了较大幅度的提高;九十年代起,国内基本上能制造大部分铁氧体生产设备,进而大大促进了我国Mn-Zn铁氧体材料产业的发展和产品性能的提高。
软磁铁氧体材料品种繁多,用途不一,不同的材料有各自配方和工艺特点,从成分上看,高磁导率材料是属于Mn-Zn铁氧体,国内外多数厂家多采用氧化物法生产。从微观上看,要求高磁导率材料的烧结体晶粒大,尺寸均匀,晶界直而且晶界上无气孔,这就决定高磁导率材料的工艺有自身的特色。以下简要归纳一下国内外高磁导率Mn-Zn铁氧体材料的主要关键工艺:
1.原材料:原材料的纯度、杂质和活性对铁氧体材料的性能有很大影响。在相同的工艺条件下,原材料纯度的提高意味着磁导率的提高。纯度高、杂质少、粒度细和活性高的材料对防止Mn-Zn铁氧体材料烧结过程中形成巨晶是非常重要的,因为巨晶会影响铁氧体的微结构,阻碍固相反应,形成非磁性相,形成内应力和退磁场,使材料矫顽力增大,功耗大,磁导率下降。
2.配方:配方是生产高磁导率Mn-Zn铁氧体材料的关键。通常在配方中提高Zn的比例可获得磁导率高的产品,目前高磁导率材料的配方(摩尔比)一般都确定为Fe2O3:MnO:ZnO=(51.5-52.5):(25.0-27.0):(21.5-23)。实际生产中必须严格控制成分偏移,成分的微小偏移都可能对Mn-Zn铁氧体材料性能产生很大影响。要得到磁导率高的材料需注意以下几方面:首先必须设法使磁晶各向异性常数 K1和饱和磁致伸缩系数λs趋于零,饱和磁化强度Ms尽可能大,尽可能降低材料的内外应力,形成精确而均匀的微结构。此外,在烧结过程中必须尽量避免Zn的挥发,可采用过量的Fe2O3和ZnO,使磁晶各向异性常数K1和饱和磁致伸缩系数λ s下降直至零。另外还必须考虑居里温度,因为过多的Zn也会降低居里温度,反而使材料失去实际使用的价值。在一定工艺条件下,最佳配方可用正交实验确定,投料时必须严格防止配方偏移。
3.制粉:制粉是Mn-Zn铁氧体生产中一个相当重要的工序,它分干法和湿法两种:干法是将氧化物原料直接球磨混合,经成型和高温烧结制成铁氧体,该方法工艺简单配方准确,但烧结活性和混合均匀性受到限制,从而制约了其材料性能的完善。湿法有化学共沉淀法、溶胶-凝胶法、水热法、超临界法及微乳液法等,一般常用湿法采用化学共沉淀法,其以碳酸盐作沉淀剂,将组分金属从混合盐溶液中同时沉淀分离出来,经烘干、焙烧制成烧结活性和成分都比较均匀的铁氧体粉末,再经成型和烧结制成Mn-Zn铁氧体,但其工艺路线较前者复杂,且因工艺条件较敏感,稳定性相对较差。
4.掺杂:掺杂是改善和提高铁氧体材料性能的有效措施,同样也适用于高磁导率材料。上世纪七十年代日本TDK公司就在高磁导率材料中有意掺入了少量Bi2O3和CaO,以改善材料的高频性能, 在100kHz以下磁导率保持在7000左右。此外,日本东北金属公司以SO3和CaO为掺杂物生产的高磁导率材料在磁导率明显提高的同时还能改善材料的比损耗系数。日本富士公司用掺入MoO 3的方法改进铁氧体材料烧结工艺,可使材料的磁导率明显提高。
5.压制:粉体的压制就是把粉料制成毛坯,因生坯密度大小和均匀性及气孔率都对材料的磁导率有很大影响。尤其是对高磁导率材料的磁芯而言,压制低气孔率的毛坯是获得高磁导率产品的先决条件之一,增加成型的压强可有效降低毛坯的气孔率。因此,压制是粉体制成毛坯的一个重要工序,大工业生产多数采用干压成型技术。虽然该技术效率较高,但毛坯内部密度不太均匀,而且加大压力对提高生坯密度效果不明显,过大压力会导致生坯层断裂等情况,为弥补干压制成型工艺的缺陷,有时也采用等静压方式压制粉体,这样可得到密度高、气孔率低、内部密度均匀的毛坯,以此提高铁氧体材料的性能。
6.烧结:铁氧体材料的烧结过程是一个物理和化学变化的结合过程,它对磁芯几何尺寸和电磁性能起着决定性作用。对高磁导率材料来说,要得到密度高、气孔率低、晶界直、晶粒大而均匀的铁氧体磁芯,就必须在烧结时严格控制烧结温度、烧结时间和烧结气氛,同时要控制Mn离子和Zn离子的变价、防止出现Zn的高温挥发配方偏移,又要保证铁氧体固相反应完全和抑制巨晶形成。所以,烧结工艺和设备也是铁氧体工序中至关重要的因素。国外起始磁导率在10000以下的材料一般在N2窑中烧结,而起始磁导率大于10000以上材料则在钟罩炉内烧结。美国使用钟罩炉工业生产铁氧体材料的磁导率μi可达15000-18000,而国内高磁导率产品一般都在N2窑中烧结,磁导率很难突破10000。由此可见,国内与国外在高磁导率铁氧体材料生产工艺技术上的存在着很大的差距。
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