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はてなキーワード: Backgroundとは
半減期はプルトニウム239の場合約2万4000年（アルファ崩壊による）。
プルトニウムはアルファ線を放出するため、体内に蓄積されると強い発癌性を持つ。
中性子を反射するタンパーを用いると核兵器中のプルトニウムピットは10kg（直径10cmの球に相当）まで減らすことができる。
1kgのプルトニウムが完全に反応したとすると、20キロトンのTNT相当の爆発エネルギーを生むことができる。
Plutonium - Wikipedia, the free encyclopedia
Plutonium is more dangerous when inhaled than when ingested.
The risk of lung cancer increases once the total dose equivalent of inhaled radiation exceeds 400 mSv.[89]
The U.S. Department of Energy estimates that the lifetime cancer risk
for inhaling 5,000 plutonium particles, each about 3 microns wide, to be 1% over the background U.S. average.
放射線の一種のアルファ線（α線、alpha ray）は、アルファ粒子の流れである。
電離作用が強いので透過力は小さく、紙や数cmの空気層で止められる。
しかし、その電離作用の強さのため、アルファ線を出す物質を体内に取り込んだ場合の内部被曝には十分注意しなければならない。
透過力は弱く、通常は数mmのアルミ板や1cm程度のプラスチック板で十分遮蔽できる。
ただし、ベータ粒子が遮蔽物によって減速する際には制動放射によりX線が発生するため、その発生したX線についての遮蔽も必要となる。
X線とは波長領域（エネルギー領域）の一部が重なっており、ガンマ線とX線との区別は波長ではなく発生機構によっている。
そのため、波長からガンマ線かX線かを割り出すことはできない。
中性子線を止めるためには鉛や水やコンクリートなど大きな質量の厚い壁が必要である。
ガイガー=ミュラー計数管は、GM計数管あるいはガイガー・カウンター(Geiger counter)
この型は、管の一方の端に放射線が容易に通過できるように窓があることからこう呼ばれる。
ガラス窓型は、アルファ線がガラス窓を通過できないのでアルファ線は検出できないが、大抵はより安価であり、ベータ線とX線を検出する用途で使われる。
ほとんどのGM管はガンマ線と2.5MeV以上のベータ線を検出する。
GM管内のガス密度が低いため、透過力の高いガンマ線は相互作用をしにくいためである。
ガンマ線を測定する目的では、NaIシンチレーション検出器の方が適しているが、逆にシンチレーション検出器は窓が厚くベータ線は透過できないので、ベータ線の検出には適していない。
内部被ばくの“証拠”撮影 長崎大研究グループ - 47NEWS（よんななニュース）
アルファ線は人体の中を極めて短い距離しか透過しない(組織の中で約40ミクロン、骨では約10ミクロン)。
時事ドットコム：機動隊員ら１３人、内部被ばくなし＝原発３号機で放水作業−放医研
マスコミは決して語らない、内部被曝の危険性 : MotoJazz
結論：大丈夫。
MvK2010
I'm going to copy paste a full blog post of a research scientist at MIT here, who explains the situation at Fukushima much better than anyone else has, his message: no worries.
This post is by Dr Josef Oehmen, a research scientist at MIT, in Boston.
He is a PhD Scientist, whose father has extensive experience in Germany’s nuclear industry. I asked him to write this information to my family in Australia, who were being made sick with worry by the media reports coming from Japan. I am republishing it with his permission.
It is a few hours old, so if any information is out of date, blame me for the delay in getting it published.
This is his text in full and unedited. It is very long, so get comfy.
I am writing this text (Mar 12) to give you some peace of mind regarding some of the troubles in Japan, that is the safety of Japan’s nuclear reactors. Up front, the situation is serious, but under control. And this text is long! But you will know more about nuclear power plants after reading it than all journalists on this planet put together.
There was and will *not* be any significant release of radioactivity.
By “significant” I mean a level of radiation of more than what you would receive on – say – a long distance flight, or drinking a glass of beer that comes from certain areas with high levels of natural background radiation.
I have been reading every news release on the incident since the earthquake. There has not been one single (!) report that was accurate and free of errors (and part of that problem is also a weakness in the Japanese crisis communication). By “not free of errors” I do not refer to tendentious anti-nuclear journalism – that is quite normal these days. By “not free of errors” I mean blatant errors regarding physics and natural law, as well as gross misinterpretation of facts, due to an obvious lack of fundamental and basic understanding of the way nuclear reactors are build and operated. I have read a 3 page report on CNN where every single paragraph contained an error.
We will have to cover some fundamentals, before we get into what is going on.
Construction of the Fukushima nuclear power plants
The plants at Fukushima are so called Boiling Water Reactors, or BWR for short. Boiling Water Reactors are similar to a pressure cooker. The nuclear fuel heats water, the water boils and creates steam, the steam then drives turbines that create the electricity, and the steam is then cooled and condensed back to water, and the water send back to be heated by the nuclear fuel. The pressure cooker operates at about 250 °C.
The nuclear fuel is uranium oxide. Uranium oxide is a ceramic with a very high melting point of about 3000 °C. The fuel is manufactured in pellets (think little cylinders the size of Lego bricks). Those pieces are then put into a long tube made of Zircaloy with a melting point of 2200 °C, and sealed tight. The assembly is called a fuel rod. These fuel rods are then put together to form larger packages, and a number of these packages are then put into the reactor. All these packages together are referred to as “the core”.
The Zircaloy casing is the first containment. It separates the radioactive fuel from the rest of the world.
The core is then placed in the “pressure vessels”. That is the pressure cooker we talked about before. The pressure vessels is the second containment. This is one sturdy piece of a pot, designed to safely contain the core for temperatures several hundred °C. That covers the scenarios where cooling can be restored at some point.
The entire “hardware” of the nuclear reactor – the pressure vessel and all pipes, pumps, coolant (water) reserves, are then encased in the third containment. The third containment is a hermetically (air tight) sealed, very thick bubble of the strongest steel. The third containment is designed, built and tested for one single purpose: To contain, indefinitely, a complete core meltdown. For that purpose, a large and thick concrete basin is cast under the pressure vessel (the second containment), which is filled with graphite, all inside the third containment. This is the so-called “core catcher”. If the core melts and the pressure vessel bursts (and eventually melts), it will catch the molten fuel and everything else. It is built in such a way that the nuclear fuel will be spread out, so it can cool down.
This third containment is then surrounded by the reactor building. The reactor building is an outer shell that is supposed to keep the weather out, but nothing in. (this is the part that was damaged in the explosion, but more to that later).
Fundamentals of nuclear reactions
The uranium fuel generates heat by nuclear fission. Big uranium atoms are split into smaller atoms. That generates heat plus neutrons (one of the particles that forms an atom). When the neutron hits another uranium atom, that splits, generating more neutrons and so on. That is called the nuclear chain reaction.
Now, just packing a lot of fuel rods next to each other would quickly lead to overheating and after about 45 minutes to a melting of the fuel rods. It is worth mentioning at this point that the nuclear fuel in a reactor can *never* cause a nuclear explosion the type of a nuclear bomb. Building a nuclear bomb is actually quite difficult (ask Iran). In Chernobyl, the explosion was caused by excessive pressure buildup, hydrogen explosion and rupture of all containments, propelling molten core material into the environment (a “dirty bomb”). Why that did not and will not happen in Japan, further below.
In order to control the nuclear chain reaction, the reactor operators use so-called “moderator rods”. The moderator rods absorb the neutrons and kill the chain reaction instantaneously. A nuclear reactor is built in such a way, that when operating normally, you take out all the moderator rods. The coolant water then takes away the heat (and converts it into steam and electricity) at the same rate as the core produces it. And you have a lot of leeway around the standard operating point of 250°C.
The challenge is that after inserting the rods and stopping the chain reaction, the core still keeps producing heat. The uranium “stopped” the chain reaction. But a number of intermediate radioactive elements are created by the uranium during its fission process, most notably Cesium and Iodine isotopes, i.e. radioactive versions of these elements that will eventually split up into smaller atoms and not be radioactive anymore. Those elements keep decaying and producing heat. Because they are not regenerated any longer from the uranium (the uranium stopped decaying after the moderator rods were put in), they get less and less, and so the core cools down over a matter of days, until those intermediate radioactive elements are used up.
This residual heat is causing the headaches right now.
So the first “type” of radioactive material is the uranium in the fuel rods, plus the intermediate radioactive elements that the uranium splits into, also inside the fuel rod (Cesium and Iodine).
There is a second type of radioactive material created, outside the fuel rods. The big main difference up front: Those radioactive materials have a very short half-life, that means that they decay very fast and split into non-radioactive materials. By fast I mean seconds. So if these radioactive materials are released into the environment, yes, radioactivity was released, but no, it is not dangerous, at all. Why? By the time you spelled “R-A-D-I-O-N-U-C-L-I-D-E”, they will be harmless, because they will have split up into non radioactive elements. Those radioactive elements are N-16, the radioactive isotope (or version) of nitrogen (air). The others are noble gases such as Xenon. But where do they come from? When the uranium splits, it generates a neutron (see above). Most of these neutrons will hit other uranium atoms and keep the nuclear chain reaction going. But some will leave the fuel rod and hit the water molecules, or the air that is in the water. Then, a non-radioactive element can “capture” the neutron. It becomes radioactive. As described above, it will quickly (seconds) get rid again of the neutron to return to its former beautiful self.
This second “type” of radiation is very important when we talk about the radioactivity being released into the environment later on.
I will try to summarize the main facts. The earthquake that hit Japan was 7 times more powerful than the worst earthquake the nuclear power plant was built for (the Richter scale works logarithmically; the difference between the 8.2 that the plants were built for and the 8.9 that happened is 7 times, not 0.7). So the first hooray for Japanese engineering, everything held up.
When the earthquake hit with 8.9, the nuclear reactors all went into automatic shutdown. Within seconds after the earthquake started, the moderator rods had been inserted into the core and nuclear chain reaction of the uranium stopped. Now, the cooling system has to carry away the residual heat. The residual heat load is about 3% of the heat load under normal operating conditions.
The earthquake destroyed the external power supply of the nuclear reactor. That is one of the most serious accidents for a nuclear power plant, and accordingly, a “plant black out” receives a lot of attention when designing backup systems. The power is needed to keep the coolant pumps working. Since the power plant had been shut down, it cannot produce any electricity by itself any more.
Things were going well for an hour. One set of multiple sets of emergency Diesel power generators kicked in and provided the electricity that was needed. Then the Tsunami came, much bigger than people had expected when building the power plant (see above, factor 7). The tsunami took out all multiple sets of backup Diesel generators.
When designing a nuclear power plant, engineers follow a philosophy called “Defense of Depth”. That means that you first build everything to withstand the worst catastrophe you can imagine, and then design the plant in such a way that it can still handle one system failure (that you thought could never happen) after the other. A tsunami taking out all backup power in one swift strike is such a scenario. The last line of defense is putting everything into the third containment (see above), that will keep everything, whatever the mess, moderator rods in our out, core molten or not, inside the reactor.
http://anond.hatelabo.jp/20110314030613
へ続く
http://blog.livedoor.jp/manamerit/archives/65453749.html
Facebookが匿名性だったらこれだけの企業価値がつくなどありえない。
実名であるがゆえの価値なのだから偽名アカウントを消すのは必須なのだ。
時間はかかるけど必ず特定される。
商売するときに相手に顔を晒すように、
ネットではそれ以上に相手に自分のBackgroundがわかる。
そしてそれを利用して商売をするのが吉。
ネットには悪が蔓延っているような印象をうけている人は多いと思うが、
それはまだシステムが追いついていないだけ。ネットはその特性上悪ははびこりにくい。
本当のワルはネットが繋がらない様なところでつながるのだ。
Firefoxのズーム機能では、背景として指定した画像が拡大されないって仕様があるの。実際、ズーム機能なんて使っている人がいるのか疑問だけど…（Ctrlと+、-の同時押しでズームイン・アウト、Ctrlと0を同時押しでリセット）。ズームインをしていくと、文字だけがでかくなっていって背景からはみ出ていっちゃうの。確かSleipnirにも同じような仕様があったはず。
CSS3で影を作れば、ズームインしていくと影もズームインしてくれて一件落着なんだけど、画像で影を作ってズームインにも対応しなきゃいけないとなるとさあ大変。影を8つに分割する必要が出てくる。
┌─┐
│ │
└─┘
こんな感じに。┌は左上に固定、┐は右上、└は左下、┘は右下。│は左端と右端に配置して縦に繰り返し、─は上端と下端に配置して横に繰り返し。こうすれば影をつけなきゃいけないブロックの大きさが変動しても、影がきれいにつきまとってくれる。
CSS3になって、背景画像を複数指定できるようになったけど、「どこからどこまで繰り返し」みたいな指定はできない。
┌ 左上 繰り返しなし
┐ 右上 繰り返しなし
└ 左下 繰り返しなし
┘ 右下 繰り返しなし
─ 上 横繰り返し
─ 下 横繰り返し
│ 左 縦繰り返し
│ 右 縦繰り返し
こういうふうになるようCSSを書いたとして、「┌ 左上 繰り返しなし」と「─ 上 横繰り返し」は左上で少しかぶるでしょ。αこみのPNGだったら重なった部分だけ色が変わっちゃう。そんなこんなで、いろいろなことをやらなきゃいけなくなっちゃうというわけなのです！
あ、ちなみにCSS3のbackground-sizeを使えば背景画像の大きさの調整ができます。
ふと思い立って昼休みに作った。経過時間別に背景色もつきます。
グループ分けとかしてるとうまく動かないかも。
// ==UserScript== // @name order_home_mymixi // @namespace http://anond.hatelabo.jp/ // @include http://mixi.jp/ // @include http://mixi.jp/home.pl // ==/UserScript== (function() { if (window != window.parent) return; var homeTds = document.evaluate('//div[@id="mymixiList"]//td', document.body, null, 7, null); for (var i = 0; i < homeTds.snapshotLength; i++) homeTds.snapshotItem(i).innerHTML = 'loading...'; GM_xmlhttpRequest({ method: 'GET', url: 'http://mixi.jp/list_friend_simple.pl', onload: function(res) { var friends = []; var bgColor = { '01': '#ffffff', '02': '#fee7c6', '03': '#ffd8a7' }; var div = document.createElement('div'); div.innerHTML = res.responseText; var tds = document.evaluate('//div[@id="friendList"]//td', div, null, 7, null); for (var i = 0; i < tds.snapshotLength; i++) { var td = tds.snapshotItem(i); var klass = td.getAttribute('class'); if (!klass || klass.search(/^iconState(01|02|03)/) == -1) continue; friends.push({ color: bgColor[RegExp.$1], anchor: td.getElementsByTagName('a')[0], name: td.getElementsByTagName('p')[0].innerHTML.replace(/^(.+)\(/, '$1 (') }); } for (var i = 0; i < homeTds.snapshotLength; i++) { var td = homeTds.snapshotItem(i); td.innerHTML = ''; td.style.background = friends[i].color; td.appendChild(friends[i].anchor); var span = document.createElement('span'); span.innerHTML = friends[i].name; td.appendChild(span); } } }); })();
firefoxのユーザースタイルシート機能を使って、増田のヘッダ部分をスクロールしても常に表示するようにしてみた。
変なところがあったら指摘頼む
@namespace url(http://www.w3.org/1999/xhtml);
@-moz-document domain("anond.hatelabo.jp") {
div#globalheader {
position: fixed !important;
display: block !important;
visibility: visible !important;
top:0% !important;
z-index:2;
}
position:relative !important;
top:50px;
z-index:1;
}
}
素敵さんが公開されているユーザースタイルシートをつかいたかった
→自分でなんとかするしかないみたいだ・・・
っちゅーことでつくったcss。
コードは整理されてないしもうやる気は残ってないし
でココで公開してしまえ
ミクシィの表示を横幅720pxの２ペインにします。
主な改造点は
・全体的に行間を狭めた。
・全体的に余白を狭めた。
・一部の背景をうっすーい灰色にした。
・さよならmikly。
・絶対位置指定divを排除（全部は無理なので目立つ部分を適当に。）
・広告をほどほどけした。
・etc...
使い方は「mixi ユーザースタイルシート」あたりで検索してくれ…
/* mixi User Style Sheet by anon */ /* based mixi 2pain User StyleSheet (by Shao) thank you ! */ .emoji{display:none !important} /* 広告*/ p.adBanner, div#diaryComment div.diaryBottomAd, div.prContents, div.sponsorList01{display:none !important} div#adBanner{display:none !important} /*ローカルナビ*/ #localNavigation ul li{position:static;} #localNavigation ul.localNaviHome img{width:80px !important;} #localNavigation ul.localNaviFriend img{width:102px !important;} a#diaryPullDownButton,a#photoPullDownButton,a#videoPullDownButton, a#reviewPullDownButton{display:none !important} li.mikly, li.review, li.movie{display:none !important} li.home img {width:73px !important} /* infomation */ div.information {line-height:1.1 !important; font-size:12px !important;} div.information h2{padding-top:10px !important; position:static !important; float:left !important; background-position: 10px 10px !important; } div.information ul{ line-height:1.1 !important;} div.information div.contents{ padding-bottom:0px !important; position:static; width: 98%;} div.information div.contents ul { padding-bottom:0px !important;} /* delete intro */ #intro{display:none !important} #bodyContents #newFriendDiary, #bodyContents #newComment, #bodyContents #newBbs, #bodyContents #newVideo, #bodyContents #newAlbum, #bodyContents #newPlaylist, #bodyContents #newReview, #bodyContents #myUpdate{ padding-bottom:5px !important; } div div.contents {line-height:1.1 !important; background:#fcfcfc;} #newMyDiary div.contents dl.contentsList02{ padding-bottom:1px;} dl.contentsList01{ line-height:1.5 !important;} dl.contentsList02{ line-height:1.5 !important;} ul.entryList01{ line-height: 1.2 !important;} dl.contentsList01 dd{padding-left:16px; background-position: 0% 0.5em;} /* 3rd column */ #bodySub{float:left !important;width:100% !important; margin:0;padding:0;} div#help{display:none !important} div.prContents, div.adBanner, p.greenpower{display:none !important} div#miklyContents{display:none !important} div#prSepecial{display:none !important} div.bodySubSection {width:224px !important; float:left !important; margin:3px !important;} div.bodySubSection div.heading01{position:static !important;} div.bodySubSection a.sectionSize{ position:static !important; margin: -20px 0 0 200px !important; } /* header*/ #headerArea{ background: none !important; height:91px !important;} #headerArea h1 a{ padding:5px 0 5px !important;text-align:left !important;width:720px !important;} #headerArea h1 img {width:93px !important;height:23px !important;} /* footer */ div#headerArea{width:720px !important} div#headerArea,div#bodyArea,div#footerArea, div#footerArea p,div#footerArea ul{width:720px !important; } div#footerArea, div#footerArea p,div#footerArea ul{width:720px !important; overflow:hidden !important; } div#footerArea ul.footerNavigation01 li { margin:0 2px !important }
国際的なIT保護機関である国際IT保護連盟(IUCIT：International Union for
Conservation of Information Technology)は19日、ウェブデザインツールなどの
興隆によりその生存が危ぶまれている「ウェブデザイナー」職を絶滅危惧種に指定した。
IUCITは、絶滅のおそれのあるIT関連職を「レッドリスト」にまとめ、自覚と職業訓練
の必要性を訴えている。現在のところウェブデザイナーの絶滅の危険性は低いとされて
いるが、今回の採択は世界的な危機感の広がりを受けてのもの。
海外ではさまざまなWebデザインツールがすでに開発されており、
国内でもCSSEZやBackground Image Makerなど、海外と同じようなサービスが
展開されている。また、オープンソースライセンスで利用できる写真を手軽に入手できる
ようになったことも、絶滅の危機感を煽る大きな原因となっている。
IUCITが発表した声明によると、今後IUCITはコーディング作業及び素材画像の作成
のみを扱うウェブデザイナーに、その職の危うさに対する自覚を促すと共に、PHP
など比較的容易に扱うことのできるプログラミング言語の習得を支援するキャンペーン
に乗り出すとのことだ。
「無料ツールやWebサービスの質が上がって、Webデザインコストが下がってきている
傾向を強く感じます。便利になるのは良いことですけど、将来への不安は募るばかり
ですよ。増田さん、何か良い解決策はないですか？アドバイスをください。」
と危機感をあらわにする。
今後、一部の独創的な発想を持つウェブデザイナー以外は駆逐されていくことが
予想され、プログラミング技術の取得など、ウェブデザイナーの生存と存続に対して
緊急な対策が求められている。
関連ソース
http://headlines.yahoo.co.jp/hl?a=20070819-00000019-zdn_n-sci
ttp://www.lingr.com/room/gauche/archives/2007/07/17#msg-12170016
ritus
Hi, I work with Google and looking for Japanese individual interested in working with Google in Tokyo. I am looking for someone with consulting/marketing background and programming/scripting skills. The location of the Google office is in Tokyo's Shibuya business area. If you know of anyone please feel free to forward my contact information.
Ritu Singh
ritus@googe.com
sorry the email is ritus@google.com
shiro
DO NOT SPAM!
取り上げるのは下の3つ。便宜的に上からapng、alphafilter、ie6pngとする。
IT戦記 - 僕も半透明 png を使うためのライブラリ作った！
アルファ画像を扱うalphafilter.jsライブラリ-とあるWEBクリエイターのblog
ウノウラボ Unoh Labs: IE6でアルファチャンネルを含むPNGを表示する
特になし。ごめんなさい。
new AlphaChanneledPNG("imageId1","/blank.gif").show();
new AlphaChanneledPNG("imageId2","/blank.gif").show();
...