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2011-04-10 12:11

2011410日 星期日                                 晴,天气不错

冰啊,要把一块冰融化,首先要先朝带冰块的水努力,再一点点地把每个小冰块融化,一般在没变成带冰块的水之前,那些人就已经死了,太冷了...

今天又回去面对了一下,其实是很小的事,我失声痛哭,就是没有眼泪,我是真的释怀了还是只是在认命?唉,又是矛盾在作怪,失去重心了,找不到矛盾的点...不对,我这是在埋怨她吗?怎么能有这么狭隘的心态?太好了,又解决了一个,哈哈哈哈哈哈.....

每次空闲下来,就会想要练习一下怎么哭。这不是伤感,是在锻炼身体,哈哈哈哈哈哈....

嘴角上扬是这个世界上最容易办到的事,对我来说,有时越痛,就会笑得越大声,可能压抑太久了,泪腺闭塞,我只能说,哭比笑让我更舒服。

哭是释放,笑是压抑。

现在的世界为什么那么冷,大概是大家都忘了怎么哭!

 
2008-05-19 11:32

Vocabulary from the programmethe stealth marketing

product placement
when companies pay for their products to be used in films and television programmes, this is called product placement

fliers
pieces of paper handed out by people in the street which contain advertising messages

word of mouth
the passing of information not through media, such as television and newspapers, but through people talking about and discussing something

stealth
an adjective used for something that is designed to be hard to detect

a scenario
a pre-prepared dramatic situation

to overhear something
to hear something accidentally

to eavesdrop
to listen deliberately to someone else's conversation

a pay-off
a benefit

 
2008-05-15 14:29

Yellow Shang

     Yellow Shang, an older sister and a simple woman, started her life in poverty and died a lonely wife after an uneasy struggle in Shenzhen. She was born in Lianhua village on January 16, 1962. A year later she had a sister and seven years later she had a brother, which burdened the poor family, who lived by farming. In 1980, the family lost its main pillar of support, their father. He suffered from arthritis. The family’s income collapsed. To support her younger sister’s and brother’s education, Yellow Shang decided to go to work in town.

At the age of eighteen, recommended by a friend of hers, she luckily got the chance to go to Shenzhen, which was a turning point in her life. Shenzhen was a new city full of opportunities. After working two years in the factory, she gave in to temptation. With the dream of a wealthy life, she followed her so-called good friends' advise and turned to prostitution. With the rich income, she rebuilt her family's house in her hometown, made her mother possible to rest and to accompany her father, and succeeded helping her sister finish the college education. She seemed to be a great daughter and a perfect sister.

She was successful, like a fish in water, running through wealthy men and got married with a rich merchant at the age of 29. After 5-year happy married life, her husband fled the home with various excuses. They had bitter quarrels every time they met. Her mother advised her that a baby may save the marriage. However, due to the former special job, her having too many boyfriends led to sterility. The irritating married life drove her mad.

As a simple woman, she just wanted to keep her husband home. She beseeched him to come home and got an astonishing and unacceptable answer. Charmed by her younger sister’s beauty, he wanted to take her as his wife and attain a son. Yellow Shang really lost her mind at that time. One night in 2001, she cheated her sister into a room of their house. After letting her husband enter it once, she locked her sister up for a whole year until she gave birth to the baby. Her sister felt heart broken and left.

She treated the baby as her own son with her husband, but he did not stay at home as she expected. She recognized she was wrong. In desperation and in a poor health, she died from a horrible disease, alone. The day after her death, Shenzhen succeeded applying to host the 26th World University Games in January 16, 2007.

 
2008-03-13 16:21

Composition

Plant Trees

If there are more trees, we will feel fresh anywhere, even beside the roads. If there are more trees, the nature may stop publishing us, human beings. If there are more trees, we don’t have to search for another ‘earth’.

As we all know, trees have the great foundation of absorbing carbon dioxide and venting oxygen we exactly need. Since more and more cars or trucks running on the roads, the residents built near the roads are cheaper. In this situation, I suggested the residents’ owner should plant more trees to fresh the air there first.

Recently, more and more horrible disasters kept attacking us, such as the flood happened a year ago and the blizzard occurred in the spring festival. It’s obvious that the nature is deeply not satisfied with us. However, we kept saying it’s the greenhouse gas’ fault, instead of noticing that it is we who created the greenhouse gas. To make up it, we should plant trees as many as we could to reduce the greenhouse gas.

The news that scientists found water on the Mars excited many people. Coins have two sides and it also applies to this news. It’s a piece of exciting news really, but on the other hand, it proved on the same time that we are finding another ‘earth’ to live in, that is to say, we are to abandon the earth we are living on now. It’s not responsible and what we absolutely should do now is to save our earth, so the first thing is to give it what it indeed needs—the trees.

Plant more trees or the cars will be banned forever. Plant more trees or we will lose the best parents—the nature. Plant more trees or we will have to live in the dark universe.

Note-writing

Dear George,

Here is a ticket to a computer fair for you. I’ve got it a few days ago, but now I can’t go for it because I have to go to visit my grandma this afternoon till next week. She is seriously sick. I think it’s a waste of not going to the computer fair, so I send it to you. Hope it’s helpful for your computer studying. To get there, you can get on the No. 12 bus, get off at the LV stop, and enter into the white building.

Yours,

Sally

 
2008-02-08 14:56

portable generators 便携式发电机

Spring Festival evening gala  春节联欢晚会,春晚

China Central Television   CCTV

to boost national morale 鼓舞国民士气

disaster relief effort     赈灾、救灾

                                            (英语点津姗姗编辑)

the Chinese Zodiac   十二生肖

   the rat, the ox, the tiger, the rabbit, the dragon, the snake, the horse, the sheep, the monkey, the rooster, the dog and the pig

 
2008-02-01 13:01

power failure 停电 Power brownouts 电力管制,限电

the trunk line between Beijing and Guangzhou 京广线

Weather term

blizzard 大风雪

blowing snow 高吹雪

drifting snow 低吹雪

snowstorm 暴风雪

snow showers 阵雪

flurries/light snow 小雪

heavy snow 大雪

snowfall 降雪

sleet 雨夹雪

snowflake 雪花

showers/rain showers 阵雨

heavy showers 强阵雨

occasional showers, scattered showers零星阵雨

isolated showers 局地阵雨(空间分布上比scattered showers范围更小的阵雨)

thunderstorms 雷暴

thundershowers 雷阵雨

storm 风暴

lightning 闪电

light showers 冻雨

ice rain 小阵雨

downpour 倾盆大雨

storm 暴风雨

drizzle 毛毛雨

light rain 小雨

meteorology 气象学

atmosphere 大气

climate 气候

temperature 气温、温度

global warming 全球变暖

El Nino phenomenon厄尔尼诺现象

La Nina phenomenon拉尼娜现象

frost

hail 冰雹

thunder

lightning 闪电

mist

fog 浓雾

cloud

haze

dew 露水

wind

land wind 陆风

hurricane 飓风

cyclone 旋风

typhoon 台风

whirlwind 龙卷风

gale 季节风

gust of wind 阵风

breeze 微风

waterspout 海上龙卷风

Sandstorm, duststorm, sand, dust 浮尘,扬沙,沙尘暴等沙尘天气

sunny interval, no rain, clearing多云间晴

sunny period, partly cloudy, partly bright, 晴间多云

cloudy, mostly cloudy 多云

bright, sunny, fair 晴(尤指白天)

fine, clear

overcast

wet, humid潮湿

drought 干旱

dry干燥

freezing冰冻

hot炎热

cold寒冷

warm暖和;升温

cool凉爽;降温

dew point 露点(点在此温度时,空气饱和并产生露珠)

humidity 湿度

visibility 能见度

(英语点津Meggie编辑)

the stranded passengers   “滞留旅客”        (英语点津Celene编辑)

The National Meteorological Center issued an orange alert.  橙色预警

 
2007-12-25 22:18

Climate change, which many scientists believe is fueled by human activities, alters rain cycles and causes increased droughts and flooding.

Rising temperatures mean some traditional crops do not grow as well as they used to. The United Nations predicts that in some African countries, crop yields could fall by half.

Oxfam researcher Kate Raworth says coping with these issues will be expensive.

"Oxfam has estimated that for all developing countries to adapt to climate change will cost at least $50 billion a year. And for that to be done with justice we believe that the rich and the most polluting countries should pay the vast share of the money to make possible for those countries most vulnerable and least responsible for causing the problem to cope with the new realities they have to deal with."

A report released by Oxfam at the conference on Tuesday says some countries are already feeling the effects of a warming planet. In South Africa, farmers are planting faster-maturing crops to adapt to unpredictable rainfall.

Bangladeshis are creating floating vegetable gardens that can thrive in spite of floods. But Mozaharul Alam, who heads Bangladesh's climate adaptation effort, says overall improvements to the food system still leave many families vulnerable.

"Most of the agriculture is subsistent in nature. So if [there is] any failure of the crop on the ground, even if there is food available in the market, unless the people has the buying capacity, that availability of the food in the market has no meaning to the vulnerable family."

Oxfam argues the United States, the European Union, Japan, Canada and Australia should be among the major sources of funds to help developing countries solve their climate change problems.

These countries have agreed in principle, but one task of the Bali Conference is to find out how much individual countries are willing to spend on climate-related issues.

It also aims to begin deciding how to divide those resources between prevention of further climate change, and adaptation to the changes that are already taking place.

The conference involves thousands of scientists, government officials and development group representatives, and runs for another 10 days.

Bush discusses 2008 foreign policy challenges

President Bush will be off to the Middle East early in the new year, and he says he has several objectives for the trip.

"One is to advance the Palestinian-Israeli peace process. Secondly, is to continue to work with our Arab friends on reconciliation with Israel. And finally is to assure people in Middle East that we understand and will show a strong commitment to the security of the region."

The seven-stop tour of the region will include his first visits to Israel and the West Bank as president.

During his news conference, the president also spoke about his hopes for political progress in Iraq. He said all of his expectations have not been met, but added the legislative process is not always smooth, even in countries with centuries-old democracies like the United States.

"Are we satisfied with the progress in Baghdad? No. But to say nothing is happening is just simply not the case."

President Bush indicated people seem to be feeling better about their lives in both Iraq and Afghanistan. He said U.S., Afghan and NATO troops are on the offensive against Taliban militants in Afghanistan, noting a review of strategy options that is currently underway.

"It makes sense for us to constantly review our strategy in a variety of theaters. That is what good governance is."

The president praised the work of NATO units from across the alliance. He urged their governments to remain engaged.

"So our objective is to help people meet a mission that they are comfortable with achieving and convince them that this is going to take a while, it is going to take time for this democratic experiment in Afghanistan to work. And I believe it will."

The president talked about his meetings during 2007 with Afghan President Hamid Karzai and other world leaders. And he looked ahead to his first contacts in 2008 with new players on the international stage.

He spoke specifically about Russia, which will elect a new president in a few months, replacing Vladimir Putin.

President Putin has been named Time magazine's 2007 'Person of the Year' for his efforts to impose stability and enhance Russia's stature as a world power.

President Bush said only time will tell whether the changes that got Vladimir Putin on the cover of Time magazine have really changed Russia for the better.

"I presume they put him on there because he was a consequential leader. And the fundamental question is consequential to what end? What will the country look like 10 years from now? My hope of course, is that Russia is a country which understands there needs to be checks and balances, free and fair elections and a vibrant press.

President Putin's likely successor is Dmitry Medvedev, who has already said he would like to see Vladmir Putin become prime minister.

WHO chief wants access to medicines for poor countries

WHO Director-General Margaret Chan says many sick people in developing countries die because they cannot afford medicine that can cure them. In some cases, she says resistance to diseases develops because they fail to be treated promptly and properly.

She blames much of this on the inability of the poor to get hold of the medicine and health care they need.

"I am fully committed to equitable access. People should not be denied access to life-saving and health-promoting interventions for unfair reasons. I am aware that the price of medicines and other products can be prohibitive, effectively blocking access to care. I have seen studies that show the limit, in dollars, to what people are able to pay to preserve even something as vital as their eyesight."

The WHO chief acknowledges the need for innovation in public health and drug research. Advocacy groups accuse pharmaceutical companies of failing to do the research needed on diseases that disproportionately affect the poor because there is little profit in it.

Dr. Chan draws a link between good health and the ability of families to work their way out of poverty.

"The challenge is to work on multiple fronts: to meet the immediate need for equitable access to quality, affordable medicines, while also working, at the same time, to stimulate innovation. The route to addressing these concerns passes through many other territories, including those where legal, economic, and trade issues have prominence. This is the reality."

The so-called WHO Intergovernmental Working Group on Public Health, Innovation and Intellectual Property was created last year in the wake of a WHO-commissioned report. It called for the pharmaceutical industry to slash the price of drugs sold in developing countries. Many drug companies say they have already done so.

The negotiations taking place are aimed at drawing up a plan of action and strategy for research and development that will be beneficial for poor countries. The final plan of action will be presented to the World Health Assembly in May.

Hillary likely to be focus of upcoming Democratic debate

Clinton heads into the debate leading in public opinion polls, but facing intensified criticism from her Democratic rivals.

Clinton has been on the defensive since the last Democratic debate two weeks ago. Clinton was asked about a plan to grant driver's licenses to illegal immigrants in New York. At first she seemed to support the idea, then backed away from it. Clinton's campaign now says she opposes the proposal, which was eventually dropped by New York's governor.

Clinton's rivals have also seized on public opinion surveys that suggest she is the most polarizing contender in the presidential race, liked and disliked by voters in roughly equal numbers.

The intensified attacks seem to have done little damage to Clinton in the polls. She leads nationally among Democrats and in the early primary state of New Hampshire. Clinton, Obama and Edwards are in a close race in Iowa, which kicks off the presidential selection process on January 3.

France grinds to halt over transportation strike

The streets of Paris lacked the usual hustle and bustle of a week day. There were plenty of cars on the streets, but no buses and virtually no metro service.

The walkout by transportation workers that began late Tuesday forced some would-be commuters, like marketing manager Benoit Aimet, to take one of the thousands of bicycles the city began renting this year.

"I am from Laumiere in eastern Paris and I wanted to go the the south," said Aimet. "So I took the bicycle to the Place de Clichy and I hoped to get a tube or a bus. But there was no bus. No tube. Nothing. So unfortunately, I am back home."

Aimet does not support the strikers. But he criticizes the conservative government of President Nicolas Sarkozy for pushing through reforms too quickly, notably on special pension benefits some workers enjoy.

The nearby metro was virtually deserted. Nobody at the ticket counter, and an announcement saying the line was not functioning because of the strike. That left Canadian Genevieve Lies and her friends to head for the Eiffel Tower on foot, a two-hour walk.

LIes, who teaches English in Paris, says she is not sure what the strike is all about. But she believes French transportation workers already have pretty good benefits.

"What is not good is that everyone else has to suffer while they are fighting for what they want. It forces us to be out of our jobs," said LIes. "I am not working for three days, and I am paid by the hour, because of them."

Polls show the majority of French do not support the strike. The government and unions were meeting Wednesday to reach a compromise.

But against Mr. Sarkozy's reforms is growing. Besides the transportation workers, students have shut down a dozen universities against separate reform legislation. Teachers, civil servants, magistrates and court clerks are also expected to go on strike later this month.

Bush talks on global climate__ change

In a bid to rally support for his proposal, President Bush brought together officials from most of the world's largest polluters to set goals for reducing greenhouse gases.

The two-day conference at the U.S. State Department is designed to improve cooperation with private industry on new technologies and set strategies for beyond 2012, when the current Kyoto protocol on climate change expires.

More than 160 nations ratified that agreement. But not the United States because President Bush says Kyoto would have hurt the U.S. economy and does not include emissions from developing nations.

Mr. Bush told the conference Friday that the United States takes the issue of climate change seriously, and will do its part to cooperate on reducing greenhouse gas emissions.

"By working together, we will set wise and effective policies. That is what I am interested in: effective policies. I want to get the job done. We have identified a problem. Let us go solve it together."

More than a dozen nations responsible for four-fifths of the world's pollution took part in the conference, including the United States, China, and India. Those three governments oppose mandatory controls on carbon dioxide sought by most European countries and the United Nations.

While America shares U.N. goals to address climate change, President Bush says individual countries must be free to strike their own balance between economic growth and environmental protection.

"Each nation will design its own separate strategies for making progress toward achieving this long-term goal," he said. "These strategies will reflect each country's different energy resources, different stages of development, and different economic needs."

The meeting in Washington followed one held Monday in New York, hosted by U.N. Secretary-General Ban Ki-moon, which President Bush did not attend. The U.N. chief says the nature and magnitude of climate change means no nation can address the challenge on its own.

"This is precisely the kind of global challenge that the United Nations is best suited to address. Indeed, I am gratified by the universal recognition that the United Nations climate process is the appropriate forum for negotiating global action. At the same time, I share the dismay of many at the slow progress of these negotiations."

U.S. Secretary of State Condoleezza Rice says the Washington conference is meant to support the next round of U.N. talks on climate change in Indonesia in December.

President Bush proposed an international fund to pay for research into clean-energy technologies and to help developing nations harness those technologies to reduce emissions.

Analysts pessimistic about US__ housing market outlook

The mortgage finance specialist at the Wells Fargo Bank in Minneapolis, Scott Anderson, says the crisis in the housing sector is getting worse. He told a National Association of Home Builders conference home prices will continue to fall. "We're going to see major declines in home prices, the likes we haven't seen since the great depression in this country over the next year. We're just starting on that process for the declines."

Earlier Wednesday the National Association of Realtors announced that sales of previously owned homes fell eight percent in September, a decline twice as steep as had been predicted. Anderson of Wells Fargo Bank says that downward trend will continue. "Home sales are still plunging in markets where underwriting standards were lax, risk-taking was high, and home prices to income ratios were even higher. Florida and Nevada are seeing the most rapid declines, about 50 percent in a year."

America's real estate and home loan market has been in decline for many months. During the sharp run-up in home prices that continued until 2005, mortgage lenders relaxed standards and promoted low interest loans to permit buyers to afford homes whose prices had dramatically risen.

In many cases, buyers did not understand that the low variable interest rates would eventually rise to higher levels, greatly increasing their monthly payments. That is the part of the reason that home loan delinquencies and foreclosures are on the rise.

Frank Nothalf is chief economist at Freddy Mac, the Federal Home Loan Mortgage Corporation. "Just between the first six months of 2006 to the first six months of 2007, the number of sub-prime loans entering foreclosure doubled nationwide. And in some markets it was substantially higher," he said.

Subprime loans are loans extended to higher-risk debtors.

Alarmed at the prospect of so many people losing their homes, Congress is preparing legislation to address the problem.

The Federal Reserve, which had been raising interest rates between 2003 and 2005, cut rates last month. But mortgage interest rates remain more or less unchanged and with credit markets in turmoil it is now increasingly difficult to obtain a fixed rate mortgage loan.

 
2007-12-25 15:22

稀土发光材料

First

1.        电磁波谱的组成 (可见光谱)

波长由长 → 短

无线电波 → 微波 → 红外线 → 可见光 → 紫外线 → X射线 → δ射线 → 宇宙射线

2.        色彩的三要素 (HSV)

     亮度 (明度,Value, luminance人眼感觉彩色光的明亮程度,反映了光的强弱。

     色调 (色相,Hue)反映了颜色的差别,取决于光的光谱成分。

     色饱和度 (Saturation) 是指彩色光呈现彩色的深浅程度(或浓度),同一色调的光,色饱和度越高,说明它的颜色越深,也反映了彩色光波长范围的大小,波长越窄,说明颜色越纯,饱和度越高。白光中没有哪种色调特别突出,其饱和度为0

     色调和色饱和度统称为色度,它即说明了光的颜色,又说明了颜色的深浅。

3.        什么是三原色原理 (三原色并不指RGB

     三种基色彼此独立,任一种基色不能由其它二种基色配出

     三种基色按不同比例混合,可以引起不同的彩色感觉

     合成色彩的亮度决定于三基色的亮度之和

RGB 三原色   R 700nm    G 546.1nm   B 435.8nm

4.        人眼两种感光细胞特点

     锥体细胞具有精细的分辨能力,能很好地分辨颜色.但感光灵敏度低。

杆体细胞感光灵敏度高,但分辨细节的能力低;不能分辨颜色。

5.        稀土元素的物理性质:稀土元素是典型的金属元素。它们的金属活泼性仅次于碱金属和碱土金属元素,而比其他金属元素活泼。

6.        稀土元素是镧系元素向一侧展开的元素。

Second

1. 稀土元素的赋存状态

稀土元素在地壳中主要以矿物形式存在,其赋存状态主要有三种:

1)稀土矿物 :独居石、氟碳铈矿、磷钇矿等

2)以类质同象置换: 磷灰石、萤石等

3)被吸附状态:被各种粘土矿物、云母类矿物。这类状态的稀土元素很容易提取。风化壳淋积型稀土矿,重稀土含量较多

2. 稀土离子4fn轨道的特点:能级很多(除了La3+Lu3+4f04f14外,其它镧系离子的4f电子可以在7个轨道上任意排布,从而产生多种光谱项和能级。+3价的镧系离子的4fn组态中共有1639个能级,能级之间可能跃迁的数目高达199177个。)

3. 发光的分类:根据激发的方式进行分类

光致发光,电致发光,阴极射线发光,X射线及高能粒子发光

Third

1. 根据基带宽度的不同,物质可以分为

导体或半导体的导电作用是通过带电粒子的运动(形成电流)来实现的,这种电流的载体称为载流子。

Forth

1. 色温:光源发射光的颜色与黑体在某一温度下辐射光色相同时,黑体的温度称为该光源的色温。

2. 气体放电光源原理

   气体→强电场作用→电离→气体放电→带电粒子或电子→与气体电离产生的其它粒子碰撞传递能量而进入激发态→ 激发态回到基态→产生电磁辐射→荧光粉发光。

3. 低压汞灯

   能量转换:60 254nm185nm的紫外光        
                      2
可见光辐射

可见光发光效率:25 lm/W

采用可透过紫外光的材料(如石英玻璃)作为外壳时,可制成紫外光源。

   选择适当的荧光粉,利用254nm的紫外光激发,可以获得不同颜色的荧光灯。

4. 高压汞灯的光谱成分特点:缺乏红光成分

   高压汞灯荧光粉——补充红光发射(铕激活红光材料不仅提高灯的光效,更重要的是改善了光的显色性。)

Fifth

1.        灯用稀土荧光粉的三大体系分别是什么?

   常用的稀土三基色荧光粉 —— 三大系列:

铝酸盐 :发现早、工艺成熟

磷酸盐:烧成温度低 300400, 光衰小,工艺不易控制,产品一致性差。

硼酸盐:光衰小,显色指数高, 但光通量较低 (合成温度范围窄)

Sixth

1.        荧光粉涂敷液的组成(荧光粉涂敷液又称粉浆,由荧光粉与黏结剂、溶剂及相关助剂按一定比例配制而成。)

2.        涂粉的要求 (均匀、致密、细腻的荧光膜,不仅关系到荧光灯的外观质量,而且对灯的光效、光衰等主要性能的影响很大。)(荧光粉的涂敷是使荧光粉以粉层的形式牢固、均匀地附着于玻管(或玻壳)的内壁。)

3.        稀土卤化物灯高显色性的原因(稀土金属卤化物灯的发光特性——在金属卤化物灯中,卤化物中金属原子的激发能级远远低于汞和卤素原子的激发能级,因而灯的光谱特性主要由卤化物中的金属元素所决定。稀土金属卤化物灯所辐射的可见光谱,比汞灯的谱线丰富得多,为十分密集的线状光谱,谱线之间的间隔非常小,以致用低分辨率的仪器进行观察时,谱线几乎构成连续光谱。

4.        对稀土卤化物荧光粉的要求——要求粉层中只存在荧光粉和不吸收可见光和紫外光、不吸附汞和氧化汞的无机永久性加固剂,不允许残留有暂时性的有机黏结剂。

5.        电弧收缩现象

稀土卤化物灯存在一个普遍的问题是电弧收缩现象。稀土碘化物加入汞弧中,电弧要产生收缩,电弧由管壁稳定型变为非稳定型,对灯的光电特性造成很大影响。与此同时,灯的管压也上升,容易造成熄弧。

电弧收缩是由于当加人灯内的金属原子的平均激发电位与其电离电位相差很大时,电离主要发生在电弧轴心附近,在外围区域电离难于发生;而激发则比较容易发生,受激的原子向外大量辐射能量,使外围区域的温度进一步降低,以致电离更难以发生,这样导电区域便集中在中心,形成了电弧收缩。

措施:稀土金属卤化物灯为解决电弧收缩而普遍采用的措施,是加一些碱金属(如钠)碘化物或碘化铊到电弧中以稳定电弧。由于钠的电离电位低,可有效地使电弧变粗,电弧成为管壁稳定型。

6.        稀土金属卤化物灯发光效率及显色性提高的方法

1)多组分卤化物

2)稀土卤化物的络合物(原因:与单一组分相比,金属卤化物的络合物具有更低的熔点、更高的蒸气压。这样既可以减少卤化物在灯中的填充量,又有利于高熔物质受激发光,而且还可以降低放电管工作温度和管壁负载,从而延长灯的使用寿命。)

3)稀土卤化物复合物

Seventh

1.        长余辉发光材料简称长余辉材料,又称夜光材料。它是一类吸收太阳光或人工光源所产生的光发出可见光,而且在激发停止后仍可继续发光的物质。

2.        为什么长余辉发光材料需有合适深度的陷阱能级?

首先,由于Dy3+的引入,在基质中产生了一种新的能级陷阱能级

其次,如果能级太浅,陷阱中的电子易于受激而返回激发态能级,余辉时间短;如果陷阱过深,则需要较高的能量才能使陷阱中的电子返回激发态能级,可能致使电子只能留在陷阱中而无法返回激发态能级.在具备长余辉的能级范围内,陷阱越深,激发所需要的能量越高,电子重新激发而产生发射的速率越慢,则余辉时间越长。

3. “余辉是指发光材料在激发停止后发出的光,一般认为发光衰减到初始亮度10%的时间为余辉时间。

Eighth

1.        长余辉发光材料研究的局限性是什么?

①对材料发光机制的研究不够充分,有些解释难于自圆其说。

②研究存在较大的局限性,例如,基质材料主要限于硫化物、铝酸盐以及硅酸盐等;铝酸盐中激活剂离子多采用Eu2+

③发光颜色较为单调,以绿色为主,缺少蓝色,尤其是缺少红色发光品种.红色长余辉材料仅限于CaS等硫化物,余辉时间不超过1h,化学性质不稳定,迫切需要开发新型的高效稳定的红色长余辉材料。

④长余辉材料的应用性能还需进一步改善,如铝酸盐材料多晶粉末受潮后发光强度显著下降的问题等。

⑤目前长余辉材料主要作为夜光材料使用,在应用领域的拓宽方面至今未能实现重大突破。人们预言长余辉材料有望应用于储能显示材料、太阳能光电转换材料、光电子信息材料。相信通过控制材料的组成、结构,改进制备工艺,稀土长余辉材料一定会在许多高新技术领域获得更为广泛的应用。

6 采用可以实现规模化生产的软化学合成方法取代高温固相反应法是觅待解决的问题。

Ninth

1. 稀土有机配合物发光过程

①配体吸收紫外光后电子由基态S0跃迁到最低激发单重态S1

S1经系间窜越到激发三重态T1;

③通过键的振动藕合由最低激发三重态T1向稀土离子振动态能级进行能量转移,稀土离子的基态电子受激发跃迁到激发态;

④电子由激发态能级返回基态时,发射稀土离子的特征荧光。

   一句话概括: 稀土离子微扰配体的发光

2. 提高配合发光效率的途径 1)引入第二配体 2)引入其它金属离子

Tenth

1. 阴极射线, 指从 阴极上 发射出来的粒子束。其本质是电子束。

Thirteenth

1.        等离子体显示原理是什么?

     利用稀有气体在一定电压作用下产生气体放电(形成等离子体),直接发射可见光或发射真空萦外光(VUV)转而激发荧光粉而间接发射可见光

 
2007-12-21 14:24

Thirteenth   燃料电池基本知识

1.        燃料电池是一种直接将燃料通过电化学反应产生低压直流电的装置,由于燃料可以不断地通入电池中,因此该电池可以连续不断地产生电能,故又被称为连续电池。 N

2.        威廉·格罗夫

3.        燃料电池的工作原理:(在酸性溶液中)

负极:H2 – 2e 2H+

正极:1/2O2 + 2H+ + 2e H2O

氢氧燃料电池的总反应可表示为: H2 + 1/2O2 H2O

工作原理:电池工作时向负极供给燃料(氢),向正极供给氧化剂(空气)。氢在负极分解成正离子H+和电子e-。氢离子进入电解质,而电子则沿外部电路移向正极。在正极上,空气中的氧同电解质中的氢离子结合,吸收抵达正极上的电子形成水。

4.        燃料电池与二次电池的区别

   燃料电池有别于一般的原电池与蓄电池,它所需参与电极反应的活性物质并不贮存在电池内部,而是全部由电池外部供给。原则上只要外部不断地供给电化学反应所需的活性物质,燃料电池就可以连续不断地工作,燃料电池实际上是将化学能转变为电能的一种特殊发电装置。

蓄电池的活性物质贮存在电池内部,电极放电后通过充电的方法使活性物质复原,实际上是一种电能贮存装置。而不能产生电能。

Sixth 镉-镍电池 —— 最早被研制成功的密封蓄电池

1.     负极是海绵状的镉,正极是用碱性氧化镍。

2.     电池型号 : 国标GB7169-87

1、系列代号与额定容量的数字相结合,GN代表镉镍电池

2、电池形状,开口不标,对密封电池Y、B、F分别表示圆形,扁形和方形。

3、放电倍率,D、Z、G、C表示低,中,高,超高。

例:   18GNY500m

           18-单体电池数

            GN-镉-镍电池

            Y-圆柱形

            500m-容量

圆柱形密封镉镍电池组,由18只容量为500A﹡h的单电池组成

3.     氧化镍电极 (氧化镍充放电曲线)

    因为刚充完电的镍电极上有NiO2,NiO2不稳定,会自动放电转换为氢氧化镍而被消耗掉。

4.     氧循环法密封原理

    使负极活性物质比正极活性物质多一些。当正极充足后,负极仍未充足。这时正极上产生的氧气在适当的电池结构下,扩散到负极,与负极活性物质发生反应被吸收掉,在负极生成未充电物质,使负极总是处于未充足状态。这样就可以不产生氢气,从而消除和避免了充电过程中两极所产生的气体。但不能消除自放电所产生的氢气。因此,要采用此方法,必须满足下列条件:

(1)          负极在电解液中稳定,不能自动溶解而析出氢气,同时负极物质过量且可以与氧气作用;

(2)          有一定的气室,便于氧气通过;

(3)          采用合适的隔膜,便于氧气通过,促进氧气快速向负极扩散。

5.     n.)电池长时间经受特定的工作循环后,自动保持这一特定的电性能倾向,称为记忆效应。

 
2007-12-07 12:14

Shareable draft

Brittle life

‘Look, there is a girl near the railings on the top floor.’ A fat guy shouted on the ground, pointing at the sky, when passing the Jiangzhai Building, which was the highest building holding 100 floors in the city.

Over few seconds, all passers-by flooded to the fat guy and raised their heads, looking for the girl. A man wearing a pair of glasses hurried to find his mobile phone in his briefcase and called the police.

A few minutes later, the police wagon got to the crowd and immediately set up the gasbag beneath the girl. Some police reached the top floor.

The girl held stick to the railings and looked down, crying and shivering. No one knew why she wanted to die, maybe so she herself did.

A policeman approached her slowly. ‘Hey, girl, that’s so dangerous….’

‘Keep away! Get away!’ She cried.

‘What’s your problem? Let’s help you, Ok?’ He comforted.

… …

An hour later, the police were wordless; the gasbag was charged again and again; the crowds were anxious and unsettled. One screamed, ‘What the hell was she doing? Jump or not?’

… …

Three hours and thirteen minutes later, she jumped down, dead. The police were shocked; the gasbag was put away; the crowds went on their life.

No one understood her but what we could figure out was if she really wanted to die, she would not wait for a so long time – three hours and thirteen minutes.

 
   
 
 
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