c****g
发帖数: 70 | 1 材料力学说的应该叫做area moment of inertia, 我手头这本书上写的是moment of
inertia for an area，有时候也较second moment of inertia。是个截面属性，用来
计算
bending 和deflection的。一般所说的moment of inertia 是有质量在里面的，也叫做
mass
moment of inertia (不太确定)， 用来计算rotation的。 |
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g******s
发帖数: 733 | 2 而google和论文中moment of inertia的单位是质量(kg)的平方乘以距离的平方？
先谢了！ |
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w*******y
发帖数: 60932 | 3 Just logged on to Playstation Plus (PS+) and noticed some more freebies, in
addition to The Simpsons Arcade Game and Final Fantasy V that has already
been mentioned.
Far Cry 2
Fatal Inertia
Mahjong Tales: Ancient Wisdom and Booster Pack
Inferno Pool
Supersonic Acrobatic Rocket-Powered Battle-Cars
|
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c*******9
发帖数: 9032 | 4 Summation of Tesla's Dynamic Theory of Gravity
An excerpt from: Occult Ether Physics
by William R. Lyne
From: Don Allen
d**[email protected]
According to Tesla's lecture prepared for the Institute of Immigrant Welfare
(May. 12, 1938), his "Dynamic Theory of Gravity" was one of two far
reaching discoveries, which he "...worked out in all details", in the years
1893 and 1894. The 1938 lecture was less than five years before his death.
More complete statements concerning these discoveries can ... 阅读全帖 |
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L***q
发帖数: 38 | 5 Volvo 一直是汽车行业安全的先锋，而且始终以安全作为企业之本，不断研发和创新，
不断有新的安全设计加入到新的产品，所以在汽车安全性能上没有另外一家汽车厂能出
其右的。除了前面说的以外，volvo还发明了ABS, Safety belts in rear seat，Rear-
facing child seat and childproof locks，Energy-absorbent bumpers。
Milestones in 80 years of Volvo safety
1944 Safety cage
1944 Laminated windscreen
1959 Three-point safety belts in front seats
1960 Padded dashboard
1964 Prototype of first rear-facing child seat
1966 Dual-circuit braking system
1966 Crumple zones
1967 Safet... 阅读全帖 |
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g*****y
发帖数: 7271 | 6 I don't think that page can be used as a base of discussing scientific facts
of swing weight. The sentence "Measure of how heavy a racquet feels when
swung, i.e. maneuverability. Also known as Moment of Inertia or Second
Moment" is way to vague to claim "swing weight = moment of inertia". The
basic physics behind these two terms is the same factor. But the two terms
can be very different.
I believe my understanding of high school physics is better than majority
people. I am definitely not a 谦虚 t... 阅读全帖 |
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g******s
发帖数: 733 | 7 基本上是按照一篇论文中类似装置的谐振频率的计算方法。实际上有4x10个fingers,图
中只画出4x6个fingers。算rotation stiffness的时候只算了一个finger，算mass
moment of inertia的时候只算了圆形微镜，忽略了fingers,因为fingers比圆形微镜小
很多。得到的谐振频率为46.7KHz。
而用商业软件算的结果是10KHz，实测的是8-10KHz。总之我的结果是实际的4倍。
估计mass moment of inertia的计算应该是对的，虽然忽略了fingers导致mass moment
of inertia 偏小。主要错误估计在rotation stiffness的计算。麻烦哪位告诉我，这
里应该怎么计算rotation stiffness？先谢了！ |
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g******s
发帖数: 733 | 8 基本上是按照一篇论文中类似装置的谐振频率的计算方法。实际上有4x10个fingers,图
中只画出4x6个fingers。算rotation stiffness的时候只算了一个finger，算mass
moment of inertia的时候只算了圆形微镜，忽略了fingers,因为fingers比圆形微镜小
很多。得到的谐振频率为46.7KHz。
而用商业软件算的结果是10KHz，实测的是8-10KHz。总之我的结果是实际的4倍。
估计mass moment of inertia的计算应该是对的，虽然忽略了fingers导致mass moment
of inertia 偏小。主要错误估计在rotation stiffness的计算。麻烦哪位告诉我，这
里应该怎么计算rotation stiffness？先谢了！ |
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l***e
发帖数: 136 | 9 Editor's note: Ravi Agrawal is CNN's New Delhi Bureau chief and was formerly
senior producer of the network's "Fareed Zakaria GPS." Follow him on
Twitter: @RaviAgrawalCNN
Hong Kong (CNN) -- I met an entrepreneur recently who was comparing doing
business in Asia's two biggest countries. "When I'm in India," he said, "I
spend the first 40 minutes of any meeting exchanging niceties. In the last
five minutes, we get to business." What about China? "We do business for 40
minutes. Right at the end, we... 阅读全帖 |
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i****x
发帖数: 17565 | 10 如果光看高速mpg，不同排量并不会拉开很多。
摩擦生热是小事，pumping loss是关键。高速巡航load不高的情况下，气门张开很小，
活塞运动等于在抽真空，这个阻力就叫pumping loss。
An engine has many moving parts that produce friction. Some of these
friction forces remain constant (as long as applied load is constant); some
of these friction losses increase as engine speed increases, such as piston
side forces and connecting bearing forces (due to increased inertia forces
from the oscillating piston). A few friction forces decrease at higher speed
, such as the friction for... 阅读全帖 |
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f*****h
发帖数: 4489 | 11 这个人说得不错 你看看下面那个工程师说的FRS 53/47才是最合理的 为什么呢？
https://www.youtube.com/watch?feature=player_embedded&v=tHVhaTNRk8E
另外你看看这个edmond说的有没有道理
4. Myth: The "ideal" weight distribution is 50/50: The vehicle has the same
weight on both the front and rear axles.Truth: While most sport-oriented
cars do have weight distributions close to 50/50, there's much more to
proper handling than just distribution. A car with 50/50 weight distribution
would handle poorly if most of the weight was at the ends of the car (i.... 阅读全帖 |
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J**********7
发帖数: 2619 | 12 我已经不爱讨论器材了，但是今天还是忍不住说两句。
没有sv Air刹车。 只有mag-z, mag-v, mag-3d， 这三种都是可伸缩的刹车片，并不是
sv spool特有的。这三种刹车构造是一样的，只是插入NS 磁极的长度不同，mag-v插入
少些，不稳定，但是轻饵效果好，比如stz103。mag-z插入深些，比较稳定，
通用型好，stz 100。 3d后来出来的，可以自己调节位置，效果最好，但是daiwa不往
下做了，原因就不说了，用用就知道了。
sv spool与刹车没有关系，主要是材料的特性使得它的inertia很大，start slow，
stop fast，所以抛投开始和最后都不容易炒粉。
以前的普通铝线杯inertia很小，惯性太大，包括现在的zillion tws，还是比较难控制
的。 |
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i*********5
发帖数: 19210 | 13 How Champions Do It
http://coachsci.sdsu.edu/swim/champion/evans.htm
JANET EVAN'S FULL STROKE AT 625 m OF HER 800 m GOLD MEDAL SWIM AT THE
BARCELONA OLYMPIC GAMES 1992
Each frame is .1 second apart. The swimmer breathes at the end of each right
arm pull.
Notable Features
Frame #1: This picture illustrates a feature of most top crawl-stroke
swimmers. The right arm entry is made at full stretch (no underwater gliding
) and is accommodated by a very linear posture in the total swimmer. The
uppe... 阅读全帖 |
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S******t
发帖数: 8388 | 14 想起了很久以前收藏的这篇文章:
Overcoming Procrastination
by Steve Pavlina, CEO, Dexterity Software
Procrastination, the habit of putting tasks off to the last possible minute,
can be a major problem in both your career and your personal life. Missed
opportunities, frenzied work hours, stress, overwhelm, resentment, and guilt
are just some of the symptoms. This article will explore the root causes of
procrastination and give you several practical tools to overcome it.
Replace "Have To" With "Want To"
First, th... 阅读全帖 |
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O******e
发帖数: 4845 | 15 我推荐大家都读一下这篇文章：
http://www.pnas.org/content/111/16/5773.full
全文：
By Bruce Alberts, Marc W. Kirschner, Shirley Tilghman, and Harold Varmus
By many measures, the biological and medical sciences are in a golden age.
That fact, which we celebrate, makes it all the more difficult to
acknowledge that the current system contains systemic flaws that are
threatening its future. A central flaw is the long-held assumption that the
enterprise will constantly expand. As a result, there is now a severe
imbalan... 阅读全帖 |
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k***i
发帖数: 662 | 16 inertia force就是ρu^2=(ρVu^2)/V=mu^2/V
即单位体积流体所携带的动能(系数1/2我没写)。
Reynolds数可以作为重要参数是因为粘性流体在低Re下受粘性力主导；在高Re下受inertia force主导。 |
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p**********m
发帖数: 472 | 17 为何受粘性力主导就是laminar flow, inertia force主导就是turbuence flow呢?
inertia force主导。 |
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t***s
发帖数: 4666 | 18 huh? I is the inertia? i thought it's the current? isn;t inertia J?
and if you understanding was correct, you wouldn't need the torque balance
equation. |
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g******s
发帖数: 733 | 19 千真万确I是inertia，I=(1/12)*密度×体积×宽度^2的公式是原论文给出的，后面还
加了一句"I is the moment of inertia of the mirror plate“。
请问如果不需要torque balance equation，怎么求alpha和V的关系？
多谢了！ |
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q****g
发帖数: 1190 | 20 I am sorry, I did not make it clear last time.
There is moment of inertia, defined as r^2 dm, and there is also area of
moment of inertia, defined as r^2 dA. Actually they are pretty much the same
as dA*rhor*(unit thickness)=dm
Thank you for your reply, but do you know which area in my questions?
Seeking help from Banzhu, renxiaoyao, .... da niu
. |
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g******s
发帖数: 733 | 21 请问角频率 omega=sqrt(rotational stiffness / mass moment of inertia) 的单位
为什么不一致呢？网上和论文中rotational stiffness的单位都是N*m/radian，mass
moment of inertia的单位都是kg*m^2,这样算出来的角频率omega的单位是sqrt(1/
radian/second^2),而不是radian /second。
先谢了！ |
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d********e
发帖数: 198 | 22 Journal of Lubrication Technology
April 1968
Volume 90, Issue 2
“The Effects of Geometry and Inertia on Face Seal Performance—Laminar Flow”
H. J. Sneck
pp. 333-341
“The Effects of Geometry and Inertia on Face Seal Performance—Turbulent
Flow"
H. J. Sneck
pp. 342-350
Email: w********[email protected]
多谢多谢！！ |
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z**********g
发帖数: 16 | 23 Discussing The Existence of “repulsion particle” And Its Significance
Zhuang Yiliong
Shanghai Institute of Science and Technology Management
Abstract:This report has advanced a assume about the existence of “
repellention” by a kind of new idea. Beginning with this, I have explained
more successfully some import theory questions in the area of the present
physics, cosmology and philosophy ect. At same time a few of new reasons
have been raised But this is only rough idea of physica... 阅读全帖 |
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l**n
发帖数: 67 | 24 This just serves as a short review of the special theory of
relativity(SR). The main concern here are some basic concepts
which will be used extensively later.
The physics statement in SR is the first postulate by Einstein.
"The laws of physics take the same form of in different inertia
frames". This is our belief. And the SR could be derived from
different approaches.
1.Started from 2nd postulate by Einstein, the speed of light is
a constant in different inertia frames. We always say 2nd postu- |
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f*******d
发帖数: 339 | 25
1. Take the foot as axis, measure the moment of inertia I1,
2. Take the neck as axis, measure the moment of inertia I2.
If the distance from the foot to the neck is d, then
mass of head ~ (I1-I2)/d.
If want to be more accurate, use CT to construct a density
model inside
the head, then integrate:-) |
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f*******d
发帖数: 339 | 26 All of these ideas of immersing body in liquid have a problem: you don't
know if there is any force through the neck.
Actually, to get moment of inertia, you don't have to spin him, you
can measure it by static force experiment. Just fix the desired part of him
(the axis) at desired position, then support the person at one or two other
points, get it balanced, and the total torque give you the moment of inertia:
I= T/g, where g is gravitational acceleration constant. |
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B*********e
发帖数: 86 | 27 【 以下文字转载自 Faculty 讨论区 】
发信人: BiggeyIssue (出大事儿了..(可算)出大事儿了...), 信区: Faculty
标 题: Re: 标 题: Re: 求建议，回国还是留下
发信站: BBS 未名空间站 (Fri Feb 1 15:23:11 2019, 美东)
~~~~~~~~~~~~~~~~~~~~~~
[回复] [回信给作者] [本篇全文] [本讨论区] [修改] [删除] [转寄] [转贴] [收藏]
[举报] [ 154 ]
发信人: BiggeyIssue (出大事儿了..(可算)出大事儿了...), 信区: Faculty
标 题: Re: 求建议，回国还是留下
发信站: BBS 未名空间站 (Fri Feb 1 15:03:14 2019, 美东)
(2019-01-29#2013)
to sunnyan (羊妈妈)和爱人__to （water77 (水)__mitbbs发考题版__mitbbs发考题版
_2019-01-25#0015-0439__s#0440__1840-2333__01-26#1852-... 阅读全帖 |
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a***c
发帖数: 2443 | 30 the talent flow probably carries more inertia than that. Even if China
reached Japan's socioeconomic status, people would still want to come to
the US just because they enjoyed being around other smart people and the
underlying trend in academia today is collaboration for fields like math
and science. I am talking about the best of the best here and they are the
ones who make the difference. For the average programmer though, it
doesn't really matter where they do their job.
The bottom line is, |
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w****j
发帖数: 5581 | 31 倒，moment of inertia都不知道，你怎么教的学生？ |
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d********a
发帖数: 3698 | 32 有一次极严重的核电厂燃料棒融化的污染！据估计其污染程度是三哩岛的457倍! 美国
官方一直到5
星期后才在报纸上悄悄的报道了这个事故.
“50 Years After America’s Worst Nuclear Meltdown
Human error helped worsen a nuclear meltdown just outside Los Angeles,
and now human inertia has stymied the radioactive cleanup for half a
century.
By Joan Trossman Bien and Michael Collins
http://www.miller-mccune.com/science-environment/50-years-after
meltdown-3510/
The Santa Susana Field Laboratory.
For Release Saturday A.M., August 29, 1959
CANOGA PARK, CA
“During an inspecti... 阅读全帖 |
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c********d
发帖数: 85 | 33 How can your theory explain the following facts:
1. Within the richest part of the society, even though they have much more
than they need, they keep fighting each other daily for prestige and fame;
they compete for who is richer and more famous; they compete for bigger
roles to influence the society. This is less obvious in the U.S. but in U.K.
Europe and even poorer nations it's standard throughout the history.
2. Within the richest part of the society, their kids have the freedom to
choose wh... 阅读全帖 |
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K**********n
发帖数: 1197 | 34
跟这帮自称理科的文科生物wsn实在纠缠不清楚。给丫们上点洋大人自己的说法吧，而
且都是学术圈的，已有reference一堆，其中一份是著名的兰德公司的报告。
另外，美国和澳洲已立法限制使用脑波扫描仪，拿脑波扫描仪扫本国公民已是联邦法的
重罪。不过这个比较难的是你无法证实谁接收了你的脑信号。所以立了法跟没立一个样。
Remote Mind Control Technology
Reprinted from SECRET AND SUPPRESSED: BANNED IDEAS AND HIDDEN
HISTORY, edited by Jim Keith, $12.95, available from
1-800-680-INET.
There had been an ongoing controversy over health effects of electromagnetic
fields (EMF) for years (e.g., extremely low frequency radiation and the
Navy's Project Sea... 阅读全帖 |
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b****u
发帖数: 1710 | 35 Butchered? There is a difference between deliberate killing and death from
failed economic policies. Otherwise, we would have to re-examine every
major leaders in the world to see whether their policies or inertia caused
any death and if so, they should be tried for such misfortunes.
I am no lover of Mao; in fact, I hate him, but lets be intellectually honest
here, instead of regurgitating same arguments I have been hearing from
some western scholars and our self-proclaimed Chinese "intellige... 阅读全帖 |
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D**S
发帖数: 24887 | 36 这个究竟是好是不好，还真不是三言两语能说得清的。
但是我的博士导师是从英国大学里干了十几年之后来美国发展的，一来就要到了tenure
.我跟他N年之后终于敢于问他为何离开英国来美国，他说英国社会被inertia所束缚，
个人无法施展。 |
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o**********e
发帖数: 18403 | 37 【 以下文字转载自 SanFrancisco 讨论区 】
发信人: onetiemyshoe (onetiemyshoe), 信区: SanFrancisco
标 题: 华人孕妇: 2015年前马圈里出生的一个难民宝宝发来贺电
发信站: BBS 未名空间站 (Thu Mar 5 14:30:00 2015, 美东)
发信人: onetiemyshoe (onetiemyshoe), 信区: LosAngeles
标 题: Re: 为了月子中心华人孕妇的利益 (转载)
发信站: BBS 未名空间站 (Thu Mar 5 14:29:44 2015, 美东)
有的孕妇有，不见得别的孕妇有。
新闻一贯这样，把有钱的拿来埋汰，
70多年前也是这样害犹太人的。
即使有钱，人生地不熟，中心出了
事，她们心中惶恐，也应该有热心靠谱
的同胞去安慰帮忙。 雪中送碳
胜过锦上添花。 虎落平阳被犬欺，
哼，以后这些大肚婆恢复过来了，
又是一条”好汉“了，说不定以后
一起去抗议SCA－5，说不定
这帮BABY中会出美国亚裔总统呢。
同胞们多积德吧。 眼睛不要太近视。
---------------... 阅读全帖 |
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d**z
发帖数: 3577 | 38
You're right, truly able people don't bother
with corrupt politicos.
First class attract first class.
Second class attract third class.
The corrupt attract even more corrupt.
Politics has a self-fulfilling inertia.
That's why self-reform is rare and rarely succeed. |
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发帖数: 1 | 39 以下内容仅供参考…
Brussels — I am in the quiet of a business lounge at a bustling European
airport. The coffee is strong and true, the croissants sinfully buttery, and
self-important men and women of all nationalities fuss about with their
laptops. And then I notice something: a prosperous Indian man of about 60,
overweight by the standards of a Brussels airport lounge but not of a New
Delhi 5-star hotel, is brought in on a wheelchair. The attendant leaves him
by a sofa seat and agrees to return when it... 阅读全帖 |
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b*********3
发帖数: 1709 | 40 Of course it is and trade wars have inertia. As for the Chinese they have
already replaced most dependency on US products so they can afford to be
magnanimous. They know they have Trump pinned down.
The unspoken part of the trade deal has already been set.
Trump had no choice. US businesses were going to cut his balls off. Trump
polls are dropping for his mishandling of the economy as reported by CNBC.
Markets are moving because for the most part, China and the US have agreed
on IP safeguards. T... 阅读全帖 |
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b*********3
发帖数: 1709 | 41 Of course it is and trade wars have inertia. As for the Chinese they have
already replaced most dependency on US products so they can afford to be
magnanimous. They know they have Trump pinned down.
The unspoken part of the trade deal has already been set.
Trump had no choice. US businesses were going to cut his balls off. Trump
polls are dropping for his mishandling of the economy as reported by CNBC.
Markets are moving because for the most part, China and the US have agreed
on IP safeguards. T... 阅读全帖 |
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b*********3
发帖数: 1709 | 42 Of course it is and trade wars have inertia. As for the Chinese they have
already replaced most dependency on US products so they can afford to be
magnanimous. They know they have Trump pinned down.
The unspoken part of the trade deal has already been set.
Trump had no choice. US businesses were going to cut his balls off. Trump
polls are dropping for his mishandling of the economy as reported by CNBC.
Markets are moving because for the most part, China and the US have agreed
on IP safeguards. T... 阅读全帖 |
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u***r
发帖数: 4825 | 43 https://time.com/5770140/millennials-change-american-politics/?utm_source=
facebook.com&utm_medium=social&utm_campaign=social-share-article&utm_content
=20200127&fbclid=IwAR36be58A6V9VvNGfu55yIWFvzqs8zNMpZsfrol02sAtggNde_
tGjMlveqI
How Millennial Leaders Will Change America
BY CHARLOTTE ALTER JANUARY 23, 2020
Love ’em or hate ’em, this much is true: one day soon, millennials will
rule America.
This is neither wish nor warning but fact, rooted in the physics of time and
the biology of human cells... 阅读全帖 |
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s********5
发帖数: 615 | 44 感谢firrysun的补充，关于氢再说2句，目前核电厂除氢（hydrogen mitigation)有几
种方式，正常工作时是pre inertia,就是安全壳里事先充氮气, 出事故后几个办法，用
化学方法吸附催化反应减少氢或氧的含量，如果氢和氧的体积比超过4%，5%，经请示上
级领导，可以局部可控制的点燃电火花，就是firryysun兄所说的ignition，但这招比
较悬，领导不签字咱不干。。。最好是使劲充氮气。 |
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s****r
发帖数: 31686 | 45 final guidance could be gps or dsmat, the later one is the digital scece
matching, however, it can be cheated too by altering the apperance of target
only inertia guidance cannot be cheated
我印象里地形匹配的战斧都退了? |
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L***6
发帖数: 8307 | 46 卡桑帮俺复习了ineptitude, inertia... |
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l******0
发帖数: 244 | 47 来自主题: RuralChina版 - 民主的代价 加州规划中横贯南北的子弹头高铁，开工日期一拖再拖，说不定最终泡汤。沿着
Central Valley 的几个城市投资房地产，曾经被认为是一个好主意。
A judge dealt a dual blow to plans for California's bullet train in a pair
of rulings handed down Monday in Sacramento.
In a separate but related case, the judge sided with Kings County farmer
John Tos, Hanford homeowner Aaron Fukuda and the Kings County Board of
Supervisors, who are suing the rail agency over its compliance with Prop. 1A
. Kenny agreed to issue a writ of mandate ordering the rail agency to re-do
its 2011... 阅读全帖 |
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l****z
发帖数: 29846 | 48 The Quiet Fury of Robert Gates
Bush and Obama's secretary of defense had to wage war in Iraq, Afghanistan—
and today's Washington
All too often during my 4½ years as secretary of defense, when I found
myself sitting yet again at that witness table at yet another congressional
hearing, I was tempted to stand up, slam the briefing book shut and quit on
the spot. The exit lines were on the tip of my tongue: I may be the
secretary of defense, but I am also an American citizen, and there is no s... 阅读全帖 |
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