News on China's scientific and technological development.

SanWenYu

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This is the news release in 2020 from Zhejiang University of Technology (浙江工业大学) about the research team of the cold atom interferometry gravimeter:
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Acccording to this news release, the project began in 2006 and was the first in China. The first generation was a prototype. The second generation made the gravimeter mobile. The current, and third, generation is a miniaturized version of the second one.

近日,在2020年度全省科学技术奖励大会上,我校理学院林强教授团队牵头完成的“基于冷原子干涉的重力精密测量技术应用”成果获得2020年度浙江省技术发明奖一等奖。这已是他第三次获得重要科技奖励,前两次分别是全国高等学校自然科学奖二等奖和国家技术发明奖三等奖。林强教授是国家自然科学基金杰出青年基金、德国洪堡基金获得者、博士生导师,也是理学院院长、浙江省量子精密测量重点实验室和协同创新中心主任。

This photo shows the size of the gravimeter, comparing to the laptop sitting on top of the cabinet.
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量子精密测量团队研制的ZAG型量子绝对重力仪
这是一项用激光冷却方法将铷原子冷却到接近绝对零度的超低温度的技术,原子将体现出本身固有的波动特性。曾经长期以来,我国在绝对重力测量领域依赖进口光学干涉型重力仪,制约了我国相关领域的发展。而林强的冷原子干涉型重力仪具有更高的测量精度,是新一代精密测量仪器的典型代表。

2006年10月,林强及其团队在国内率先开展了冷原子绝对重力仪和重力梯度仪研究。

在国家 863、973 计划及国家自然科学基金项目的支持下,先后研制了第一代(原理验证和实验室样机)、第二代(可移动式量子重力仪)、第三代(小型化量子绝对重力仪)等系列样机,不仅实现了我国在该领域的技术突破,而且实现了重力测量仪器从无到优的历史跨越。

2016 年,中国计量科学研究院在亚太计量规划组织(APMP)框架下主办“第一届亚太区域绝对重力仪关键比对”,这是我国境内第一次主办国际绝对重力仪关键比对。林强团队与浙江大学联合研发的“可移动式冷原子干涉重力仪”参加该次比对。

作为该次国际比对中唯一一台采用量子精密测量技术研制的新型绝对重力仪,也是我国第一台走出实验室,参加国际比对的冷原子干涉重力仪。这台冷原子干涉重力仪在比对中取得了良好的比对结果,性能达到国际先进水平。

Zhejiang University of Technology is not the only institute working on this kind of gravimeters. According to
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, Huazhong University of Science and Technology has created a cold atom interferometry gavimeter, too. Perhaps their focus is more on the precision and accuracy than on small size and mobility. [This web site does not allow me to copy their content. I took a screenshot of this picture.]

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SanWenYu

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A team of Chinese heart disease experts successfully completed a transcatheter aortic valve replacement (TAVR) surgery using artificial heart valves made from polymer.

TAVR surgeries used to require organic artificial heart valves that are made from ox or pig organs. These heart valves are difficult to make and expensive. They also have a relatively short life in human bodies, from 10 to 15 years.

The patient is a 80 year old male. He has recovered from the surgery and is in good condition to be discharged from the hospital.

Chinese researchers created the polymer heart valves which last twice as long, up to 20 to 25 years. These valves are easy to make and can be mass produced on fully automated machines. The raw materials also cost a lot less than the organic heart valves.

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上海7月12日电 (记者 陈静)心脏瓣膜病是指,由于先天性发育异常或其他各种病变,引起的心脏瓣膜及其附属结构发生功能上等的异常。

记者12日获悉,今后,中国瓣膜病的治疗进入“聚合物”(polymer)新时代。与传统的生物瓣膜相比,这种新型材料的心脏瓣膜使用寿命延长了一倍,可达20-25年之久。

据了解,中国科学院院士、复旦大学附属中山医院心内科专家葛均波及其团队的多位专家为患者江老伯成功实施经皮主动脉瓣置换术(TAVR),植入了“聚合物瓣膜”。葛均波指出,能够将聚合物瓣膜由研究阶段转化应用至临床,是瓣膜技术和加工方式的革命性改变。
葛均波告诉记者,被临床应用多年的动物心包组织有较好的耐久性及抗栓性能,但其使用寿命有一定局限性,一般为10-15年,且加工缝合要求很高,成本也高,不易剪裁成一些特殊的形状。这位专家介绍,随着材料学的进展,聚合物瓣膜可一定程度弥补动物心包瓣膜的不足,其更容易加工剪裁。在体外模拟实验中,一些聚合物瓣膜显示出比传统牛心包瓣膜更久的使用寿命,可达25年。同时,聚合物瓣膜无需抗凝,且开闭时也不会产生噪音,适合更年轻的病人。

采访中,记者了解到,葛均波院士团队从动物实验阶段就参与了相关企业自主研发的新型材料瓣膜的相关研究。这种瓣叶具有零钙化、低凝血、高生物相容性的优点。据介绍,从生产工艺上,聚合物瓣膜可实现全自动化工业生产,产品原材料成本大大降低,合格率显著提升;同时该瓣膜的设计独特,大大降低了传导阻滞并发症的发生,并且还拥有预装、全可回收的特性。
 

SanWenYu

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Paper in English:
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Flexible THz Carrier-Envelope Phase Shifter Based on Metamaterials​

The ability to manipulate terahertz (THz) waveform is important for its applications. Despite rapid progress in metamaterials (MMs), the carrier-envelope phase (CEP) control for THz pulse is still challenging due to its broadband feature. THz scanning tunneling microscope (THz-STM), as an emerging technique combining both high temporal and spatial resolution, imposes additional requirements. Here, an ultra-thin and flexible THz CEP shifter with five groups of different MM arrays is proposed. The CEP shifter is based on a specified split-ring resonator with a pair of cross-oriented gratings to enhance transmission efficiency. Simulation and experimental results show that the CEP of the THz pulse is modulated by passing through different MM arrays in turn, which can be shifted as high as 2π. The CEP shifter has good tolerance to wide-angle oblique incidence and structural bending, which is expected to be used as a key component for THz-STM. The structure of the CEP shifter has many potential applications, including THz wave focusing, beam-steering, spatial phase modulation, and structured light generation.

News release in Chinese:
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近日,中国科学院空天信息创新研究院广州园区王天武研究团队关于太赫兹(THz)载波包络移相器的研发成果【《基于超材料的柔性太赫兹载波包络移相器》(Flexible THz Carrier-Envelope Phase Shifter Based on Metamaterials)】,发表在《先进光学材料》(Advanced Optical Materials)上。
作为太赫兹扫描隧道显微镜系统的核心部件,该载波包络移相器由不同的人工微结构阵列组成(图1)。研究团队首次利用“超材料”在亚波长厚度和不改变THz电场极化的情况下实现了对宽带THz载波包络相位(CEP)的消色差可控相移,其CEP的相移高达2π。与传统的THz载波包络移相器相比,该移相器具有超薄、柔性、低插损、易于安装和操作等优点。

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图1.(a)移相器的单元结构示意图,(b)整体和局部光学照片。

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图2.(a、b)模拟和实验获得的不同CEP值对应的THz时间波形变化,(c、d)广角入射和样品弯曲形变对器件性能的影响。
 

Strangelove

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Robot 'surgeon' saves lives, wins acclaim abroad​


By MA SI | China Daily | Updated: 2022-07-13 10:55

Surgeon Tian Wei said in 2015, he was faced with one of the most challenging orthopedic surgeries he had seen in his 30-year career.

A 43-year-old patient had complained of progressive numbness in the limbs on his right side for 14 months. The cause was a deformity in an upper cervical vertebra.

The patient was in dire need of surgery to implant a screw to help support the vertebrae in his neck, but the operation was risky. Any minor mistake could lead to paralysis or life-threatening hemorrhaging. Many hospitals were unwilling to treat him.

But Tian, who was then president of Beijing Jishuitan Hospital, decided to do the surgery-with a little help from another "surgeon".

The operation was completed in an hour with help from a surgery robot with a 3D high-definition visual system that can "see" the internal orthopedic structure and a mechanical "hand" that can guide surgical tools to the proper location with an accuracy of within 1 millimeter.

"That was the world's first robot-assisted surgery on the upper cervical vertebrae," Tian said, describing the 2015 clinical trial. "The homegrown robot is more precise than foreign products."

The robot was developed by Tinavi Medical Technologies Co Ltd, a Chinese pioneer in medical robots, in partnership with Jishuitan Hospital. Since then, the Beijing-based company has launched new generations of orthopedic surgical robots, managed a product that could be massively produced and brought China's first homegrown orthopedic surgical robot to the market. By the end of last year, the company's robots had been used in more than 20,000 orthopedic surgeries in China.

China has an average of 20 million bone injury cases annually, with almost four out of five requiring surgical treatment, according to an article published by the renowned medical science journal Nature in 2020. These injuries usually involve complicated structures deep inside the body.

Traditional bone surgeries typically demand a high degree of steady surgical experience, as well as force control and a clear view of the injuries. In such cases, the need for deep incisions and exposure to multiple X-rays may elevate medical risks. Tinavi said its robots aim to apply minimally invasive orthopedic solutions to these difficulties.

Tian, who is now an academician at the Chinese Academy of Sciences, said it is notable that midsized hospitals in China are more eager to buy orthopedic surgery robots than large hospitals.

"In the past, midsized hospitals did not dare to perform operations that were very sophisticated, and they would recommend patients transfer to large hospitals. But now, surgical robots are able to provide a great deal of assistance in carrying out such surgeries," Tian said.

In December, Tinavi's TiRobot II, a robotics-guided orthopedic surgical system, obtained a Canadian Standards Association (CSA) certificate, which the company said made it the first orthopedic surgical robot from China with technology qualified for entry into the North American market.

The CSA is a not-for-profit membership-based association based in Toronto. It develops consensus standards to help protect the health and safety of Canadians and is also recognized around the world.

The robotics-guided orthopedic surgical system is applied in trauma surgery on the cervical spine, thorax, lumbar area, sacrum, pelvis and limbs. It was certified in accordance with the latest industrial standards, including product safety regulations, medical software, availability and specialized standard of robot performance, the company said.

"The surgical robot's complexity is an aggregation of many modern high-tech elements," said Ge Yanqing, vice-president of the Canadian Standards Association Group. "The surgical robot is more technologically sophisticated and precise, with higher added value, than other robots. In China, surgical robots have been applied to orthopedics, neurosurgery, cardiac surgery, gynecology and other operations."

Xu Jin, CEO of Tinavi, said it is well known that medical standards and requirements in North America are among the strictest in the world. "Therefore, the CSA Group certificate is a recognition of the company's techniques and quality, and may pave the way for Tinavi to obtain necessary approvals to enter the international market," Xu said.

Huang Junhui, secretary of the board of directors at Tinavi, said the CSA certification is equivalent to a prerequisite for submitting an application to the United States Food and Drug Administration.

"The CSA is a certification body recognized by the FDA. After this certification, we have the qualifications to apply to the FDA."

Tinavi, founded in 2006, holds over 100 patents, the company said. It was listed on the Science and Technology Innovation Board of the Shanghai Stock Exchange in July 2020 and became the first listed medical robot enterprise in China, raising about 448 million yuan ($66.5 million).

This year, a new integrated surgical treatment called Viper Prime&TiRobot was launched on the market. This new product was jointly developed by US healthcare giant Johnson & Johnson and Tinavi, and it has integrated TiRobot and Viper Prime, an advanced, minimally invasive implant system of Johnson& Johnson. The companies said it provides surgeons with efficient and intelligent services and will benefit more patients with spinal problems.

The move marked the latest step in cooperation between Johnson &Johnson and Tinavi. In October 2019, the two sides signed an agreement on business and research cooperation.
 

Wuhun

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In 2012, Huazhong University of Science and Technology (Wuhan) developed a cold rubidium atom interferometry with vibration isolator with resolution comparable state-of-the-art cold atom gravimeters

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Since then, China has been the World leader in cold atom interferometry tech with only two competitors, i.e. America and France.

In the same year, CNRS/France reported the first operation of an airborne atom interferometer

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Huazhong team developed an 87Rb atom interferometer using stimulated Raman transitions. They added a 2D magneto-optical trap to increase the atom number and improve the detection signal-to-noise ratio, and a better optical phase-locked system to reduce the phase noise. Sensitivity of ~ 4.2 μGal/√Hz was reached.

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In the same year Sandia/America broke the record
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2014

CNRS/France reported the best sensitivity without any ground based vibration isolation system in an underground expt.
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Huazhong achieved sensitivity of 67 μGal/√Hz, they reclaimed the lead.

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NIST+PTB (Germany) - Transportable strontium optical clock

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2015


Huazhong - Uncertainty of gravity measurements contributed by the single-photon shift corrected
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2016


CNRS/France reported highest rotation stability
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Huazhong reported the first ever test of the Universality of Free Fall with atoms in different spin orientations,
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2017

UC Berkley + Zhejiang demonstrated multi-axis atom interferometry with a single-diode laser that can do all functions like atom trapping, interferometry, and detection. With rotation sensitivity 300 μrad/s/√Hz.
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2018

Chinese Academy of Science – World’s first In-orbit operation of an atomic clock based on laser-cooled 87Rb atoms;
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Chinese Academy of Science designed a compact portable laser system for cold atom interferometers. The laser system was mounted on a single module, and experiencing 1200-km-long truck transportation.
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In the same year, they achieved sensitivity = 230 μGal/√Hz, World’s highest. This time the laser system only contained one 780 nm seed laser, and stimulated beams coupled with pair of cooling beams by using a liquid crystal based polarization control.

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National Institute of Metrology (Beijing) also reached sensitivity of 44 μGal/√Hz.

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UC Berkeley used atom interferometry with a cloud of cesium atoms to successfully measure quantum electrodynamics.

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2019

Zhejiang University and Zhejiang University of Technology achieved sensitivity = 300 μGal/√Hz, World’s highest.
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NIST/ University of Colorado - Single-Source Multi-axis Cold-Atom Interferometer in a Centimeter-Scale Cell;

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2020

Chinese Academy of Science - External-cavity diode laser (ECDL) for space based strontium optical clock

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2021

Huazhong - Car-based portable cold atom interferometry; Sensitivity = 1.9 mGal/√Hz

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Huazhong – 3D position of an atomic cloud;
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National University of Defense Technology (Changsha) - Vibration isolation system

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2022

Naval University of Engineering (Wuhan) - Underwater based vibration isolation system;

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ONERA/France – Moving aircraft/ship based cold atom interferometry;

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Huazhong – World’s highest rotation sensitivity = 40 nrad/√Hz; an improvement on the sensitivity by factor of 32, paves the way to study the Earth’s crust with a quantum sensor.

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Huazhong – Aircraft/ship based cold atom interferometry with first ever vibration noise suppression factor >50.
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UC Berkeley (3/6 Chinese) - Aircraft based cold atom interferometry; Sensitivity = 37 Gal/Hz; Sensor payload = 100-150 Kg.
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Chinese Academy of Science - Cold atom interferometry with highest level of compactness; sensor volume<100 liter.
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SAST+Huazhong+Nanhang – Space-borne Atom-Interferometry; sensitivity of 1.9 mE/Hz1/2 ; accuracy of 0.2 cm@100 km.
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National University of Defense Technology (Changsha) -
Estimating the uncertainty of an atom gravimeter;
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Large-scale cold atom interferometer –

China – Chines Academy of Science; Wuhan based;
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America – Stanford + Johns Hopkins + Fermi Lab + Northwestern + Oxford + Cambridge


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France – CNRS -
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Overbom

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A great achievement for human civilisation
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China’s court AI reaches every corner of justice system, advising judges and streamlining punishment​

“The smart court SoS (system of systems) now connects to the desk of every working judge across the country,” said Xu Jianfeng, director of the supreme court’s information centre in a report published on Tuesday in Strategic Study of CAE, an official journal run by the Chinese Academy of Engineering.
The system, powered by machine learning technology, automatically screens court cases for references, recommends laws and regulations, drafts legal documents and alters perceived human errors, if any, in a verdict.
The journal report said AI had cut a judge’s average workload by over a third, and saved Chinese citizens 1.7 billion working hours from 2019 to 2021.
It also said society had saved more than 300 billion yuan (US$45 billion) during the same period – equal to about half of total lawyers’ fees in China last year.
As an unprecedented engineering project, “the wide application of the smart court system has made a significant contribution to the judicial advancement of human civilisation”, Xu and his colleagues said.

When starting six years ago, the smart court system served merely as a database. But in recent years it has been used more in the decision-making process.
As required by the supreme court, a judge must consult AI on every case. If the judge rejects the machine’s recommendation, the machine demands a written explanation for records and auditing.
But for the supreme court, AI delivers the rule of law to a great part of China, where there are significant differences in regional development, governance and income.
According to the supreme court report, the AI reads, analyses and learns from nearly 100,000 cases across the nation every day while keeping an eye on the progress of every case for any hints of malpractice or corruption.
Verdict enforcement has long been an issue for Chinese courts which have been deemed lacking in manpower. The court’s AI addresses it by finding and seizing the property of a convict almost instantly and putting it up for online auction.
 

SanWenYu

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Meanwhile this is how judges behave in a certain country:

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In that same country:
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Judge grew more brazen, prosecutor says Use of sex toy called more frequent as time passed without complaints.​

Donald Thompson, who retired last year, used a device called a penis pump infrequently at first, "and only during witness testimony, special prosecutor Pattye High told a judge during a pretrial hearing.

By 2003, the episodes had become frequent, "and when no one was testifying, High said, repeating testimony expected next week during Thompson's trial.

"As he became more and more comfortable that no one was going to say anything about this, he became more and more brazen, High said.
Instead, it shows that Thompson masturbated in court "over and over and over again. ... It is a continuing course of conduct, she said.
 
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