A Trove of Masterpieces

The special exhibition“The Greats of Six Centuries:Masterpieces from the Museo Nacional Thyssen-Bornemisza,”held in Shanghai provides profound insight into the evolution of Western culture,lifestyle,and social landscapes over the 600 years.

Experimental Study on Entropy Features in Machining Vibrations of A Thin-Walled Tubular Workpiece

In machining processes,chatter vibrations are always regarded as one of the major limitations for production quality and efficiency.Accurate and timely monitoring of chatter is helpful to maintain stable machining operations.At present,most chatter monitoring methods are based on the energy level at specified chatter frequencies or frequency bands.However,the spectral features of chatter could change during machining operations due to complexity and time-varying dynamics of the physical machining process.The purpose of this paper is to investigate the time-varying chatter features in turning of thin-walled tubular workpieces from the perspective of entropy.The airborne acoustics was selected as the source of information for machining condition monitoring.First,corresponding to the distinguishing surface topographies relevant to machining conditions,the features of the sound signal emitted during turning of the thin-walled cylindrical workpieces were extracted using the spectral analysis and wavelet packet transform,respectively.It was shown that the dominant vibration frequency as well as the energy distribution could shift with the transition of the machining status.After that,two relative entropy indicators based on the spectrum and the wavelet packet energy were constructed to identify chattering events in turning of the thin-walled tubes.The experimental results demonstrate that the proposed indicators could accurately reflect the transition of machining conditions with high sensitivity and robustness in comparison with the traditional FFT-based methods.The achievement of this study lays the foundations of the online chatter monitoring and control technique for turning of the thin-walled tubular workpieces.

Study on Problems and Countermeasures in the Management of Spot Check of Chinese Herbal Pieces

Objective To provide suggestions for optimizing the sampling management of Chinese herbal pieces and improving the quality Chinese herbal pieces.Methods Logical reasoning method was used to analyze the problems in the drug spot check of Chinese herbal pieces based on the data of drug quality published by the National Medical Products Administration from 2013 to 2021,combined with the current provisions and implementation of drug spot check management in China.Results and Conclusion At present,there are some problems in the drug spot check of Chinese herbal pieces,such as fewer varieties of Chinese herbal pieces in the national drug spot check,the unreasonable sampling links,the insufficient territorial management in some areas,and error-prone sample extraction.It is suggested that the actual quantity and overall quality of Chinese herbal pieces should be fully considered in the formulation of sampling plan.Besides,the variety coverage of drug spot check of traditional Chinese medicine should be strengthened.In the planning,the sampling links shall be made as a whole,and the credit rating and distribution of drug production,operation and use units within the jurisdiction shall be fully combined.While strengthening the sampling management at the production end in areas with concentrated industries,regional special drug spot check should be carried out or the administrative forces at the provincial,municipal and county levels should be fully mobilized to avoid local protection.In the assigned tasks,the name of Chinese herbal pieces should be accurately expressed to avoid the sampling errors of Chinese herbal pieces with the same original medicinal materials and different processing methods.

Treasures in the Museum

This is the armor bestowed by the emperor of the Yuan Dynasty to the leader of Sagya sect in Xizang.It is composed of a helmet and an armor.With a chest circumference of 112 cm and a length of 8o cm,the armor is formed by more than 1,000 pieces of iron armor woven and connected together with leather laces.This set of armor illustrates the relationship between the central court of the Yuan Dynasty and the local authority of Xizang,and serves as a testament to the unity of the country during the Yuan Dynasty.

旅行,探索世界的美

第一部分语言基础(共两节,满分24分)第一节单句填空(共15小题;每小题1分,满分15分)1. One interesting aspect of this bilingual series is that it caters to both the domestic and foreign markets, especially in reading for both____(pleasant) and language learning.2. As is known to us,____(curtain) are large pieces of material which hang from the top of a window.

针对BitTorrent协议中Piece消息的隐写分析方法

网络隐写是当前网络攻击中常见的一种隐蔽通信方式,给网络安全造成了极大隐患。BitTorrent网络作为一种使用极为广泛的协议,拥有巨大流量,是隐藏信息的极佳载体。近来,有研究者提出了一种基于Piece消息的网络隐写方法,公开文献中尚无有效的检测算法。针对此,提出一种基于多特征分类的检测方法。提取正常和含密Piece消息数据流;提取网络数据流时间序列的均值、方差与信息熵特征;使用SVM分类器给出检测结果。实验结果显示,在观测窗口为1000个数据包时,该方法对基于Piece消息隐写的检测率可达94.7%。

FPSO船体结构建造Piece Mark进度报表开发与应用

本文针对国外业主对Piece Mark表的提交需求,结合海洋石油工程股份有限公司的PCMS系统,采用VSTO编程技术,对该进度报表进行了研究和开发,并在某国外FPSO船体建造项目中进行了应用。

Torsional vibration analysis of lathe spindle system with unbalanced workpiece

For the purpose of analyzing the torsional vibration caused by the gravitational unbalance torque arisen in a spindle system when it is machining heavy work piece,a 10-DOF lumped parameter model was made for the machine tool spindle system with geared transmission.By using the elementary method and Runge-Kutta method in Matlab,the eigenvalue problem was solved and the pure torsional vibration responses were obtained and examined.The results show that the spindle system cannot operate in the desired constant rotating speed as far as the gravitational unbalance torque is engaged,so it may cause bad effect on machining accuracy.And the torsional vibration increases infinitely near the resonant frequencies,so the spindle system cannot operate normally during these spindle speed ranges.

Identification of Kinematic Errors of Five-axis Machine Tool Trunnion Axis from Finished Test Piece

Compared with the traditional non-cutting measurement,machining tests can more accurately reflect the kinematic errors of five-axis machine tools in the actual machining process for the users.However,measurement and calculation of the machining tests in the literature are quite difficult and time-consuming.A new method of the machining tests for the trunnion axis of five-axis machine tool is proposed.Firstly,a simple mathematical model of the cradle-type five-axis machine tool was established by optimizing the coordinate system settings based on robot kinematics.Then,the machining tests based on error-sensitive directions were proposed to identify the kinematic errors of the trunnion axis of cradle-type five-axis machine tool.By adopting the error-sensitive vectors in the matrix calculation,the functional relationship equations between the machining errors of the test piece in the error-sensitive directions and the kinematic errors of C-axis and A-axis of five-axis machine tool rotary table was established based on the model of the kinematic errors.According to our previous work,the kinematic errors of C-axis can be treated as the known quantities,and the kinematic errors of A-axis can be obtained from the equations.This method was tested in Mikron UCP600 vertical machining center.The machining errors in the error-sensitive directions can be obtained by CMM inspection from the finished test piece to identify the kinematic errors of five-axis machine tool trunnion axis.Experimental results demonstrated that the proposed method can reduce the complexity,cost,and the time consumed substantially,and has a wider applicability.This paper proposes a new method of the machining tests for the trunnion axis of five-axis machine tool.

A Dual-Platform Laser Scanner for 3D Reconstruction of Dental Pieces

This paper presents a dual-platform scanner for dental reconstruction based on a three-dimensional(3D)laser-scanning method.The scanner combines translation and rotation platforms to perform a holistic scanning.A hybrid calibration method for laser scanning is proposed to improve convenience and precision.This method includes an integrative method for data collection and a hybrid algorithm for data processing.The integrative method conveniently collects a substantial number of calibrating points with a stepped gauge and a pattern for both the translation and rotation scans.The hybrid algorithm,which consists of a basic model and a compensation network,achieves strong stability with a small degree of errors.The experiments verified the hybrid calibration method and the scanner application for the measurement of dental pieces.Two typical dental pieces were measured,and the experimental results demonstrated the validity of the measurement that was performed using the dual-platform scanner.This method is effective for the 3D reconstruction of dental pieces,as well as that of objects with irregular shapes in engineering fields.

Surface Magnet Gears with a New Magnet Arrangement and Optimal Shape of Stationary Pole Pieces

In mechanical gear systems, dust, noise, vibration, and tooth wear are generated by frictions among gear teeth, and suppressing friction requires lubrication. Magnetic gears transmit torque by magnetic forces without contact and so avoid contact-related problems. The present paper discusses magnet arrangements and the shape of stationary gear teeth to improve transmission torque in surface magnet type magnetic gear transmission mechanisms.

“a piece of+名词”与其修饰语

在“a piece of+名词”结构中,作修饰语的形容词出现在piece 之前与出现在名词之前这两种情况都有。例如: a piece of good luck;a piece of bad news 与 a finepiece of work;a delicate piece of mechanism 等等。还可以举出许多例子。那么,这是否就等于说该结构中的形容词可以任意放在上述两个位置中的一个上呢?也不尽然。笔者查阅了若干词典。

Ocular hypertension secondary to obesity: cortisol, the missing piece of the pathophysiological puzzle?

Dear Editor,Obesity has nowadays become a global public health challenge due to its rapidly growing prevalence and interconnection with a wide spectrum of comorbidities.

Ten Years Dedication Blossom on the Delicate Piece——Ordifen Cup 2014 China Lingerie Design ContestLaunches in Beijing

In the afternoon of October 29th,2014,Ordifen Cup 2014 China Lingerie Design Contest unveiled during China Fashion Week.Jointly held by China Fashion Association and Ordifen International Group,the contest presented us a grand feast with the essence of Ordifen’s ten years dedication.Tiny but delicate,the lingerie condenses the charisma of both culture and fashion in the small piece of cloth.Time goes so fast all in the blink of an eye.

A systematic review and meta-analysis to compare the effects of Chinese herbal pieces and granule in different diseaseherbal pieces

Objective:Compared to Chinese herbal piecesherbal pieces,the quality of TCM granule is stable and controllable,it is also a convenient alternative to decocting herbs.However,whether they are as clinically effective as Chinese herbal piecesherbal pieces is still controversial.In this study,a systematic review and meta-analysis were performed to assess the clinical efficacy of TCM granules and Chinese herbal piecesherbal pieces.Methods:A search of online databases for eligible articles was performed,including PubMed,Embase,Cochrane Library,Web of Science,China National Knowledge Internet,WanFang,and Chongqing VIP Information,searching from the inception of these databases to 2020.The Cochrane Handbook 5.1.0 was used to independently identify the trials,extract data,and assess the risk of bias.The meta-analysis was performed via RevMan 5.3 software.Results:A total of 98 eligible articles were included.After classification and statistical analysis of the related diseases,a meta-analysis was performed on 8 types of illnesses(cold,hypertension,migraine,osteoporosis,and diseases of the digestive system,such as gastritis,gastric ulcer,colitis,epigastric pain)included in 66 randomized controlled trials to compare the clinical efficacy and adverse events of TCM granules and Chinese herbal pieces.Meta-analysis showed that compared with Chinese herbal piecesherbal pieces,TCM granules had similar effectiveness and safety in treating cold,hypertension,and osteoporosis,but a higher response rate in migraines and a better effect in reducing migraine duration and higher response rate on diseases of the digestive system.Conclusion:Compared with the traditional decoctions,TCM formula granules had the same efficacy and safety,moreover,they had higher efficacy and safety in treating migraines and digestive system diseases.

Considerations in the management of single-piece intraocular lenses outside the capsular bag

AIM: To investigate the outcomes of off label singlepiece acrylic intraocular lenses(SPA-IOL) ciliary sulcus placement compared to three-piece IOL(3P-IOL). METHODS: The charts of eight consecutive eyes of patients who received sulcus-placed SPA-IOLs between 2006 and 2009 were reviewed. None of the patients underwent IOL exchange. Charts of six age-matched patients who received sulcus placed 3P-IOLs were reviewed as a control group. RESULTS: Mean follow up was 16 mo for SPA-IOL and 23 mo for 3P-IOL. Five of 8 patients in the SPA-IOL group required chronic use of IOP lowering medications at final follow up. Of these, one patient needed glaucoma implant surgery for uncontrolled IOP. One patient in the 3P-IOL group used chronic aqueous suppression pre- and postoperatively. Four of eight eyes with SPAIOL were treated with chronic topical steroids and or non-steroidal anti-inflammatory drugs for cystoid macu-la edema, chronic uveitis, pigment dispersion syndrome or a combination of the above, compared to none in the control group. Mean best-corrected visual acuity was 20/35 in the SPA-IOL group and 20/47 in the 3PIOL group.CONCLUSION: Sulcus placed SPA-IOLs are associated with increased ocular morbidity. In select cases good visual acuity may be achieved. Due to postoperative rotation of sulcus placed toric SPA-IOLs stable astigmatism correction cannot be achieved. Alternative intraocular lenses should be considered when in-the-bag placement of SPA-IOL is not possible.

Single Piece Dental Implant: A Remedy for Atrophic Ridges: Review

Implant placement in severely atrophic jaws is especially challenging because of the poor quality and quantity of the future implant bed. Although various bone augmentation procedure like ridge augmentation, sinus lift these procedures are possible today but it may lead to surgical morbidity they increase the risks and costs of dental implant treatment as well as the number of necessary operations. Also sometimes the patient is not agreeing for such extensive surgical procedures, according to the well-known implantological rules for dental restorations, crestal implants are indicated in situations when an adequate vertical bone supply is given but single piece dental implant (basal implants) is a viable treatment option derives support from the basal bone area which usually remains free from the infection and less prone to resorption.

寻找日本连载动画《One Piece》成功的钥匙

《One Piece》又名《海贼王》,于1997年开始连载以来,其影响力不容小觑,被誉为日本三大国民动漫之一。这是一部连载超过十年的动画作品,本文试从创作者、叙事、文化、配乐等方面浅析《One Piece》成功的原因。

The analysis of structural complexity of Piano Pieces ＂dedicated to Alice＂

Beethoven is a famous German pianist, composer, and conductor, and he set the culmination of Western classical, created a romantic music camp precedent. The size of his music in general is very ambitious, mostly concertos, symphonies, operas and other large works, technical approach and structure used is quite complex, people are left with a deep impression. But it works, while small piano pieces, also has music research value, ＂dedicated to Alice＂ is one of the few Beethoven piano pieces. This paper focuses on creative background ＂dedicated to Alice,＂ this elaborate piano works by the complexity of the analysis of the structure of this work is that it reflects the author＇ s ideological soul to explore their musical value.