Channel Coding at Finite Blocklength and Its Application in 6G URLLC

To support mission-critical applications, such as factory automation and autonomous driving, the ultra-reliable low latency communications (URLLC) is adopted in the fifth generation (5G) mobile communications network, which requires high level of reliability and low latency. Naturally, URLLC in the future 6G is expected to have a better capability than its 5G version which poses an unprecedented challenge to us. Fortunately, the potential solution can still be found in the well-known classical Shannon information theory. Since the latency constraint can be represented equivalently by blocklength, channel coding at finite blocklength plays an important role in the theoretic analysis of URLLC. Applying these achievements in rapidly development of massive MIMO techniques gives rise to a new theory on space time exchanging. It tells us that channel coding can also be performed in space domain, since it is capable of providing the same coding rate as that in time domain. This space time exchanging theory points out an exciting and feasible direction for us to further reduce latency in 6G URLLC. .

Recent Progress in Surface Integrity Research and Development

1.Introduction Surface integrity has great significance for the quality and performance of machined components,and has therefore been increasingly recognized by industry.In particular,within certain industries that require high reliability,such as the aerospace industry,surface integrity is one of the most relevant indexes used to evaluate the quality of machined parts.Thus,obtaining updated knowledge on surface integrity is of great interest to both the academic community and industry[1].

9,10-二羟基硬脂酸钠的性能研究

以油酸为原料,双氧水为氧化剂采用一锅法合成了9, 10-二羟基硬脂酸钠(SDHS),该合成方法效率高、污染小,产物结构经核磁与质谱表征,产物纯度经气相色谱和液相色谱确定。研究了SDHS在表面张力、乳化、泡沫、润湿、去污等方面的性能。结果表明,SDHS的纯度较高且表面活性较好,可以在低浓度下稳定O/W乳状液;SDHS是一类低泡型表面活性剂且泡沫稳定性较差;SDHS具有良好的润湿性能和较好的去污性能,适用于洗涤类产品配方中。

Analysis of Style of Rockery Building and Stone Stacking Technique in the Royal Garden of the Song Dynasty: A Case Study of Genyue Royal Garden

Rockery building and stone stacking is a technique commonly used in building of classical gardens.Its emergence allows the fairy thought of"one pond and three mountains"to be reflected in different classical gardens.In the Northern Song Dynasty,the style of rockery building and stone stacking in the royal garden was an artistic climax in the history of the garden,and the technique of rockery building and stone stacking in Genyue Royal Garden was considered as the beginning of specialization.Through sorting out the records of the royal gardens in the Song Dynasty,this paper summarized the content of studying the royal gardens of the Song Dynasty,and systematically sorted out the development history of the techniques and styles of the royal gardens of the Song Dynasty and applied them into construction of some gardens.

Source-specific risk assessment for cadmium in wheat and maize:Towards an enrichment model for China

Cadmium (Cd) pollution of agricultural soil is of public concern due to its high potential toxicity and mobility.This study aimed to reveal the risk of Cd accumulation in soil and wheat/maize systems,with a specific focus on the source-specific ecological risk,human health risk and Cd enrichment model.For this we investigated more than 6100 paired soil and grain samples with 216 datasets including soil Cd contents,soil pH and grain Cd contents of 85 sites from China.The results showed that mining activities,sewage irrigation,industrial activities and agricultural practices were the critical factors causing Cd accumulation in wheat and maize cultivated sites.Thereinto,mining activities contributed to a higher Cd accumulation risk in the southwest China and Middle Yellow River regions;sewage irrigation influenced the Cd accumulation in the North China Plain.In addition,the investigated sites were classified into different categories by comparing their soil and grain Cd contents with the Chinese soil screening values and food safety values,respectively.Cd enrichment models were developed to predict the Cd levels in wheat and maize grains.The results showed that the models exhibited a good performance for predicting the grain Cd contents among safe and warning sites of wheat (R2=0.61 and 0.72,respectively);while the well-fitted model for maize was prone to the overestimated sites (R2=0.77).This study will provide national viewpoints for the risk assessments and prediction of Cd accumulation in soil and wheat/maize systems.

Tribological behaviour of fused deposition modelling printed short carbon fibre reinforced nylon composites with surface textures under dry and water lubricated conditions

Fused deposition modelling(FDM)printed short carbon fibre reinforced nylon(SCFRN)composites were fabricated.The friction and wear behaviour of printed materials were systematically investigated under both dry sliding and water lubricated conditions.The results showed that with short fibre enhancements,the printed SCFRN achieved a lower friction coefficient and higher wear resistance than nylon under all tested conditions.Further,under water lubricated conditions,the printed SCFRN exhibited a low,stable friction coefficient due to the cooling and lubricating effects of water.However,the specific wear rate of the printed specimens could be higher than that obtained under dry sliding conditions,especially when the load was relatively low.The square textured surface was designed and created in the printing process to improve materials’tribological performance.It was found that with the textured surface,the wear resistance of the printed SCFRN was improved under dry sliding conditions,which could be explained by the debris collection or cleaning effect of surface texture.However,such a cleaning effect was less noticeable under lubricated conditions,as the liquid could clean the surface effectively.On the other hand,surface textures could increase the surface area exposed to water,causing surface softening due to the higher water absorption rate.As a result,the samples having surface textures showed higher wear rates under lubricated conditions.The work has provided new insights into designing wear resistant polymer materials using three-dimensional(3D)printing technologies,subjected to different sliding conditions.