美国遏制中国应用程序的策略及其影响

中国应用程序近年来在美国市场迅猛发展,同时也在该国引发诸多争议。自特朗普执政以来,美国基于“国家安全关切”对在美运营的中国应用程序开展评估,并推动一系列限制性措施。具体而言,美国遏制中国应用程序的策略围绕“政策限制”“法律规制”“舆论抵制”的主线展开,是美国以“全政府”“全社会”组织模式诉诸对华战略竞争的集中体现。美国系统性遏制中国应用程序的背后,存在科技竞争、资源竞争、经济竞争与叙事竞争四种相互关联的逻辑。美国遏制中国应用程序是美国对华“科技战”的重要一环,此举不仅在美国国内引发了广泛争议,导致中美关系“过度安全化”,同时也进一步加剧了全球数据流动的碎片化态势。

A Review of Comminution Age Method and Its Potential Application in the East China Sea to Constrain the Time Scale of Sediment Source-to-Sink Process

The East China Sea(ECS) is a river-dominated epicontinental sea, linking the Asian continent to the northwestern Pacific via the large rivers originating from Tibetan Plateau. The relevant huge influx of riverine detritus has developed unique sedimentary systems in the ECS during the Quaternary, offering ideal terrestrial archives for reconstructing Quaternary paleoenvironmental changes and studying land-sea interactions. Overall, two characteristic river systems dominate the sedimentary systems and sediment source to sink transport patterns in the ECS, represented by the Changjiang(Yangtze River) and Huanghe(Yellow River) for the large river system and Taiwan rivers for the small river system. Given this, the sediments derived from both river systems bear distinct features in terms of parent rock lithology, provenance weathering and sediment transport. Previous studies mostly focus on either the ‘source' discrimination or the ‘sink' records of the sedimentary system in the ECS, while the source to sink process linking the land and sea, in particular its time scale, has been poorly understood. Here we introduce a newly-developed dating technique, the ‘comminution age' method, which offers a quantitative constraint on the time scale of sediment transfer from its ultimate source to the final depositional sink. This novel method is of great significance for improving our understanding on the earth surface processes including tectonic-climate driven weathering, and sediment recycling in relation to landscape evolution and marine environmental changes. The application of comminution age method in the ECS will provide important constraints on sediment source-to-sink process and more evidences for the construction of late Quaternary paleoenvironmental changes under these unique sedimentary systems.

Application of coal mine roof rating in Chinese coal mines

The coal mine roof rating(CMRR) is a measure of roof quality or structure competency for bedded roof types typically of underground coal mines. The CMRR has been used widely in the US, South Africa,Canada and Australia. In order to investigate the application of the CMRR system in Chinese coal mines,two coal mines in China located in Panjiang Coal Field in Guizhou Province were investigated. Field data were collected which is required to calculate the CMRR value based on underground exposure. The CMRR values of 11 locations in two coal mines were calculated. The investigations demonstrated that the chance of mine roof failure is very low if the CMRR value is more than 50, given adequate support is installed in mine. It was found that the CMRR guideline are useful to preliminarily investigate stability in Panjiang Coal Field mines.

Effects of a symptom management intervention based on group sessions combined with a mobile health application for persons living with HIV in China:A randomized controlled trial

Objective:This study aims to evaluate the effects of a symptom management intervention(SMI)based on symptom management group sessions combined with a mobile health(mHealth)application(app)on the knowledge of symptom management,the certainty of symptom self-management,symptom severity,symptom distress,medication adherence,social support,and quality of life among persons living with HIV(PLWH)in China.Methods:A parallel randomized controlled trial with 61 PLWH was conducted in Shanghai,China.The participants in the control group(n¼30)downloaded the Symptom Management(SM)app according to their needs and preferences,and received routine follow-ups.The participants in the intervention group(n¼31)were guided to download and use the SM app,and received four tailored weekly group sessions at routine follow-ups.Each group session lasted for approximately 2 h and targeted one of the major modules of the SM app.All the outcomes were assessed at baseline and post-intervention.The study was registered with the Chinese Clinical Trial Registry(ChiCTR1900024821).Results:The symptom management knowledge and certainty of symptom self-management were significantly improved after the intervention(all P<0.01).Compared with the control group,the scores of symptoms reasons knowledge score improved 11.47 points(95%CI:3.41,19.53)and scores of symptoms self-management knowledge score improved 12.80 points(95%CI:4.55,21.05)in the intervention group after controlling for covariates.However,other outcomes did not show statistically significant differences between the intervention group and the control group(P>0.05).Conclusion:The SMI could improve PLWH’s symptom management knowledge and certainty of symptom self-management.Multi-center studies with larger sample sizes and longer follow-ups are needed to further understand the effects of SM app on ameliorating symptom severity and symptom distress.More innovative strategies are also needed to promote and maintain the sustainability of the SM app.

Using Multi-destination ZTCM to Evaluate the Recreational Values of Cultural Sights:an Application to Jiayuguan,China

This study explained the importance of environmental protection in tourism development and illustrated the relationship between recreational resource valuation and environmental consideration.We compare different models of travel cost method and reiterates long-time existing problems of multi-destination and treats of time opportunity cost(TOC).Taking Jiayuguan's cultural sights as an example,we establish an updated method called multidestination zonal tourism cost method to evaluate the recreational values(RVs) of selected three cultural sights.We divide trip packages of Jiayuguan's tourists into 11 portfolios.Each portfolio can be seen as a separate commodity,and each commodity has its own demand curve.According to demand curves we can calculate consumer surplus(CS) of different portfolios of tourist destinations and later we sum up the total travel costs(including travel expenditure and TOC) and CS to come to the RVs of each portfolio.We then apply suitable proportions to calculate the RVs between different destinations in the portfolio.In the end,we add up all the RVs calculated for the objective destination.Using this method,we draw conclusions that Jiayuguan's RV in 2006 includes national and international values,summing up to 738.4762 million yuan.The tourist expenditure,CS and TOC of Jiayuguan is proportionating 62.96,32.28 and 4.76%,respectively.This study is also an example of non-market valuation of cultural tourism resources.

Advances in alternating electromagnetic field data processing for earthquake monitoring in China

The alternating electromagnetic(EM) field is one of the most sensitive physical fields related to earthquakes. There have been a number of publications reporting EM anomalies associated with earthquakes. With increasing applications and research of artificial-source extremely low frequency EM and satellite EM technologies in earthquake studies, the amount of observed data from the alternating EM method increases rapidly and exponentially, so it is imperative to develop suitable and effective methods for processing and analyzing the influx of big data. This paper presents research on the self-adaptive filter and wavelet techniques and their applications to analyzing EM data obtained from ground measurements and satellite observations, respectively. Analysis results show that the self-adaptive filter method can identify both natural- and artificial-source EM signals, and enhance the ratio between signal and noise of EM field spectra, apparent resistivity, and others. The wavelet analysis is capable of detecting possible correlation between EM anomalies and seismic events. These techniques are effective in processing and analyzing massive data obtained from EM observations.

Chinese brushes： From controllable liquid manipulation to template-free printing microlines

As a traditional writing instrument for calligraphy and painting, the Chinese brush has enjoyed a high reputation over the last 5,000 years due to its ability to controllably handle liquid ink, and has been widely used to deposit ink into certain characters or figures as a means of cultural communication. In this mini-review, we first show how the key to the controllable liquid transfer in a Chinese brush lies in the anisotropic multi-scale structural features of the freshly emergent hairs. Then, drawing inspiration from this, applications in controllable liquid pumping, highly efficient liquid transfer and template-free printing microlines are addressed. We envision that the fundamentals of Chinese brushes and their applications in liquid manipulation mentioned in this review may also be extended to other liquid phase functional material systems.

A novel procedure for pollen-based quantitative paleoclimate reconstructions and its application in China

Traditionally, the evaluation of pollen-based quantitative paleoclimate reconstructions focuses on the ability of calibration sets to infer present climatic conditions and/or the similarity between fossil and modem assemblages. Objective criteria for choosing the most appropriate climate parameter（s） to be reconstructed at a specific site are thus lacking. Using a novel approach for testing the statistical significance of a quantitative reconstruction using random environmental data, in combination with the advantageous large environmental gradients, abundant vegetation types and comprehensive modem pollen databases in China, we describe a new procedure for pollen-based quantitative paleoclimatic reconstructions. First, the most significant environmental variable controlling the fossil pollen assemblage changes is identified. Second, a calibration set to infer changes in this targeted variable is built up, by limiting the modem ranges of other environmental variables. Finally, the pollen-based quantitative reconstruction is obtained and its statistical significance assessed. This novel procedure was used to reconstruct the mean annual precipitation （Pann） from Gonghai Lake in the Lvliang Mountains, and Tianchi Lake in the Liupan Mountains, on the eastern and western fringe of the Chinese Loess Plateau, respectively. Both Pann. reconstructions are statistically significant （p〈0.001）, and a sound and stable correlation relationship exists in their common period, showing a rapid precipitation decrease since 3300 cal yr BP. Thus, we propose that this procedure has great potential for reducing the uncertainties associated with pollen-based quantitative paleoclimatic reconstructions in China.