Non-crossing Quantile Regression Neural Network as a Calibration Tool for Ensemble Weather Forecasts

Despite the maturity of ensemble numerical weather prediction(NWP),the resulting forecasts are still,more often than not,under-dispersed.As such,forecast calibration tools have become popular.Among those tools,quantile regression(QR)is highly competitive in terms of both flexibility and predictive performance.Nevertheless,a long-standing problem of QR is quantile crossing,which greatly limits the interpretability of QR-calibrated forecasts.On this point,this study proposes a non-crossing quantile regression neural network(NCQRNN),for calibrating ensemble NWP forecasts into a set of reliable quantile forecasts without crossing.The overarching design principle of NCQRNN is to add on top of the conventional QRNN structure another hidden layer,which imposes a non-decreasing mapping between the combined output from nodes of the last hidden layer to the nodes of the output layer,through a triangular weight matrix with positive entries.The empirical part of the work considers a solar irradiance case study,in which four years of ensemble irradiance forecasts at seven locations,issued by the European Centre for Medium-Range Weather Forecasts,are calibrated via NCQRNN,as well as via an eclectic mix of benchmarking models,ranging from the naïve climatology to the state-of-the-art deep-learning and other non-crossing models.Formal and stringent forecast verification suggests that the forecasts post-processed via NCQRNN attain the maximum sharpness subject to calibration,amongst all competitors.Furthermore,the proposed conception to resolve quantile crossing is remarkably simple yet general,and thus has broad applicability as it can be integrated with many shallow-and deep-learning-based neural networks.

增韧水凝胶的研究进展

水凝胶由交联聚合物网络和大量水组成。与生物组织类似的结构,使得水凝胶广泛应用于人类生活和生物医药领域。但现今水凝胶的进一步应用仍然受限于其较差的力学性能。为此,文中综述了近些年科研工作者们在水凝胶增韧方面的研究进展,并从增韧机理出发,划分为杂交交联、互穿网络、高功能交联剂及其他新型体系,深入分析各种能量耗散机理。此外,还展望了水凝胶未来的增韧机理的发展方向及前景。

Xylo-oligosaccharides preparation through acid hydrolysis of hemicelluloses isolated from press-lye

The preparation of xylo-oligosaccharides(XOSs)through hydrolysis of hemicelluloses was studied.The hemicelluloses were isolated from the press lye discharged in the production of viscose,which contained about 30%xylan.Then,a factorial experimental design was applied to compare the influences of several factors including the concentrations of sulphuric acid and hemicelluloses,the duration and temperature of the hydrolysis,on the conversion of xylan,and the selectivity for the product–XOSs.The results showed that the hydrolysis duration affects the yield of XOSs to the greatest extent.It is difficult to obtain a high yield of XOSs with sulphuric acid as the hydrolysis catalyst.

Strategies of minimally invasive treatment for intrahepatic and extrahepatic bile duct stones

Cholellthiasis is a kind of common and multiple diseases. In recent years, traolttonal laparommy has been challenged by a minimally invasive surgery. Through literature review, the therapeutic method, effect, and complications of minimally invasive treatment of intrahepatic and extrahepatic bile duct stones by combining our practical experience were summarized as follows. （1） For intrahepatic bile duct stones, the operation may be selected by laparoscopie liver resection, laparoscopic common bile duct exploration （LCBDE）, or percutaneous transhepatic cholangioscopy. （2） For concomitant gallstones and common bile duct stones, the surgical approach can be selected as follows： laparoscopic cholecystectomy （LC） combined with endoscopic sphincterotomy （EST） or endoscopic papillary balloon dilatation, LC plus laparoscopic transcystic common bile duct exploration, LC plus LCBDE, and T-tube drainage or primary suture. （3） For concomitant intrahepatic and extrahepatic bile duct stones, laparoscopic liver resection, choledochoscopy through the hepatic duct orifice on the hepatectomy cross section, LCBDE, EST, and percutaneous transhepatic cholangioscopic lithotripsy could be used. According to the abovementioned principle, the minimally invasive treatment approach combined with the surgical technique and equipment condition will be significant in improving the therapeutic effect and avoiding the postoperative complications or hidden dangers of intrahepatic and extrahepatic bile duct stones.

Porous fixed-bed photoreactor for boosting C-C coupling in photocatalytic CO_(2)reduction

Solar-driven CO_(2)conversion to chemical fuels in an aqueous solution is restricted not only by photocatalysts but also by mass transfer.Here,a regulatable three-phase interface on a porous fixed-bed is constructed for efficient C-C coupling in photocatalytic CO_(2)reduction.The photocatalytic results show that∼90%selectivity towards C^(2+)products is obtained by a Cu/Cd_(0.5)Zn_(0.5)S photocatalyst,with a yield of 6.54μmol/h(an irradiation area of 0.785 cm^(2)),while only 0.94μmol/h(an irradiation area of 19.625 cm^(2))is achieved with a commonly used suspension photocatalytic reactor.We find that under the same CO_(2)feed rate,the local CO_(2)concentration in this porous fixed-bed photoreactor is obviously higher than in the suspension photoreactor.The larger local CO_(2)coverage derived from a higher CO_(2)supply and aggregation enhances the C-C coupling,thereby generating more C^(2+).Even an observable three-phase interface on the porous fixed-bed can be regulated by adjusting the CO_(2)supply,for which the optimal gas inlet rate is 5-10 sccm.

Technological innovations on direct carbon mitigation by ordered energy conversion and full resource utilization

Coal consumption leads to over 15 billion tons of global CO_(2) emissions annually,which will continue at a considerable intensity in the foreseeable future.To remove the huge amount of CO_(2),a practically feasible way of direct carbon mitigation,instead of capturing that from dilute tail gases,should be developed;as intended,we developed two innovative supporting technologies,of which the status,strengths,applications,and perspective are discussed in this paper.One is supercritical water gasification-based coal/biomass utilization technology,which orderly converts chemical energy of coal and low-grade heat into hydrogen energy,and can achieve poly-generation of steam,heat,hydrogen,power,pure CO_(2),and minerals.The other one is the renewables-powered CO_(2) reduction techniques,which uses CO_(2) as the resource for carbon-based fuel production.When combining the above two technical loops,one can achieve a full resource utilization and zero CO_(2) emission,making it a practically feasible way for China and global countries to achieve carbon neutrality while creating substantial domestic benefits of economic growth,competitiveness,well-beings,and new industries.