积碳失活催化剂的再生

催化反应常伴随着积碳的生成,而积碳又可以通过覆盖催化剂酸性位点或者堵塞催化剂孔道而引起催化剂失活,表现为产物选择性的降低.根据不同的失活机理可以将催化剂失活分为永久性失活和可逆性失活,而积碳失活一般是可逆的,可以通过再生的方式来除去积碳并恢复催化剂活性.对于工业生产而言,为了保证反应的连续运行,失活催化剂的及时再生是非常必要的.尽管前人已经做了大量的研究,并尝试不同的再生方法来除去催化剂积碳,但发展一种操作简单、高效和经济的再生方法仍然是一个巨大的挑战.目前工业催化剂积碳失活后最常用的再生手段是氧化再生,其主要以空气或氧气为再生气体,将积碳转化为一氧化碳、二氧化碳和水等.但空气或氧气氧化再生为强放热反应,放出的大量热量及生成的水蒸气会对催化剂的组分及结构带来一定的影响.虽然以臭氧和氮氧化物为再生气体可以有效降低再生温度,但是作为有毒有害气体,它们的排放受到严格的限制,这也阻碍了其进一步工业化应用.与氧化再生相比,二氧化碳或水蒸气气化再生可以有效降低再生过程中的放热量,并将无价值的积碳转化为高品质的合成气,同时减少二氧化碳的排放.但由于二氧化碳和水蒸气的氧化性较弱,需要较高的再生温度,对催化剂的水热稳定性提出了更高的要求.此外,在氢气气氛下,可以通过加氢裂解除去积碳,但同样需要较高的再生温度或压力.通过添加金属或金属氧化物等添加剂,可以有效降低再生温度并增加再生速率,但也可能会引起催化剂中毒,造成催化剂的永久性失活,所以需要严格控制添加剂的含量.本文分析了目前常用的几种再生方法的优缺点及面临的挑战,并对未来的研究重点及研究方向进行了展望.

Investigation of the oil-seawater mixed flow under an electromagnetic field

The electromagnetic separation method is a new approach to treat ship-based marine oily wastewater,in which oil droplets are dispersed in seawater(oil-seawater mixed flow).In order to clarify the separation process and determine the separation characteristics,the flow field and volume fraction of the oil droplets of the oil-seawater mixed flow under an applied electromagnetic field with different operating conditions were investigated by 2D numerical simulations with the Eulerian model.The results show that:(1)the downward Lorentz force causes seawater to flow downwards and the oil droplets to move upwards due to the electromagnetic separation force in the effective section of the separation channel;(2)the volume fraction of the oil droplets at the top of the outlet section increases with the current density,magnetic field,and the diameter of the oil droplet and decreases with the inlet velocity of the oily seawater.The results provide useful guidance for the design of electromagnetic separation devices of the oil-seawater mixed flow.

透风型挡风板不同孔隙度大小防风特性的二维数值模拟

本文通过建立二维非定常不可压N-S方程,采用变分多尺度方法对N-S方程进行求解并应用freefem软件对不同孔隙度,不同孔径的透风型挡风板在给定风场进行数值模拟。研究了不同孔隙度下,不同孔径透风型挡风板与不设挡风板及不透型挡风板对风场的影响。结果表明,挡风板具有较好的防风特性,适当孔隙度的透风型挡风板较不透型防风特性好。同时不同孔隙度挡风板对风场影响差异明显,同时相同孔隙度不同孔径挡风板也有较明显差异。在本实验意义下,孔隙度为20%孔径为0.5 cm,高度为50 cm挡风板具有较好的防风特性,在高200 cm,长为500 cm的风场中可以形成198 cm左右的板后涡流长度,形成涡流长度明显长于其他透风型挡风板。

Simulation and prediction of monthly accumulated runoff,based on several neural network models under poor data availability

Most previous research on areas with abundant rainfall shows that simulations using rainfall-runoff modes have a very high prediction accuracy and applicability when using a back-propagation(BP), feed-forward, multilayer perceptron artificial neural network(ANN). However, in runoff areas with relatively low rainfall or a dry climate, more studies are needed. In these areas—of which oasis-plain areas are a particularly good example—the existence and development of runoff depends largely on that which is generated from alpine regions. Quantitative analysis of the uncertainty of runoff simulation under climate change is the key to improving the utilization and management of water resources in arid areas. Therefore, in this context, three kinds of BP feed-forward, three-layer ANNs with similar structure were chosen as models in this paper.Taking the oasis–plain region traverse by the Qira River Basin in Xinjiang, China, as the research area, the monthly accumulated runoff of the Qira River in the next month was simulated and predicted. The results showed that the training precision of a compact wavelet neural network is low; but from the forecasting results, it could be concluded that the training algorithm can better reflect the whole law of samples. The traditional artificial neural network(TANN) model and radial basis-function neural network(RBFNN) model showed higher accuracy in the training and prediction stage. However, the TANN model, more sensitive to the selection of input variables, requires a large number of numerical simulations to determine the appropriate input variables and the number of hidden-layer neurons. Hence, The RBFNN model is more suitable for the study of such problems. And it can be extended to other similar research arid-oasis areas on the southern edge of the Kunlun Mountains and provides a reference for sustainable water-resource management of arid-oasis areas.

Digital Image Watermarking Algorithm Based on Fast Curvelet Transform

A digital image watermarking algorithm based on fast curvelet transform is proposed. Firstly, the carrier image is decomposed by fast curvelet transform, and, the watermarking image is scrambled by Arnold transform. Secondly, the binary watermarking image is embedded into the medium frequency coefficients according to the human visual characteristics and curvelet coefficients. Experiment results show that the proposed algorithm has good performance in both invisibility and security and also has good robustness against the noise, cropping, filtering, JPEG compression and other attacks.

An Adaptive Anomaly Detection Algorithm Based on CFSFDP

CFSFDP(Clustering by fast search and find of density peak)is a simple and crisp density clustering algorithm.It does not only have the advantages of density clustering algorithm,but also can find the peak of cluster automatically.However,the lack of adaptability makes it difficult to apply in intrusion detection.The new input cannot be updated in time to the existing profiles,and rebuilding profiles would waste a lot of time and computation.Therefore,an adaptive anomaly detection algorithm based on CFSFDP is proposed in this paper.By analyzing the influence of new input on center,edge and discrete points,the adaptive problem mainly focuses on processing with the generation of new cluster by new input.The improved algorithm can integrate new input into the existing clustering without changing the original profiles.Meanwhile,the improved algorithm takes the advantage of multi-core parallel computing to deal with redundant computing.A large number of experiments on intrusion detection on Android platform and KDDCUP 1999 show that the improved algorithm can update the profiles adaptively without affecting the original detection performance.Compared with the other classical algorithms,the improved algorithm based on CFSFDP has the good basic performance and more room of improvement.

Classification,Hazards and Countermeasures of Agricultural Environmental Pollution Emergencies

Agricultural environmental pollution emergencies have become a hot research topic because of the high incidence and influence depth.This paper introduces classification and features of agricultural environmental pollution emergencies:by pollutant type,it falls into organic pollution emergencies and inorganic pollution emergencies;by the approach of entering agricultural environment,it falls into water resource agricultural environmental pollution emergencies and non-water resource agricultural environmental pollution emergencies.Hazards of agricultural environmental pollution emergencies are analyzed from 4 perspectives:personal security,indirect loss,ecological environment and social stability.In view of the hazards,countermeasures are given to deal with the pollution emergencies as(i)establishing a risk evaluation mechanism for agricultural environment;(ii)enhancing the capacity of handling agricultural environmental pollution emergencies;(iii)introducing new management concepts for environmental emergencies,and cultivating keen emergency management consciousness.

Integrating Intangible Cultural Heritage into Ideological and Political Courses in Colleges and Universities

China's intangible cultural heritage as an important part and the soul of the traditional Chinese culture is the cultural treasure of China and even the world.As the concept of cultural protection is deeply rooted in the minds of people,the state attaches increasing importance to intangible cultural heritage.The unique forms of cultural expressions and the special places of these expressions are deeply rooted in the Chinese culture and they should also be an important content in China's efficient ideological and political education.This article mainly explores the significance of intangible cultural heritage in ideological and political teaching as well as the strategies to effectively integrate intangible cultural heritage into ideological and political teaching in order to achieve the educational purposes of condensing the consensus of traditional Chinese culture,enhancing the cultural consciousness among teachers and students in colleges and universities,and enhancing the patriotic enthusiasm and cultural confidence.

Comparative analysis of chemical profiles of Radix Astragali between ultrafine granular powder and sliced traditional material

Radix Astragali,one of the most popular herbs in traditional Chinese medicine(TCM),is used to strengthen the immune system,protect liver function,fight bacteria and viruses,and treat diabetes,heart failure and seasonal allergies.In recent years,a new form of Radix Astragali material processed by cell wall disrupting technology,namely ultrafine granular powder(UGP)has been introduced into the market.In order to determine chemical consistency and homogeneity of the UGP material prepared from sliced traditional materials(TM)of Radix Astragali,multiple batches of the UGP and TM samples derived from Astragalus membranaceus var.mongholicus were analyzed by UHPLC/DAD-MS using isoflavones and triterpenoid glycosides as marker compounds.The results demonstrated that the chemical profiles of UGP was identical or similar to that of TM,but UGP was highly homogeneous in terms of marker compound contents as assessed,e.g.,by the relative standard deviation values of the nine marker compounds in the range of 8.55%−43.80%for TM2 compared against 1.70%−8.38%for UGP2.Macromolecular component preparation and 1H NMR analyses indicated that TM4 and its corresponding UGP4 produced similar polysaccharides,but the later had approximately two-fold dissolution rate of the polysaccharides when compared to the former(yield 7.22±0.35%vs 3.39±0.20%).This study confirms that UGP of Radix Astragali is chemically consistent and homogenous,supporting its use as a promising material in TCM prescriptions.

Eligibility of C-BIOPRED severe asthma cohort for type-2 biologic therapies

To the Editor:Patients with severe persistent asthma experience greater morbidity with more impairment in quality of life despite higher use of health care resources and being treated with existing asthma treatments such as inhaled corticosteroids and b-agonists,and sometimes oral corticosteroid(OCS)therapy.Type-2(T2)high asthma has been identified as a phenotype that responds to targeted T2 biologic therapies such as anti-IgE,anti-interleukin(IL)5,or anti-IL5Ra and anti-IL4Ra monoclonal antibodies,which are currently available in Europe and North America,and are currently introduced in the rest of the world.[1]

健康照明应用研究发展与展望

本质感光视网膜神经节细胞(intrinsically photosensitive retinal ganglion cells,ipRGC),通过视网膜下丘脑束(retinohypothalamic tract,RHT)与下丘脑视交叉上核(suprachiasmatic nucleus,S CN)等在大脑区域形成投射(即非视觉通路),对人的生理产生影响.这一非视觉效应的发现赋予了照明研究与应用全新内涵,即通过照明技术与智能控制技术的有机结合,因人、因时、因地合理控制照度及其分布,为用户创造"安全、舒适、有益身心"的健康照明光环境.而发光二极管(light emitting diode,LED)照明技术的应用和健康照明新内涵又对基于视觉感知的评价指标提出了新的要求.本文对照明与视觉、非视觉通路的影响相关研究成果进行综述,提出我国健康照明光环境的研究与实施的思考和判断.

Combination of western medicine and Chinese traditional patent medicine in treating a family case of COVID-19

In December 2019,an outbreak of novel coronavirus(2019-nCoV)occurred in Wuhan,Hubei Province,China.By February 14,2020,it has led to 66492 confirmed patients in China and high mortality up to^2.96%(1123/37914)in Wuhan.Here we report the first family case of coronavirus disease 2019(COVID-19)confirmed in Wuhan and treated using the combination of western medicine and Chinese traditional patent medicine Shuanghuanglian oral liquid(SHL).This report describes the identification,diagnosis,clinical course,and management of three cases from a family,suggests the expected therapeutic effects of SHL on COVID-19,and warrants further clinical trials.

Effects of Shuanghuanglian oral liquids on patients with COVID-19:a randomized,open-label,parallel-controlled,multicenter clinical trial

We conducted a randomized,open-label,parallel-controlled,multicenter trial on the use of Shuanghuanglian(SHL),a traditional Chinese patent medicine,in treating cases of COVID-19.A total of 176 patients received SHL by three doses(56 in low dose,61 in middle dose,and 59 in high dose)in addition to standard care.The control group was composed of 59 patients who received standard therapy alone.Treatment with SHL was not associated with a difference from standard care in the time to disease recovery.Patients with 14-day SHL treatment had significantly higher rate in negative conversion of SARS-CoV-2 in nucleic acid swab tests than the patients from the control group(93.4%vs.73.9%,P=0.006).Analysis of chest computed tomography images showed that treatment with high-dose SHL significantly promoted absorption of inflammatory focus of pneumonia,which was evaluated by density reduction of inflammatory focus from baseline,at day 7(mean difference(95%CI),−46.39(−86.83 to−5.94)HU;P=0.025)and day 14(mean difference(95%CI),−74.21(−133.35 to−15.08)HU;P=0.014).No serious adverse events occurred in the SHL groups.This study illustrated that SHL in combination with standard care was safe and partially effective for the treatment of COVID-19.

Evaluation of the efficacy and safety of hydroxychloroquine in comparison with chloroquine in moderate and severe patients with COVID-19

Dear Editor,Since December 2019,severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has been rapidly spreading worldwide.Hydroxychloroquine and chloroquine are candidates for the treatment of coronavirus disease 2019(COVID-19)owing to its antiviral effect and immunomodulation properties.

Organ function support in patients with coronavirus disease 2019:Tongji experience

Coronavirus disease 2019(COVID-19)is a highly contagious disease and a serious threat to human health.COVID-19 can cause multiple organ dysfunction,such as respiratory and circulatory failure,liver and kidney injury,disseminated intravascular coagulation,and thromboembolism,and even death.The World Health Organization reports that the mortality rate of severe-type COVID-19 is over 50%.Currently,the number of severe cases worldwide has increased rapidly,but the experience in the treatment of infected patients is still limited.Given the lack of specific antiviral drugs,multi-organ function support treatment is important for patients with COVID-19.To improve the cure rate and reduce the mortality of patients with severe-and critical-type COVID-19,this paper summarizes the experience of organ function support in patients with severe-and criticaltype COVID-19 in Optical Valley Branch of Tongji Hospital,Wuhan,China.This paper systematically summarizes the procedures of functional support therapies for multiple organs and systems,including respiratory,circulatory,renal,hepatic,and hematological systems,among patients with severe-and critical-type COVID-19.This paper provides a clinical reference and a new strategy for the optimal treatment of COVID-19 worldwide.

Dogs lacking Apolipoprotein E show advanced atherosclerosis leading to apparent clinical complications

Atherosclerotic cardiovascular disease resulting from dysregulated lipid metabolism is the leading cause of morbidity and mortality worldwide.Apolipoprotein E(ApoE)plays a critical role in cholesterol metabolism.Knockouts in lipid-metabolizing proteins including ApoE in multiple model organisms such as mice and rats exhibiting elevated levels of cholesterol have been widely used for dissecting the pathology of atherosclerosis,but few of these animal models exhibit advanced atherosclerotic plaques leading to ischemia-induced clinical symptoms,limiting their use for translational studies.Here we report hypercholesterolemia and severe atherosclerosis characterized by stenosis and occlusion of arteries,together with clinical manifestations of stroke and gangrene,in ApoE knockout dogs generated by CRISPR/Cas9 and cloned by somatic cell nuclear transfer technologies.Importantly,the hypercholesterolemia and atherosclerotic complications in F0 mutants are recapitulated in their offspring.As the ApoE-associated atherosclerosis and clinical manifestations in mutant dogs are more similar to that in human patients compared with those in other animal models,these mutant dogs will be invaluable in developing and evaluating new therapies,including endovascular procedures,against atherosclerosis and related disorders.