XY-S型催化剂在全密度聚乙烯装置上的应用

从流化床反应器基本工艺出发,通过对反应过程中的乙烯分压,n(H2)/n(C2H4),n(C4H8)/n(C2H4),两种催化剂质量比等的调整,反应器静电、流化床上下部的线型低密度聚乙烯(LLDPE)质量比、松密度、反应压力等参数均受控。催化剂活性随着XY-S型催化剂加入比例的增大而下降,w(XY-S)为100%时,催化剂平均活性达6.572 t/kg,与w(XY-S)为50%,70%相比,催化剂活性下降了14.3%～18.7%。产品合格率达100%,国产XY-S型催化剂在全密度聚乙烯装置上成功应用,基本满足装置长周期运行,达到了降低生产成本和催化剂国产化的目的。

INTERNET-BASED MACHINING PARAMETER OPTIMIZATION AND MANAGEMENT SYSTEM FOR HIGH-SPEED MACHINING

The theory and its method of machining parameter optimization for high-speed machining are studied. The machining data collected from workshops, labs and references are analyzed. An optimization method based on the genetic algorithm (GA) is investigated. Its calculation speed is faster than that of traditional optimization methods, and it is suitable for the machining parameter optimization in the automatic manufacturing system. Based on the theoretical studies, a system of machining parameter management and optimization is developed. The system can improve productivity of the high-speed machining centers.

Carbon quantum dot preparation and application to detecting active ingredients in traditional Chinese medicine

Carbon quantum dots(CQDs)are fluorescent carbon nanomaterials that have been applied to biology,medicine,and optoelectronics,owing to their significant advantages such as simple synthesis methods,low cost,and widely available sources of raw synthesis materials.This review summarizes CQD preparation methods,which include hydrothermal and microwave-assisted synthesis methods,as well as separation methods such as centrifugation,dialysis,and filtration.Additionally,we review the application of CQDs in the detection of active ingredients,primarily phenolic compounds,in traditional Chinese medicine.We also discuss the quenching mechanism of CQD fluorescence using the active ingredients of traditional Chinese medicine.Limitations such as insufficient test selectivity,weak fluorescence intensity,and an unclear quantitative relationship between preparation methods and properties should be resolved for the efficient use of CQDs to detect active ingredients in Chinese medicine.

Metabonomics/metabolomics analysis technology and its application in quality control of traditional Chinese medicines

Chinese medicines are an important part of traditional Chinese medicines,but their'safe,effective,stable and controllable'issue still remains to be solved.The rise of metabonomics in 20th century,consistent with the overall adjustment concept of multi-component,multi-level,multi-target,multi-metabolic pathways of traditional Chinese medicines,is conducive to solve basic problems in their quality control.This paper systematically describes recent application and development of 1H-NMR metabonomics techniques,LC-MS metabonomics techniques and GC-MS metabonomics techniques in the quality control of traditional Chinese medicines.It provides a new reference for Chinese medicines and the identification and quality assessment of their products.

Probability Prediction Model for Landslide Occurrences in Xi'an, Shaanxi Province, China

Landslides are increasing since the 1980s in Xi'an, Shaanxi Province, China. This is due to the increase of the frequency and intensity of precipitation caused by complex geological structures, the presence of steep landforms, seasonal heavy rainfall, and the intensifcation of human activities. In this study, we propose a landslide prediction model based on the analysis of intraday rainfall(IR) and antecedent effective rainfall(AER). Primarily, the number of days and degressive index of the antecedent effective rainfall which affected landslide occurrences in the areas around Qin Mountains, Li Mountains and Loess Tableland was established. Secondly, the antecedent effective rainfall and intraday rainfall were calculated from weather data which were used to construct critical thresholds for the 10%, 50% and 90% probabilities for future landslide occurrences in Qin Mountain, Li Mountain and Loess Tableland. Finally, the regions corresponding to different warning levels were identified based on the relationship between precipitation and the threshold, that is; "A" region is safe, "B" region is on watch alert, "C" region is on warning alert and "D" region is on severe warning alert. Using this model, a warning program is proposed which can predict rainfall-induced landslides by means of real-time rain gauge data and real-time geo-hazard alert and disaster response programs. Sixteen rain gauges were installed in the Xi'an region by keeping in accordance with the regional geology and landslide risks. Based on the data from gauges, this model accurately achieves the objectives of conducting real-time monitoring as well as providing early warnings of landslides in the Xi'an region.

Monte-Carlo based cascade control approach with focus on real overactuated space systems

The present research relies on a cascade control approach through the Monte-Carlo based method in the presence of uncertainties to evaluate the performance of the real overactuated space systems.A number of potential investigations in this area are first considered to prepare an idea with respect to state-of-the-art.The insight proposed here is organized to present attitude cascade control approach including the low thrust in connection with the high thrust to be implemented,while the aforementioned Monte-Carlo based method is carried out to guarantee the approach performance.It is noted that the investigated outcomes are efficient to handle a class of space systems presented via the center of mass and the moments of inertial.And also a number of profiles for the thrust vector and the misalignments as the disturbances all vary in its span of nominal variations.The acquired results are finally analyzed in line with some well-known benchmarks to verify the approach efficiency.The key core of finding in the research is to propose a novel 3-axis control approach to deal with all the mentioned uncertainties of space systems under control,in a synchronous manner,as long as the appropriate models in the low-high thrusts are realized.

Developing a Framework of the Sourcing Process A Case Study of Finnish Companies With Chinese Suppliers

The paper analyzes five Finnish case companies to study the sourcing process from China. A framework of a six-stage sourcing process is developed that includes finding and choosing suppliers, making contracts and orders, performing production and quality control, planning logistics, inspecting purchases, and developing supply chain management. Each stage describes the activities from the channels of seeking suppliers to cooperative areas for further development. The case study illustrates the practices of sourcing from China are actually quite similar to the sourcing process in other countries. The study highlights that quality control is the core issue in sourcing from China. Moreover, the difference in understanding sustainable quality affects supplier screening and quality control. Close cooperation on quality control is the key to managing the supply chain to increase competitive advantage through sourcing from China.

Simulation on Soot Emission Control in Stoker-Fired Boiler by Secondary Air

A work on soot emission control simulation in stoker-fired boiler by secondary air has been done. Some models such as k-e, combustion, radiation, and soot Khan-Greeves have been adopted. Soot production and emission has been reduced by secondary air; the highest mass concentration is reduced from 7.46 × 10^-14 to 6.94 × 10^15; mass concentration of soot is decreased from 1.12 ×10^-15 to 9.25 ×10^-32 in the upper areas.

Characteristics of China's Automobile Recall Actions

For the purpose of enhancing automobile safety and the effectiveness of recalls,increasing manufacturers' quality control capabilities,and reducing defects,we investigated thestatus of recalls over the last five years.We have examined patterns and trends in motor vehiclesafety recalls using databases from China,Europe and the United States.A recall rate parameterwas developed to evaluate the level of recall enforcement based on analyzing the reasonsfor recalls and manufactures' characteristics.Moreover,there were substantial differencesin the recall rates of China compared with those in other countries,indicating that Chinese manufacturersneed to take more active action in recall.

Application of UHPLCMS/ MS method in determining the content of multiingredient in hospital preparations

In the present study, we established an ultra-high pressure liquid chromatography-tandem mass spectrometry （UHPLC-MS/MS） method to simultaneously determine 11 compounds in two hospital preparations （Shegan mixture and Gandi capsules）, including ephedrine, caffeic acid, ferulic acid, rutin, scutellarin, belamcandin, baicalin, baicalein, astragaloside IV, irisflorentin and wogonin. The chromatographic separation was conducted on ZORBAX SB-C18 （2.1 mm×50 mm, 1.8 μm）. Eleven analytes and IS were detected using ESI and MRM combined with positive and negative scanning switch. Caffeic acid, ferulic acid, scutellarin and belamcandin were detected using negative ion mode detection, whereas ephedrine, rutin, baicalin, baicalein, astragaloside IV, irisflorentin and wogonin were detected using positive ion mode detection. The quantification limits of ephedrine, caffeic acid, scutellarin, belamcandin, baicalin, baicalein, irisfiorentin and wogonin were 4.90×10^-3 ng/mL, 7.80 ng/mL, 6.8 ng/mL, 5.3×10^-2 ng/mL, 4.20×10^-3 ng/mL, 4.6×10^-2 ng/mL, 1.44×10^-4 ng/mL, 4.85 ng/mL, 0.23 ng/mL, 3.18× 10^-4 ng/mL and 2.95× 10^-4 ng/mL, respectively. The detection limits of these components were 2.90× 10^-4 ng/mL, 0.77 ng/mL, 2.0 ng/mL, 0.016 ng/mL, 1.3×10^-3 ng/mL, 3.33×10^-4 ng/mL, 4.32×10^-5 ng/mL, 1.46 ng/mL, 0.07 ng/mL, 9.5×10^-5 ng/mL and 8.84× 10^-5 ng/mL, respectively. All calibration curves showed good linearity （R^2〉0.99） within the test range. The RSD values of intra-day and inter-day precision were less than 5%, and the average recovery rates of the 11 components ranged fi＇om 80% to 120%. In conclusion, our newly developed method was simple, rapid, sensitive and accurate. It could be used to determine ephedrine, caffeic acid, ferulic acid, rutin, scutellarin, belamcandin, baicalin, baicalein, astragaloside IV, irisflorentin and wogonin in Shegan mixture and Gandi capsules, which was helpful for the quality control of drugs.

Approaches to establish Q-markers for the quality standards of traditional Chinese medicines

Traditional Chinese medicine(TCM) has played a pivotal role in maintaining the health of Chinese people and is now gaining increasing acceptance around the global scope. However, TCM is confronting more and more concerns with respect to its quality. The intrinsic "multicomponent and multitarget" feature of TCM necessitates the establishment of a unique quality and bioactivity evaluation system, which is different from that of the Western medicine. However, TCM is investigated essentially as"herbal medicine" or "natural product", and the pharmacopoeia quality monographs are actually chemicalmarkers-based, which can ensure the consistency only in the assigned chemical markers, but, to some extent, have deviated from the basic TCM theory. A concept of "quality marker"(Q-marker), following the "property-effect-component" theory, is proposed. The establishment of Q-marker integrates multidisciplinary technologies like natural products chemistry, analytical chemistry, bionics, chemometrics,pharmacology, systems biology, and pharmacodynamics, etc. Q-marker-based fingerprint and multicomponent determination conduce to the construction of more scientific quality control system of TCM.This review delineates the background, definition, and properties of Q-marker, and the associated technologies applied for its establishment. Strategies and approaches for establishing Q-marker-based TCM quality control system are presented and highlighted with a few TCM examples.

Zeolite diagenesis and its control on petroleum reservoir quality of Permian in northwestern margin of Junggar Basin,China

Recently, silicate diagenesis has been the focus of many studies because of its impact on porosity and permeability in sedimentary rocks. In the process of diagenetic evolution, the crystallization, cementation, and corrosion of zeolite （as a diagenetic mineral） have different effects on properties of Permian reservoirs in the study area. In the Permian sediments in the no,inwestern margin of the Junggar Basin, Zeolite minerals have formed during diagenesis in an open hydrologic system, related to the hydration of abundant volcanic glass. Chemical property of groundwater, pH of pore water, cation property and ratios have directly influenced the transformation among various zeolites and the dissolution of zeolite mineral. The main species of zeolite include analcime, heulandite, and laumontite. Transformations of these minerals during diagenesis are： volcanic glass→ clinoptilolite→analcime→heulandite→laumontite. Corrosion of analcime obviously improved reservoir quality. Extensive heulandite cementation developed and intensively reduced reservoir pore spaces. Early zeolite cementation protected pore structure against compaction and provided substance for late dissolution. The dissolution of analcime was closely related with the organic acid recharged by hydrocarbon source rocks and the NaHCO3 type formation water in the Permian, and was sensitive to permeability of rocks. Within the CaCl2 type formation water, heulandite and laumontite were hardly dissolved. In the study area, the belt with dissolved analcime is the area for the development of secondary pores and favorable reservoirs.