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Crystal modification of rifapentine using different solvents

Kun ZHOU, Jun LI, Jianhong LUO, Dongsheng ZHENG,

《化学科学与工程前沿(英文)》 2010年 第4卷 第1期   页码 65-69 doi: 10.1007/s11705-009-0302-6

摘要: Rifapentine crystals with different habits were prepared by recrystallization from selected solvents, such as methanol, ethanol, chloroform, and acetic acid. Scanning electron microscopy, X-ray powder diffractometry, infrared spectrometry, and differential scanning calorimetry were used to investigate the physicochemical characteristics of the prepared crystals. The comparative dissolution behaviors of the newly developed crystals and of rifapentine without being treated were also studied. Results show that the newly developed crystals were different from each other with respect to physical properties but were identical chemically. Needle-shaped crystals were obtained from methanol, ethanol, and chloroform solvents, and the block-shaped crystals were obtained from acetic acid solvent. X-ray diffraction spectra and differential scanning calorimetry investigation on those developed crystals clearly indicate that rifapentine has different crystal structure modification. When the crystal was obtained from acetic acid, the change of crystal habit was originated from the crystal structure modification. The dissolution rate of newly developed crystals was found to be higher than that of rifapentine without being treated. However, the modified crystal obtained from acetic acid shows the lower dissolution rate than crystals obtained from other solvents.

关键词: identical     scanning calorimetry     different     comparative dissolution     structure modification    

Improved dissolution and anti-inflammatory effect of ibuprofen by solid dispersion

null

《医学前沿(英文)》 2012年 第6卷 第2期   页码 195-203 doi: 10.1007/s11684-012-0189-3

摘要:

The purpose of this study was to improve the dissolution rate and anti-inflammatory effect of ibuprofen by a solid dispersion (SD) method. Initial screening was developed based on drug solubility in carriers in the liquid state to select a suitable water-soluble carrier system for the preparation of SDs. The dissolution of ibuprofen in urea was higher than in PEG4000 or mannitol. Thus, urea was selected as the carrier for the preparation of SDs. SDs were characterized in terms of dissolution, differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. Solid dispersion-based (SDBT) and conventional (CT) tablets were prepared by the wet granulation method. The anti-inflammatory effect of SDBT was evaluated using the mouse ear edema test with xylene. In vitro release results indicated that the ibuprofen dissolution rate was improved by the SD. SD characterization results suggested that ibuprofen partly precipitates in crystalline and amorphous forms after SD preparation and that ibuprofen and urea do not interact. SDBT displayed more significant anti-inflammatory effects than CT. The dissolution rate and anti-inflammatory effect of ibuprofen were significantly enhanced by the ibuprofen-urea SD.

关键词: ibuprofen     solid dispersion     physical mixture     dissolution     anti-inflammatory effect    

Research progress on hydrothermal dissolution and hydrolysis of lignocellulose and lignocellulosic waste

Yan ZHAO, Wenjing LU, Jiajun CHEN, Xiangfeng ZHANG, Hongtao WANG

《环境科学与工程前沿(英文)》 2014年 第8卷 第2期   页码 151-161 doi: 10.1007/s11783-013-0607-z

摘要: Ethanol production from lignocellulosic waste has attracted considerable attention because of its feasibility and the generation of valuable products. Previous studies have shown that pretreatment and hydrolysis are key processes for lignocellulose conversion. Hydrothermal process is a promising technique because of its efficiency to break down the lignocellulosic structures and produce fermentable hexoses. Most studies in this field have therefore focused on understanding these processes or optimizing the parameters, but commonly reported low yields of fermentable hexoses. The inability to produce high yields of fermentable hexoses is mainly attributed to inadequate information on the conversion mechanisms of lignocellulose, particularly the reaction rules of dissolution, which is a limiting step in the entire conversion process. This paper critically reviewed the progress done in the research and development of the hydrothermal dissolution and hydrolysis of lignocellulose. Principles, processes, and related studies on separate dissolution and asynchronous hydrolysis of lignin, hemicellulose, and cellulose are presented. Potential research prospects are also suggested.

关键词: lignocellulosic waste     hydrothermal conversion     separate dissolution     asynchronous hydrolysis     mechanism    

Cadmium removal mechanistic comparison of three Fe-based nanomaterials: Water-chemistry and roles of Fe dissolution

《环境科学与工程前沿(英文)》 2022年 第16卷 第12期 doi: 10.1007/s11783-022-1586-8

摘要:

● nZVI, S-nZVI, and nFeS were systematically compared for Cd(II) removal.

关键词: Nano zero valent iron     Sulfided zero valent iron     FeS     Cd(II) immobilization     Fe dissolution    

Effects of rotor and stator geometry on dissolution process and power consumption in jet-flow high shear

Lin Yang, Wenpeng Li, Junheng Guo, Wei Li, Baoguo Wang, Minqing Zhang, Jinli Zhang

《化学科学与工程前沿(英文)》 2021年 第15卷 第2期   页码 384-398 doi: 10.1007/s11705-020-1928-7

摘要: The jet-flow high shear mixer (JF-HSM) is a new type of intensified equipment with special configurations of the rotor and the stator. The mass transfer property and power consumption were studied in the solid-liquid system for a series of JF-HSMs involving different configuration parameters, such as rotor diameter, rotor blade inclination, rotor blade bending direction, stator diameter, and stator bottom opening diameter. The flow characteristics were examined by computational fluid dynamic simulations. Results indicate that the turbulent power consumption of the JF-HSM is affected by the change in rotor blade inclination and stator bottom opening. With the increase in the shear head size and the change in the rotor into a backward-curved blade, the solid-liquid mass transfer rate can be remarkably increased under the same input power. Dimensionless correlations for the mass transfer coefficient and power consumption were obtained to guide the scale-up design and selection of such a new type of equipment to intensify the overall mixing efficiency.

关键词: jet-flow high shear mixer     solid particle dissolution     power consumption characteristics     CFD Simulation    

The Development and Comparative Analysis of Engineering Project Management Modes

Ji-wei Zhu,Li-nan Zhou,Ming-yuan Yu,Zhao Zhai

《工程管理前沿(英文)》 2015年 第2卷 第4期   页码 351-358 doi: 10.15302/J-FEM-2015060

摘要: Engineering project management is the whole process of project construction management activities up to the point of achieving the goals of engineering construction, which adopts the means of planning, organizing, leading, and controlling. In addition, engineering project management modes are the works of project management and the technical guarantee of project success. For the quality and efficient transformation demands of the Chinese construction industry in the process of marketization, internationalization and informatization, based on the connotation and development path of engineering project management modes, the 16 main and new kinds of project management modes both domestically and abroad are divided into trading mode, financing mode and management mode. These have led to comparative analysis and brief commentary. Finally, it will be pointed out that the engineering project management modes move throughout the whole management process, the combined model and the expansion development of financing model. This work will provide reference for project participants to choose the appropriate project management modes and better understand building company transformation.

关键词: engineering projects     management mode     comparative analysis     development trend    

Comparative lipidomic analysis of

Bin QIAO, Hong-Chi TIAN, Ying-Jin YUAN

《化学科学与工程前沿(英文)》 2012年 第6卷 第4期   页码 461-469 doi: 10.1007/s11705-012-1223-3

摘要: Variations in the composition and level of phospholipids (PLs) in yeast cells during industrial ethanol fermentation processes were analyzed. A comparative lipidomic method was used to investigate the changes in total cellular PLs during continuous and fed-batch/batch processes. The phospholipid metabolism in yeast changed during both processes, mainly due to the presence of long-chain poly unsaturated fatty acids (PUFA) that contained phosphatidyglycerol (PG), phosphatidylethanolamine (PE) and phosphatidylserine (PS). The complexity of the media affected the growth of the yeast and the membrane composition. Yeast incorporated lots of exogenous saturated and PUFAs from the feedstock during the fermentations. During the continuous fermentation, there was an increase in PLs with shorter chains as the fermentation progressed and early in process there were more long-chains. During the fed-batch/batch process, the PG species increased as the fermentation progressed. This is probably due to an inositol deficiency in the earlier part of the fermentation.

关键词: lipidomics     systems biology     phospholipids     stirred-tank     saccharomyces cerevisiae     biorefinery engineering    

Last Planner System and Scrum: Comparative analysis and suggestions for adjustments

Roshan POUDEL, Borja GARCIA de SOTO, Eder MARTINEZ

《工程管理前沿(英文)》 2020年 第7卷 第3期   页码 359-372 doi: 10.1007/s42524-020-0117-1

摘要: This study provides a critical review of the concepts of Agile, Lean, Scrum, and Last Planner System (LPS). A comparative analysis is conducted between LPS and Scrum to expand LPS by considering Scrum’s best practices. Eight dimensions, namely, 1) origins, 2) main purpose, 3) overall system/framework process, 4) tools or artifacts maintained by the team, 5) team composition and main roles, 6) regular events or team meetings, 7) metrics/dashboards, and 8) approach to learning, are evaluated. After analyzing side by side the eight dimensions, it was found that many aspects from Scrum already exist in LPS in the same or similar form. However, the authors identify four main elements from Scrum that can be leveraged to improve the LPS benchmark, such as considering the Scrum “Increment” concept into LPS, having a clear definition of roles and responsibilities, or adding an equivalent to a Scrum Master to have a designated “rule keeper” in LPS. These opportunities to be considered in new LPS benchmarks need to be tested and validated with real applications. To the best of the authors’ knowledge, this work is the first to comprehensively compare Scrum (Agile) and LPS (Lean) and could be seen as a contribution toward the evolution of the Last Planner System for the academic and industrial environments.

关键词: Lean Construction     Last Planner System     Agile     Scrum     comparative analysis     AEC projects     project teams    

Layer-like FAU-type zeolites: A comparative view on different preparation routes

Bastian Reiprich, Tobias Weissenberger, Wilhelm Schwieger, Alexandra Inayat

《化学科学与工程前沿(英文)》 2020年 第14卷 第2期   页码 127-142 doi: 10.1007/s11705-019-1883-3

摘要: The creation of intergrown layer-like zeolite crystals is one route to form hierarchical zeolites. Faujasite-type (FAU-type) zeolites are among the industrially most important zeolites and the implementation of hierarchical porosity is a promising way to optimise their catalytic and adsorptive performance. After a short general survey into routes for the preparation of hierarchical pore systems in FAU, we will review the currently existing strategies for the synthesis of FAU with layer-like morphology. Those strategies are mainly based on the presence of morphology modifying agents in the synthesis mixture. However, a very recent approach is the synthesis of layer-like FAU-type zeolite crystals assembled in an intergrown manner in the absence of such additives, just by finely adjusting the crystallization temperature. This additive-free preparation route for layer-like FAU, which appears very attractive from an ecological as well as economic point of view, is highlighted in this review. Concluding, a comparison, including powder X-ray diffraction, scanning and transmission electron microscopy, nitrogen physisorption and elemental analysis, between conventional FAU and three layer-like FAU obtained by different synthesis routes was carried out to show the structural, morphological and textural differences and similarities of these materials.

关键词: FAU     hierarchical zeolite     layer-like morphology    

Robotic distal pancreatectomy versus conventional laparoscopic distal pancreatectomy: a comparative study

null

《医学前沿(英文)》 2015年 第9卷 第3期   页码 356-360 doi: 10.1007/s11684-015-0404-0

摘要:

Robotic system has been increasingly used in pancreatectomy. However, the effectiveness of this method remains uncertain. This study compared the surgical outcomes between robot-assisted laparoscopic distal pancreatectomy and conventional laparoscopic distal pancreatectomy. During a 15-year period, 35 patients underwent minimally invasive approach of distal pancreatectomy in our center. Seventeen of these patients had robot-assisted laparoscopic approach, and the remaining 18 had conventional laparoscopic approach. Their operative parameters and perioperative outcomes were analyzed retrospectively in a prospective database. The mean operating time in the robotic group (221.4 min) was significantly longer than that in the laparoscopic group (173.6 min) (P = 0.026). Both robotic and conventional laparoscopic groups presented no significant difference in spleen-preservation rate (52.9% vs. 38.9%) (P = 0.505), operative blood loss (100.3 ml vs. 268.3 ml) (P = 0.29), overall morbidity rate (47.1% vs. 38.9%) (P = 0.73), and post-operative hospital stay (11.4 days vs. 14.2 days) (P = 0.46). Both groups also showed no perioperative mortality. Similar outcomes were observed in robotic distal pancreatectomy and conventional laparoscopic approach. However, robotic approach tended to have the advantages of less blood loss and shorter hospital stay. Further studies are necessary to determine the clinical position of robotic distal pancreatectomy.

关键词: distal pancreatectomy     pancreatic neoplasm     robotic surgery    

Oral product input to the GI tract: GIS an oral product performance technology

Gordon L. Amidon, Yasuhiro Tsume

《化学科学与工程前沿(英文)》 2017年 第11卷 第4期   页码 516-520 doi: 10.1007/s11705-017-1658-7

摘要: The patient receives a pharmaceutical product, not a drug. The pharmaceutical products are formulated with a drug, an active ingredient to produce the maximum therapeutic effect after oral absorption. Therefore, it is the product we must optimize for the patients. In order to assure the safety and efficacy of pharmaceutical products, we need an predictive tool for oral product performance in patients. Currently, we are a surprisingly long way from accomplishing that objective. If the 20th century was the ‘age of the drug’, i.e., the ‘magic bullet’, the 21st century must become the ‘age of the guided missile’, i.e., the delivery system, including the form of the active pharmaceutical ingredient (API) (‘drug’). The physical form of the drug and the delivery system must be optimized to maximize the therapeutic benefits of pharmaceutical products for humans. Oral immediate release (IR) dosage forms cannot be optimal for all drugs or likely even any drugs (APIs). Still, the formulation of pharmaceutical products has to be optimized for patients. But how do we optimize oral delivery of drugs? It is usually through ‘trial and error’, in humans! We need a better way to optimize the oral dosage forms. We have suggested to select different dissolution methodologies for this optimization based on BCS Subclasses. In this article, we present the predicted drug dissolution profile of ketoconazole as a model drug from our laboratory utilizing a gastrointestinal simulator (GIS), which is an adaptation of the ASD system. GIS consists of three chambers representing stomach, duodenum, and jejunum, to create the human gastrointestinal tract-like environment and enable the control the gastric emptying rate. This dissolution system allows the monitoring of the drug dissolution phenomena and the observation of the supersaturation and the precipitation of pharmaceutical products, which is useful information to predict dissolution of pharmaceutical products. This system can provide the actual input needed to accurately predict the input into the systemic circulation required by many of the absorption prediction packages available today.

关键词: GIS     in vivo predictive dissolution     ketoconazole     BCS subclassification     supersaturation    

Comparative transcriptomics revealed enhanced light responses, energy transport and storage in domestication

Zhiqiang XIA,Xin CHEN,Cheng LU,Meiling ZOU,Shujuan WANG,Yang ZHANG,Kun PAN,Xincheng ZHOU,Haiyan WANG,Wenquan WANG

《农业科学与工程前沿(英文)》 2016年 第3卷 第4期   页码 295-307 doi: 10.15302/J-FASE-2016126

摘要: Cassava is a staple food, feed and bioenergy crop important to the world especially in the tropics. Domesticated cassava is characterized by powerful carbohydrate accumulation but its wild progenitor is not. Here, we investigated the transcriptional differences of eight cDNA libraries derived from developing leaf, stem and storage root of cassava cv. Arg7 and an ancestor line, W14, using next generation sequencing system. A total of 41302 assembled transcripts were obtained and from these, 25961 transcripts with FPKM≥3 in at least one library were named the expressed genes. A total of 2117, 1963 and 3584 transcripts were found to be differentially expressed in leaf, stem and storage root (150 d after planting), respectively, between Arg7 and W14 and ascribed to 103, 93 and 119 important pathways in leaf, stem and storage root, respectively. The highlight of this work is that the genes involved in light response, such as those for photosystem I (PSA) and photosystem II (PSB), other genes involved in light harvesting, and some of the genes in the Calvin cycle of carbon fixation were specially upregulated in leaf. Genes for transport and also for key rate-limiting enzymes (PFK, PGK and PK, GAPDH) coupling ATP consumption in glycolysis pathway were predominantly expressed in stem, and genes for sucrose degradation (INVs), amylose synthesis (GBSS) and hydrolysis (RCP1, AMYs), the three key steps of starch metabolism, and transport associated with energy translocation (ABC, AVPs and ATPase) and their upstream transcription factors had enhanced expression in storage root in domesticated cassava. Co-expression networks among the pathways in each organs revealed the relationship of the genes involved, and uncovered some of the important hub genes and transcription factors targeting genes for photosynthesis, transportation and starch biosynthesis.

关键词: cassava     comparative transcriptomics     energy transport     photosynthesis     starch synthesis    

The current phosphate recycling situation in China and Germany: a comparative review

null

《农业科学与工程前沿(英文)》 2019年 第6卷 第4期   页码 403-418 doi: 10.15302/J-FASE-2019287

摘要:

Phosphorus (P) is an indispensable element for organisms but the primary source of P—mineral phosphate resources—are non-renewable. Agricultural production has a high demand for fossil phosphate resources, but the resulting phosphate-rich residues are lack of management. This leads to rapid reserves depletion and severe phosphate pollution risks. One sustainable way is to reuse the phosphate dispersed in various residues such as sewage sludge and livestock manure. Diverse techniques have emerged to recover phosphate from wastes to close the phosphate cycle. While it is a global issue, the regional situations regarding potential phosphate scarcity and its management differ strongly. China is rich in phosphate resources, but over-exploitation has greatly increased the risk of phosphate rocks depletion, while in Germany the P resources depend on imports, but there is commitment to keep a balance between import and utilization. This had led to great differences in the way the two countries deal with the “re-use” of phosphate in waste. China is now in a transition phase from the simple terminal pollution control to “waste” reuse and nutrient resources recycling. One sign of this tendency is the mandatory garbage classification and preparation for further processing and recycling. This was first implemented in Shanghai in 2019, whereas Germany has been following the legal framework for waste management since the 19th century. There are a series of laws to control the nutrient loss from municipal and agricultural activities, as for instance with sewage sludge ordinance and fertilizer legislation. Many of these laws have been newly revised recently. Sewage sludge cannot be directly utilized on farmland as organic fertilizer any more. Alternatively, phosphate and other nutrients should be recovered from sewage sludge. Advanced phosphate recovery technologies and related nutrient recycling schemes are proceeding. This review summarizes the current situation of phosphate-containing residues management and phosphate reuse in China and Germany. The state legislation and policies, which would affect the phosphate recycling concept are presented as well. As there are various kinds of phosphate-containing residues, different phosphate recovery technologies can be applied. Those technologies are discussed from their mechanism and suitability.

关键词: phosphate recovery     manure     sewage sludge     ordinances     technologies    

医学专业目录设置的国际比较及对策研究

余中光,张鹏俊,张知新,王辰

《中国工程科学》 2020年 第22卷 第1期   页码 139-145 doi: 10.15302/J-SSCAE-2020.01.018

摘要:

医学专业目录设置对于促进医学学科发展、培养合格的医学人才具有重要意义,在高等院校实施一流学科建设的背景下,健全、科学的专业目录显得尤为重要。为助力我国医学学科发展,本文运用文献分析法梳理了我国医学专业设置现状,系统比较了中国、美国、英国的医学专业目录类别与特点。研究发现,当前我国医学专业目录设置存在专业目录不统一、专业设置数量和内容相对滞后、临床医学专业过早专科化、与住院医师规范化培训专业目录衔接不畅等问题;建议采取统一医学专业目录、丰富学科内涵、体现交叉学科特点、建立规范的医学专业准入和退出机制等举措,推进医学专业目录与国际接轨,为培养合格、规范的医学人才提供路径指引。

关键词: 医学     专业目录     临床医学     比较分析    

Modeling of specific structure crystallization coupling with dissolution

Yuanhui JI, Hongliang QIAN, Chang LIU, Xiaohua LU, Xin FENG, Xiaoyan JI,

《化学科学与工程前沿(英文)》 2010年 第4卷 第1期   页码 52-56 doi: 10.1007/s11705-009-0301-7

摘要: In this paper, the research framework for specific structure crystallization modeling has been proposed in which four steps are required in order to investigate the rigorous crystallization modeling by thermodynamics. The first is the activity coefficient model of the solution, the second is Solid-Liquid equilibrium, the third and fourth are the dissolution and crystallization kinetics modeling, respectively. Our investigations show that the mechanisms of complex structure formation and microphase transition can be analyzed by combining the dissolution and crystallization kinetics modeling. Moreover, the formation mechanism of the porous KCl has been analyzed, which may provide a reference for the porous structure formation in the advanced material synthesis.

关键词: structure crystallization     activity coefficient     reference     KCl     dissolution    

标题 作者 时间 类型 操作

Crystal modification of rifapentine using different solvents

Kun ZHOU, Jun LI, Jianhong LUO, Dongsheng ZHENG,

期刊论文

Improved dissolution and anti-inflammatory effect of ibuprofen by solid dispersion

null

期刊论文

Research progress on hydrothermal dissolution and hydrolysis of lignocellulose and lignocellulosic waste

Yan ZHAO, Wenjing LU, Jiajun CHEN, Xiangfeng ZHANG, Hongtao WANG

期刊论文

Cadmium removal mechanistic comparison of three Fe-based nanomaterials: Water-chemistry and roles of Fe dissolution

期刊论文

Effects of rotor and stator geometry on dissolution process and power consumption in jet-flow high shear

Lin Yang, Wenpeng Li, Junheng Guo, Wei Li, Baoguo Wang, Minqing Zhang, Jinli Zhang

期刊论文

The Development and Comparative Analysis of Engineering Project Management Modes

Ji-wei Zhu,Li-nan Zhou,Ming-yuan Yu,Zhao Zhai

期刊论文

Comparative lipidomic analysis of

Bin QIAO, Hong-Chi TIAN, Ying-Jin YUAN

期刊论文

Last Planner System and Scrum: Comparative analysis and suggestions for adjustments

Roshan POUDEL, Borja GARCIA de SOTO, Eder MARTINEZ

期刊论文

Layer-like FAU-type zeolites: A comparative view on different preparation routes

Bastian Reiprich, Tobias Weissenberger, Wilhelm Schwieger, Alexandra Inayat

期刊论文

Robotic distal pancreatectomy versus conventional laparoscopic distal pancreatectomy: a comparative study

null

期刊论文

Oral product input to the GI tract: GIS an oral product performance technology

Gordon L. Amidon, Yasuhiro Tsume

期刊论文

Comparative transcriptomics revealed enhanced light responses, energy transport and storage in domestication

Zhiqiang XIA,Xin CHEN,Cheng LU,Meiling ZOU,Shujuan WANG,Yang ZHANG,Kun PAN,Xincheng ZHOU,Haiyan WANG,Wenquan WANG

期刊论文

The current phosphate recycling situation in China and Germany: a comparative review

null

期刊论文

医学专业目录设置的国际比较及对策研究

余中光,张鹏俊,张知新,王辰

期刊论文

Modeling of specific structure crystallization coupling with dissolution

Yuanhui JI, Hongliang QIAN, Chang LIU, Xiaohua LU, Xin FENG, Xiaoyan JI,

期刊论文