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Solid and liquid phase equilibria in mixtures of N, N-dimethylacetamide with chlorinated hydrocarbons

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Chinese Science Bulletin 1997年第11期42卷 918-921页

作者： che, GQ Peng, WL che, B Department of chemistry Zhongshan University Guangzhou China

IN refs.[1,2],we studied the solid and liquid phase equilibria in mixtures of tetra-chloromethane with oxygen and nitrogen-containing compounds,intermolecular interactionswith the formation of solid molecular addition... 详细信息

关键词： phase diagram solid and liquid equilibrium N N-dimethylacetamide.

estimating thermohaline variability of the equatorial Pacific Ocean from satellite altimetry

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Science China earth Sciences 2016年第11期59卷 2213-2222页

作者： SUN che MA Xiao Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China National Laboratory for Marine Science and Technology Qingdao 266071 China State Key Laboratory of Satellite Ocean environment Dynamics Second Institute of Oceanography State Oceanic Administration Hangzhou 310012 China

The vertical thermohaline structure in the western equatorial Pacific is examined with a Gravest empirical Mode(GeM)diagnosis of in-situ mooring measurements. The poor GeM performance in estimating deep thermohaline variability from satellite altimetry confirms a lack of vertical coherence in the equatorial ocean. Mooring observation reveals layered equatorial water with phase difference up to 6 months between thermocline and sub-thermocline variations. The disjointed layers reflect weak geostrophy and resemble pancake structures in non-rotating stratified turbulence. A coherency theorem is then proved, stating that traditional stationary GeM represents in-phase coherent structure and can not describe vertically out-of-phase variability. The fact that stationary GeM holds both spatial and temporal coherence makes it a unique tool to diagnose vertical coherent structure in geophysical flows. The study also develops a non-stationary GeM projection that captures more than 40% of the thermohaline variance in the equatorial deep water.

关键词： equatorial Pacific TRITON buoys Satellite altimetry GeM vertical coherence

enhanced release of the poorly soluble drug itraconazole loaded in ordered mesoporous silica

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Science China chemistry 2015年第3期58卷 400-410页

作者： Xiao Liu Shunai che State Key Laboratory of Metal Matrix Composites School of chemistry and chemical engineering Shanghai Jiao Tong University

It is known that the energy of the amorphous state of itraconazole loaded in ordered mesoporous materials is high relative to that of the crystalline state and is responsible for enhanced solubility and dissolution rate. We investigated the effects of particle size(0.7–5μm), mesostructure(2D p6 mm, cubic Ia-3d and cubic Fm-3m) and pore size(2.2–15.4 nm) of mesoporous silicas on the release performance of itraconazole. Results indicated that the release performance was not influenced by the particle sizes tested here, that the release performance increased with increasing pore diameter due to the lower probability of drug molecules colliding to recrystallize in large pores, and that the release performance was decreased in the cage-type pore structure(Fm-3m) compared to that in the cylindrical pore structures(p6mm and Ia-3d) because of the small entrance to the cagelike pores that retards the drug release.

关键词： itraconazole poorly soluble enhanced release mesoporous silica

An altimetric transport index for Kuroshio inflow northeast of Taiwan Island

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Science China earth Sciences 2015年第5期58卷 697-706页

作者： YAN XiaoMei SUN che Institute of Oceanology Chinese Academy of Sciences

The Kuroshio inflow northeast of Taiwan Island plays an important role in the heat and nutrient balances over the east China Sea(eCS). Based on merged satellite altimeter data and the PCM-1 mooring observation at the east Taiwan Channel(eTC), the study employs a correlation iteration scheme to find the optimal transport index for the Kuroshio inflow. The sea level difference with the highest correlation to the eTC transport is across the eCS shelf break rather than along the PCM-1 line. The counter-intuitive result is caused by large signal noise and poor track coverage of altimeters near the Taiwan coast. The optimal altimetric index is highly correlated with the two-year in-situ measurements as well as the ten-year output of the global assimilation model. It serves as a better estimator of Kuroshio inflow than those using tidal gauge data, and helps pinpoint a 5 cm mismatch of mean sea level in the Keelung tidal record. The mean transport of Kuroshio inflow based on the twenty-year altimetric index is 20.55 Sv with a standard deviation of 3.05 Sv. Wavelet spectrum of the index reveals that semi-annual period dominates the Kuroshio variation northeast of Taiwan Island.

关键词： Kuroshio inflow east Taiwan Channel tidal record in-situ mooring altimeter

Water mass characteristics in the western North Pacific based on a streamfunction projection

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Science China earth Sciences 2015年第11期58卷 2067-2077页

作者： MA Xiao SUN che Institute of Oceanology Chinese Academy of Sciences College of earth Sciences University of Chinese Academy of Sciences

A streamfunction projection method called gravest empirical mode(GeM) is applied to the hydrographic section at 137°e to filter out eddy noises in the western North Pacific and derive quantitative ensemble-average water mass properties in the North equatorial Current region. The GeM fields capture more than 80% of total property variances in the thermocline layer. The core layer structures of key water masses, including the North Pacific Tropical Water(NPTW) and the North Pacific Intermediate Water(NPIW), are examined with a definition of water mass boundary based on property gradient. It shows that a tongue of maximal root-mean-square(RMS) residual exists in the upper half of NPIW for all water properties. These subsurface RMS tongues appear to be close to sharp property gradients. It is the first time a GeM diagnosis is applied to nutrient data, which reveals a drastic difference of N/P reaction rate ratio above and below the maximal-nutrient core at 1250 m. Additionally, a GeM velocity reconstruction successfully produces the North equatorial Undercurrent(NeUC), demonstrating the stable thermal-wind nature of this newly-discovered current.

关键词： streamfunction projection gravest empirical mode water masses western North Pacific

Coded Modulation Faster-than-Nyquist Transmission with Precoder and Channel Shortening Optimization

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China Communications 2021年第2期18卷 49-64页

作者： Hui che Yong Bai School of Information and Communication engineering Beijing University of Posts and TelecommunicationsBeijing 100876China School of Information and Communication engineering Hainan UniversityHaikou 570228China

Faster-than-Nyquist(FTN)signaling can improve the spectrum efficiency(Se)of the transmission *** this paper,we propose a coded modulation FTN(CM-FTN)transmission scheme with precoder and channel shortening(CS)optimization to improve bit error rate(BeR)performance and reduce the complexity of FTN *** our proposal,the information rate(IR)or spectral efficiency(Se)is employed and verified as a better performance metric for CM-FTN than the minimum euclidian distance(MeD).The precoder of CM-FTN is optimized for maximizing the IR criterion using the bare-bones particle swarm optimization(BB-PSO)***,a three-carrier CM-FTN system model is used to capture the broadening effect of *** targeting for the IR maximization,the inter-symbol interference(ISI)length for CS is optimized to reduce the receiver complexity without performance *** results demonstrate that our method has a 0.6dB precoding gain compared with the nonprecoding scheme and a maximum of 87.5%of the complexity of FTN equalizer is reduced without BeR loss.

关键词： faster-than-Nyquist coded modulation information rate minimum euclidian distance precoder channel shortening

Word sense disambiguation using semantic relatedness measurement

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2006年第10期7卷 1609-1625页

作者： YANG che-Yu Department of Computer Science and lnformation engineering Tamkang University Taipei 25137 Taiwan China

All human languages have words that can mean different things in different contexts, such words with multiple meanings are potentially “ambiguous”. The process of “deciding which of several meanings of a term is intended in a given context” is known as “word sense disambiguation (WSD)”. This paper presents a method of WSD that assigns a target word the sense that is most related to the senses of its neighbor words. We explore the use of measures of relatedness between word senses based on a novel hybrid approach. First, we investigate how to “literally” and “regularly” express a “concept”. We apply set algebra to WordNet’s synsets cooperating with WordNet’s word ontology. In this way we establish regular rules for constructing various representations (lexical notations) of a concept using Boolean operators and word forms in various synset(s) defined in WordNet. Then we establish a formal mechanism for quantifying and estimating the semantic relatedness between concepts—we facilitate “concept distribution statistics” to determine the degree of semantic relatedness between two lexically expressed con- cepts. The experimental results showed good performance on Semcor, a subset of Brown corpus. We observe that measures of semantic relatedness are useful sources of information for WSD.

关键词： Word sense disambiguation (WSD) Semantic relatedness WordNet Natural language processing

Mesoporous Silica Microspheres Composited with SBA-15s for Resonance Frequency Reduction in a Miniature Loudspeaker

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chemical Research in Chinese Universities 2020年第5期36卷 760-767页

作者： ZHANG Xinyue che Shunai School of chemistry and chemical engineering State Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong UniversityShanghai 200240P.R.China

Microspheres composited with mesoporous SBA-15 particles and silica were investigated as fillers in miniature loudspeakers to study the factors influencing the resonance frequency offsets(RFOs).Mesoporous silica microspheres(MSMs)were prepared by self-assembling SBA-15 mesoporous silica in a microemulsion synthesis *** formation process involved the fabrication of a stable O/W microemulsion of tetrabutyl orthosili-cate(TBOS)and hexadecyltrimethylammonium bromide(C16TAB)and encapsulation of *** RFO increased and then decreased with increasing particle size(in the length range of 0.7—5.5 μm and in the width range of 0.2—0.45 μm),increased with increasing pore size(in the range of 7.0—9.4 nm)of SBA-15s,and increased with decreasing particle size(105—900 μm)of MSMs.

关键词： Mesoporous silica microsphere Microemulsion SBA-15 Resonance frequency offset

M-BCJR Algorithm with Channel Shortening Based on Ungerboeck Observation Model for Faster-than-Nyquist Signaling

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China Communications 2021年第4期18卷 88-98页

The M-BCJR algorithm based on the Ungerboeck observation model is a recent study to reduce the computational complexity for faster-than-Nyquist(FTN)signaling[1].In this paper,we propose a method that can further reduce the complexity with the approximately same or better bit error rate(BeR)performance compared to[1].The information rate(IR)loss for the proposed method is less than 1%compared to the true achievable IR(AIR).The proposed improvement is mainly by introducing channel shortening(CS)before the M-BCJR *** our proposal,the Ungerboeck M-BCJR algorithm and CS can work together to defeat severe inter-symbol interference(ISI)introduced by FTN *** ISI length for the M-BCJR algorithm with CS is optimized based on the criterion of the IR *** the two cases=0.5 and=0.35,compared to Ungerboeck M-BCJR without CS benchmark[1],the computational complexities of Ungerboeck M-BCJR with CS are reduced by 75%.Moreover,for the case=0.35,the BeR performance of Ungerboeck M-BCJR with CS outperforms that of the conventional M-BCJR in[1]at the low signal to noise ratio region.

关键词： M-BCJR Ungerboeck model channel shortening FTN reduced-complexity turbo equalization