Two-dimensional covalent organic frameworks(2D COFs)feature extendedπ-conjugation and ordered stacking sequence,showing great promise for high-performance photocatalysis.Periodic atomic frameworks of 2D COFs facilita...Two-dimensional covalent organic frameworks(2D COFs)feature extendedπ-conjugation and ordered stacking sequence,showing great promise for high-performance photocatalysis.Periodic atomic frameworks of 2D COFs facilitate the in-plane photogenerated charge transfer,but the precise ordered alignment is limited due to the non-covalentπ-stacking of COF layers,accordingly hindering out-of-plane transfer kinetics.Herein,we address a chiral induction method to construct a parallelly superimposed stacking chiral COF ultrathin shell on the support of SiO_(2) microsphere.Compared to the achiral COF analogues,the chiral COF shell with the parallel AA-stacking structure is more conducive to enhance the built-in electric field and accumulates photogenerated electrons for the rapid migration,thereby affording superior photocatalytic performance in hydrogen evolution from water splitting.Taking the simplest ketoenamine-linked chiral COF as a shell of SiO_(2) particle,the resulting composite exhibits an impressive hydrogen evolution rate of 107.1 mmol g^(-1)h^(-1)along with the apparent quantum efficiency of 14.31% at 475 nm.Furthermore,the composite photocatalysts could be fabricated into a film device,displaying a remarkable photocatalytic performance of 178.0 mmol m^(-2)h^(-1)for hydrogen evolution.Our work underpins the surface engineering of organic photocatalysts and illustrates the significance of COF stacking structures in regulating electronic properties.展开更多
Physicochemical and mineralogical characteristics of an alkali leaching residue of wolframite were studied by XRD,SEM−EDS,chemical phase analysis,mineral liberation analyzer(MLA),and TG−DSC methods.Batch leaching test...Physicochemical and mineralogical characteristics of an alkali leaching residue of wolframite were studied by XRD,SEM−EDS,chemical phase analysis,mineral liberation analyzer(MLA),and TG−DSC methods.Batch leaching tests,toxicity characteristic leaching procedure(TCLP)tests and Chinese standard leaching tests(CSLT)were conducted to determine the environmental mobility of toxic elements.The results show that,due to the high contents of W,Fe,Mn,Sn,and Nb,the residue is with high resource value,but the content of a toxic element,As,is also high.The existing minerals of the investigated elements mainly occur as monomer particles,but it is difficult to extract these valuable metals by conventional acid leaching due to their mineral properties.The release of As increases over time in acidic environment.The leaching concentration of all investigated harmful elements through TCLP is within the limiting value,while the leaching concentration of As through CSLT exceeds the limiting value by more than 4 times,so the residue is classified as hazardous solid waste based on the Chinese standard.A process for valuable metals recovery from this residue was proposed.Preliminary experimental results indicated that the main valuable metals could be extracted effectively.展开更多
To study the impact of an artificial waterfall using reclaimed water on volatile organic compounds (VOCs) in air, air samples around the waterfall sight and over the CASS pond of a wastewater treatment plant were co...To study the impact of an artificial waterfall using reclaimed water on volatile organic compounds (VOCs) in air, air samples around the waterfall sight and over the CASS pond of a wastewater treatment plant were collected and VOCs were analyzed by MC-MS with USEPA Method TO-14. The total volatile organic compounds (TOVCs) concentration of a background sample is 2112 μg/m^3, and the sample over the CASS pond has a TVOC concentration of 1858μg/m^3. The TVOC concentrations of air samples within 10 m of the artificial waterfall are between 3216 μg/m^3 and 6362 μg/m^3, which are 1.52 - 3.0 times that of the background sample. The VOCs in air sample impacted by reclaimed water or waste water exhibit a relatively high proportion of toluene but low proportion of benzene. B/T/E/X ( Benzene/Toluene/Ethylbenzene/Xylene ) ratio of the air sample around the artificial water fall is(O. 36/11.78/1/1.10). Health risk assessment (HRA) was done with the USEPA four-step approach. The result indicates that the artificial waterfall using reclaimed water indeed leads to the increase of human risk value. The total risk value of the sample around the waterfall is 2. 8 - 1.6 times that of the background sample. However, the total risk value of the air sample around the waterfall (2. 8 × 10^-6 ) for common people is still lower,compared to the acceptable public risk level( 10^-5 ). For occupational workers of the wastewater treatment plant, the sum of lifetime non-carcinogenic and carcinogenic risk values ( 1.26 × 10^ -5 ) is higher than that of the acceptable public risk level.展开更多
As only about 15% of the total time of people in Hong Kong was spent outdoors, it would be more valuable if the associated effectiveness and impact of the recently proposed abatement measures could be expressed in ter...As only about 15% of the total time of people in Hong Kong was spent outdoors, it would be more valuable if the associated effectiveness and impact of the recently proposed abatement measures could be expressed in terms of the improvement in the total exposure levels. This paper uses an exposure assessment model developed from the local microenvironment concentration data together with our surveyed time activity patterns to evaluate the effectiveness of the proposed air pollution abatement policy. Prior to the enforcement of abatement measures, about 2.5% of the young group and 1.2% of the adult group having their exposure levels exceeded that defined by the current 8-hour PM10 standard (180 μg/m3). With the enforcement of abatement measures, only 0.3% of the adult group would be restored to a safe level.展开更多
For many clustering algorithms,it is very important to determine an appropriate number of clusters,which is called cluster validity problem.In this paper,a new clustering validity assessment index is proposed based on...For many clustering algorithms,it is very important to determine an appropriate number of clusters,which is called cluster validity problem.In this paper,a new clustering validity assessment index is proposed based on a novel method to select the margin point between two clusters for in-ter-cluster similarity more accurately,and provides an improved scatter function for intra-cluster similarity.Simulation results show the effectiveness of the proposed index on the data sets under consideration regardless of the choice of a clustering algorithm.展开更多
The coal processing methods used at the Zarand coal washery plant are the heavy medium bath,jigs,and flotation.The coal-containing materials that are fed to the plant are acquired from different mines,and they have di...The coal processing methods used at the Zarand coal washery plant are the heavy medium bath,jigs,and flotation.The coal-containing materials that are fed to the plant are acquired from different mines,and they have different washability properties.In this paper,the validity of Mayer curve (M-curve),the conventional method for determining coal washability,was evaluated on blending of raw coals that are fed to the plant.Washability curves were prepared for the hand-blended samples and compared with the washability predicted by the Mayer curves.Different samples from different seams and mines were blended by hand in 50:50 ratios,and sink and float tests were performed;the resulting washability curves were in good agreement with the washability curves predicted using the Mayer method for the same blending ratio.This work resulted in the preparation of the optimum plant feed that can be achieved from the blending of different coal samples to produce the best plant yield at a given ash content.展开更多
The IASB stated that in the review of the conceptual framework, if measurement uncertainty is very high, a measurement basis different from fair value may provide more appropriate information. Level 3 fair value measu...The IASB stated that in the review of the conceptual framework, if measurement uncertainty is very high, a measurement basis different from fair value may provide more appropriate information. Level 3 fair value measurements are inappropriate for areas (called "Level 4" by the author) in which models are not formulated and that have material uncertainty in measurement. The purpose of this paper is to elucidate "measurement uncertainty", which impacts "faithful representation" in fair value measurement, from the perspective of "verifiability". To do so, it will employ a conceptual examination of the limits of Level 3 fair value measurement based on IFRS 13 (Fair Value Measurement). While taking into consideration recent discussions on reviewing conceptual framework, the author will reorganize the conceptual categories of verifiability (i.e., clarification of the "reasonable verifiability" categories) to underpin the fact that material uncertainties in measurement have obstructed constructing faithful representation. In addition, the author will discuss the problem that the dichotomy of direct and indirect found in IASB is not accurate enough to fully understand the concept of verifiability. In this context, the author will also suggest that the concept of verifiability, reorganized through "reasonable verifiability", can satisfy the requirements for constructing faithful representation.展开更多
This paper concerns with modeling and design of an algorithm for the portfolio selection problems with fixed transaction costs and minimum transaction lots. A mean-variance model for the portfolio selection problem is...This paper concerns with modeling and design of an algorithm for the portfolio selection problems with fixed transaction costs and minimum transaction lots. A mean-variance model for the portfolio selection problem is proposed, and the model is formulated as a non-smooth and nonlinear integer programming problem with multiple objective functions. As it has been proven that finding a feasible solution to the problem only is already NP-hard, based on NSGA-II and genetic algorithm for numerical optimization of constrained problems (Genocop), a multi-objective genetic algorithm (MOGA) is designed to solve the model. Its features comprise integer encoding and corresponding operators, and special treatment of constraints conditions. It is illustrated via a numerical example that the genetic algorithm can efficiently solve portfolio selection models proposed in this paper. This approach offers promise for the portfolio problems in practice.展开更多
Nowadays, most people' s financial literacy is not high enough in face with the rapid development of economic situation.And currently the popularity of financial education is in a state of scarcity.Thus many countrie...Nowadays, most people' s financial literacy is not high enough in face with the rapid development of economic situation.And currently the popularity of financial education is in a state of scarcity.Thus many countries have taken measures to make financial education more effective. Financial education can not only help financial consumers make wise choice, but also beneficial to the smooth operation of market economy.To some degree, it can also avoid financial crisis.This article introduces the content of financial education and the basic situation of financial education in some developed countries in the first place, and then describes the evaluation of its effectives to raise people' s awareness of financial education and to emphasize the necessity of the evaluation of its effectiveness.展开更多
Traditional portfolio theory assumes that the return rate of portfolio follows normality. However, this assumption is not true when derivative assets are incorporated. In this paper a portfolio selection model is deve...Traditional portfolio theory assumes that the return rate of portfolio follows normality. However, this assumption is not true when derivative assets are incorporated. In this paper a portfolio selection model is developed based on utility function which can capture asymmetries in random variable distributions. Other realistic conditions are also considered, such as liabilities and integer decision variables. Since the resulting model is a complex mixed integer nonlinear programming problem, simulated annealing algorithm is applied for its solution. A numerical example is given and sensitivity analysis is conducted for the model.展开更多
The analysis used simple finite elements is performed to simulate the tensile behavior of corroded reinforcing bars extracted from three actual concrete structures. The cross-sectional area of the elements is set to h...The analysis used simple finite elements is performed to simulate the tensile behavior of corroded reinforcing bars extracted from three actual concrete structures. The cross-sectional area of the elements is set to have the actual distribution measured by 3D laser scanner system. The variable factor in the analysis is the length of the elements. The analysis results show that the length of the elements has a major influence on the deformation capacity after yielding. The calculated stress-strain curves, obtained using the elements with a length that is 2 times the bar diameter, are in good agreement with the tensile test results. The calculated stress-strain curves are modeled using a bi-linear model to facilitate the FEA (finite element analysis) of an overall concrete structure. From the analysis results, both the tensile and yield strengths decrease in proportion to the reduction of the minimum cross-sectional area of corroded bars. The ultimate strain has a remarkable decrement as the reduction of the minimum cross-sectional area. Formulas for determining these values are proposed as a function of the decrement ratio of the minimum cross-sectional area of a corroded bar.展开更多
Objective To provide objective basis for clinical decision through efficacy evaluation of randomized controlled trial on moxibustion in treatment of urinary retention.Methods Chinese National knowledge Infrastructure...Objective To provide objective basis for clinical decision through efficacy evaluation of randomized controlled trial on moxibustion in treatment of urinary retention.Methods Chinese National knowledge Infrastructure(CNKI),China Biology Medicine disc(CBM),VIP,Wanfang Data,and Sciencedirect were retrieved.The objects screened were from January 1,1990 to June 30,2013.Irrelevant,repeated and non-randomized controlled trials were excluded,and randomized controlled trials on moxibustion in treatment of urinary retention conforming to the inclusive criteria were selected.The quality of randomized controlled trials conforming to the inclusive criteria was evaluated using Jadad Scale,and the trials were analyzed statistically via RevMan5.2software.The randomized controlled trials on moxibustion in treatment of urinary retention were evaluated systematically through Cochrane systematic review.Results Nineteen references with better homogeneity were included into the study.Based on Meta-analysis result,the consolidated effect size OR=6.95,95%C/(5.12,9.44),consolidated effect size test Z=12.43,P〈0.000 01,and the difference was statistically significant,indicating that the moxibustion group might be superior to control group,and the efficacy of moxibustion in treatment of urinary retention was better.It was shown from funnel plot that the subjects distributed symmetrically,indicating small bias of study.Conclusion Moxibustion in treatment of urinary retention has a certain efficacy but there are some small sample size and low-quality literature in the study,big sample size and high-quality and formal randomized controlled trials are needed to study in the futher.展开更多
The most recent in vitro tests used to determine metal bioaccessiblility are generally time-consuming and expensive. This study aimed at determining potential relationships between the concentrations of metals extract...The most recent in vitro tests used to determine metal bioaccessiblility are generally time-consuming and expensive. This study aimed at determining potential relationships between the concentrations of metals extracted using single-extraction methods and the concentrations of bioaccessible metals assessed by a harmonised in vitro test, the Unified BARGE Method (UBM). A total number of 27 soil samples were collected from kitchen gardens and lawns with various physicochemical parameters and contamination levels. Significant relationships were obtained between Cd, Pb and Zn extracted in gastric and gastrointestinal phases and using single extractions. The best relationhips were established using acetic and citric acids for Cd, whereas for Pb, citric acid and ethylenedi- aminetetraacetic acid (EDTA) were identified as the best extractants. These relationships were improved by means of a linear multiple regression with a downward stepwise procedure involving agronomic parameters (soil cation exchange capacity and assimilated P). This method highlighted the fact that the cation exchange capacity and P contents in soils were the two main parameters that controlled the human bioaccessibility of Cd, Pb and Zn in the gastric phase. Besides, the metal concentrations extracted with the acetic and citric acids correlated well with the metal concentrations in the gastric and gastrointestinal phases, suggesting that the bioaceessible metals were mainly in a soluble form, weakly bound to the organic matter and associated with the carbonates and the Fe and Mn oxides/hydroxides in soils.展开更多
Hypertension is associated with at least 7.6 million annual deaths worldwide.While pharmacotherapy may provide good control for blood pressure,it sometimes induces adverse effects.Meanwhile,acupuncture has been used f...Hypertension is associated with at least 7.6 million annual deaths worldwide.While pharmacotherapy may provide good control for blood pressure,it sometimes induces adverse effects.Meanwhile,acupuncture has been used for the treatment of cardiovascular diseases,such as hypertension,coronary artery disease,and stroke,but its mechanisms of actions remain poorly understood.The efficacy of acupuncture depends on multiple constituent elements including acupoints,manipulation skills,and implementation programs,which are termed as acupuncture prescription.This review summarized the previous information of experimental use of acupuncture on animals including species,hypertension models,acupoints selection,acupoint location,stimulation protocols,and evaluation of effectiveness to provide useful guidance for researchers when performing acupuncture in animal experiments.展开更多
Twenty-one typical coupled large samples were chosen from areas within and surrounding nature reserves on the Tibetan Plateau using the large sample comparison method(LSCM).To evaluate the effectiveness of the nature ...Twenty-one typical coupled large samples were chosen from areas within and surrounding nature reserves on the Tibetan Plateau using the large sample comparison method(LSCM).To evaluate the effectiveness of the nature reserves in protecting the ecological environment,the alpine grassland net primary production(NPP) of these coupled samples were compared and the differences between them before and after their establishment as protected areas were analyzed.The results showed that:(1) With respect to the alpine grassland NPP,the ecological and environmental conditions of most nature reserves were more fragile than those of the surrounding areas and also lower than the average values for the Tibetan Plateau.(2) Of the 11 typical nature reserves selected,the positive trend in the NPP for Manzetang was the most significant,whereas there was no obvious trend in Taxkorgan.With the exception of Selincuo,the annual NPP growth rate in the nature reserves covered by alpine meadow and wetland was higher than that in nature reserves consisting of alpine steppe and alpine desert.(3) There were notable findings in 21 typical coupled samples:(a) After the establishment of the nature reserves,the annual rate of increase in the NPP in 76% of samples inside nature reserves and 82% of samples inside national nature reserves was higher than that of the corresponding samples outside nature reserves.(b) The effectiveness of ecological protection of the Mid-Kunlun,Changshagongma,Zoige and Selincuo(Selin Co) nature reserves was significant; the effectiveness of protection was relatively sig-nificant in most parts of the Sanjiangyuan and Qiangtang nature reserves,whereas in south-east Manzetang and north Taxkorgan the protection effectiveness was not obvious.(c) The ecological protection effectiveness was significant in nature reserves consisting of alpine meadow,but was weak in nature reserves covered by alpine steppe.This study also shows that the advantage of large sample comparison method in evaluating regional ecology change.Careful design of the samples used,to ensure comparability between the samples,is crucial to the success of this LSCM.展开更多
OBJECTIVE: To assess the safety and effectiveness of Dengzhanxixin injection(DZI) extracted from Dengzhanxixin(Herba Erigerontis Breviscapi) and identify its potential risks.METHODS: A series of studies were conducted...OBJECTIVE: To assess the safety and effectiveness of Dengzhanxixin injection(DZI) extracted from Dengzhanxixin(Herba Erigerontis Breviscapi) and identify its potential risks.METHODS: A series of studies were conducted on the production process, quality standards, and pharmacology. Postmarketing clinical studies and literature reviews including adverse reactions(ADR),adverse events(ADE), case analysis and systematic reviews were also conducted. Data from the hospital information system and spontaneous reporting system were analyzed.RESULTS: The acute toxicity test indicated that the Lethal Dose 50 test( LD 50) dosage was 250 times more than the clinical maximum daily dosage(6mg/kg). In long-term toxicity tests, rats experi-enced renal tubular damage at 480 mg/kg. However, the dose of 120 mg/kg is safe and non-toxic,which is 40 times above the clinical daily maximum. Beagles had increased serum creatinine at160 mg/kg. In a prospective study, 15 962 cases experienced 16 ADR/ADE. The rate of ADR/ADE was0.1002%. ADR symptoms included rash(16.00%),chills(16.00%), and fever(16.00%).CONCLUSION: There is significant evidence that DZI is safe and effective in a clinical setting.展开更多
The design of selective and efficient covalent organic frameworks(COFs)based electrocatalysts with tunable morphology for efficient CO_(2) reduction reaction(CO_(2)RR)to CH_(4) is highly desirable.Here,two kinds of an...The design of selective and efficient covalent organic frameworks(COFs)based electrocatalysts with tunable morphology for efficient CO_(2) reduction reaction(CO_(2)RR)to CH_(4) is highly desirable.Here,two kinds of anthraquinone-based COFs(i.e.,AAn-COF and OH-AAn-COF)with tunable 1D superstructures(e.g.,nanofibers(NF)and hollow tubes(HT))have been produced via Schiff-base condensation reaction.Interestingly,a rarely reported nanosheet-based self-template mechanism and a nanosheet-crimping mechanism have been demonstrated for the production of COF-based nanofibers and hollow tubes,respectively.Besides,the obtained COF-based superstructures can be post-modified with transition metals for efficient CO_(2)RR.Specifically,AAn-COF-Cu(NF)and OH-AAn-COF-Cu(HT)exhibit superior faradaic-efficiency with CH_(4)(FECH_(4))of 77%(-128.1 mA cm^(-2),-0.9 V)and 61%(-99.5 mA cm^(-2),-1.0 V)in a flow-cell,respectively.Noteworthy,the achieved FECH_(4) of AAn-COF-Cu(NF)(77%)is the highest one among reported crystalline COFs.This work provides a general methodology in exploring morphology-controlled COFs for electrocatalytic CO_(2)RR.展开更多
文摘Two-dimensional covalent organic frameworks(2D COFs)feature extendedπ-conjugation and ordered stacking sequence,showing great promise for high-performance photocatalysis.Periodic atomic frameworks of 2D COFs facilitate the in-plane photogenerated charge transfer,but the precise ordered alignment is limited due to the non-covalentπ-stacking of COF layers,accordingly hindering out-of-plane transfer kinetics.Herein,we address a chiral induction method to construct a parallelly superimposed stacking chiral COF ultrathin shell on the support of SiO_(2) microsphere.Compared to the achiral COF analogues,the chiral COF shell with the parallel AA-stacking structure is more conducive to enhance the built-in electric field and accumulates photogenerated electrons for the rapid migration,thereby affording superior photocatalytic performance in hydrogen evolution from water splitting.Taking the simplest ketoenamine-linked chiral COF as a shell of SiO_(2) particle,the resulting composite exhibits an impressive hydrogen evolution rate of 107.1 mmol g^(-1)h^(-1)along with the apparent quantum efficiency of 14.31% at 475 nm.Furthermore,the composite photocatalysts could be fabricated into a film device,displaying a remarkable photocatalytic performance of 178.0 mmol m^(-2)h^(-1)for hydrogen evolution.Our work underpins the surface engineering of organic photocatalysts and illustrates the significance of COF stacking structures in regulating electronic properties.
基金the financial supports from the National Key R&D Program of China(No.2019YFC1907400)the National Natural Science Foundation of China(Nos.51904351,51620105013)。
文摘Physicochemical and mineralogical characteristics of an alkali leaching residue of wolframite were studied by XRD,SEM−EDS,chemical phase analysis,mineral liberation analyzer(MLA),and TG−DSC methods.Batch leaching tests,toxicity characteristic leaching procedure(TCLP)tests and Chinese standard leaching tests(CSLT)were conducted to determine the environmental mobility of toxic elements.The results show that,due to the high contents of W,Fe,Mn,Sn,and Nb,the residue is with high resource value,but the content of a toxic element,As,is also high.The existing minerals of the investigated elements mainly occur as monomer particles,but it is difficult to extract these valuable metals by conventional acid leaching due to their mineral properties.The release of As increases over time in acidic environment.The leaching concentration of all investigated harmful elements through TCLP is within the limiting value,while the leaching concentration of As through CSLT exceeds the limiting value by more than 4 times,so the residue is classified as hazardous solid waste based on the Chinese standard.A process for valuable metals recovery from this residue was proposed.Preliminary experimental results indicated that the main valuable metals could be extracted effectively.
基金the Military Scientific Research Project (Grant No.c8630)
文摘To study the impact of an artificial waterfall using reclaimed water on volatile organic compounds (VOCs) in air, air samples around the waterfall sight and over the CASS pond of a wastewater treatment plant were collected and VOCs were analyzed by MC-MS with USEPA Method TO-14. The total volatile organic compounds (TOVCs) concentration of a background sample is 2112 μg/m^3, and the sample over the CASS pond has a TVOC concentration of 1858μg/m^3. The TVOC concentrations of air samples within 10 m of the artificial waterfall are between 3216 μg/m^3 and 6362 μg/m^3, which are 1.52 - 3.0 times that of the background sample. The VOCs in air sample impacted by reclaimed water or waste water exhibit a relatively high proportion of toluene but low proportion of benzene. B/T/E/X ( Benzene/Toluene/Ethylbenzene/Xylene ) ratio of the air sample around the artificial water fall is(O. 36/11.78/1/1.10). Health risk assessment (HRA) was done with the USEPA four-step approach. The result indicates that the artificial waterfall using reclaimed water indeed leads to the increase of human risk value. The total risk value of the sample around the waterfall is 2. 8 - 1.6 times that of the background sample. However, the total risk value of the air sample around the waterfall (2. 8 × 10^-6 ) for common people is still lower,compared to the acceptable public risk level( 10^-5 ). For occupational workers of the wastewater treatment plant, the sum of lifetime non-carcinogenic and carcinogenic risk values ( 1.26 × 10^ -5 ) is higher than that of the acceptable public risk level.
文摘As only about 15% of the total time of people in Hong Kong was spent outdoors, it would be more valuable if the associated effectiveness and impact of the recently proposed abatement measures could be expressed in terms of the improvement in the total exposure levels. This paper uses an exposure assessment model developed from the local microenvironment concentration data together with our surveyed time activity patterns to evaluate the effectiveness of the proposed air pollution abatement policy. Prior to the enforcement of abatement measures, about 2.5% of the young group and 1.2% of the adult group having their exposure levels exceeded that defined by the current 8-hour PM10 standard (180 μg/m3). With the enforcement of abatement measures, only 0.3% of the adult group would be restored to a safe level.
文摘For many clustering algorithms,it is very important to determine an appropriate number of clusters,which is called cluster validity problem.In this paper,a new clustering validity assessment index is proposed based on a novel method to select the margin point between two clusters for in-ter-cluster similarity more accurately,and provides an improved scatter function for intra-cluster similarity.Simulation results show the effectiveness of the proposed index on the data sets under consideration regardless of the choice of a clustering algorithm.
基金supports for this work that were received from the Zarand coal washing R&D center and Science and Research Branch (Tehran) of Islamic Azad University
文摘The coal processing methods used at the Zarand coal washery plant are the heavy medium bath,jigs,and flotation.The coal-containing materials that are fed to the plant are acquired from different mines,and they have different washability properties.In this paper,the validity of Mayer curve (M-curve),the conventional method for determining coal washability,was evaluated on blending of raw coals that are fed to the plant.Washability curves were prepared for the hand-blended samples and compared with the washability predicted by the Mayer curves.Different samples from different seams and mines were blended by hand in 50:50 ratios,and sink and float tests were performed;the resulting washability curves were in good agreement with the washability curves predicted using the Mayer method for the same blending ratio.This work resulted in the preparation of the optimum plant feed that can be achieved from the blending of different coal samples to produce the best plant yield at a given ash content.
文摘The IASB stated that in the review of the conceptual framework, if measurement uncertainty is very high, a measurement basis different from fair value may provide more appropriate information. Level 3 fair value measurements are inappropriate for areas (called "Level 4" by the author) in which models are not formulated and that have material uncertainty in measurement. The purpose of this paper is to elucidate "measurement uncertainty", which impacts "faithful representation" in fair value measurement, from the perspective of "verifiability". To do so, it will employ a conceptual examination of the limits of Level 3 fair value measurement based on IFRS 13 (Fair Value Measurement). While taking into consideration recent discussions on reviewing conceptual framework, the author will reorganize the conceptual categories of verifiability (i.e., clarification of the "reasonable verifiability" categories) to underpin the fact that material uncertainties in measurement have obstructed constructing faithful representation. In addition, the author will discuss the problem that the dichotomy of direct and indirect found in IASB is not accurate enough to fully understand the concept of verifiability. In this context, the author will also suggest that the concept of verifiability, reorganized through "reasonable verifiability", can satisfy the requirements for constructing faithful representation.
文摘This paper concerns with modeling and design of an algorithm for the portfolio selection problems with fixed transaction costs and minimum transaction lots. A mean-variance model for the portfolio selection problem is proposed, and the model is formulated as a non-smooth and nonlinear integer programming problem with multiple objective functions. As it has been proven that finding a feasible solution to the problem only is already NP-hard, based on NSGA-II and genetic algorithm for numerical optimization of constrained problems (Genocop), a multi-objective genetic algorithm (MOGA) is designed to solve the model. Its features comprise integer encoding and corresponding operators, and special treatment of constraints conditions. It is illustrated via a numerical example that the genetic algorithm can efficiently solve portfolio selection models proposed in this paper. This approach offers promise for the portfolio problems in practice.
文摘Nowadays, most people' s financial literacy is not high enough in face with the rapid development of economic situation.And currently the popularity of financial education is in a state of scarcity.Thus many countries have taken measures to make financial education more effective. Financial education can not only help financial consumers make wise choice, but also beneficial to the smooth operation of market economy.To some degree, it can also avoid financial crisis.This article introduces the content of financial education and the basic situation of financial education in some developed countries in the first place, and then describes the evaluation of its effectives to raise people' s awareness of financial education and to emphasize the necessity of the evaluation of its effectiveness.
文摘Traditional portfolio theory assumes that the return rate of portfolio follows normality. However, this assumption is not true when derivative assets are incorporated. In this paper a portfolio selection model is developed based on utility function which can capture asymmetries in random variable distributions. Other realistic conditions are also considered, such as liabilities and integer decision variables. Since the resulting model is a complex mixed integer nonlinear programming problem, simulated annealing algorithm is applied for its solution. A numerical example is given and sensitivity analysis is conducted for the model.
文摘The analysis used simple finite elements is performed to simulate the tensile behavior of corroded reinforcing bars extracted from three actual concrete structures. The cross-sectional area of the elements is set to have the actual distribution measured by 3D laser scanner system. The variable factor in the analysis is the length of the elements. The analysis results show that the length of the elements has a major influence on the deformation capacity after yielding. The calculated stress-strain curves, obtained using the elements with a length that is 2 times the bar diameter, are in good agreement with the tensile test results. The calculated stress-strain curves are modeled using a bi-linear model to facilitate the FEA (finite element analysis) of an overall concrete structure. From the analysis results, both the tensile and yield strengths decrease in proportion to the reduction of the minimum cross-sectional area of corroded bars. The ultimate strain has a remarkable decrement as the reduction of the minimum cross-sectional area. Formulas for determining these values are proposed as a function of the decrement ratio of the minimum cross-sectional area of a corroded bar.
基金Supported by National Natural Science Foundation of China:81072883,81173342Hebei Education Department Research Foundation:Z2014145
文摘Objective To provide objective basis for clinical decision through efficacy evaluation of randomized controlled trial on moxibustion in treatment of urinary retention.Methods Chinese National knowledge Infrastructure(CNKI),China Biology Medicine disc(CBM),VIP,Wanfang Data,and Sciencedirect were retrieved.The objects screened were from January 1,1990 to June 30,2013.Irrelevant,repeated and non-randomized controlled trials were excluded,and randomized controlled trials on moxibustion in treatment of urinary retention conforming to the inclusive criteria were selected.The quality of randomized controlled trials conforming to the inclusive criteria was evaluated using Jadad Scale,and the trials were analyzed statistically via RevMan5.2software.The randomized controlled trials on moxibustion in treatment of urinary retention were evaluated systematically through Cochrane systematic review.Results Nineteen references with better homogeneity were included into the study.Based on Meta-analysis result,the consolidated effect size OR=6.95,95%C/(5.12,9.44),consolidated effect size test Z=12.43,P〈0.000 01,and the difference was statistically significant,indicating that the moxibustion group might be superior to control group,and the efficacy of moxibustion in treatment of urinary retention was better.It was shown from funnel plot that the subjects distributed symmetrically,indicating small bias of study.Conclusion Moxibustion in treatment of urinary retention has a certain efficacy but there are some small sample size and low-quality literature in the study,big sample size and high-quality and formal randomized controlled trials are needed to study in the futher.
基金the Nord-Pas de Calais Council and Agence de l’Environnement et de la Matrise de l’Energie (ADEME), France, for the financial support of this research
文摘The most recent in vitro tests used to determine metal bioaccessiblility are generally time-consuming and expensive. This study aimed at determining potential relationships between the concentrations of metals extracted using single-extraction methods and the concentrations of bioaccessible metals assessed by a harmonised in vitro test, the Unified BARGE Method (UBM). A total number of 27 soil samples were collected from kitchen gardens and lawns with various physicochemical parameters and contamination levels. Significant relationships were obtained between Cd, Pb and Zn extracted in gastric and gastrointestinal phases and using single extractions. The best relationhips were established using acetic and citric acids for Cd, whereas for Pb, citric acid and ethylenedi- aminetetraacetic acid (EDTA) were identified as the best extractants. These relationships were improved by means of a linear multiple regression with a downward stepwise procedure involving agronomic parameters (soil cation exchange capacity and assimilated P). This method highlighted the fact that the cation exchange capacity and P contents in soils were the two main parameters that controlled the human bioaccessibility of Cd, Pb and Zn in the gastric phase. Besides, the metal concentrations extracted with the acetic and citric acids correlated well with the metal concentrations in the gastric and gastrointestinal phases, suggesting that the bioaceessible metals were mainly in a soluble form, weakly bound to the organic matter and associated with the carbonates and the Fe and Mn oxides/hydroxides in soils.
基金the National Basic Research Program of China:the Epigenetic Regulatory Mechanism of the Specificity of Acupoints(973 Program,No.2012CB518501)the National Natural Science Foundation of China:the Regulatory Mechanism of AS-Neuron Crosstalk With Energy for Promoting Synaptic Plasticity in Hippocampus Treated by Acupuncture(No.81202743)+1 种基金Deacetylation Modification in Personalized Medicine for Acupuncture-Based Weight-Loss(No.81303019)Mechanistic Study of STAT5-miR-193b Pathway in Obesity and Weight Loss by Acupuncture(No.81273838)
文摘Hypertension is associated with at least 7.6 million annual deaths worldwide.While pharmacotherapy may provide good control for blood pressure,it sometimes induces adverse effects.Meanwhile,acupuncture has been used for the treatment of cardiovascular diseases,such as hypertension,coronary artery disease,and stroke,but its mechanisms of actions remain poorly understood.The efficacy of acupuncture depends on multiple constituent elements including acupoints,manipulation skills,and implementation programs,which are termed as acupuncture prescription.This review summarized the previous information of experimental use of acupuncture on animals including species,hypertension models,acupoints selection,acupoint location,stimulation protocols,and evaluation of effectiveness to provide useful guidance for researchers when performing acupuncture in animal experiments.
基金The Strategic Priority Research Program of the Chinese Academy of Sciences,No.XDB03030500National Key Technology Research and Development Program,No.2013BAC04B02+1 种基金Key Foundation Project of Basic Work of the Ministry of Science and Technology of China,No.2012FY111400National Natural Science Foundation of China,No.41171080,No.41201095
文摘Twenty-one typical coupled large samples were chosen from areas within and surrounding nature reserves on the Tibetan Plateau using the large sample comparison method(LSCM).To evaluate the effectiveness of the nature reserves in protecting the ecological environment,the alpine grassland net primary production(NPP) of these coupled samples were compared and the differences between them before and after their establishment as protected areas were analyzed.The results showed that:(1) With respect to the alpine grassland NPP,the ecological and environmental conditions of most nature reserves were more fragile than those of the surrounding areas and also lower than the average values for the Tibetan Plateau.(2) Of the 11 typical nature reserves selected,the positive trend in the NPP for Manzetang was the most significant,whereas there was no obvious trend in Taxkorgan.With the exception of Selincuo,the annual NPP growth rate in the nature reserves covered by alpine meadow and wetland was higher than that in nature reserves consisting of alpine steppe and alpine desert.(3) There were notable findings in 21 typical coupled samples:(a) After the establishment of the nature reserves,the annual rate of increase in the NPP in 76% of samples inside nature reserves and 82% of samples inside national nature reserves was higher than that of the corresponding samples outside nature reserves.(b) The effectiveness of ecological protection of the Mid-Kunlun,Changshagongma,Zoige and Selincuo(Selin Co) nature reserves was significant; the effectiveness of protection was relatively sig-nificant in most parts of the Sanjiangyuan and Qiangtang nature reserves,whereas in south-east Manzetang and north Taxkorgan the protection effectiveness was not obvious.(c) The ecological protection effectiveness was significant in nature reserves consisting of alpine meadow,but was weak in nature reserves covered by alpine steppe.This study also shows that the advantage of large sample comparison method in evaluating regional ecology change.Careful design of the samples used,to ensure comparability between the samples,is crucial to the success of this LSCM.
基金Supported by National Science and Technology Major Projects for"Major New Drugs Innovation and Development":Study on Key Technologies of Postmarketing Evaluation for Chinese Medicine(No.2009ZX09502-030)
文摘OBJECTIVE: To assess the safety and effectiveness of Dengzhanxixin injection(DZI) extracted from Dengzhanxixin(Herba Erigerontis Breviscapi) and identify its potential risks.METHODS: A series of studies were conducted on the production process, quality standards, and pharmacology. Postmarketing clinical studies and literature reviews including adverse reactions(ADR),adverse events(ADE), case analysis and systematic reviews were also conducted. Data from the hospital information system and spontaneous reporting system were analyzed.RESULTS: The acute toxicity test indicated that the Lethal Dose 50 test( LD 50) dosage was 250 times more than the clinical maximum daily dosage(6mg/kg). In long-term toxicity tests, rats experi-enced renal tubular damage at 480 mg/kg. However, the dose of 120 mg/kg is safe and non-toxic,which is 40 times above the clinical daily maximum. Beagles had increased serum creatinine at160 mg/kg. In a prospective study, 15 962 cases experienced 16 ADR/ADE. The rate of ADR/ADE was0.1002%. ADR symptoms included rash(16.00%),chills(16.00%), and fever(16.00%).CONCLUSION: There is significant evidence that DZI is safe and effective in a clinical setting.
基金supported by the National Natural Science Foundation of China(21871141,21871142,21901122,22071109 and 92061101)the Natural Science Research of Jiangsu Higher Education Institutions of China(19KJB150011)+3 种基金China Postdoctoral Science Foundation(2018M630572 and 2019M651873)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX201171)Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Foundation of Jiangsu Collaborative Innovation Center of Biomedical Functional Materials.
文摘The design of selective and efficient covalent organic frameworks(COFs)based electrocatalysts with tunable morphology for efficient CO_(2) reduction reaction(CO_(2)RR)to CH_(4) is highly desirable.Here,two kinds of anthraquinone-based COFs(i.e.,AAn-COF and OH-AAn-COF)with tunable 1D superstructures(e.g.,nanofibers(NF)and hollow tubes(HT))have been produced via Schiff-base condensation reaction.Interestingly,a rarely reported nanosheet-based self-template mechanism and a nanosheet-crimping mechanism have been demonstrated for the production of COF-based nanofibers and hollow tubes,respectively.Besides,the obtained COF-based superstructures can be post-modified with transition metals for efficient CO_(2)RR.Specifically,AAn-COF-Cu(NF)and OH-AAn-COF-Cu(HT)exhibit superior faradaic-efficiency with CH_(4)(FECH_(4))of 77%(-128.1 mA cm^(-2),-0.9 V)and 61%(-99.5 mA cm^(-2),-1.0 V)in a flow-cell,respectively.Noteworthy,the achieved FECH_(4) of AAn-COF-Cu(NF)(77%)is the highest one among reported crystalline COFs.This work provides a general methodology in exploring morphology-controlled COFs for electrocatalytic CO_(2)RR.