让珠心算课堂生活化

将生活引入珠心算课堂,有效地激发学生们的学习热情,让珠心算课堂富有生活情节,创设轻松的学习氛围,努力减轻学生负担,提高课堂效率。

Fast algorithm for constructing neighbor-joining phylogenetic trees

To improve the performance of Saitou and Nei＇s algorithm （SN） and Studier and Keppler＇s improved algorithm （SK） for constructing neighbor-joining phylogenetic trees and reduce the time complexity of the computation, a fast algorithm is proposed. The proposed algorithm includes three techniques. First, a linear array A[N] is introduced to store the sum of every row of the distance matrix （the same as SK）, which can eliminate many repeated computations. Secondly, the value of A [i] is computed only once at the beginning of the algorithm, and is updated by three elements in the iteration. Thirdly, a very compact formula for the sum of all the branch lengths of operational taxonomic units （OTUs） i and j is designed, and the correctness of the formula is proved. The experimental results show that the proposed algorithm is from tens to hundreds times faster than SN and roughly two times faster than SK when N increases, constructing a tree with 2 000 OTUs in 3 min on a current desktop computer. To earn the time with the cost of the space and reduce the computations in the innermost loop are the basic solutions for algorithms with many loops.

对国民经济大核算体系的思想探析

任何事物的发展,都有一定的逻辑基础蕴含其中。那么,当我们探讨如何正确建立国民经济大核算体系的模式时,同样有必要从国民经济核算的发展史去寻找它的逻辑基础。以马克思主义哲学为基本工具,以国民经济核算原理为基础,从国民经济核算思想发展的逻辑脉络上,去探讨了国民经济大核算体系的发展模式。

A Comparative Study of Agricultural Informatization for China and Beyond

[Objective] The aim was to discuss the classification of agricultural informatization in some developed countries, and conclude the revelation to Chinese agricultural informatization. [Method] The research was made by comparison, according to the development impetus. [Result] The results show that foreign agricultural informatization is mainly divided into three categories： the first category is the government leading; the second category is the industry self-help; the third category is typical demonstration. Since the reform and opening, Chinese agricultural informatization has made considerable achievements. [Conclusion] The agricultural informatization is significant to promote the update of the traditional agriculture, and it is also essential to Chinese agricultural sustainability.

Application of cross-cultural cognitive pragmatic analysis to translation education

Translation is cross-cultural activity existing between two different language signs. In the process of translating, translators can not get out of the influence of cultural elements. From the angle of cross-cultural pragmatic contrasting, the author makes analysis of the problems of difference existing between the volume of information borne or transmitted between two different language signs in the process of translating under the influence of cultural elements, and points out that to study these problems, translators must consider a series of problems about cross-cultural cognitive context. This article also makes cross-cultural pragmatic contrastive analysis in world view difference, register difference, imaginative difference and metaphor difference. The author introduces the method of cross-cultural pragmatic contrastive analysis and suggests taking a series of measures to improve translation education.

Optimization and experimental research on a new-type short cylindrical cup-shaped harmonic reducer

In order to obtain a new-type short cylindrical cup-shaped flexspline that can be applied to space mechanisms,the APDL language of ANSYS software was employed to develop a parameterized equivalent contact model between a flexspline and a wave generator. The validity of the parameterized equivalent contact model was verified by comparing the results of the analytic value of the contact model and the value calculated by the theoretical formula. The curvilinear trend of stress was obtained by changing the structural parameter of the flexspline. Based on the curvilinear trend of stress,multi-objective optimizations of key structural parameters were achieved. Flexspline,wave generator,and circular spline of a new 32-type short cylindrical cup-shaped harmonic reducer were designed and manufactured. A performance test bench to carry out tests on the harmonic reducer was designed. Contrast experiments were implemented to determine the efficiency of the new 32-type short cylindrical cup-shaped harmonic reducer and the conventional 32-type harmonic reducer under different conditions. The experimental results reveal that there is approximately equality in terms of efficiency between the new 32-type short cylindrical cup-shaped harmonic reducer and the conventional 32-type harmonic reducer. The volume of the flexspline of the new 32-type short cylindrical cup-shaped harmonic reducer is reduced by approximately 30% through multi-objective optimization. When the new 32-type short cylindrical cup-shaped harmonic reducer is used on the wheel of a rover prototype,the mass of the wheel hub is decreased by 0.42 kg. Test analysis of wheel motion verifies that the new 32-type short cylindrical cup-shaped harmonic reducer can meet the requirements regarding bearing capacity and efficiency.

Study on oil–source correlation by analyzing organic geochemistry characteristics: a case study of the Upper Triassic Yanchang Formation in the south of Ordos Basin, China

In the south of the Ordos Basin, the oil source of the Upper Triassic Yanchang Formation is confused all the time, which affects further exploration. In this study, oil sources from the oil layers of Ch6, Ch8 and Ch9 are all analyzed and confirmed. Through their carbon isotope value and biomarkers, characteristics of crude oils from the Yanchang Formation are analyzed. Then, the oil–source relation is discussed, with the source rocks' features.Finally, the oil–source relation is calculated through cluster analysis. It is believed that the oils from the Yanchang Formation deposit in a similar redox environment, with weak oxidation–weak reduction, and have all entered maturity stage. Ch9 crude oil is more mature than crude oils from Ch6 and Ch8, and has more advanced plants and fewer algae. Gas chromatography(GC) and gas chromatography–mass spectrometry(GC–MS) analysis show that crude oils from Ch6 and Ch8 may come from Ch7, and Ch9 crude oil may not. Cluster analysis displays that crude oils from Ch6 and Ch8 have closer squared Euclidean distance with Ch7 source rocks than Ch9 crude oil does,indicating crude oils from Ch6 and Ch8 stem from Ch7 source rocks. And Ch9 crude oil has rather close squared Euclidean distance with Ch9 source rocks, illustrating Ch9 crude oil may be from Ch9 source rocks. This research may provide the theoretical basis for the next exploration deploy in the south of Ordos Basin.

Coronary Artery Vasospasm with Acute Myocardial Infarction in a Male Patient： Case Report

We present a 48-year-old male patient with a history of classic precordialgia, ST-segment elevation in inferior leads （II, III and aVF）, with t：oponin m：d CK-MB （creatine kinase-MB） elevated on the day of admission that received conventional anti-ischemic treatment. Hemodynamically stable, symptom-free, is referred to cardiac catheterization. In the selective catheterization of the left coronary artery, a moderate lesion was observed in the middle third of the anterior descending coronary artery; in the right coronary artery, a subocclusive proximal lesion with TIMI （thrombolysis in myocardial infarction） II. We performed a single projection m：d opted for angioplasty. Before, it was decided to re-evaluate the left coronary artery, m：d it was observed in the contrast test that anterior descending artery was occluded. Intra-coronary nitroglycerin and new contrast injection were performed, which showed totally open descending artery with TIMI III, without obstructive lesions as initially suggested, and improvement of pain. It was a severe coronary vasospasm. When a new contrast injection was performed in the right coronary, with a therapeutic catheter, the disappeaxance of the subocclusive lesion and the presence of a normal coronary flow were observed, although there was a moderate plaque in its proximal third, which motivated the maintenance of angioplasty with stent placement in a proxhnal third of right coronary artery. During the passage of the intracoronary guidewire it was once again evident that diffuse coronary artery vasoreactivity was present; the procedure was successfully completed.

Isolation and characterization of bioactive fungi from shark Carcharodon carcharias' gill with biopharmaceutical prospects

Until recently, little was known about the fungi found in shark gills and their biomedicinal potential. In this article, we described the isolation, bioactivity, diversity, and secondary metabolites of bioactive fungi from the gill of a shark （Carcharodon carcharias）. A total of 115 isolates were obtained and grown in 12 culture media. Fifty-eight of these isolates demonstrated significant activity in four antimicrobial, pesticidal, and cytotoxic bioassay models. Four randomly selected bioactive isolates inhibited human cancer cell proliferation during re-screening. These active isolates were segregated into 6 genera using the internal transcribed spacer-large subunit （ITS-LSU） rDNA-sequence BLAST comparison. Four genera, Penicillium, Aspergillus, Mucor, and Chaetomium were the dominant taxa. A phylogenic tree illustrated their intergenera and intragenera genetic diversity. HPLC-DAD-HRMS analysis and subsequent database searching revealed that nine representative strains produced diverse bioactive compound profiles. These results detail the broad range of bioactive fimgi found in a shark＇s gills, revealing their biopharmaceutical potential. To the best of our knowledge, this is the first study characterizing shark gill fungi and their bioactivity.

Building Long-Term Care Insurance System in China

The objective is to explore the foundation of the elderly long-term care insurance system in China, which is to face the problem resulted from aging of the population. Adopting the contrastive analysis to introduce briefly the long-term care insurance system in German, Japan and America for our learning. Therefore, China＇s long-term care insurance system could not totally indiscriminately imitate the mandatory long-term care insurance system in German and Japan, it also could not copy the business model of nursing insurance system in America. The conclusion is that long-term care insurance system in China should use the experience of developed countries based on the basic national conditions, doing some relative works, such as establishing policies and regulations, strengthening personnel training, and improving the market specification.

Automatic Optimization of Chirp Setting Parameters in Medical Ultrasound Contrast Imaging

Medical ultrasound contrast imaging is a powerful modality undergoing successive developments in the last decade to date Lately, pulse inversion has been used in both ultrasound tissue harmonic and contrast imaging. However, there was a tradeoff between resolution and penetration. Chirp excitations partially solved the tradeoff, but the chirp setting parameters were not optimized. The present work proposes for the first time combining chirp inversion with ultrasound contrast imaging, with the motivation to improve the contrast, by automatically optimizing the setting parameters of chirp excitation, it is thus an optimal command problem. Linear chirps, 5 μm diameter microbubbles and gradient ascent algorithm were simulated to optimize the chirp setting parameters. Simulations exhibited a gain of 5 dB by automatic optimization of chirp inversion relative to pulse inversion. The automatic optimization process was quite fast. Combining chirp inversion with ultrasound contrast imaging led to a maximum backscattered power permitting high contrast outcomes and optimum parameters.

An experimental comparison of water based alumina and silica nanofluids heat transfer in laminar flow regime

Experimental investigations were carried out to determine the Al2O3/water and SiO2/water nanofluids flowing through a circular tube. convective heat transfer performance and pressure drop of Measurements show that the addition of small amounts of nano-sized Al2O3 particles to the base fluid increases heat transfer coefficients considerably, while the result for the silica nanofluids contradicts with the alumina nanofluids and this leads to some interesting results. In the case of alumina nanofluids, an average increase of 16% in convective heat transfer coefficient is observed with an average penalty of 28% in pressure drop. Moreover, flow resistance increases significantly compared to the base fluid even at very low concentrations of nanofluids. Finally, measured heat transfer coefficients are compared with predicted ones from the correlation of Shah under the same conditions.

Numerical study on the spatially varying drag coefficient in simulation of storm surges employing the adjoint method

From the simulation of storm surges resulting from Typhoons 7203 and 8509 in the Bohai Sea, Yellow Sea and East China Sea, water level data at tide stations are assimilated into a two-dimensional storm surge model, to study the spatially varying drag coefficient (DC) by employing the adjoint method. In this study, the DC at some grid points is uniformly selected as the independent DC, while the DC at other grid points is obtained through linear interpolation of the independent DC. The DC at independent points is optimized by employing the adjoint assimilation method, and global optimization is achieved by optimizing the independent DC. To demonstrate the method's performance, three comparative experiments are carried out. In the first experiment, the DC is treated as a constant. In the second and third experiments, the DC is derived using an empirical formula. Comparing the experimental results, it is found that the simulation accuracy for both Typhoons 7203 and 8509 increases greatly when optimizing the independent DC. However, the number of independent points makes no great difference to the precision of simulation. Moreover, the DC inverted from Typhoons 7203 and 8509 differs in some sea areas because of the different typhoon tracks. However, the spatial distribution of the inverted DC, for both Typhoons 7203 and 8509, demonstrates a clear effect of the DC on the storm surge modeling near the coastal areas where the DC is highest or lowest.

A Comparative Study on Heat Transfer Performance of Typical Petrochemical Reactors

The performance of heat transfer is a key issue for reactor design in petrochemical industry. Since the heat transfer in reactors is a complicated process and depends on multiple parameters, the evaluation of the heat transfer performance is usually challenging, and few previous studies gave an overall view of heat exchange performance of different types of reactors. In this review, heat transfer coefficients of two types of petrochemical reactors, including the packed bed and the fluidized bed, were systematically analyzed and compared based on a number of reported correlations. The relationship between heat transfer coefficients and fluid flow velocity in different reactors has been well established, which clearly demonstrates the varying range of their heat transfer coefficients. Heat transfer coefficients of gas-phase packed bed can exceed 200 W/m^2·K, rather than the suggested values(17—89 W/m^2·K) mentioned in the literature. The fluidized bed shows better performance for both two-phase and three-phase beds as compared to the packed bed. Systems with liquid phase also show better heat transfer performance than other phases because of the larger heat capacity of liquid. Thus the industrial three-phase fluidized beds have the best heat transfer performance with an overall heat transfer coefficient of greater than 1 000 W/m^2·K. The heat transfer results provided by this review can afford not only new insights into the heat transfer in typical reactors, but also the basis and guidelines for reactor design and selection.

Biomass Vapogasification in Fluidized Bed： Modelling of Char Population Balance and Experimental Validation

The article presents a population balance model by mass developed for studying char gasification by steam occuring in a fluidized bed. The model has been validated by comparison with existing theoretical and experimental cases. Its main goal is to have a better understanding on particles size distribution behaviour during operation of the fluidized bed, and in particular to be applied on the case of Fast Internally Circulating Fluidized Beds for char gasification. Results have shown that the initial properties of the fluidized bed particles （bed and size distribution） are almost not involved in the steady state obtained in continous operation, which is excusively dependent on the properties of the fed particles flow rate and size distribution, the withdrawal flow rate and the reaction properties. Morevoer, it has been proven that the steady state fluidized bed mass and size distribution may be theroretically controlled by an adequate choice of feeding and withdrawal flow rates.

Experimental study of fatigue degree quantification for multi-feature fusion identification

A comprehensive quantification method of fatigue degree is proposed concerning subjective and objective quantifications.Using the fatigue degree test software,fatigue degree is objectively quantified by analyzing the reaction and operation abilities of drivers about traffic signals.By comparison experiment with that EEG signal based,multivariate statistical analysis and fusion identification based on BP neural network(BPNN) results show that the experimental procedure is simple and practical,and the proposed method can reveal the correlation between fatigue feature parameters and fatigue degree in theory,and also can achieve accurate and reliable quantification of fatigue degree,especially under the associated action of multiple fatigue feature parameters.

Dynamics of Quantum Discord in Asymmetric and Local Non-Markovian Environments

The non-Markovian decoherence of quantum and classical correlations is analytically obtained when two qubits are asymmetrically subjected to the bit flip channel and phase flip channel. For one class of initial mixed states, quantum correlations quantified by quantum discord decay synchronously with classical correlations. The discovery that the decaying rates of quantum and classical correlations suddenly change at the characteristic time is physically interpreted by the distance from quantum state to the closest classical states. In a large time interval, quantum correlations are greater than classical correlations. The quantum and classical correlations can be preserved over a longer period of time via the kernel characterizing the environment memory effects.

Use of laser speckle contrast imaging to reveal changes in temperature and blood perfusion in the skin of healthy subjects after administration of heated moxa sticks and Daiwenjiu ointment

OBJECTIVE: To investigate the influence of heated moxa sticks( "moxibustion") and Daiwenjiu ointment(DO) on changes in temperature and blood perfusion volume on the skin of the backs of healthy subjects.METHODS: DO was spread on the left side of the body, and the right side of the body was treated with a heated moxa stick. Images denoting blood perfusion and body temperature were collected 7-8 cm lateral to the spinous process of the sixth thoracic vertebra using laser speckle contrast imaging(LSCI). Data obtained from eight-frame images were analyzed and used to calculate the mean blood perfusion volume. Simultaneously,blood-perfusion images were collected from the body surface and used to compare the change in blood flow on the body surface and the actual position of imaging.RESULTS: After moxibustion, a rapid increase in blood perfusion volume and body temperature was noted in the local skin surface. The maximum blood perfusion volume and body temperature was noted at 20 min(P<0.05). At 80-110 min after the spreading of DO, a gradual increase was noted in blood perfusion volume(P<0.05) and body temperature(P<0.05) compared with the baseline level. The maximum blood perfusion volume was at 110 min.CONCLUSION: Using LSCI, these data revealed a rapid and sharp increase in blood perfusion volume and body temperature after treatment with moxibustion, but the respective changes seen in the DO group were gradual and moderate.