Structure optimization of the organ-pipe cavitating nozzle and its erosion ability test on hydrate-bearing sediments

Cavitating jet is a promising drilling rate improvement technology in both the marine natural gas hydrate (NGH) fluidization exploitation method and the integrated radial jet drilling and completion method. In present study, we aim to improve the efficiency of jet erosion and extracting NGH. With a computational fluid dynamics (CFD) method, the pressure, velocity and cavitation field characteristics of organ-pipe cavitating jet (OPCJ) are analysed. The divergent angle, throat length, and divergent length of OPCJ nozzle are preferred to obtain stronger jet cavitation erosion effect. Laboratory experiments of gas hydrate-bearing sediments (GHBS) erosion by OPCJ and conical jet (CJ) are conducted to compare and validate the jet erosion performance. The impinging models of OPCJ and CJ are constructed to study the impact characteristics. Results show that the preferred values of divergent angle, throat length, and divergent length are 15°, 1d, and 3d, respectively, in present simulation conditions. For GHBS, the OPCJ possesses the advantages of high efficiency and low energy consumption. Moreover, the OPCJ has higher penetration efficiency, while showing equivalent penetration ability compared to CJ. During the impinging process, the OPCJ can induce stronger impact pressure and turbulence effect, and also shows stronger chambering effect and bottom cleaning ability compared to CJ. This study presents the erosion performance of OPCJ and CJ on GHBS, and provides preliminary insights on the potential field applications in NGH exploitation.

Quantifying the natural growth rate of hepatocellular carcinoma:A real-world retrospective study in southwestern China

BACKGROUND In recent years,approximately half of the newly diagnosed cases and mortalities attributed to hepatocellular carcinoma(HCC)have been reported in China.Despite the high incidence of HCC,there remains a paucity of data regarding the natural growth pattern and the determination of optimal surveillance intervals specific to the Chinese population.AIM To quantify the natural tumor growth pattern of HCC in regional China.METHODS A retrospective analysis was performed on patients from a single institution in Southwest China who had undergone two or more serial dynamic computed tomography or magnetic resonance imaging scans between 2014 and 2020,without having received any anti-cancer therapy.Tumor growth was assessed using tumor volume doubling time(TVDT)and tumor growth rate(TGR),with volumes measured manually by experienced radiologists.Simple univariate linear regression and descriptive analysis were applied to explore associations between growth rates and clinical factors.RESULTS This study identifies the median TVDT for HCC as 163.4 d,interquartile range(IQR)72.1 to 302.3 d,with a daily TGR of 0.42%(IQR 0.206%-0.97%).HCC growth patterns reveal that about one-third of tumors grow indolently with TVDT exceeding 270 d,another one-third of tumors exhibit rapid growth with TVDT under 90 d,and the remaining tumors show intermediate growth rates,with TVDT ranging between 3 to 9 months.CONCLUSION The identified TGRs support biannual surveillance and follow-up for HCC patients in certain regions of China.Given the observed heterogeneity in HCC growth,further investigation is warranted.

Evaluation of Water Losses by Evaporation in the Nakanbe Basin

A numerical approach to heat and mass transfer in a large water reservoir is presented. This water reservoir is likened to a parallelepiped reservoir whose vertical and lower walls are adiabatic and impermeable. The equations that govern natural convection in water are solved by the finite volume method and Thomas’salgorithm. The adequacy between the velocity and pressure fields is ensured by the SIMPLE algorithm. We are going to evaluate the water losses by evaporation from three dams in the Nakanbé basin in Burkina Faso for a period of thirty years, that is to say from January 1, 1991, to March 15, 2020. The three dams have a rate of evaporation greater than 40% of the volume of water stored. Indeed the rate of evaporation in each dam increases with the water filling rate in the reservoir: we have observed the following results for each dam in the Nakanbé basin;for the date of 02/27/1988 to 03/13/2020., the Loumbila dam received a total volume of stored water of 22.02 Mm3 and 10.57 Mm3 as the total volume of water evaporated at the same date. At the Ouaga dam (2 + 3), it stored a water volume of 4.06 Mm3 and evaporated 2.03 Mm3 of its storage volume from 01/01/1988 to 05/07/2016. Finally, with regard to the Bagré dam, it stored 745.16 Mm3 of water and 365.13 Mm3 as the volume of water evaporated from 01/01/1993 to 03/31/2020.

Theoretical Study on the Structures, Vibrational Spectra, and the Nature of the Intermediate Hydrogen Bond of Schiff Bases

Semi-empirical method PM3 was used to study the geometry and vibrational spectrum of N-(2-hydroxy-l-naphthyl-methylene)-l-pyrenamine (NPY) with the intermediate hydrogen bond. Results are comparable to experimentations. Based on results of both NPY and its model, N-(2-hydroxy-l-naphthyl-methylene)aniline, it was found that the N-(2-hydroxy-l-naphthyl-methylene) group is principally responsible for the special hydrogen bonding through conjugation effect.

First principle study on the possibilities of magnetism in one-dimensional In and Tl atomic wires with the full-potential linearized augmented plane wave method

Using ab initio total energy calculations with the full-potential linearized augmented plane wave method, the possibilities of magnetism in one-dimensional In and Tl wires were explored and their properties as the function of geometric structures were studied. The results suggest that the linear In and Tl wires show magnetization at the equilibrium bond distance with magnetic moments of 0.71 and 0.67 μB/atom, respectively. Allowing ions to relax, the wires were deformed as zigzag structures, but no dimerization occurs. The zigzag wires also exhibit spontaneous magnetization, although the magnetic moments are lower than those of straight wires.

The First Principles Study of Hydrogen Adsorption on Ni-Decorated LiB(001) Surface

The hydrogen adsorption on the one and three Ni-decorated LiB （001） 2 × 2 surface is investigated by the first principles study. It is demonstrated that Ni atoms are preferentially adsorbed on the top B atom, and form a covalent bond of NiB and an ionic bond of NiLi on the surface. Four H2 molecules can adsorb on the one- Ni-decorated LiB （001） surface, and the average adsorption energy is in a range from -0.35 to -0.58eV/H2. The charge population analysis shows that the dipole moments on the Ni decorated surface is responsible for the polarization and adsorption of H2. Then, we show that three Ni atoms can be decorated on the LiB （001） 2 × 2 surface, and form a Ni3B nano cluster on the surface, which agrees with experimental results. Three Ni- decorated LiB （001） can adsorb up to six H2 molecules, indicating that the Ni-decorated LiB （001） system might be a promising hydrogen storage material.

The Core Mechanism of Natural Selection: How the Natural Cycle of Potassium Resources Affects the Biological Evolution and the Change of Human Society

Darwin’s theory of evolution believes that biological evolution is a process of natural selection. This theory has been supported by much evidence, but the internal biological mechanism is not clear. Here, I elaborate on the cycle of potassium resources on the earth and the biological utilization and efficiency, which may be the core mechanism of natural selection and affect the evolution of organisms and the development of human society.

翻译学归结论视角下Of Studies两个中译本比较研究

弗朗西斯·培根的说理性散文Of Studies论说了读书的作用、方法和好处,结构紧凑,语言说服力强。翻译学归结论认为,翻译本身具有关联性,“关联”为翻译的第一原则;同时,翻译使译语文本无限趋近于源语文本,使得两种语篇之间达到最大程度的对等,“趋同”为翻译的第二原则。本文从翻译学归结论的视角出发,选取流传较广的王佐良和曹明伦的译本进行对比分析,探讨王、曹两译本在词类转换、语态转换、增译法、减译法等翻译技巧的处理上所存在的异同,以期为后来译者提供借鉴之处,并丰富Of Studies中译本的研究视角。通过对比分析发现,两个中译本在意义传达、形式呈现、修辞对等方面,做到了源语文本和译语文本之间动态的对等,使原作者的意图符合目的语读者的期待,最大程度上趋近于原作,很好地体现了关联原则和趋同原则。

Applying“First Principles of Instruction”as a Design Theory of the EFL Classroom:Findings from an Empirical Study

How to benefit the learners learning English as a foreign language(EFL)from the aspect of instructional design aroused the concerns of many teachers and researchers.The main purpose of this study is to address the question of how teachers can design and implement EFL classroom that benefit the learners.Specifically,the“First Principles of Instruction,”advocated by Merrill(2002),was applied by the English teachers to conduct their day-to-day pedagogical practices.The corresponding effects of this theory in designing EFL classroom activities were reported in this study.Two research questions are formulated as follows:(1)Does the“First Principles of Instruction”benefit the EFL classroom designing in the aspect of student achievement?If yes,what is the effect?(2)How do the English teachers perceive the“First Principles of Instruction”to design EFL classroom?While observing the EFL classroom activities and interviewing the college English teachers,an empirical study was done to perceive how college English teachers could best apply these principles to design EFL classroom activities.

A Four-Pronged Analysis on the Skeptics of the Belt and Road

Although many people around the world have positively responded to China’s Belt and Road Initiative, there are still some who are skeptical about it. This paper runs a four-pronged analysis on this phenomenon from the dimensions of scientific principles, mentalities,cognitions and senses. The author believes that people’s opinions on the Belt and Road reflect their outlook on China, the world and the West. They are a mirror reflecting how the international community sees China and how Chinese see the world in a time of unprecedented change. In order to alleviate this skepticism and to promote the construction of the Belt and Road from confidence to conscientiousness, this paper strives to transcend the current international relations theories by integrating Chinese characteristics to set up a new, comprehensive Belt and Road Study so that people can jointly discuss, strengthen, enjoy and study the Belt and Road Initiative, and eventually bring people’s mentality to a rational perspective on it, rather than one characterized by raw emotion.

Natural Selection and Thermodynamics of Biological Evolution

The author of this article proposes that the representation of Charles Darwin and Alfred Wallace’s theory on “variation and selection” in the living world is a reflection of the action of hierarchical thermodynamics. Hierarchical thermodynamics is based on the law of temporal hierarchies and on the principle of substance stability. This principle enables the transmission of thermodynamic information between lower and higher structural hierarchies, in both forward and reverse direction: from nucleic acids to higher structural hierarchies and back. The principle of substance stability, in fact, is the main dynamical and thermodynamic mechanism of natural selection. It is alleged that the natural selection of atoms, molecules, organisms, populations, and other hierarchical structures takes place under the action of a variety of internal factors within organisms and the external environmental factors that can be considered as tropisms. Forms (design) of living organisms are formed as a result of spontaneous and non-spontaneous processes that lead to the adaptation of living systems to the environment. The selection is carried out as a result of the impacts of different energy types and the principle of substance stability at all levels of hierarchical structures. Actions of tropisms are presented by various members of the generalized Gibbs equation.

Study on Active Principle and Modernization of Chinese Drugs

The people as a whole cannot live for one day without drug, and the requirement of drugs would never come to an end or stay on the same level. Pharmaceutical industry, being of great significance, has become a new and important one in economic growth in the 21st century. Therefore, the modernization of Chinese drugs has also become a hot spot in public opinion in recent years.

Pilot Trial on the Efficacy and Safety of a Natural Mineral Water Rich in Hydrogen Carbonate on Functional Dyspepsia and Heartburn

Background: Dyspepsia and heartburn are among the most frequent complaints of the upper gastrointestinal tract impacting quality of life. The present study aimed to investigate the impact of drinking a natural mineral water (medicinal product category “Heilwasser” in Germany) high in hydrogen carbonate (Staatl. Fachingen STILL) on functional dyspeptic complaints and heartburn. Methods: 56 men and women with self-reported heartburn were enrolled to this one-arm pilot study. They had to drink 1.5 L of a hydrogen carbonate rich mineral water each day over a course of six weeks. Participants reported the number and duration of heartburn episodes in a daily dairy. The Reflux Disease Questionnaire (RDQ), Quality of Life in Reflux and Dyspepsia questionnaire (QOLRAD) and the Gastrointestinal Quality of Life Index (GILQI) were used to assess the therapeutic course of the treatment and the Short Form Health Survey (SF-12) to assess general quality of life. Mean ± standard deviation were calculated and pre- and post-treatment changes were compared using the Wilcoxon test. Results: The consumption of a hydrogen carbonate rich mineral water decreased the number of heartburn episodes per week significantly by 4.8 ± 8.2 at the end of the study (p < 0.001). The duration of episodes was also significantly reduced by 25.7 minutes after six weeks of intervention (p < 0.001). Accordingly, the subjectively perceived severity of heartburn, regurgitation and dyspeptic complaints as well as the GERD dimension as assessed by Reflux Disease Questionnaire improved significantly. There was a significant improvement in the disease-specific quality of life as measured by the Gastrointestinal Quality of Life Index (p < 0.001) and by the Quality Of Life in Reflux and Dyspepsia (p < 0.001) questionnaires and the general health-related quality of life as assessed by SF-12 (p < 0.007). Conclusions: The present pilot study provides evidence that supplementation with natural mineral water rich in hydrogen carbonate may improve heartburn and dyspeptic symptoms, which finally resulted in an improvement of the subjectively perceived quality of life. Drinking mineral water rich in hydrogen carbonate may be an alternative remedy for the treatment of dyspeptic symptoms and heartburn. Trial Registration: Eudra CT No 2013-001256-36.

Understanding class silence in China： Approach from the perspective of intercultural study

Chinese students tend to keep silent in class and bear in mind what has been taught passively rather than expressing their ideas actively like westem students, which concems Chinese teachers deeply because of the unsatisfactory class production. From the perspectives of ＂face＂ in Politeness Principle on the basis of cultural dimensions, this paper mainly focuses on class silence with a comparison between different cultures in the east and west, explores the true reasons for its happening in China and constructs a reference research for follow-up studies.

First-principles study on the mechanical properties of M2CT2（M=Ti,Zr,Hf;T=O,F,OH） MXenes

Two-dimensional(2D)transition metal carbides known as MXenes belong to a new branch of 2D material family,and their fundamental properties vary with their compositions and surface functionalizations.In this study,the structural and ideal mechanical properties of M2C-type MXenes and their functionalized M2CT2 MXenes(M=Ti,Zr,Hf;T=O,F,OH)were systematically examined via first-principles methods.The stress–strain curves of the MXenes under homogenous biaxial and uniaxial tension are identified,and the fundamental quantities(e.g.,Young’s modulus,in-plane stiffness,and Poisson’s ratio)are addressed.With significantly higher strength and extended critical strains,the M2CO2 MXenes exhibit optimal flexibility when compared with that of M2C,M2CF2,and M2C(OH)2.Additionally,Hf2CT2 exhibits optimal tensile performance under uniaxial or biaxial tension when compared to that of Ti2CT2 and Zr2CT2.The Young’s modulus,in-plane stiffness,and Poisson’s ratio of MXenes with different surface functionalization increase in a sequence corresponding to OH\F\O.Furthermore,the effects of vacancy on the mechanical properties of MXenes are further explored and indicate that vacancy can significantly weaken the tensile properties of MXenes that are considered.Moreover,vacancy also results in a certain anisotropy of stress along armchair and zigzag directions even under the biaxial tension condition.

Pragmatic Studies of Politeness in Chinese and English Culture

Polite words and expression can shorten the communication distance,ease the tension and conflict. As cultures are diverse, politeness is diverse. This paper is mean to explain the politeness in pragmatic use and its cultural specificity.

A Comparative Study of Nature's Subjectivity in Walden and Tang Poems

Thoreau's Walden and Chinese Tang Poems both attach great importance to nature,devoting large paragraphs to the depiction of it.The significance of this phenomenon is discussed in this paper.Based on the method of close reading and comparative study,it is found that nature,portrayed by Thoreau and Tang poets share one important character,that is,nature assumes subjectivity as an individual being.

The Application of Natural Elements in Interior Landscape Design and its Principal Analysis

The rapid development of the decoration industry creates a good development space for interior decoration,and the public pays more attention to the integration of natural elements in the process of interior decoration.In this regard,this article introduces the ways in which natural elements are embodied in indoor landscapes,and expounds the principles of using natural elements in indoor landscapes,hoping to provide references for relevant personnel.