Ferroelectricity induced by the absorption of water molecules on double helix SnIP

We study the ferroelectricity in a one-dimensional(1D)system composed of a double helix SnIP with absorbing water molecules.Our ab initio calculations reveal two factors that are critical to the electrical polarization.The first one is the orientation of polarized water molecules staying in the R2 region of SnIP.The second one is the displacement of I atom which roots from subtle interaction with absorbed water molecules.A reasonable scenario of polarization flipping is proposed in this study.In the scenario,the water molecule is rolling-up with keeping the magnitude of its electrical dipole and changing its direction,meanwhile,the displacement of I atoms is also reversed.Highly tunable polarization can be achieved by applying strain,with 26.5%of polarization enhancement by applying tensile strain,with only 4%degradation is observed with 4%compressive strain.Finally,the direct band gap is also found to be correlated with strain.

Research on the cultural transmission of college students under the background of the ＂double first-class＂university construction

Throughout the world＇s first-class universities, the university culture is the soul of the universities＇ survival and development, and the cultural competitiveness has become an important symbol of the core competitiveness of the universities. The first-class university culture is very important to the construction of the ＂double first-class＂. Therefore, our country should bring the university cultural construction into the big pattern of the ＂double first-class＂ construction, guide the construction of the university cultures with the socialist core values, strengthen the cultural confidence, inherit the Chinese excellent traditional cultures, pay attention to the rational exchange of the multicultural cultures, highlight the Chinese characteristics of the first-class university cultures, and realize the dream of the Chinese nation of a power of the higher education.

Textual Form and Cultural Affect: William Empson′s Double-Plot and Raymond Williams′s Structure of Feeling

By insisting on the primacy of double-plot, Empson brackets the sometimes deceptive appearances of a text′s content to uncover and disengage the more fundamental double-plot system at work within the defining structure of the text. Empson′s thinking about the reception of double-plot structures enables Raymond Williams′s early formulations of structure of feeling, in particular the gesturing this perplexing, underdeveloped, but persistent concept makes towards understanding collective response to cultural forms. This article explores the implications of the reception of double-plot structures, drawing out the assumptions inscribed in Empson′s claims about processes at work as an audience engages with these dramatic structures.

Exceptionally high genetic variance of the doubled haploid(DH)population of poplar

Doubled haploid(DH)plants have been widely used for breeding and biological research in crops.Pop ulus spp.have been used as model woody plant species for biological research.However,the induction of DH poplar plants is onerous,and limited biological or breeding work has been carried out on DH individuals or populations.In this study,we provide an effective protocol for poplar haploid induction based on an anther culture method.A total of 96 whole DH plant lines were obtained using an F1hybrid of Populus simonii×P.nigra as a donor tree.The phenotypes of the DH population showed exceptionally high variance when compared to those of half-sib progeny of the donor tree.Each DH line displayed distinct features compared to those of the other DH lines or the donor tree.Additionally,some excellent homozygous lines have the potential to be model plants in genetic and breeding studies.

Liquid holdup measurement with double helix capacitance sensor in horizontal oil-water two-phase flow pipes

This paper presents the characteristics of a double helix capacitance sensor for measurement of the liquid holdup in horizontal oil–water two-phase flow. The finite element method is used to calculate the sensitivity field of the sensor in a pipe with 20 mm inner diameter and the effect of sensor geometry on the distribution of sensitivity field is presented. Then, a horizontal oil–water two-phase flow experiment is carried out to measure the response of the double helix capacitance sensor, in which a novel method is proposed to calibrate the liquid holdup based on three pairs of parallel-wire capacitance probes. The performance of the sensor is analyzed in terms of the flow structures detected by mini-conductance array probes.

EFFECT OF GEAR WIDTH AND HELIX ANGLE ON FACTOR OF DYNAMIC LOAD OF DOUBLE CIRCULAR ARC HELICAL GEARING

Based on theory of mechanical dynamics, meshing characteristic as well as thedynamic model of double circular arc helical gearing, an analysis approach and a computer programhave been developed for studying the state of dynamic load and factor of dynamic load of thegearing, the changing situation of dynamic load and dynamic load factor vs some affecting factorssuch as gear width, helix angle and accuracy grade etc are investigated. A series of conclusions areobtained: ①With the increasing in the values of gear width, the dynamic load factor appears slowdecreasing tendency in most region of gear width. ②When the accuracy grades of the gearing areimproved, the values of dynamic load factor decrease. ③The value of dynamic load factor appears adecreasing tendency with the increasing of value of helix angle at the same ratio of criticalrotational speed.

Middle or low water pressure direct spiral double helix converging nozzle structure optimization and flow field analysis

In order to solve the problem of using new nozzle is proposed in fire rescue robot. middle or low water pressure to form fine water mist, a Existing water mist nozzles are basically used for high pressure and in large size, complex structure and poor low pressure atomization effect in comparison with requirement of snake-like fire rescue robots. On the basis of comprehensive typical spray noz- zles, a direct spiral double helix converging nozzle （DSDHCN） is proposed, which has the advanta- ges of small volume, light weight, simple structure, and convenient installation. To make the spray nozzle have good performance, and meet the requirements of more efficient fire extinguishing, a nu- merical study is carried out to analyze the internal and external full flow field of nozzle. A gas-liquid two-phase flow is applied to simulate the external full flow field of nozzle with VOF model in fluent software. The simulation results show the real situation of water flow out of the atomization nozzle and the water jet trajectory. Some simulations about middle or low water pressure direct spiral double he- lix converging optimized nozzle have been done in 30bar pressure. The simulation results show that the optimized nozzle structure not only makes the spray droplets have a good cone angle, but also have a sufficient axial velocity,which proves the structure rationality of the proposed optimized nozzle.

The charge transfer via a double helix DNA

This paper reports a double helix model of charge transfer in DNA molecule. The calculated results show that the transmission characteristics of DNA are not only related to the longitudinal transfer but also to the helicity of molecule. It finds that there are four transmission bands centred at 0.92, 3.07, 7.75 and 8.87eV, also the width and intensity of bands corresponding to the helix direction are less than that of the longitudinal direction. With the increase of hopping energy, transmission bands become wide so that the transmission ability is enhanced.

Explore the Mystery of the Origin of the Double Helix and the Biomembrane

In nature, the most possible reason that helix is chosen as the basic structure of life molecule is based on its simplest chiral three-dimensional structure. The process of the conversion from chemical molecules to double helical molecules is completed by the topology effect which belongs to the simplest way to form helix, and no external power is needed;moreover, the energy of double helix has fixed drive direction [1]. The dual-branch loop helix (II)—the transition state of double helix has many uses, for example, it can be turned to double helix, and it may be broken into two fragments of a and b which can construct more complicated structures. So the dual- branch loop helix (II) can provide special "building block" of assembling biomembrane and other life molecules.

Design and motion control analysis of double helix wall climbing robot

For the detection environment of complex walls such as high-rise buildings,a double helix wall climbing robot(DHWCR)with strong adsorption force and good stability is designed and developed,which uses symmetrical propellers to provide adsorption force.The symmetrical driving structure can provide smooth thrust for the DHWCR,so that the robot can be absorbed to the wall surface with different roughness.A left and right control frame with multiple degrees of freedom is designed,which can adjust the fixed position of the brushless propeller motor in the front and back directions,realize the continuous adjustable thrust direction of the robot,and improve the flexibility of the robot movement.Using the front wheel steering mechanism with universal joint,the steering control of the DHWCR is realized by differential control.In the vertical to ground transition,the front and rear brushless motors can provide the pull up and oblique thrust,so that the DHWCR can smoothly transition to the vertical wall.The motion performance and adaptability of the DHWCR in the horizontal ground and vertical wall environment are tested.The results show that the DHWCR can switch motion between the horizontal ground and vertical wall,and can stably adsorb on the vertical wall with flexible attitude control.The DHWCR can move at a fast speed.The speed on the horizontal ground is higher than that on the vertical wall,which verifies the feasibility and reliability of the DHWCR moving stably on the vertical wall.

Gametic selection in a doubled haploid population derived from anther culture of indica/japonica hybrid of Oryza Sativa L.

It is one of the key problems for application ofanther culture in hybrid breeding, geneticanalysis, and molecular mapping whether thedoubled haploid (DH) population derived fromanther culture of rice crosses represents a ran-dom array of the microspore population, i.e.whether gametic selection occurs in androgene-sis. A DH population including 132 lines de-

重瓣大花萱草“Double Firecracker”组培快繁技术

建立一套完整的重瓣大花萱草"Double Firecracker"的组织培养快繁体系。选取"Double Firecracker"的花茎为外植体。结果表明:适合重瓣大花萱草"Double Firecracker"花茎的最佳消毒方法为75%乙醇30s+0.1%HgCl210min,最佳的愈伤组织诱导培养基为MS+0.2mg·L-1 NAA+3mg·L-16-BA,最佳的不定芽诱导与增殖培养基为MS+0.1mg·L-1 NAA+2.0mg·L-1 6-BA,最佳的生根培养基为1/2 MS+0.2mg·L-1NAA。为"Double Firecracker"的大规模生产提供基础数据。

SnIP-type atomic-scale inorganic double-helix semiconductors: Synthesis, properties, and applications

Flexible inorganic double helical semiconductors similar to DNA have fueled the demand for efficient materials with innovative structures and excellent properties.The recent discovery of tin phosphide iodide(SnIP),the first carbon-free double helical semiconductor at an atomic level,has opened new avenues of research for semiconducting devices such as thermoelectric and sensor devices,solar cells,and photocatalysis.It has drawn significant academic attention due to its high structural flexibility,band gap in the visible spectrum range,and non-toxic elements.Herein,the recent progress in developing SnIP,including its prestigious structure,versatile and intriguing properties,and synthesis,is summarized.Other analogues of SnIP and SnIP-based hybrid materials and their applications in photocatalysis are also discussed.Finally,the review concludes with a critical summary and future aspects of this new inorganic semiconductor.

Development and Characterization of Elite Doubled Haploid Lines from Two Indica Rice Hybrids

Despite significant yield advantage over inbred rice, the adoption rate of hybrid rice in India is very low due to the high seed cost and poor quality of the produce. To alleviate the problem, we initiated a doubled haploid （DH） breeding approach to develop new lines from two elite indica rice hybrids （CRHR5 and CRHR7） through rapid fixation of homozygosity in the recombinants. In vitro culture of the rice anthers resulted in 243 and 186 fertile DH lines of CRHR5 and CRHR7, respectively. Flow cytometric and pollen fertility analyses confirmed the DH ploidy status of the regenerations. Morpho-agronomic evaluation revealed 100% uniformity and stability for all the characters in the DH lines of both hybrids. Nineteen promising DH lines of each hybrid were advanced to A2 generation for yield evaluation. The yield levels of the DH lines ranged from 5 097-6 965 kg/hm^2 for CRHR5 and 5 141-7 235 kg/hm^2 for CRHR7, which were at par or higher than the parental hybrids. Physico-chemical characterization and cooking quality analyses revealed significant and acceptable values for grain length and width, alkali spreading value, amylose content and water uptake ratio of the selected DH lines. Three DH lines, CR5-10, CR5-49, CR5-61 from CRHR5, and four DH lines, CR7-5, CR7-7, CR7-12 and CR7-52 from CRHR7, showed significant grain yield and quality characteristics and have been recommended for multi-location trials for subsequent release as new indica doubled haploid rice varieties.

What Governs the Unzipping Process of Double-Stranded DNA

The unzipping process of double-stranded DNA is analysed using a discrete model at the base level [Chin. Phys. Lett. 22 （2005）1540]. The numerical results are consistent with the experimental observations on the force-displacement behaviour including the sequence-dependence. We find that the hydrogen bond interaction in a base pair is crucially important to the force-displacement profile.

Genetic Diversity Analysis of Elite Doubled Haploid Rice Genotypes for Yield Attributing Traits in White Nile State, Sudan

The development of new rice varieties is highly dependent on genetic diversity in desirable agronomic traits. Therefore, this study aimed to identify potential genotypes having the characters of Korean varieties (Tongil-type) and japonica developed through doubled haploid (DH) technology to apply in our breeding materials. 35 elite DH lines derived from another culture of Korean and African rice along with two local checks were planted in a randomized complete block design with three replications during the two seasons of 2019 and 2020. All evaluated genotypes exhibited a wide and significant variation in the ten measured traits. The highest heritability related to high genetic advance was recorded for the number of tiller/plant, grain yield t/ha, number of filled grain per panicle, and thousand grain weights (g). Genotypic coefficient of variation and genetic advance were recorded for number of tiller/plant, number of filled grain per panicle, 1000 grain weight and grain yield t/ha in both seasons. Moreover, there was a highly significant and positive correlation of grain yield with number of filled grain per panicle (0.65), number of tiller/plant (0.64) and number of panicle per m2 (0.54). Cluster analysis based on grain yield components trait grouped the 37 rice genotypes into four clusters. Cluster B was the largest and consisted of 13 genotypes. Finally, it could be concluded that, based on number of productive tillers, number of filled grain/panicle, number of panicle per m2, and grain yield, the lines KF170506, KF170509, KF170542, KF170530, KF170543, KF170500 and KF170510 were high potential for further selection for new type of irrigated rice. In addition, hybridization of these 7 high-yielding could be used to achieve higher heterosis among the genotypes. Furthermore, this evaluation could be useful in developing reliable selection indices for improving rice breeding programs.

中国职业教育文化传统的解释与正名——“大器之谓”及其当代价值

传承中华优秀传统文化背景之下,中华优秀传统职业教育文化的传承成为职业教育领域的重要课题。每当中国职业教育发展陷入困境中,人们总是习惯归咎于“君子不器”的文化传统,但却忽视了“经世致用”的文化取向。这实际上归结于对职业教育文化传统的误读而不是文化传统本身的问题。据此,采介谱系学的基本范式,秉持后传统理论、民族性线索与复杂性场域等解释依据,在针对“君子不器”与“经世致用”文化“双螺旋构型”的审鉴中,解析出指向“大器”铸成的职业教育文化根脉,以此明晰“大器”的培养取向在于兼备德艺周厚、通艺通道的“中国式”博雅工匠。“大器”的当代价值,可在我国职业教育文化传承、文化创新、文化治理、文化效用方面发挥新的牵引作用,从而为我国职业教育高质量发展挖掘新的文化自信。

基于双螺旋式加热器的柔性MEMS流量传感器

针对传统流量传感器的量程限制,提出了一种基于双螺旋结构加热器的柔性基底微机电系统(MEMS)热式流量传感器。在基底上打出均匀通孔阵列以降低热传导损耗,两对测温电阻对称分布在加热器两侧,以获得较宽量程,在微小流量与大流量下均表现出较高灵敏度。采用基于惠斯通电桥的检测电路实现输出电压的测量,同时保持加热器与环境温度恒定温差200 K,对电阻自热进行补偿。传感器工作温度-100~400℃,量程为0~60 m/s;低流速下灵敏度约为12.75 V/(m·s^(-1)),分辨率可达0.001 mm/s,高流速下灵敏度约为1.4 mV/(m·s^(-1)),功耗低至1.3 mW。

“双万计划”背景下体育专业大学生核心素养培育研究

文章运用专家访谈法、文献资料法和案例分析法等研究方法,在“双万计划”背景下对体育专业大学生核心素养培育进行研究,从体育专业大学生核心素养的结构出发,探究其研究价值,提出以做体育文化人为导引,更新培育方式;以德术相长为根基,完善课程结构;“学-练-赛”与“五心”培育相结合,更新培养思路;以知行合一及勇于担当为思想,强化培养目标的策略,以丰富核心素养研究的理论成果。

中国共产党推进中华民族共同体意识成长的历史进程与基本经验

中华民族共同体意识是在客观历史进程与主观人为建构相互耦合的“双螺旋结构”中得以生成发展的。中国共产党自成立以来就有意识地推进中华民族共同体意识成长,成为引领这项事业发展的核心力量。运用文本分析、历史分析和规范分析方法梳理百余年来中国共产党推进中华民族共同体意识成长进程,可以将其划分为五个阶段,分别是建党到新中国成立时期从“自在”到“自觉”的初步探索、新中国成立到社会主义改造基本完成时期从“自觉”到“自为”的逐渐成熟、全面建设社会主义时期的曲折与徘徊、社会主义建设新时期的复苏与加速,以及新时代以来在“自为”之路全方位、多维度的成长与迈进。百余年来中国共产党推进中华民族共同体意识成长经验表明:必须坚持党的领导;中华民族愿意接受并坚决拥护党的领导。这是中国共产党推进中华民族共同体意识成长不断走向胜利的首要前提和根本原因。