GeoGebra用于酸碱滴定曲线精准绘制及滴定终点误差计算

酸碱滴定曲线和滴定终点误差是分析化学课程中酸碱滴定章节的重要教学内容。针对此内容提出了“强模型化、融信息化、增可视化和去公式化”的总教学策略,形成了以电荷平衡关系式、稀释定律和形态分布系数等为底层逻辑的“三步模型法”滴定方程推演过程;采用GeoGebra软件为信息化手段,实现了滴定方程的可视化和数字解。

分析化学教学中引入动态缓冲容量“去公式化”计算的新策略

缓冲容量是分析化学重要内容。目前教材中缓冲容量计算没有考虑缓冲溶液与样品溶液混合时体积的变化,这种不考虑体积变化的缓冲容量被称为“静态”缓冲容量。而在实际应用中,往往缓冲溶液与样品溶液混合后的体积远远大于缓冲溶液的原始体积,此时需要考虑“动态”缓冲溶液。这里提出了一种“动态”缓冲容量问题的“去公式化”解决方案,它完全基于学科思想的底层逻辑,不会增加学生学习的记忆负担。

Development and Application of a Power Law Constitutive Model for Eddy Current Dampers

Eddy current dampers (ECDs) have emerged as highly desirable solutions for vibration control due to theirexceptional damping performance and durability. However, the existing constitutive models present challenges tothe widespread implementation of ECD technology, and there is limited availability of finite element analysis (FEA)software capable of accurately modeling the behavior of ECDs. This study addresses these issues by developing anewconstitutivemodel that is both easily understandable and user-friendly for FEAsoftware. By utilizing numericalresults obtained from electromagnetic FEA, a novel power law constitutive model is proposed to capture thenonlinear behavior of ECDs. The effectiveness of the power law constitutive model is validated throughmechanicalproperty tests and numerical seismic analysis. Furthermore, a detailed description of the application process ofthe power law constitutive model in ANSYS FEA software is provided. To facilitate the preliminary design ofECDs, an analytical derivation of energy dissipation and parameter optimization for ECDs under harmonicmotionis performed. The results demonstrate that the power law constitutive model serves as a viable alternative forconducting dynamic analysis using FEA and optimizing parameters for ECDs.

仪器分析课程中绿色度概念的引入

将绿色度引入仪器分析课程中,在简述绿色化学、绿色分析化学以及绿色液相色谱的基础上,重点讲述HPLCEAT和CHEMS-1两种表征绿色度的方法,包括它们的使用、应用范围、局限性,并对它们绿色度结果进行了相关性分析。HPLC-EAT和CHEMS-1均可以用于表征液相色谱的绿色度,计算过程易于学生掌握。

虚拟仿真软件辅助液相色谱分离条件的绿色优化实验

由于耗时长、废液多等制约因素,大学高效液相色谱(HPLC)实验均未涉及分离条件的优化,实验中学生只是“照方抓药”完成操作练习,其面向特定分离对象构建HPLC分析方案的实践能力并未得到有效培养。为此,我们提出一种改进方案:将色谱进样练习和大黄蒽醌类化合物的检测实验有机结合起来,在不延长学时的前提下,采用虚拟仿真软件HPLC Simulator进行色谱条件优化。学生在进样练习实验中通过分工协作获取不同温度、不同流动相配比条件下的保留时间数据;在全体同学共享实验数据的基础上,利用HPLC Simulator软件实现色谱分离条件的绿色优化。软件模拟输出的最优色谱条件在第二次课上得到实验验证。这种改进措施将原本枯燥无味的色谱进样练习升华为探索性的实验,激发了学生的学习热情。可使学生在有限的学时内掌握色谱条件的优化方法,培养学生利用信息技术解决实际问题的能力,提高信息化背景下的实验教学质量。另外,通过分工协作数据共享可以更好地培养学生的团队合作精神。

Hypoxia-Mediated Upregulation of Semaphorin 3A during Pulp Revascularization

Semaphorin 3A could be involved in angiogenesis and also enhanced bone formation was investigated in many researches. In our current study, we firstly investigated that canal obliteration might be present in some regenerative endodontic procedures cases clinically. After the establishment of the model of apical periodontitis in the maxillary first molars of rats, pulp revascularization was performed in mesial root canal. Histological sections showed that most of the tissues growing into the root canal were not real pulp tissue, but cementoid, osteoid and periodontal-like membrane. Moreover, we detected that the expression of Semaphorin 3A increased in the mesial root canal. When we used CoCl2 to induce hypoxic environment, the expression of genes and proteins, Hypoxia inducible factor-1α, Vascular endothelial growth factor, and Semaphorin 3A in dental pulp stem cells were both upregulated. In conclusion, hypoxia mediated the high expression of Semaphorin 3A in DPSC might be involved tissue regeneration during pulp vascularization.

Numerical simulation of tumor-induced angiogenesis influenced by the extra-cellular matrix mechanical environment

To investigate tumor-induced angiogenesis under the influence of the mechanical environments inside and outside the tumor, mathematical model of tumor angiogenesis was developed. In the model, extra-cellular matrix （ECM） was treated as a thin plane. The displacement of ECM is obtained from the force balance equation consisted of the ECs traction, the ECM visco-elastic forces and the exter- nal forces. Simulation results show that a layered capillary network is obtained with a well vascularized region at the periphery of the tumor. The present model can be used as a valid theoretical method in the basic researches in tumorinduced angiogenesis.

Strengthening Brand Construction and Improving the Competitiveness of Tropical Distinctive Agricultural Products in Hainan

Brand construction plays an increasingly important role in marketing and competition in modern agricultural industry. There are problems in brand construction of tropical distinctive agricultural products in Hainan,including less famous brand products,weak core competence,strengthening declaration and ignoring management as well as imperfect marketing system,therefore resource integration should be stressed to develop famous brand products and technological innovation should be strengthened to promote core competence of enterprise.

Improved Superconducting Qubit State Readout by Path Interference

High fidelity single shot qubit state readout is essential for many quantum information processing protocols. In superconducting quantum circuit, the qubit state is usually determined by detecting the dispersive frequency shift of a microwave cavity from either transmission or reflection. We demonstrate the use of constructive interference between the transmitted and reflected signal to optimize the qubit state readout, with which we find a better resolved state discrimination and an improved qubit readout fidelity. As a simple and convenient approach, our scheme can be combined with other qubit readout methods based on the discrimination of cavity photon states to further improve the qubit state readout.

Development Mode and Recommendations for Industrialization of Tropical Agricultural Science and Technology

Industrialization of tropical agricultural science and technology is an essential part of tropical agricultural technological innovation.This paper firstly analyzed development mode of industrialization of tropical agricultural science and technology in Chin and then came up with recommendations for developing industrialization of tropical agricultural science and technology.

Risk Assessment of Perioperative Infection about 263 Diabetic Patients Undergoing Small Bowel Lateral-lateral Anastomos(intestinal bypass)

Ojectie:Aalyze and summarize the risks ssopenat of peripeative ifecioo of 263 diabetic patients undergoing small bowel lateral-lateral astomps(intestinal bypass)in the small intstine's side.discuss the managenial metbods of antimicrobial agents during the perioperative period Methods:Retospectively apalyze the dinial data of patients who underwent laparoscopic small bowel lateral anastomosis(ntestinal bypass)fnom Japary 2018 to December 2018.The patients with HB.AIC≥9.0%were selected a5 the observation group and patients with HBAIC<9.0%as the control group.Resuls:The decling range of the arverage value about blood ghucose in the observaion group was geater tho that in the comtrol goup The iference was stisicaly significant(P<0.05).The average postoperative neutophil nio of the observation group as higher than that of the control group;and the difference was saistically signifcant(P<0.05).The proportion of patients with postopenive bodty temperarure over 37 degees in the observation group was higher than that in the cootol group.Conchusion:Lapunoscopic latena anastomosis(intestinal boypass surgery)may cause intestinal fluid overflow and inesinal flora ectopic.for the diabetic patients with poor blood glucose control,perioperative risk of infection increased,we should consider strengthening the gade of antimicrobial agents in preventive apliation,better cover gram-negative bacteria and annerobic bacteria.

理论揭示锂硫电池第二放电平台的主要液固相转换机制

锂硫电池因其高理论能量密度、环境友好和低廉的成本而被认为是前景广阔的新型储能设备,但在放电后半程中缓慢的还原动力学严重阻碍其实际应用.虽然各种先进的正极材料改善了反应动力学,但硫还原反应(SRR)的复杂机理给提高锂硫电池性能设下许多障碍.深入研究其电催化机理是指导阴极材料设计和应用的重要环节.本文将揭示从Li_(2)S_(3);向Li_(2)_(S))(2)/Li_(2)_(S)的转化机制,即揭示从液相多硫化物到固相多硫化物的硫还原反应.以Ti、V、Fe、Co和Ni单原子催化剂为正极催化材料,建立基于密度泛函理论计算的电催化模型.中间产物^(*)LiS、^(*)LiS_(2)被用作预测反应路径、速率决定步骤和过电位的描述因子.这项工作解释了放电后期可溶多硫化物向不溶多硫化物的转化机理,为设计先进的高性能锂硫电池电催化剂提供了指导.

Emerging hierarchical mesoporous materials of covalent organic frameworks

Benefiting from abundant exposed active sites,minimized diffusion resistance of guest molecules,facilitated mass transfer process and enhanced storage capacity,covalent organic frameworks(COFs)have gained widespread scientific attention[1–4].Further construction of mesopores regarding pore engineering(pore size,pore geometry,pore volume,and framework compositions)in COFs can improve mass transport,accessibility as well as size-selectivity of the special guest moieties,thus exhibiting potential in catalysis,energy storage and separation and so on[5,6].

Generalized Isospectral-Nonisospectral Modified Korteweg-de Vries Integrable Hierarchies and Related Properties

In this article, a new technique for deriving integrable hierarchy is discussed, i.e., such that are derived by combining the Tu scheme with the vector product. Several classes of spectral problems are introduced by threedimensional loop algebra and six-dimensional loop algebra whose commutators are vector product, and the six-dimensional loop algebra is derived from the enlargement of the three-dimensional loop algebra. It is important that we make use of the variational method to create a new vector-product trace identity for which the Hamiltonian structure of the isospectral integrable hierarchy is worked out. The derived integrable hierarchies are reduced to the modified Korteweg-de Vries(mKdV) equation, generalized coupled mKdV integrable system and nonisospectral mKdV equation under specific parameter selection. Starting from a 3×3 matrix spectral problem, we subsequently construct an explicit N-fold Darboux transformation for integrable system(2.8) with the help of a gauge transformation of the corresponding spectral problem. At the same time, the determining equations of nonclassical symmetries associated with mKdV equation are presented in this paper. It follows that we investigate the coverings and the nonlocal symmetries of the nonisospectral mKdV equation by applying the classical Frobenius theorem and the coordinates of a infinitely-dimensional manifold in the form of Cartesian product.

Near-zero-dispersion soliton and broadband modulational instability Kerr microcombs in anomalous dispersion

The developing advances of microresonator-based Ker cavity solitons have enabled versatile applications ranging from communication,signal processing to high-precision measurements.Resonator dispersion is the key factor determining the Kerr comb dynamics.Near the zero group-velocity-dispersion(GVD)regime,low-noise and broadband microcomb sources are achievable,which is crucial to the application of the Kerr soliton.When the GVD is almost vanished,higher-order dispersion can significantly affect the Kerr comb dynamics.Although many studies have investigated the Kerr comb dynamics near the zero-dispersion regime in microresonator or fiber ring system,limited by dispersion profles and dispersion perturbations,the near-zero-dispersion soliton structure pumped in the anomalous dispersion side is still elusive so far.Here,we theoretically and experimentally investigate the microcomb dynamics in fiber-based Fabry-Perot microresonator with ultra-small anomalous GVD.We obtain 2/3-octave-spaning microcombs with~10 GHz spacing,>84 THz span,and>8400 comb lines in the modulational instability(MI)state,without any external nonlinear spectral broadening.Such widely-spanned Ml combs are also able to enter the soliton state.Moreover,we report the first observation of anomalous-dispersion based near-zero-dispersion solitons,which exhibits a local repetition rate up to 8.6 THz,an individual pulse duration<100 fs,a span>32 THz and>3200 comb lines.These two distinct comb states have their own advantages.The broadband MI combs possess high conversion efficiency and wide existing range,while the near-zero-dispersion soliton exhibits relatively low phase noise and ultra-high local repetition rate.This work complements the dynamics of Kerr cavity soliton near the zero-dispersion regime,and may stimulate cross-disciplinary inspirations ranging from dispersion-controlled microresonators to broadband coherent comb devices.

Low temperature sensitivity on-chip Fouriertransform spectrometer based on dual-layer Si_(3)N_(4)spiral waveguides

On-chip Fourier-transform spectrometers(FTSs)based on Mach–Zehnder interferometer(MZI)arrays suffer from severe central wavelength and fringe contrast variation due to fabrication errors.Even though a calibration matrix can be employed to correctly retrieve the input spectra,environmental temperature variation greatly degrades the retrieving performance.In this paper,we devise a dual-layer Si_(3)N_(4) waveguide interferometer to reduce the temperature sensitivity.The beating of the even and odd supermodes in the dual-layer waveguide generates periodic intensity fluctuations in the spectrum.Since these two modes have similar modal profiles,their thermal sensitivity and propagation loss are relatively balanced,leading to a low temperature sensitivity and a high interference extinction ratio.We designed and fabricated a passive FTS based on a 32-channel dual-layer Si_(3)N_(4) waveguide array.Experimental results show that the temperature sensitivity is reduced to 10 pm/°C,which is almost half that of single-layer Si_(3)N_(4) MZI-based FTSs.With this chip,we accurately reconstructed various types of optical spectra,including single and two sparse laser lines,and broadband optical spectra.Our method can fit a wide wavelength range,which is a promising technology to improve the practical applications of on-chip FTSs.

Frequency-tunable microwave quantum light source based on superconducting quantum circuits

A non-classical light source is essential for implementing a wide range of quantum information processing protocols,including quantum computing,networking,communication and metrology.In the microwave regime,propagating photonic qubits,which transfer quantum information between multiple superconducting quantum chips,serve as building blocks for large-scale quantum computers.In this context,spectral control of propagating single photons is crucial for interfacing different quantum nodes with varied frequencies and bandwidths.Here a deterministic microwave quantum light source was demonstrated based on superconducting quantum circuits that can generate propagating single photons,time-bin encoded photonic qubits and qudits.In particular,the frequency of the emitted photons can be tuned in situ as large as 200 MHz.Even though the internal quantum efficiency of the light source is sensitive to the working fre-quency,it is shown that the fidelity of the propagating photonic qubit can be well preserved with the time-bin encoding scheme.This work thus demonstrates a versatile approach to realizing a practical quantum light source for future distributed quantum computing.

Magnetic spin–orbit interaction of light

We study the directional excitation of optical surface waves controlled by the magnetic field of light.We theoretically predict that a spinning magnetic dipole develops a tunable unidirectional coupling of light to transverse electric(TE)polarized Bloch surface waves(BSWs).Experimentally,we show that the helicity of light projected onto a subwavelength groove milled into the top layer of a 1D photonic crystal(PC)controls the power distribution between two TE-polarized BSWs excited on both sides of the groove.Such a phenomenon is shown to be solely mediated by the helicity of the magnetic optical field,thus revealing a magnetic spin-orbit interaction of light.Remarkably,this magnetic optical effect is clearly observed via a near-field coupler governed by an electric dipole moment:it is of the same order of magnitude as the electric optical effects involved in the coupling.This opens up new degrees of freedom for the manipulation of light and offers desirable and novel opportunities for the development of integrated optical functionalities.

Porous graphene paper for supercapacitor applications

Graphene paper shows a great promise for the electrical energy storage. However, the high stability, purity and specific surface area have become stringent requirements for supercapacitor applications. Finding methods to tackle these problems is rather challenging. Here, we develop a facile method to prepare porous graphene papers with a thickness 0.5 mm by a thermal shock to the layer-structure graphene paper self-assembled on Cu foil under nitrogen flowing. The as-prepared porous graphene paper exhibits a large specific capacitance of 100 Fg-1at the scan rate of 100 mVs-1with high stability and purity without any residual chemical reagents, showing a promising potential for supercapacitor applications. The high electrochemical properties are mainly attributed to the high-specific area and the improved conductivity of the porous graphene paper performed by the multieffect of reducing, cleaving and expanding to the layer-structure graphene paper by high-energy thermal heating during the thermal shock process. This work paves a pathway to the facile preparation of porous graphene paper for supercapacitor applications.

3DRGO-NiFe2O4/NiO nanoparticles for fast and simple detection of organophosphorus pesticides

The residues of organophosphorus pesticide(OPs)on fruits and vegetables pose a threat to human health,so it is very meaningful to explore simple and fast detect methods for OPs residual.In this work,nickel ferrite/nickel oxide nanoparticles co-loaded three-dimensional reduced graphene oxide(3DRGONiFe2O4/NiO NPs),as a new low cost nanocomposite,was prepared.Based on its high performance mimetic peroxidase activity,a colorimetric method for the detection of OPs has been developed.Dichlorvos was chosen as model compounds to evaluate the detection performance.The detection linear range for dichlorvos is from 50μg/mL to 2.5×10^4μg/mL with a detection limit of 10μg/mL.Furthermore,a test paper can be developed based on the 3 DRGO-NiFe2O4/NiO NPs for visual detection of dichlorvos,and the image information of the paper sensor can be converted into digital signal and quantitative detection by a smartphone.Notably,this method can also be used to detect dichlorvos in real samples,including vegetables and fruits.Thus,the developed naked assay holds great potential in simple,inexpensive and rapid detection of OPs in fruit and vegetable samples.