蘑菇培养料中微生物的研究

本文对蘑菇培养料中分离获得的霉菌、放线菌和细菌进行鉴定和对其生理、生化特性进行测定,对某些菌株在蘑菇生长过程中的作用及作用规律也作了研究.通过研究,初步认为在放线菌和霉菌中有数株菌株对蘑菇的生长有直接或间接的促进作用     

物理学的发展对物理教学的新要求

科学、技术和教育的发展历史,说明了教育与科学是相互影响、相互促进的,历史上每一次科学技术的革命,必然伴随着相应的教育的进步。以德国为例:1810—1920年的110年间,正是德国科学兴旺发达的时期,而在这段时间以及这之前的一段时间,也正好是德国教育的发达期,意大利、英国、法国、美国等历史上的发达国家都有过同样的经历。这说明:科学兴旺与教育发达是一致的,科学兴旺发达的国家也是教育发达的国家,且教育的发达应超前于科学的兴旺。因此要求教育的发展必须与科学的发展相适应,而科学的发展又必然会给教育提出新的课题。 同样,物理学作为一门科学,由于理论和实验之间的密切联系及众多的物理学家的努力,在认识客观世界规律方面已经取得了令人瞩目的成就。物理学已经深入到了各个领域。电气化、原子能、空间科学、光纤通讯得到迅猛发展。难以想象,没有现代物理学的发     

球状胶束中表面活性剂脱附的离子调控机制

建立耦合伞状采样的粗粒度分子动力学方法,研究球状胶束中表面活性剂分子的脱附过程,揭示表面活性剂聚集数、盐种类及浓度对表面活性剂脱附过程的影响机制。发现球状胶束半径及偏心率均随聚集数增加而增大,盐浓度的影响主要取决于抗衡离子的半径和吸附特性,半径更大、吸附更强的水杨酸根离子对胶束结构的影响更为显著;基于伞状采样方法获得了表面活性剂脱附自由能、脱附时间等关键参数,发现球状胶束中表面活性剂脱附自由能和脱附时间均随聚集数和盐浓度呈非单调变化,揭示其主要机制为离子吸附引起的静电屏蔽作用;发现自由能在表面活性剂脱附过程中起主导作用,结合胶束热力学理论发展了临界胶束浓度预测方法,获得了临界胶束浓度下胶束尺寸的分布范围。     

无源空心波导谐振腔横模模式的竞争与转换

本文提出并采用非对角化的分析法研究无源空心波导谐振腔横模模式间的竞争与转换。从计算EH_(1m)类波导本征模在腔内的转换矩阵中发现:在模式的传输过程中,存在着横模模式间的相互转换,而且其互换的能量不相等。在一定的腔设计条件下,会出现高阶横模向低阶横模的能量净流动,这有利于谐振腔横模模式的选择和基模输出功率的提高。     

杂多阴离子的NMR和ESR研究——P-V-W Keggin阴离子的31P、51V、17O-NMR谱

本文合成了六种含有P-V-W和V-V-W Keggin结构的杂多阴离子,并研究了它们的³¹P、⁵¹V、¹⁷O-NMR谱,对于PV_xW_12-xO₄₀^(x+3)-(x=1~4)阴离子,当x=1时,³¹P和⁵¹V-NMR谱只有一条线,并且此线化学位移和pH无关。当x ≥ 2时,谱线数目随着x迅速增加,其原因是几何异构体的数目和类型迅速增加。它们的化学位移δ_p,和δ_v。依赖于溶液的酸性和x,即δ_p,随pH值和x增加而减少,而δ_v,却随pH和x的增加而增加。最后简短讨论了桥氧上质子化的影响。     

物理解题中隐含条件的挖掘——以2019年高考全国Ⅰ卷、Ⅱ卷、Ⅲ卷选择题为例

隐含条件的挖掘和准确把握,在很多时候对于物理问题的快速解决起着关键性的作用,在审题过程中能快速找出隐含条件,并利用隐含条件解题更是在考试过程中准确高效解题的最好方法.本文以2019年高考全国Ⅰ卷、Ⅱ卷、Ⅲ卷选择题为例详细分类探讨了物理解题中隐含条件的挖掘这一问题,希望对于学生如何在题目中快速找出隐含条件有所帮助.     

Study of total ionizing dose radiation effects on enclosed gate transistors in a commercial CMOS technology

This paper studies the total ionizing dose radiation effects on MOS (metal-oxide-semiconductor) transistors with normal and enclosed gate layout in a standard commercial CMOS (compensate MOS) bulk process. The leakage current, threshold voltage shift, and transconductance of the devices were monitored before and after $\gamma $-ray irradiation. The parameters of the devices with different layout under different bias condition during irradiation at different total dose are investigated. The results show that the enclosed layout not only effectively eliminates the leakage but also improves the performance of threshold voltage and transconductance for NMOS (n-type channel MOS) transistors. The experimental results also indicate that analogue bias during irradiation is the worst case for enclosed gate NMOS. There is no evident different behaviour observed between normal PMOS (p-type channel MOS) transistors and enclosed gate PMOS transistors.     

First principle study of LiXS_2(X=Ga,In) as cathode materials for Li ion batteries

From first principle calculations, we demonstrate that LiXS_2(X = Ga, In) compounds have potential applications as cathode materials for Li ion batteries. It is shown that Li can be extracted from the LiXS_2 lattice with relatively small volume change and the XS_4 tetrahedron structure framework remains stable upon delithiation. The theoretical capacity and average intercalation potential of the LiGaS_2(LiInS_2) cathode are 190.4(144._2) m Ah/g and 3.50 V(3.53 V). The electronic structures of the LiXS_2 are insulating with band gaps of _2.88 eV and 1.99 eV for X = Ga and In, respectively.However, Li vacancies, which are formed through delithiation, change the electronic structure substantially from insulating to metallic structure, indicating that the electrical conductivities of the LiXS_2 compounds should be good during cycling.Li ion migration energy barriers are also calculated, and the results show that Li ion diffusions in the LiXS_2 compounds can be as good as those in the currently widely used electrode materials.     

Multi-scale computation methods: Their applications in lithium-ion battery research and development

Based upon advances in theoretical algorithms, modeling and simulations, and computer technologies, the rational design of materials, cells, devices, and packs in the field of lithium-ion batteries is being realized incrementally and will at some point trigger a paradigm revolution by combining calculations and experiments linked by a big shared database,enabling accelerated development of the whole industrial chain. Theory and multi-scale modeling and simulation, as supplements to experimental efforts, can help greatly to close some of the current experimental and technological gaps,as well as predict path-independent properties and help to fundamentally understand path-independent performance in multiple spatial and temporal scales.