The hydrothermal method synthesized the first cobalt ferrite and cobalt oxide nanoparticles in this article. The synthesized nanoparticles were then subjected to various analyzes such as X-ray diffraction patterns, scanning electron microscopy images, infrared spectroscopy, and vibration sample magnetometer to ensure their properties and prepare the nanoparticles for the next step. Then, 6% by weight of nanoparticles were added to the epoxy resin as a reinforce, and a polymer matrix composite was made. After making the composites according to the ASTM D638 standard, they were subjected to a tensile test. The results showed that the nanoparticles were prepared very fine, uniform, high purity, and had good magnetic properties. Also, hydrothermal was a suitable method for the synthesis of these nanoparticles. Furthermore, samples made using cobalt ferrite nanoparticles offer better tensile properties than samples made with cobalt oxide. However, in general, the tensile properties of composites have improved compared to pure polymers. پرونده مقاله

In this research, nanoparticles of copper ferrite was synthesized by hydrothermal method and nanoparticles of copper hydroxide was synthesized by ultrasonic method. Then, to check the properties of these nanoparticles, analyzes such as X-ray diffraction pattern (XRD), scanning electron microscope (SEM), vibrating sample magnetometry (VSM) and infrared spectroscopy (IR) were taken. The results of analyzes showed that the nanoparticles were prepared in a completely uniform, fine and homogeneous manner and no agglomeration was seen in them. In addition, these nanoparticles had good magnetic properties and the peaks of the X-ray diffraction pattern were consistent with the standard peaks. In the next step, 5% by weight of copper ferrite and copper hydroxide nanoparticles were added to the epoxy resin and then mixed together by a stirrer. In the next step, the epoxy resin was subjected to ultrasonic waves and after the complete distribution of nanoparticles in the field, it was placed in the vacuum chamber for bubble removal and finally poured into the mold. Finally, various tests were taken from the composites, such as: thermal properties test (TGA) and flame resistance test (UL-94). پرونده مقاله

In this study, the effect of integer Hall effect on nanoribbons of boron nitride at the presence of impurity function concerning magnetic resistance in terms of filling ratio was investigated. First, a dopant will be applied to the system in the form of Dirac Delta function, at the presence of this dopant, Landau levels will be divided into extended and localized levels giving rise to Hall step. In this model, the Aharanov-Boehm fluctuations are observed and impurity eradicates stagnation in energy levels. In fact, by increasing the width and height of the quantum dot destroys the step, and finally, the quantum-hall effect vanishes Then, another dopant will be applied to the system in the form of quantum dot. By increase of the width and height of quantum dot, the Hall step will fade and quantum Hall effect will disappear. The more the increase of quantum hall domain, the faster the Hall step and therefore quantum effect will fade. پرونده مقاله

In this article, nickel oxide and nickel ferrite nanoparticles were first synthesized using an ultrasonic method as a simple, fast, eco-friendly, and cost-effective method. To ensure the properties of the nanoparticles and to avoid problems in the following steps, the nanoparticles are synthesized under various analyzes such as scanning electron microscopy (SEM) images, infrared spectroscopy (IR), an X-ray diffraction pattern (XRD), and Vibrating sample magnetometry (VSM). In the next step, using these nanoparticles and epoxy resin, a polymer matrix composite was made. Then, the composites were tested for corrosion against acid and hardness tests based on the ASTM D2583-13 standard. The results showed that the structure of the manufactured nanoparticles is very uniform and homogeneous. In addition, the hardness of composites made from nickel ferrite and nickel oxide nanoparticles was improved compared to pure polymer, and composites made from nickel ferrite had better hardness than composites made from nickel oxide. Also, the acid corrosion test results showed that creating a composite layer around aluminum can protect it against acid corrosion. پرونده مقاله

در کار حاضر به بررسی آثار فشار و آنتالپی بروی ترکیب دی سولفید مولیبدن در چارچوب نظریۀ تابعی چگالی و با کد کوانتوم اسپرسو با امواج تخت و پتانسیل تبادلی تقریب شیب تعمیم یافته بار پایسته پرداخته شده است. خواص الکترونی ترکیب برای مقایسه با اعمال فشار رسم و محاسبه شد. ساختار نواری دی سولفید مولیبدن ماهیت نیم رسانایی را با گافی حدود 2/27 الکترون ولت را داد، که گاف به دست آمده بزرگتر از نتایج دیگر پژوهش ها بوده است. چگالی حالت ها برای ترکیب دی سولفید مولیبدن رسم شده است و ماهیت نیم رسانایی ترکیب را تأیید می کند. گاف به دست آمده از چگالی حالت ها با نتایج دیگر کارها سازگاری بیشتری دارد و مقدار آن حدود 1/3 الکترون ولت به دست آمده است. نتایج محاسبات چگالی حالات جزئی نشان داد که نقش اوربیتال d اتم مولیبدن و p اتم گوگرد بیشتر است. در ادامه فشار های مختلف را اعمال شده است. با اعمال فشارهای مثبت ثابت شبکه افزایش می یابد و ابتدا گاف نواری کاهش سپس در یک انرژی کمی افزایش و در ادامه باز کاهش را دارد تا ساختار از ماهیت نیم رسانا به فلز تبدیل گردد. با اعمال فشارهای منفی ثابت شبکه کاهش و گاف نواری کاهش یافته و در همان اعمال فشارهای اولیه از ماهیت نیم رسانایی خارج و به سمت خاصیت فلزی میل کرده است. پرونده مقاله