Green synthesis of novel in-situ micro/submicron-Cu paste for semiconductor interconnection

A green method for the synthesis of in-situ Cu paste is developed. Cu particles are prepared through chemical reduction by selecting a special copper source, reducing agent, and solvent. Then the reaction solution is directly concentrated to obtain an in-situ Cu paste. The synthesis of Cu particles and the preparation of Cu paste are conducted simultaneously, and the process of separation, purification, drying, storage, and re-dispersion of powder are reduced. Particles are not directly exposed to air, thus the oxidation of micro/nano-Cu is effectively prevented, and the agglomeration of particles caused by drying and dispersion operations is simultaneously reduced. Furthermore, the proposed method has a certain universality, and different types of Cu sources can be used to prepare in-situ paste with different sizes and morphologies. The entire preparation process is simple, efficient, green, and the yield can reach 99.99%, which breaks through the bottleneck of the application of traditional micro/nano-Cu materials. Copper acetate based in-situ paste is sintered for 30 min at 260 °C and 2 MPa in a reducing atmosphere. The shear strength, resistivity, and thermal conductivity reach 55.26 MPa, 4.01 × 10-8 Ω·m, and 92.75 W/(m·K), respectively, which could meet the interconnection application of power semiconductor devices.

ANALISIS KADAR POLIFENOL DAN AKTIVITAS ANTIOKSIDAN YANG TERDAPAT PADA EKSTRAK BUAH : STUDI KEPUSTAKAAN

ABSTRACTPolyphenols are one of the largest categories of phytochemicals and are the most widely distributed among various types of plants and fruits. Polyphenols can also inhibit, prevent, and reduce oxidation by free radicals, which are good for health. Analysis of polyphenol content starts from the sample preparation process which includes the extraction of solid and liquid samples. The types of solvents commonly used for extraction are ethanol, methanol, and acetone. Furthermore, the analysis of polyphenol levels uses the Folin-Ciocalteau analysis method. The results of the review show that ripe bisbul fruit extract (Diospyros blancoi A. DC.) which was extracted using ethanol as a solvent had the highest polyphenol content and yield of several fruit extracts reported in this review. Meanwhile, the extract of green grapes (Vitis vinifera Linn. Var. Chinsiang) which was extracted using ethanol as a solvent had the lowest levels and yields of polyphenols. The highest antioxidant activity was shown by samples of red dragon fruit extract (Hylocereus polyrhizus (f.a.c weber) britton & rose). Meanwhile, the lowest antioxidant activity was shown by samples of Watermelon (Citrullus lanatus) fruit extract.Keywords: Pholyphenol, Extracts, Solvents, Folin CiocalteauABSTRAKPolifenol adalah salah satu kategori terbesar dari fitokimia yang paling banyak penyebarannya diantara berbagai jenis tanaman dan buah-buahan. Polifenol juga dapat menghambat, mencegah, mengurangi oksidasi oleh radikal bebas sehingga baik untuk kesehatan. Analisis kadar polifenol dimulai dari proses preparasi sampel yang meliputi ekstrasi sampel padat dan ekstraksi sampel cair. Jenis pelarut yang umum digunakan saat pengekstrakan yaitu etanol, metanol, dan aseton. Selanjutnya analisis kadar polifenol menggunakan metode analisis folin ciocalteau. Hasil review menunjukkan Ekstrak buah bisbul matang (Diospyros blancoi A. DC.) yang diekstrak menggunakan pelarut etanol memiliki kadar dan rendemen polifenol yang tertinggi dari beberapa ekstrak buah yang dilaporkan dalam review ini. Sedangkan ekstrak buah anggur hijau (Vitis vinifera Linn. Var. Chinsiang) yang diekstrak menggunakan pelarut etanol memiliki kadar dan rendemen polifenol yang terendah. Aktivitas antioksidan yang tertinggi ditunjukkan oleh sampel ekstrak buah naga Merah (Hylocereus polyrhizus (f.a.c weber) britton & rose) dibandingkan sampel lain dalam review ini. Sedangkan aktivitas antioksidan yang terendah ditunjukkan oleh sampel ekstrak buah Semangka (Citrullus lanatus) dibandingkan sampel lain dalam review ini.Kata kunci: Polifenol, ekstraksi, pelarut, folin ciocalteau

A modular framework for optimal scheduling of industrial processes

This paper proposes an extended Petri net formalism as a suitable language for composing optimal scheduling problems of industrial production processes with real and binary decision variables. The proposed approach is modular and scalable, as the overall process dynamics and constraints can be collected by parsing of all atomic elements of the net graph. To conclude, we demonstrate the use of this framework for modeling the moulding sand preparation process of a real foundry plant.

Efficient and Stable Low-cost Perovskite Solar Cells Enabled by Using the Surface Passivated Carbon as Counter Electrode

Carbon-based hole-transport-layer free perovskite solar cells (C-PSCs) have attracted much attention due to their low cost, simple preparation process and high stability. However, the efficiency of C-PSCs is far behind...

Influence of sample preparation process on basic properties of biofuels

The characteristic properties of non-wood biomass used in combustion processes are monitored, such as water content, ash, volatile matter. Biomass is usually not homogenous and of suitable dimensions for these determinations. This is the reason for the necessary adjustment of samples for analysis. But modifying the samples may change their properties. In this publication, the influence of the grinding process in a rotor mill on the content of water, volatile matter and ash in non-wood biomass samples was studied. Samples of flax, Crambe abyssinica, amaranth and rye were analyzed. All analyses showed moisture loss from the sample during grinding and in the case of flax, the loss of volatile matter was observed. It means the rotor mill is suitable for sample preparation prior to analysis. But for oil plants it is necessary to choose another mill or adjustment method.