Zhejiang University

About: Zhejiang University is a education organization based out in Hangzhou, Zhejiang, China. It is known for research contribution in the topics: Catalysis & Population. The organization has 161257 authors who have published 183264 publications receiving 3417592 citations. The organization is also known as: Chekiang University & Zheda.

Potential of microporous metal–organic frameworks for separation of hydrocarbon mixtures

Abstract: In the process industries, the separation of mixtures of hydrocarbons is important both for the preparation of feedstocks and for use as end products. The constituents, hydrocarbons, are either aliphatic or aromatic, saturated or unsaturated, with a large variation in the number of carbon atoms. Using microporous metal–organic frameworks (MOFs), a number of different separation strategies can be employed to achieve the desired separation performance. The strategies include selective binding with the metal atoms of the framework, exploiting differences in molecular packing efficiencies within the ordered pore structures, utilizing selectivities based on the framework flexibility and gate-opening mechanisms, and molecular sieving. Various strategies are discussed in this article, along with perspectives for future research and development for improving the separation performance.

Removing batch effects in analysis of expression microarray data: an evaluation of six batch adjustment methods.

Abstract: The expression microarray is a frequently used approach to study gene expression on a genome-wide scale. However, the data produced by the thousands of microarray studies published annually are confounded by “batch effects,” the systematic error introduced when samples are processed in multiple batches. Although batch effects can be reduced by careful experimental design, they cannot be eliminated unless the whole study is done in a single batch. A number of programs are now available to adjust microarray data for batch effects prior to analysis. We systematically evaluated six of these programs using multiple measures of precision, accuracy and overall performance. ComBat, an Empirical Bayes method, outperformed the other five programs by most metrics. We also showed that it is essential to standardize expression data at the probe level when testing for correlation of expression profiles, due to a sizeable probe effect in microarray data that can inflate the correlation among replicates and unrelated samples.

Passive technologies for future large-scale photonic integrated circuits on silicon: polarization handling, light non-reciprocity and loss reduction

Abstract: Silicon-based large-scale photonic integrated circuits are becoming important, due to the need for higher complexity and lower cost for optical transmitters, receivers and optical buffers. In this paper, passive technologies for large-scale photonic integrated circuits are described, including polarization handling, light non-reciprocity and loss reduction. The design rule for polarization beam splitters based on asymmetrical directional couplers is summarized and several novel designs for ultra-short polarization beam splitters are reviewed. A novel concept for realizing a polarization splitter–rotator is presented with a very simple fabrication process. Realization of silicon-based light non-reciprocity devices (e.g., optical isolator), which is very important for transmitters to avoid sensitivity to reflections, is also demonstrated with the help of magneto-optical material by the bonding technology. Low-loss waveguides are another important technology for large-scale photonic integrated circuits. Ultra-low loss optical waveguides are achieved by designing a Si3N4 core with a very high aspect ratio. The loss is reduced further to <0.1 dB m−1 with an improved fabrication process incorporating a high-quality thermal oxide upper cladding by means of wafer bonding. With the developed ultra-low loss Si3N4 optical waveguides, some devices are also demonstrated, including ultra-high-Q ring resonators, low-loss arrayed-waveguide grating (de)multiplexers, and high-extinction-ratio polarizers. Newly developed photonic components could allow large-scale photonic integrated circuits to be built on silicon substrates. Daoxin Dai from Zhejiang University, China, alongside co-workers from the University of California, USA, have proposed several new optical technologies for use in photonic integrated circuits, which substitute or work alongside electrical circuits in optical devices. The researchers have designed new ultrashort polarization-handling devices that split high-intensity beams of light, and a ring optical isolator that reduces reflections. The team have also created a new waveguide based on silicon nitride that can guide optical waves with a minimal loss of energy. These new technologies will allow scientists to construct higher performance, more compact optical devices.

Structure-designed synthesis of FeS2@C yolk–shell nanoboxes as a high-performance anode for sodium-ion batteries

Abstract: Pyrite (FeS2) is an attractive anode material for sodium-ion batteries (SIBs) with a high theoretical capacity of 894 mAh g−1. However, its practical application is greatly hindered by the rapid capacity fading caused by the large volume expansion upon sodiation. Tuning the morphology and structure at nanoscale and applying a higher cut-off voltage are essential to address this issue. Here, a facile etching method coupled with a novel sulfidation-in-nanobox strategy is developed to synthesize unique FeS2@C yolk–shell nanoboxes. The as-obtained FeS2@C nanoboxes reveal excellent sodium storage performance. The remarkable electrochemical properties are attributed to the elaborate yolk–shell nanoarchitecture. In particular, it delivers a high specific capacity of 511 mAh g−1 at 100 mA g−1 after 100 cycles. Furthermore, a high specific capacity of 403 mAh g−1 even at 5 A g−1 is delivered. Most impressively, a stable capacity of 330 mAh g−1 can still be retained at 2 A g−1 even after 800 cycles.