Nadine Godehardt, the Chinese Constitution of Central Asia: Regional and Intertwined Actors in International Relations (Palgrave Macmillan, 2014)

This is an engaging piece of work which takes an innovative approach on Chinese expert discourse on Central Asia – analysing how Chinese define Central Asia. At the same time the author offers an inside perspective on Chinese voices whose meanings are rarely examined in Chinese International Relations (IR) studies. The volume is thus a contribution to theorising the China-Central Asia regional security from IR perspective imbued with recent theories. The author argues there has, as yet, not been a ‘post-regionalist' movement in IR. According to the author, most regional studies are built upon a similar ontological premise, one which characterises in particular the relationship between researchers and the world, as well as how researchers produce knowledge about the world. In chapter two, the author focuses on two areas: first, regions and regionalism and second, typologies of regional order. The former is clustered along two lines: first, cooperation- comprising the different approach to regionalism and second, security – which refers to approaches such as the Regional Security Complex (RSC) theory. DOI: 10.5281/zenodo.336711

Polarization Dependent Switching of Asymmetric Nanorings with a Circular Field

We experimentally investigated the switching from onion to vortex states in asymmetric cobalt nanorings by an applied circular field. An in-plane field is applied along the symmetric or asymmetric axis of the ring to establish domain walls (DWs) with symmetric or asymmetric polarization. A circular field is then applied to switch from the onion state to the vortex state, moving the DWs in the process. The asymmetry of the ring leads to different switching fields depending on the location of the DWs and direction of applied field. For polarization along the asymmetric axis, the field required to move the DWs to the narrow side of the ring is smaller than the field required to move the DWs to the larger side of the ring. For polarization along the symmetric axis, establishing one DW in the narrow side and one on the wide side, the field required to switch to the vortex state is an intermediate value

Intrinsic Photoconductivity of Few-layered ZrS2 Phototransistors via Multiterminal Measurements

We report intrinsic photoconductivity studies on one of the least examinedlayered compounds, ZrS2.Few-atomic layer ZrS2 field-effect transistorswere fabricated on the Si/SiO2 substrate and photoconductivity measurements were performed using both two- and four-terminal configurationsunder the illumination of 532 nm laser source. We measured photocurrentas a function of the incident optical power at several source-drain (bias)voltages. We observe a significantly large photoconductivity when measured in the multiterminal (four-terminal) configuration compared to thatin the two-terminal configuration. For an incident optical power of 90nW, the estimated photosensitivity and the external quantum efficiency(EQE) measured in two-terminal configuration are 0.5 A/W and 120%,respectively, under a bias voltage of 650 mV. Under the same conditions,the four-terminal measurements result in much higher values for both thephotoresponsivity (R) and EQE to 6 A/W and 1400%, respectively. Thissignificant improvement in photoresponsivity and EQE in the four-terminal configuration may have been influenced by the reduction of contactresistance at the metal-semiconductor interface, which greatly impacts thecarrier mobility of low conducting materials. This suggests that photoconductivity measurements performed through the two-terminal configurationin previous studies on ZrS2 and other 2D materials have severely underestimated the true intrinsic properties of transition metal dichalcogenides andtheir remarkable potential for optoelectronic applications

High Energy Density in layered 2D Nanomaterial based Polymer Dielectric Films

Dielectric capacitors are critical components in electronics and energy storage devices. The polymer based dielectric capacitors have advantages of flexibility, fast charge and discharge, low loss, and graceful failure. Elevating the use of polymeric dielectric capacitors for advanced energy applications such as electric vehicles (EVs) however requires significant enhancement of their energy densities. Here, we report a polymer thin film heterostructure based capacitor of poly(vinylidene fluoride)/poly(methyl methacrylate) with stratified 2D nanofillers (Mica or h-BN nanosheets) (PVDF/PMMA-2D fillers/PVDF), that shows enhanced permittivity, high dielectric strength and an ultra-high energy density of 75 J/cm3 with efficiency over 79%. Density functional theory calculations verify the observed permittivity enhancement. This approach of using oriented 2D nanofillers based polymer heterostructure composites is expected to be universal for designing high energy density thin film polymeric dielectric capacitors for myriads of applications

Fabrication of Flexible Oriented Magnetic Thin Films with Large in-plane Uniaxial Anisotropy by Roll-to-roll Nanoimprint Lithography

Here, we report wafer scale fabrication of densely packed Fe nanostripe-based magnetic thin films on a flexible substrate and their magnetic anisotropy properties. We find that Fe nanostripes exhibit large in-plane uniaxial anisotropy and nearly square hysteresis loops with energy products (BH)max exceeding 3 MGOe at room temperature. High density Fe nanostripes were fabricated on 70 nm flexible polyethylene terephthalate (PET) gratings, which were made by roll-to-roll (R2R) UV nanoimprintlithography technique. Observed large in-plane uniaxial anisotropies along the long dimension of nanostripes are attributed to the shape. Temperature dependent hysteresis measurements confirm that the magnetization reversal is driven by non-coherent rotation reversal processes.Comment: 17 pages, 6 figure