Surface enhanced Raman scattering (SERS) is a trace detection technique that extends even to single molecule detection. Its potential application to the noninvasive recognition of lung malignancies by detecting volatile organic compounds (VOCs) that serve as biomarkers would be a breakthrough in early cancer diagnostics. This application, however, is currently limited by two main factors: (1) most VOC biomarkers exhibit only weak Raman scattering; and (2) the high mobility of gaseous molecules results in a low adsorptivity on solid substrates. To enhance the adsorption of gaseous molecules, a ZIF-8 layer is coated onto a self-assembly of gold superparticles (GSPs) in order to slow the flow rate of gaseous biomarkers and depress the exponential decay of the electromagnetic field around the GSP surfaces. Gaseous aldehydes that are released as a result of tumor-specific tissue composition and metabolism, thereby acting as indicators of lung cancer, are guided onto SERS-active GSPs substrates through a ZIF-8 channel. Through a Schiff base reaction with 4-aminothiophenol pregrafted onto gold GSPs, gaseous aldehydes are captured with a 10 ppb limit of detection, demonstrating tremendous prospects for in vitro diagnoses of early stage lung cancer.

Main Text:Following the recent isolation of monolayer CrI3 1 , there has been a surge of new twodimensional van der Waals magnetic materials 2-12 , whose incorporation in van der Waals heterostructures offers a new platform for spintronics 5-8 , proximity magnetism 13 , and quantum spin liquids 14 . A primary question in this burgeoning field is how exfoliating crystals to the few-layer limit influences their magnetism. Studies on CrI3 have shown a different magnetic ground state for ultrathin exfoliated films 1,5,6 but the origin is not yet understood. Here, we use electron tunneling through few-layer crystals of the layered antiferromagnetic insulator CrCl3 to probe its magnetic order, finding a ten-fold enhancement in the interlayer exchange compared to bulk crystals. Moreover, temperatureand polarization-dependent Raman spectroscopy reveal that the crystallographic phase transition of bulk crystals does not occur in exfoliated films. This results in a different low temperature stacking order and, we hypothesize, increased interlayer exchange. Our study provides new insight into the connection between stacking order and interlayer interactions in novel two-dimensional magnets, which may be relevant for correlating stacking faults and mechanical deformations with the magnetic ground states of other more exotic layered magnets, such as RuCl3 14 .A key family of van der Waals magnets is the layered transition metal trihalides, which have been studied for decades as prototypical magnetic insulators 15-17 and as a platform for quasitwo-dimensional magnetism [18][19][20] . In the chromium trihalides, the Cr atoms are arranged in a honeycomb structure, with each Cr atom surrounded by six halide atoms in an octahedral geometry (Fig. 1a). The bulk crystals undergo a crystallographic phase transition from a monoclinic phase (space group C2/m) at room temperature to a rhombohedral phase (space group R3 " ) at low temperatures (below about 240 K for CrCl3 21 ). While the intralayer lattice spacings are largely

The current generation of coupled climate models run at the Geophysical Fluid Dynamics Laboratory (GFDL) as part of the Climate Change Science Program contains ocean components that differ in almost every respect from those contained in previous generations of GFDL climate models. This paper summarizes the new physical features of the models and examines the simulations that they produce. Of the two new coupled climate model versions 2.1 (CM2.1) and 2.0 (CM2.0), the CM2.1 model represents a major improvement over CM2.0 in most of the major oceanic features examined, with strikingly lower drifts in hydrographic fields such as temperature and salinity, more realistic ventilation of the deep ocean, and currents that are closer to their observed values. Regional analysis of the differences between the models highlights the importance of wind stress in determining the circulation, particularly in the Southern Ocean. At present, major errors in both models are associated with Northern Hemisphere Mode Waters and outflows from overflows, particularly the Mediterranean Sea and Red Sea.

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Optimising the supported modes of atom or ion dispersal onto substrates, to synchronously integrate high reactivity and robust stability in catalytic conversion, is an important yet challenging area of research. Here, theoretical calculations first show that three-coordinated copper (Cu) sites have higher activity than four-, two- and one-coordinated sites. A site-selective etching method is then introduced to prepare a stacked-nanosheet metal–organic framework (MOF, CASFZU-1)-based catalyst with precisely controlled coordination number sites on its surface. The turnover frequency value of CASFZU-1 with three-coordinated Cu sites, for cycloaddition reaction of CO 2 with epoxides, greatly exceed those of other catalysts reported to date. Five successive catalytic cycles reveal the superior stability of CASFZU-1 in the stacked-nanosheet structure. This study could form a basis for the rational design and construction of highly efficient and robust catalysts in the field of single-atom or ion catalysis.

Deterministic assembly of nanoparticles with programmable patterns is a core opportunity for property-by-design fabrication and large-scale integration of functional materials and devices. The wet-chemical-synthesized colloidal nanocrystals are compatible with solution assembly techniques, thus possessing advantages of high efficiency, low cost, and large scale. However, conventional solution process suffers from tradeoffs between spatial precision and long-range order of nanocrystal assembly arising from the uncontrollable dewetting dynamics and fluid flow. Here, a capillary-bridge manipulation method is demonstrated for directing the dewetting of nanocrystal inks and deterministically patterning long-range-ordered superlattice structures. This is achieved by employing micropillars with programmable size, arrangement, and shape, which permits deterministic manipulation of geometry, position, and dewetting dynamics of capillary bridges. Various superlattice structures, including one-dimensional (1D), circle, square, pentagon, hexagon, pentagram, cross arrays, are fabricated. Compared to the glassy thin films, long-range-ordered superlattice arrays exhibit improved ferroelectric polarization. Coassembly of nanocrystal superlattice and organic functional molecule is further demonstrated. Through introducing azobenzene into superlattice arrays, a switchable ferroelectric polarization is realized, which is triggered by order-disorder transition of nanocrystal stacking in reversible isomerization process of azobenzene. This method offers a platform for patterning nanocrystal superlattices and fabricating microdevices with functionalities for multiferroics, electronics, and photonics.

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Redesigning heterogeneous catalysts so that they can simultaneously integrate the efficiency and durability under reaction environments with respect to gas fuel production, such as hydrogen (H2), oxygen (O2), or carbon monoxide (CO), has proven challenging. In this work, we report the successful template-assisted printing-based assembly of platinum (Pt) nanoparticles (NPs) into striped-pattern (SP) superlattices to produce H2. In comparison to drop-casting flat Pt NPs films, SP superlattices lead to higher mass transference and smaller bubble stretch force, representing a general strategy to improve the efficiency and durability of pre-existed Pt catalysts for the hydrogen evolution reaction (HER), as well as higher current densities than commercial Pt/C, Pt NP films, and many of the other Pt-based or non-Pt-based HER catalysts reported in the literature. The generic nature of template-assisted printing leads to flexibility in the composition, size, and shape of the constituent NPs or molecules, and thus extends such an accelerated technique for producing the oxygen evolution reaction and electrochemical reduction of CO2 to CO.