On the Shape-Selected, Ligand-Free Preparation of Hybrid Perovskite (CH3NH3PbBr3) Microcrystals and Their Suitability as Model-System for Single-Crystal Studies of Optoelectronic Properties

Hybrid perovskite materials are one of the most promising candidates for optoelectronic applications, e.g., solar cells and LEDs, which can be produced at low cost compared to established materials. Although this field of research has seen a huge upsurge in the past decade, there is a major lack in understanding the underlying processes, such as shape-property relationships and the role of defects. Our aerosol-assisted synthesis pathway offers the possibility to obtain methylammonium lead bromide (MAPbBr3) microcrystals from a liquid single source precursor. The differently shaped particles are aligned on several substrates, without using a directing agent or other additives. The obtained particles show good stability under dry conditions. This allows us to characterize these materials and their pure surfaces at the single-crystal level using time- and spatially resolved methods, without any influences of size-dependent effects. By optimizing the precursor for the aerosol process, we were able to eliminate any purification steps and use the materials as processed. In addition, we performed theoretical simulations to deepen the understanding of the underlying processes in the formation of the different crystal facets and their specific properties. The model system presented provides insights into the shape-related properties of MAPbBr3 single crystals and their directed but ligand-free synthesis.

IDENTIFICATION OF FACTORS INFLUENCING LAND VALUE FOR STATE'S ASSETS MASS APPRAISAL PURPOSES: EVIDENCE FROM INDONESIA

Land value is an important element in a decision making. The estimation of land value conducted individually based on comparables. This approach often faces difficulties due to the large quantities of such assets with limited capacity of valuers. This research aimed to build a model to effectively identify the main property attributes that shape property value and quantify the effect of unobserved variables on value. We observed 628 property data in Jakarta collected by the Directorate General of State Asset Management (DGSAM) as part of their valuation activities in 2018. The results of this study provide an evidence that structural equation model (SEM) can be effectively used to identify property attributes that significantly affect property value, particularly for valuing state-owned assets.

4D Printing Pre-Strained Structures for Fast Thermal Actuation

Four-dimensional (4D) printing is an emerging technology by adding the dimension of time-dependent reconfiguration into 3D printing. It enables the 3D printed structure to change the shape, property, or functionality under external stimuli such as temperature, magnetic field, and light, etc. Among the existing 4D printed structures, thermal responsive structures are widely used for their easy operation. However, the slow actuation of the thermal responsive structures impedes the applications like soft robotics. In the current work, a pre-strained strategy is proposed to accelerate the actuation of thermal responsive structures. A 4D printing platform that can apply strain during the printing process is constructed to fabricate the pre-strained structures under the aid of in-situ tensile of the printing base. A bilayer structure with one pre-strained layer and the other non-pre-strained layer is integrally printed. Through experiments and the finite element analysis, it is demonstrated that the aspect ratio has little effect on the deformation of the bilayer structure, whereas the pre-strain plays a key role in the deformation and also greatly accelerates the actuation of the bilayer structure. Based on the 4D printed pre-strained bilayer structure, an energy-free gripper is fabricated and a fully soft crawler is printed to achieve a high running speed.

4D Printing: A Review on Recent Progresses

Since the late 1980s, additive manufacturing (AM), commonly known as three-dimensional (3D) printing, has been gradually popularized. However, the microstructures fabricated using 3D printing is static. To overcome this challenge, four-dimensional (4D) printing which defined as fabricating a complex spontaneous structure that changes with time respond in an intended manner to external stimuli. 4D printing originates in 3D printing, but beyond 3D printing. Although 4D printing is mainly based on 3D printing and become an branch of additive manufacturing, the fabricated objects are no longer static and can be transformed into complex structures by changing the size, shape, property and functionality under external stimuli, which makes 3D printing alive. Herein, recent major progresses in 4D printing are reviewed, including AM technologies for 4D printing, stimulation method, materials and applications. In addition, the current challenges and future prospects of 4D printing were highlighted.

On the classification of two-qubit group orbits and the use of coarse-grained 'shape' as a superselection property

Recently a complete set of entropic conditions has been derived for the interconversion structure of states under quantum operations that respect a specified symmetry action, however the core structure of these conditions is still only partially understood. Here we develop a coarse-grained description with the aim of shedding light on both the structure and the complexity of this general problem. Specifically, we consider the degree to which one can associate a basic `shape' property to a quantum state or channel that captures coarse-grained data either for state interconversion or for the use of a state within a simulation protocol. We provide a complete solution for the two-qubit case under the rotation group, give analysis for the more general case and discuss possible extensions of the approach.

Legalized Rent-Seeking: Eminent Domain in Kazakhstan

Cornell International Law Journal: Vol. 50 : No. 1 , Article 2Kazakhstan ranks consistently low on measures of property rights protection and the rule of law more generally.1 Echoing these evaluations, existing literature emphasizes the degree to which informal institutions shape property relations in personalist, authoritarian regimes, like Kazakhstan. The expectation is that formal institutions like law and courts fail to restrain or otherwise influence state agents’ rent-seeking behavior. In effect, they serve primarily as ornamentation. Regardless, these explanations fail to explain why both citizens and the State regularly turn to these institutions to settle property disputes. This Article focuses on conflicts over eminent domain and finds that in these cases the law provides lower and upper bounds for officials’ rent-seeking behavior. Within these limits, law combines with informal practices to determine legal outcomes. Although the law and courts sometimes provide citizens with opportunities for limited redress, they also help facilitate and legitimize officials’ use of eminent domain for personal enrichment.