A study of lead-free (K0.5N0.5)NbO3 piezoelectric ceramics processed by additive manufacturing

Lead-free (K[Formula: see text]N[Formula: see text]NbO3 piezoelectric ceramics have drawn wide attention due to its environment-friendly and excellent piezoelectric performance. Since the difficulty of post-processing of ceramics limit its further development and practical application, three-dimensional (3D) printing technology has been developed in this work. A homogeneous piezoelectric ceramic suspension with 40 vol% modified (K[Formula: see text]N[Formula: see text]NbO3 nanoparticles can be 3D printed well based on a stereolithography process. In addition, by the post heat treatment under different sintering temperature, a density value of 4.31[Formula: see text]g[Formula: see text]cm[Formula: see text] with the relative density of about 96% was obtained in the sample sintered at 1120[Formula: see text]C, which results in the larger dielectric constant and lower dielectric loss in this sample. These printed ceramics exhibit two successive phase transitions and reduce with increase of sintering temperature at measured temperature range.

Multiple rotor modes and how to trigger them: complex cation ordering in the family of relaxing hybrid formates

A combination of structural, dielectric and calorimetric studies is used to describe a highly atypical behaviour of novel hybrid formate [NH3(CH2)3NH2(CH2)3NH3][Mn(HCOO)3]3, incorporating large triprotonated molecular cation. Two successive phase transitions,...

Chiral Symmetry Breaking in Liquid Crystals: Appearance of Ferroelectricity and Antiferroelectricity

The study of chiral symmetry breaking in liquid crystals and the consequent emergence of ferroelectric and antiferroelectric phases is described. Furthermore, we show that the frustration between two phases induces a variety of structural phases called subphases and that resonant X-ray scattering is a powerful tool for the structural analysis of these complicated subphases. Finally, we discuss the future prospects for clarifying the origin of such successive phase transition.

PENERAPAN MODEL PEMBELAJARAN KOOPERATIF TIPE NHT UNTUK MELATIHKAN KETERAMPILAN METAKOGNITIF PADA MATERI ASAM BASA KELAS XI SMAN 1 WARU

Penelitian ini memiliki tujuan mendeskripsikan keterlaksanaan model pembelajaran dengan modelkooperatif tipe NHT, aktivitas peserta didik, dan melatihkan keterampilan metakognitif pada materi asambasa. Rancangan yang digunakan dalam penelitian yaitu One Group Pre-test Post-test pada kelas XI MIA6 SMAN 1 Waru sebanyak 36 peserta didik. Hasil penelitian yang telah dilakukan menunjukkan : 1) Nilaiketerlaksanaan model pembelajaran kooperatif tipe NHT pada tiap-tiap fase berturut-turut sebesar 4,00;3,33; 4,00; 3,89; 3,93; dan 3,85 pada pertemuan pertama, pada pertemuan 2 berturut-turut sebesar 4,00;3,56; 4,00; 4,00; 4,00; dan 4,00, pada pertemuan 3 berturut-turut sebesar 4,00; 4,00; 4,00; 4,00; 4,00; dan3,70, dengan kategori sangat baik. 2) Aktivitas peserta didik pada pertemuan 1, 2, dan 3 yang memilikipersentase lebih besar adalah peserta didik saat melakukan percobaan (monitoring skills) yang mempunyaipersentase rata-rata sebesar 23,90%, 17,40%, dan 18,30% dibanding dengan aktivitas peserta didik yanglainnya. 3) Keterampilan metakognitif mengalami peningkatan yang baik memperoleh N-gain sebesar80,56% dengan kategori tinggi. Berdasarkan hasil penelitian dapat disimpulkan bahwa penerapan modelkooperatif tipe NHT dapat melatihkan keterampilan metakognitif pada materi asam basa meningkat secarabaik.Kata kunci: NHT, keterlaksanaan, aktivitas, keterampilan metakognitif.AbstractThis study aims to describe the implementation of learning models with NHT type cooperative models,student activities, and practice the metacognitive skills on acid-base material. The design used in the studyis One Group Pre-Test Post-test in class XI MIA 6 SMAN 1 Waru as many 36 students. The results of theresearch that have done show: 1) The value of the implementation of the NHT type of cooperative learningmodel in each successive phase is 4.00; 3.33; 4.00; 3.89; 3.93; and 3.85 at the first meeting, at the 2ndmeeting in a row at 4.00; 3.56; 4.00; 4.00; 4.00; and 4.00, at the 3rd meeting in a row at 4.00; 4.00;4.00; 4.00; 4.00; and 3.70, with a perfect category. 2) Student activities at meetings 1, 2, and 3 that havea Higher percentage are students when conducting experiments (monitoring skills), which have an averagerate of 23.90%, 17.40%, and 18.30% compared to the activities of other students. 3) Metacognitive skillshad a good increase in N-gain of 80.56% with a high category. Based on results of the study, it could beconcluded that the implementiton of NHT type cooperative model can practice metacognitive skills on acidbase material to increase correctly.Keywords: NHT, Feasibility, Activity, Metacognitive skills.PENDAHULUANPendidikan pada saat ini menjadi hal yangsangat krusikal bagi semua aspek kehidupan, yangdimana pemerintah dan masyarakat memegangperanan yang sangat penting. Banyak perubahanyang terjadi pada sistem pendidikan guna dapatmeningkatkan kualitas sumber daya manusia.Pengembangan kualitas sumber d

A Veritable Zoology of Successive Phase Transitions in the Asymmetric q-Voter Model on Multiplex Networks

We analyze a nonlinear q-voter model with stochastic noise, interpreted in the social context as independence, on a duplex network. The size of the lobby q (i.e., the pressure group) is a crucial parameter that changes the behavior of the system. The q-voter model has been applied on multiplex networks, and it has been shown that the character of the phase transition depends on the number of levels in the multiplex network as well as on the value of q. The primary aim of this study is to examine phase transition character in the case when on each level of the network the lobby size is different, resulting in two parameters q1 and q2. In a system of a duplex clique (i.e., two fully overlapped complete graphs) we find evidence of successive phase transitions when a continuous phase transition is followed by a discontinuous one or two consecutive discontinuous phase transitions appear, depending on the parameter. When analyzing this system, we even encounter mixed-order (or hybrid) phase transition. The observation of successive phase transitions is a new quantity in binary state opinion formation models and we show that our analytical considerations are fully supported by Monte-Carlo simulations.

Structures and phase transitions of (BrCH2CH2NH3)2CdBr4 and (BrCH2CH2CH2NH3)2CdBr4 as investigated by 81Br NQR, DTA, and single-crystal X-ray diffraction

The crystal structures of (BrCH2CH2NH3)2CdBr4 (1) and (BrCH2CH2CH2NH3)2CdBr4 (2) have been determined at T = 113 K: orthorhombic, Pbcn, a = 843.8(4), b = 775.4(4), c = 2339.6(11) pm, Z = 4 for 1; orthorhombic, Pbcn, a = 858.7(3), b = 783.6(2), c = 2519.4(7) pm, Z = 4 for 2. Both crystals are isomorphic, showing distinctive layered perovskite-related structures, in which the cations orient their aliphatic parts toward each other in their cation layers and connect to the infinite anion layers with their ammonium parts through N–H · · · Br hydrogen bonds. 81Br NQR and differential thermal analysis measurements for both compounds revealed the existence of successive phase transitions as seen in n-(CH3CH2CH2NH3)2CdBr4 (3). These phase transitions appear to be induced by the activated motions of the cations. The changes in the hydrogen bonding schemes resulting from the motions of the cations lead to the different phases of the respective crystals.