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Reducing the switching energy and improving the switching speed of ferroelectrics remain an important goal in the pursuit of electronic devices with ultralow energy consumption and ultrafast response. Molecular ferroelectrics with concise dipole switching mechanism and facile structural tunability are a good platform for manipulating the ferroelectric domains. A methodology is demonstrated to manipulation of ferroelectric domain switching by tailor-made lattice parameters of molecular ferroelectrics, by following which, we succeeded in lowering the threshold electric field and improving the dynamics of ferroelectric switching. Our findings advance the fundamental understanding of microscopic mechanism and provide important insights in controllable tuning of ferroelectric domain switching.

Endowing bulk electrocaloric polymers with excellent thermal conductivity is a superior solution to the high-efficient and precise management of tremendous heat from high-power-density electronic devices. Semi-crystalline polymer P(VDF-TrFE-CFE), i.e., poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene), has a predominant amorphous phase of randomly entangled chains and abundant interface, leading to localized behavior in phonon heat conduction and thereby low thermal conductivity. To enhance the thermal transport performance, electrocaloric polymer films were mechanically stretched or fabricated by electrospun to achieve highly aligned molecular chains. Chain orientation brought about a 2.4- and 1.6-times increase in the thermal diffusion coefficient of the stretched and electrospun films, respectively. Interestingly, after mechanical stretching, the thermal conductivity of the film was increased by a factor of two. In contrast, the electrospun film had a slightly lower thermal conductivity than that of the unoriented one. A remarkable discrepancy in the electrocaloric properties was observed, where the stretched polymer film reached a much higher adiabatic temperature change under an applied electric field than that of the electrospun film. Our strategy provides a perspective on designing a promising thermal management system through the integration of active refrigeration and passive heat dissipation in bulk electrocaloric polymers.

SrxBa1-xNb2O6 ceramics were prepared via the high-temperature solid-state reaction method. Structural, ferroelectric, electrocaloric effect and pyroelectric energy harvesting capabilities of SrxBa1-xNb2O6 ceramics were reported. The main structural phase of tetragonal tungsten bronze with Sr-doped was detected by X–ray diffraction. It was found that the ferroelectric hysteresis loops became slimmer after the temperature higher than Curie temperature of SrxBa1-xNb2O6 ceramics, which was a representative feature of relaxor ferroelectric. In addition, we presented the positive peak values of electrocaloric at vicinity of Curie temperature which was affected by the applied electric field for all samples. It is worth noting that the pyroelectric energy harvesting property is the first time investigated by using Olsen cycle for SrxBa1-xNb2O6 ceramic. The maximum pyroelectric energy harvesting density was 170 kJ m−3 for x = 0.6 in SrxBa1-xNb2O6 with the temperature range from 293 to 433 K. The experimental results indicated that better pyroelectric energy harvesting property and larger electrocaloric effect of SrxBa1-xNb2O6 ceramic benefited from the higher Sr/Ba ratio. Finally, energy-storage capacity for SrxBa1-xNb2O6 ceramic was obtained from the ferroelectric hysteresis loop and the maximum room-temperature energy-storage efficiency was 86.37% with x = 0.6 under 60 kV cm−1.

BaCexTi1−xO3 (BCT) ceramics at x = 0.025, 0.05, 0.075 and 0.1 were prepared by the traditional solid state reaction route and sintered at 1540 °C for 6 h. The microstructural, dielectric, electrocaloric, and pyroelectric performances of BCT were systematically explored. Hysteresis loops were measured under various temperatures, and the electrocaloric effect (ECE) was calculated for all samples. The results showed that BaCe0.075T0.925O3 had the best ECE which exhibited a large adiabatic temperature change of 0.81 K, an isothermal entropy change of 0.82 JK−1kg−1 and an electrocaloric strength of ∼0.28 Km/MV. Further, the pyroelectric figure of merits (FOMs) were analyzed and the results indicated that BaCe0.1T0.9O3 would be a better candidate for pyroelectric devices which exhibited high pyroelectric coefficient (p) of 7.82 × 10−4 Cm−2K−1 and FOM of high detectivity (Fd) of 10.39 μPa−1/2. These results in this work would facilitated the development of the electrocaloric and pyroelectric performance of Ce-doped BaTiO3 ceramics.

Multi-functional electronic skin is of paramount significance for wearable electronics in health monitoring, medical analysis, and human-machine interfacing systems. In order to achieve the function of natural skin, mechanical sensing with high sensitivity is an important feature of electronic skin. Inspired by the spinosum structure under the skin, herein, we fabricate a new capacitive pressure sensor with two-dimensional transition-metal carbides and nitrides (MXene) and ferroelectric polymer (P(VDF-TrFE-CFE)) as an active layer and micropatterned Cr-Au deposited on polydimethylsiloxane as flexible electrodes. Such a method is facile, effective, easily operated, and low-cost. The device design provides great capacitive change as a consequence of large deformation under pressure. Benefiting from the randomly distributed microstructure and high dielectric constant of the active layer, the device demonstrates high sensitivity with great linearity (16.0 kPa−1 for less than 10 kPa), that is, a low detection limit of 8.9 Pa, and quick response. A series of dynamic physiological signals, including typing, knuckle motion, and voice recognition can be facilely detected, making it a competitive candidate in the field of wearable electronics.

Objective Single-dose intravenous (IV) injection of ketamine has shown rapid but transient antidepressant effects. The strategy of repeated-dose ketamine infusions to maintain antidepressant effects has received little systematic study. This study was conducted to examine the efficacy and tolerability of six ketamine infusions in Chinese patients with unipolar and bipolar depression. Methods Ninety seven patients with unipolar (n = 77) and bipolar (n = 20) depression received repeated ketamine infusions (0.5 mg/kg over 40 min) with continuous vital sign monitoring. Depressive symptoms were measured by the Montgomery-Asberg Depression Rating Scale (MADRS). Suicidal ideation was assessed using the Scale for Suicidal Ideations (SSI)-part 1. Anxiety symptoms were evaluated with the 14-item Hamilton Anxiety Scale (HAMA). Adverse psychopathological and dissociative effects were assessed using the Brief Psychiatric Rating Scale (BPRS)-positive symptoms and Clinician Administered Dissociative States Scale (CADSS), respectively. Patients were assessed at baseline, 4 and 24 h, and 3, 4, 5, 6, 8, 9, 10, 11, 12, 13 and 26 days. Results After six ketamine infusions, the response and remission rates were 68.0% and 50.5%, respectively. There were significant decreases in MADRS, SSI-part 1, and HAMA scores within four hours following the first ketamine infusion, and the decreases were sustained over the subsequent infusion period. The nonresponder subgroup manifested rapid significant improvement in suicidal ideations throughout the course of treatment. After the six ketamine infusions, the response was positively associated with the response at 24 h after the first infusion (OR = 8.94), personal income ≥4000 yuan/month (OR = 3.04), and no history of psychiatric hospitalization (OR = 3.41). Only CADSS scores had a mild but marginally significant increase after the first infusion but with a significant BPRS score decrease. Conclusion Six ketamine infusions were safe and effective in patients with unipolar and bipolar depression. The rapid and robust antidepressant and antisuicidal effects of ketamine infusion within four hours were sustained following the subsequent infusions.

Lead-free ferroelectric ceramics (1-x) BaTiO3–xBi(Mg1/2Ti1/2)O3 (x = 0.0–0.07) were synthesized by conventional solid state reaction method and the correlation of structure, dielectric, ferroelectric and impedance properties were investigated. It was found that Tm and εm showed decreasing trend with the increase of BMT content. The high-temperature dielectric relaxation behaviour was observed in all the samples. The activation energy calculated from impedance (Ea) and conductivity (Econd), which revealed that the relaxation behaviours were linked with the migration of OVs. The values of Ea were almost equivalent to Econd. It was concluded that the short-range hopping of oxygen vacancy contributed to the dielectric relaxation and long-distance movement of doubly ionized oxygen vacancies contributed to the conduction. On the other hand, with increasing BMT contents, it was found that P-E loops became slimmer and slimmer, which indicated the increase of relaxor behaviour. The temperature dependence of P-E loops for 0.98BT–0.02BMT ceramic clearly showed the transition process from ferroelectric to relaxed ferroelectrics. Keywords: BT–BMT ceramic, Dielectric, Ferroelectric, Impedance, Oxygen vacancies

Ba(HfxTi1–x)O3 ferroelectric ceramics were prepared by a conventional solid-state reaction process, and the correlation of structure, dielectric, ferroelectric, and electrocaloric properties were studied. The consequences indicated that the TC of Ba(HfxTi1–x)O3 ceramics decreased, while TT–O and TO–R increased with the increase of hafnium content. Large electrocaloric effect values of 1.64 K (117 °C) and 1.21 K (76 °C) were observed for Ba(HfxTi1–x)O3 with x = 0.05 compositions. And, corresponding electrocaloric coefficients respectively were 0.33 and 0.24 K·mm·kV–1. In addition, compared with the second-order phase transition region, larger electrocaloric coefficients (ΔTf /ΔE ≥ 0.19 K·mm·kV–1) were obtained in the first-order phase transition region for all compositions. Meanwhile, the maximum values of electrocaloric coefficients ΔTf /ΔE = 0.38 K·mm·kV–1 was achieved in a smaller electric field for Ba (HfxTi1–x)O3 with x = 0.03 compositions.

The microstructure, dielectric property and electrocaloric effect were investigated in the lead-free (1-x)BaTiO3–x (BiMg1/2Ti1/2)O3 ((1-x) BT–x BMT, x = 0.0–0.05) ferroelectric ceramics. Under the low electric field (E ≤ 20 kV cm−1), the coexistence of a positive and negative electrocaloric effect was obtained in (1-x)BT–x BMT (x ≤ 0.04) ceramics system using the Maxwell relation. Negative electrocaloric behavior disappears and the positive electrocaloric effect was only observed at high electric field (E ≥ 25 kV cm−1). Firstly, the values of both negative electrocaloric effect under low electric field of E ≤ 20 kV cm−1 (NECE) and positive electrocaloric effect in the high electric field of E ≥ 25 kV cm−1 (PECE) increase, then decrease with increasing BMT content in the ceramics. The 0.98BT-0.02BMT ceramic shows the excellent PECE and NECE capabilities. The corresponding giant electrocaloric effect values of −0.37 K (42 °C) at 20 kV cm−1 and 1.21 K (143 °C) at 55 kV cm−1 were observed. These results show great potential in achieving large cooling power as refrigerants.

Recently, the energy crisis become more and more intense and people are gradually committed to new energy storage devices to ease the pressure. Composite energy storage ceramics are extensively explored for its splendid dielectric/ferroelectric performances. In this research, it is the first time that the (1 − x)BaTiO3-xBi(Mg1/2Hf1/2)O3 (BT-BMH) lead-free ferroelectric ceramics are prepared by traditional solid-state method. By introducing BMH into BT lattice, normal ferroelectric can be induced to relaxor ferroelectric. Especially in the case of high BMH doping (x ≥ 0.05), the relaxation dispersion behaviors are more obvious. As addition BMH goes up, the hysteresis loops gradually shrink to sublinear, which is conducive to the high efficiency of energy storage performance of ceramic capacitors. Meanwhile, the recoverable energy of BT–BMH (x = 0.1) ceramics can reach 3.38 J/cm3 with efficiency of nearly 87% at a relatively low electric field of 240 kV/cm. In addition, the optimized ceramic samples possess excellent stability of variable temperatures and frequencies, showing the potential for storage application.

The arm system is the central part in the design of a portable crane. The purpose of this program is to assure that the load moves approximately along the path of the horizontal direction in the process of luffing, through the optimization of the bars’ length of the arm system. Using vectors in the mathematical model, we figured out the coordinates of the bottom point of the truck-beam according to the geometric relationships of the four-bar linkage. With the appliance of proper algorithm and the idea of visualization, we calculated the reasonable length of the bars in MATLAB and transformed the results into software ultimately. The design is suitable for different types of portable cranes, and the software is very convenient and can be used in engineering.

The structure, dielectric, ferroelectric property and high-temperature dielectric relaxation behaviors (HTRBs) were systematically studied for the first time in the Ba(Hf x Ti1−x )O3 ferroelectric ceramics. It was noted that the T C of the Ba(Hf x Ti1−x )O3 ceramics decreases, while T O and T R increases with the increase of Hf quantity. Furthermore, the HTRBs were observed in all samples. Mechanisms of HTRBs were studied from complex impedance and ac conductivity, exposing that it was concerned with the drifting of oxygen vacancies (OVAs). Based on the value of theoretical calculation for activation energy, it was concluded that the HTRBs were attributed to the short distance hopping of the OVAs and the conduction was ascribed to the long-range move of doubly-ionized OVAs in Ba(Hf x Ti1−x )O3 system. Meanwhile, electron paramagnetic resonance spectra were measured to detect the defects in BHTO ceramics. The results showed that the OVAs-related defect signals were observed at g = 1.942. In addition, the dielectric constant peak of relaxation could be significantly restrained by O2 annealing. This further proved that the HTRBs being associated with the defect of oxygen.

Northern hybridization with five HERV-K family members, previously cloned from human teratocarcinoma genomic DNA, indicated that two (HERV-(K)27 and -(K)67) of the five clones are expressed in these teratocarcinoma cells. These two clones are closely related (98.49%), however, and Northern blot hybridization lacks the specificity to distinguish between their respective mRNAs. Therefore, PCR analysis with mixed oligonucleotide primers homologous to conserved retroviral pol gene regions was employed to amplify cDNA synthesized from teratocarcinoma cell RNA. This amplification scheme yielded two novel HERV-K family members, HERV-(K)55 and HERV-(K)91. Clone HERV-(K)55 has approximately 98% nucleotide sequence identity to clones HERV-(K)27 and -(K)67. Subsequent RNase protection assays confirmed the expression of HERV-(K)55 and indicated that clones HERV-(K)27 and -(K)67 were not expressed in these cells. One interpretation is that the HERV-(K)27 and -(K)67 probes detected transcripts of clone HERV-(K)55 or other closely-related elements because of their high homologies. In addition, clone HERV-(K)91, which has approximately 81% nucleotide sequence identity to clones HERV-(K)27, -(K)67, and -(K)55, was obtained only from teratocarcinoma 2102E-Pr cells, but the RNase protection assay showed that this clone is also expressed in other human teratocarcinoma cell lines.

Nucleotide sequence comparisons of the pol gene among 47 retroelements identified two very conserved regions, separated by a span of approximately 640 bp, that have not been previously reported. A set of mixed oligonucleotide primers, 5'-MOP-2 and 3'-MOP-2, homologous to these two conserved pol regions was constructed for use in detection of retroelements. When MOPs-2 were employed in PCR amplification studies, products of about 0.64 kb in size were amplified from human and mouse genomic DNAs and from HIV-1 proviral DNA, but not from negative control plasmid DNAs. The PCR products amplified with MOPs-2 from human LuC-1 teratocarcinoma cell DNA were subcloned and sequenced. Five clones of approximately 0.64 kb in size were identified, and sequence comparisons with all entries in GenBank indicated that these five clones have highest homology, in a range of 64.31 to 98.65%, with the corresponding pol region of HERV-K10 and HM-16 of the human endogenous retrovirus-K (HERV-K) family. Southern hybridizations at high stringency demonstrated that these five clones are present in all human DNAs tested. The evolutionary relationships of these clones with the equivalent pol region of other retroelements were defined by phylogenetic analyses that placed three clones into the HERV-K family and two clones into a new family of human endogenous retroelements. In addition, clone HERV-(K)73 contains the smaller PV1b pol segment that was reported to be selectively expressed in blood leukocytes of patients with polycythemia vera.

Comparisons of pol gene nucleotide and reverse transcriptase (RT) amino acid sequences of 47 retroviruses, 3 caulimoviruses, and 5 hepadnaviruses showed that approximately one-third of the gene at the 5' end is much more conserved than other pol regions. The most conserved regions on both the nucleotide and amino acid sequences were chosen for construction of phylogenetic trees. The maximum-parsimony and distance-matrix methods were used for analyses of aligned amino acid sequences; these two methods, and the compatibility method, were used to analyze the aligned nucleotide sequences. Essentially identical majority-rule consensus trees were produced by these different methods from both the pol gene nucleotide and RT amino acid sequences, which divided the 55 retroelements into six major groups. The reliability of the phylogenetic trees was probed with the bootstrapping of 100 replicates of the original sequence alignments. The grouping results were shown to be statistically significant by multiple comparisons with the least-significant-difference procedure.