Recent Advances and Future Prospects for Memristive Materials, Devices, and Systems.

Memristive technology has been rapidly emerging as a potential alternative to traditional CMOS technology, which is facing fundamental limitations in its development. Since oxide-based resistive switches were demonstrated as memristors in 2008, memristive devices have garnered significant attention due to their biomimetic memory properties, which promise to significantly improve power consumption in computing applications. Here, we provide a comprehensive overview of recent advances in memristive technology, including memristive devices, theory, algorithms, architectures, and systems. In addition, we discuss research directions for various applications of memristive technology including hardware accelerators for artificial intelligence, in-sensor computing, and probabilistic computing. Finally, we provide a forward-looking perspective on the future of memristive technology, outlining the challenges and opportunities for further research and innovation in this field. By providing an up-to-date overview of the state-of-the-art in memristive technology, this review aims to inform and inspire further research in this field.

Effects of different Bacillus licheniformis and Bacillus subtilis ratios on nutrient digestibility, fecal microflora, and gas emissions of growing pigs.

The objective of this study was to evaluate the effects of different mixing ratios of Bacillus licheniformis and Bacillus subtilis in diets on nutrient digestibility, fecal microflora, and odor gas emissions of growing pigs. A total of four crossbred ([Landrace × Yorkshire] × Duroc) barrows with average body weight (BW) of 41.2 ± 0.7 kg were randomly allotted four diets over four periods in a 4 × 4 Latin square design. Treatments were as follows: Control (CON, basal diet), CON + 0.2% probiotic complex (L4S6, B. licheniformis and B. subtilis at a 4:6 ratio), CON + 0.2% probiotic complex (L5S5, B. licheniformis and B. subtilis at a 5:5 ratio), CON + 0.2% probiotic complex (L6S4, B. licheniformis and B. subtilis at a 6:4 ratio). Dietary probiotic supplementation showed higher crude protein (CP) digestibility values and lower Escherichia coli counts in fecal samples than the CON group (p < 0.05). There was no significant difference in NH3 or H2S emission until day 3. The positive effect of H2S and NH3 emissions was detected earlier with the L4S6 and L5S5 compared to the L6S4, which had a lower ratio of B. subtilis. Both the L4S6 and L5S5 probiotic complexes significantly decreased the fecal H2S and NH3 emission in days 4 and 6 (p < 0.05). On day 7, all probiotic complexes decreased (p < 0.05) H2S and NH3 emissions than the CON group. Our results agreed that the dietary supplementation of Bacillus licheniformis and Bacillus subtilis complexes in growing pigs can significantly improve CP digestibility and reduce fecal E. coli counts, NH3 and H2S emissions. Notably, the higher mixing ratio of Bacillus subtilis in probiotic supplementation is more effective in reducing the odor of manure.

Effects of forage level and chromium-methionine chelate supplementation on performance, carcass characteristics and blood metabolites in Korean native (Hanwoo) steers.

A feeding trial was carried out to determine the effects of chromium methionine (Cr-Met) chelate and forage level over two years, 1(st) fattening and 2(nd) fattening period on growth parameters, carcass characteristics and blood metabolites of 46 Korean native (Hanwoo, Bos Taurus, BW = 183 ± 44 kg) steers. Treatments were: 1) Steers in the low forage (LF) group were fed diets that consisted of 60% concentrate and 40% forage; 2) Steers in the high forage (HF) group were fed diets that consisted of 40% concentrate and 60% forage. Following the 1(st) fattening period, steers (BW = 480 ± 37.6 kg) were randomly assigned to four treatment groups: LF (40 F plus no Cr-Met supplementation in the 2(nd) fattening period), LFCM (40LF plus added 400 ppb of Cr-Met during the 2(nd) fattening period), HF (60 F plus no added Cr-Met during the 2(nd) fattening period) and HFCM (60 F plus added 400 ppb of Cr-Met in the 2(nd) fattening period). Dry matter intake of the treatment diets did not differ during the raising and 1(th) fattening period (P > 0.05). The ADG in the raising period showed no difference between the 40 F and 60 F groups (P > 0.05). Carcass characteristics including rib-eye area and meat yield index were higher in HF than the other treatment groups (P < 0.05). The HF group tended to show a higher (P = 0.08) marbling score than the LF group whereas the HFCM group showed a higher marbling score than the LFCM group (P < 0.05). HDL was higher and LDL lower in groups fed with Cr-Met than in other groups whereas glucose showed the lowest value in HF group (P < 0.05). Triglyceride (TG), Cholesterol, PUN and total protein (TP) were the same among all treatment groups (P > 0.05). The Insulin concentration in the blood was significantly higher for the HFCM group than for the LF, LFCM and HF groups (P < 0.05). It is concluded that supplementation of chromium-methionine chelate could improve meat quality in beef steers.

Effect of nanopyramid bottom electrodes on bipolar resistive switching phenomena in nickel nitride films-based crossbar arrays.

The improved resistive switching (RS) performance characteristics of nickel nitride (NiN) films-based crossbar array (CBA) memory resistors-such as reduction in the operating voltages, reset current and current/voltage variations; no initial forming process; and set/reset speeds--are demonstrated using nanopyramid-patterned (NPP) platinum-bottom electrodes. Compared with a conventional CBA sample with flat-bottom electrodes, both the voltage and the current of the set and reset operations are respectively reduced when NPP samples are used. The drastic reduction in the variation of the operating voltage and current is of particular interest. We explain the RS process using the model of the redox-reaction-mediated formation and rupture of the conducting filaments in the NiN films, based on the capacitance-voltage and conductance-voltage characteristics under different resistance states.

Size-dependent resistive switching properties of the active region in nickel nitride-based crossbar array resistive random access memory.

The size-dependent resistive switching (RS) properties of the active region in a 1 x 1 NiN-based crossbar array (CBA) resistive random access memory (ReRAM) are investigated in the range of 2 x 2 µm2 to 8 x 8 µm2. In the forming test, the forming voltage is reduced by decreasing the cell size of the active region. Compared to the 8 x 8 µm2 CBA ReRAM, the forming voltage of the 2 x 2 µm2 CBA ReRAM was reduced from 8 V to 6.2 V. In addition, V(SET/RESET) and the current for the reset operation are reduced in the current-voltage (I-V) results by reducing the cell size, while the current at a high-resistance state (HRS) is increased. As a result, the current ratio between the HRS and a low-resistance state (LRS) is reduced. On the other hand, the variation of V(SET) for I-V curves repetitively acquired 100 times is decreased by decreasing the cell size in the reliability test. Further, the current at the HRS for the 2 x 2 µm2 CBA ReRAM is the most stable with the smallest current variation for 1000 s in the retention test. These results show that reducing the active region in the CBA ReRAM structure is effective for improving the reliability of ReRAM cells because it reduces the operating voltage and current as well as the variation of V(SET) and the current at the HRS.