By establishing oxy-fuel combustion, direct water injection and waste heat recovery within conventional diesel engine, the compression ignition-internal combustion Rankine cycle (CI-ICRC) concept can ...be realized. It is capable of achieving ultra-high thermal efficiency and low emission. There have been studies on DWI timing in homogeneous charge compression ignition (HCCI) mode, but no systematic researches within CI-ICRC. Therefore, a prototype CI-ICRC engine is established in this work, the cycle performance (including in-cylinder pressure, heat release rate, brake thermal efficiency, etc.) and emission characteristics under different DWI timings are compared. The prototype engine was operated at 800 r/min. DWI temperature, pressure and duration are kept constant at 433 K, 35 MPa and 2 ms. The results indicate that DWI before combustion is more effective in reducing combustion intensity. The optimum DWI timing within this study is 320℃A, while the brake thermal efficiency (BTE) reaches the maximum of 46.6 % with a coefficient of variation close to 1 %. NOx and soot emissions are optimized but CO and HC emissions slightly increased with the utilization of DWI. The experimental results can provide guidance for future CI-ICRC engine optimization, and can also be utilized in providing reference information for DWI utilization within other novel internal combustion engine (ICE) concepts.
Kerr soliton frequency comb generation in monolithic microresonators recently attracted great interests as it enables chip-scale few-cycle pulse generation at microwave rates with smooth ...octave-spanning spectra for self-referencing. Such versatile platform finds significant applications in dual-comb spectroscopy, low-noise optical frequency synthesis, coherent communication systems, etc. However, it still remains challenging to straightforwardly and deterministically generate and sustain the single-soliton state in microresonators. In this paper, we propose and theoretically demonstrate the excitation of single-soliton Kerr frequency comb by seeding the continuous-wave driven nonlinear microcavity with a pulsed trigger. Unlike the mostly adopted frequency tuning scheme reported so far, we show that an energetic single shot pulse can trigger the single-soliton state deterministically without experiencing any unstable or chaotic states. Neither the pump frequency nor the cavity resonance is required to be tuned. The generated mode-locked single-soliton Kerr comb is robust and insensitive to perturbations. Even when the thermal effect induced by the absorption of the intracavity light is taken into account, the proposed single pulse trigger approach remains valid without requiring any thermal compensation means.
Stable octave-spanning supercontinuum (SC) in the mid-infrared (MIR) region finds extensive applications in spectroscopy, metrology, biochemistry, etc. The absorption of conventional silicon- or ...silicon oxide-dominated nonlinear media makes SC generation in MIR region technically challenging. In this paper, we propose ultrabroadband MIR-SC generation using a suspended germanium-membrane ridge waveguide. We theoretically showed that when pump pulses centered at 4.8 μm with pulse width at 180 fs and peak power at 800 W are injected into a 4-mm-long proposed ridge waveguide, the SC generated ranges from 1.96-12 μm (about 2.6 octaves), extending deep into the "fingerprint" region. The first-order coherence is calculated to confirm the stability of the generated SC. The performance of the SC-based frequency comb is also investigated by assuming a 100-pulses pump source at a repetition rate of 100 kHz.
Tumor‐induced angiogenesis has been shown to suppress immune responses. One mechanism is to suppress leukocyte–endothelial cell interaction by down‐regulating the expression of adhesion molecules, ...such as intercellular adhesion molecule (ICAM)‐1, vascular cell adhesion molecule (VCAM)‐1 and E‐selectin on the tumor endothelium, which enables tumor cells to escape immune surveillance. Calreticulin (CRT), a chaperone protein mainly located in the endoplasmic reticulum, has been shown to exert anti‐angiogenic activity and inhibit tumor growth. Here, we demonstrate that in addition to inhibiting angiogenesis, CRT also enhances the expression of both ICAM‐1 and VCAM‐1 on tumor endothelial cells. This expression results in enhanced leukocyte–endothelial cell interactions and increased lymphocyte infiltration into tumors. Therefore, combining intramuscular CRT gene transfer with intratumoral cytokine gene therapies significantly improves the antitumor effects of immunotherapy by markedly increasing the levels of tumor‐infiltrating lymphocytes. This combined treatment increased the levels of infiltrating lymphocytes to those achieved using four times the cytokine dosage. The combined therapy also resulted in lower levels of immunosuppressive molecules and higher levels of activated T‐cells in the tumor microenvironment than immunotherapy alone. In conclusion, this study describes a new antitumor mechanism of CRT that involves the up‐regulation of tumor endothelial adhesion molecules and the enhanced infiltration of tumor‐specific lymphocytes. Thus, CRT treatment can make tumor cells more vulnerable to immunotherapy and improve the therapeutic efficacy of immunotherapy.
We designed a structure of dual-coupled ridge waveguide in thin-film lithium-niobate-on-insulator (LNOI) and numerically studied the highly efficient, broadband, and flattened dispersive ...wave-enhanced supercontinuum generation in the mid-infrared region. By leveraging the mode coupling of the proposed dual-coupled waveguide structure, one of the supermodes, namely the anti-symmetric mode, can produce additional zero-dispersion wavelengths in the mid-infrared region, and consequently multiple normal dispersion regions for dispersive wave emission. Given the rich geometrical degrees of freedom powered by this dual-coupled LNOI waveguide structure, we can tailor the dispersion profile so that a well-established mode-locked fiber laser in the telecommunication band can serve as the pump. Thus, the whole system can potentially be fiber-to-chip integrated and packaged, enabling a compact, cost-effective, and low system-complexity platform. We numerically show that the broadband dispersive wave covering the wavelength range of 1.92~3.55 μm (−20 dB level, near octave-spanning) with spectral flatness of 6.31 dB can be achieved using a 1550 nm, 190 pJ femtosecond pump seed. When the dual hump-shaped spectrum is obtained, the conversion efficiency of the mid-infrared dispersive wave can be up to 19.31%. The influence of the pumping conditions on the performance of mid-infrared dispersive wave generation was also studied. This work provides a competitive candidate for efficient, broadband, and flattened mid-infrared spectrum generation, which can find important applications in spectroscopy, metrology, and communication.
K-ion batteries (KIBs) have drawn much attention due to the abundant potassium reserves and wide accessibility as well as high energy density, which can be designed for large-scale energy storage ...systems. As the most promising anode materials for KIBs, graphitic carbons, especially those with an intermediate structure between the crystalline graphite and amorphous carbons become a hot research focus because of the improved rate capability and enhanced diffusion-controlled capacity at low voltage regions. Herein, we first review the structures of graphitic carbons in the view of graphitic domains and the structure changes in their K-ion intercalation compounds. Then, we summarize the preparation mechanisms and characterizations of graphitic carbons and the influence factors in their degree of graphitization. Furtherly, we illustrate the strategies to optimize their K-ion storage properties from four aspects, namely graphitic domain design, microstructure engineering, electrochemical active component regulation, and defect engineering. Finally, we propose the issues that urgently need to be solved in graphitic carbons and the possible solutions. We hope that this view could offer some inspiration for the further designing and optimizing of graphitic carbons for practical KIBs.
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•A new luminescent Ni(II)-CP was constructed from a semi-rigid tricarboxylate acid.•The sensing property toward Hacac was mainly investigated.•The probable sensing mechanisms are also studied in more ...detail.
Through a solvothermal reaction between the corresponding nickel(II) sulfate, π-electron rich tri-carboxylate ligand 4-(2′,3′-dicarboxylphenoxy) benzoic acid (H3L) and 1,2-bis (4-pyridyl) ethylene (bpe) molecule, a novel three-dimensional (3D) nickel-based coordination polymer (Ni-CP), namely Ni3(L)2(bpe)3(H2O)4·(H2O)6 (1) was successfully constructed. The structure was established by single-crystal X-ray diffraction, which reveals that 1 features a new 3,4,4-connected topology with the point symbol of (105·12) (4·102)2 (4·85)2. Subsequently, some studies on optical properties of compound 1 were carried out. Interestingly, the results suggest that compound 1 exhibits excellent applications as a fluorescent sensor for the recognition of Hacac via a fluorescence quenching approach. The detection limit can be as low as 10.19 µM. The possible mechanisms of the fluorescence turn-off effect were also discussed in detail. This work presents a case for monitoring Hacac concentrations in water samples.
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We proposed and demonstrated an athermal microring resonator in high index-contrast chalcogenide glass film GeSbSe with SU-8 cladding. Due to the negative thermo-optic coefficient of SU-8, we ...experimentally achieved near athermal behavior with a minimum thermally induced resonance shift of 2 pm/°C at around 1550 nm, over twenty times less than that of a regular chalcogenide waveguide. We also demonstrated that the device has a low-temperature sensitivity of < 10 pm/°C over an optical bandwidth of ∼100 nm. Moreover, the power-dependent transmission spectra of the resonator show that polymer SU-8 can improve thermal stability of the device at high input power, thus highly appealing for nonlinear applications.
For the requirements of rigorous CO2 and emissions regulations, steam assist technology is an effective method for thermal efficiency enhancement. However, few studies apply steam assist technology ...in modern internal combustion engines. Stimulated by its application prospects, the present study proposes a thermodynamic analysis on the in-cylinder steam assist technology. An ideal engine thermodynamic model combined with a heat exchanger model is established. Some critical parameters, such as steam injection temperature, injection pressure and intake pressure, are calculated under different steam injection masses. The thermal efficiency boundaries are also analyzed at different compression ratios to investigate the maximum potential thermal efficiency of the technology. The analysis shows that the in-cylinder steam-assisted cycle has the potential to increase engine efficiency considerably. Both steam injection temperature and injection mass improve thermal efficiency. Considering the energy trade-off relationship between steam and exhaust gas, the maximum gain in thermal efficiency achieved with the cycle is 14.5% at a compression ratio of 10. The optimum thermal efficiency can be increased from 54.0% to 59.71% by increasing the compression ratio from 10 to 16. The mechanism lies in the specific heat ratio enhancement from a thermodynamic perspective, which improves the thermal-heat conversion efficiency. The results provide considerable guidance for the future experimental and numerical studies of in-cylinder steam assist technology into modern engines.
In previous works, inverse design methods have primarily focused on manipulating the optical power to achieve specific design targets. In this paper, we use the inverse design method to enable the ...precise engineering of the optical phase. As a proof of concept, we present a series of phase shifters (PSs) with varying phase shifts, which are inversely designed and theoretically validated on the silicon-on-insulator (SOI) platform. The designed PSs exhibit remarkable accuracy, with deviations of below 1°. These proposed PSs feature an ultra-compact footprint of 3 µm in length and offer superior fabrication tolerances compared to conventional structures. Over the 1535–1565 nm bandwidth, the discrepancy between the actual and target phase shifts remains below ±1° for all phase shifters, while the insertion loss is consistently below 0.035 dB. Moreover, the feasibility of the designed five PSs is verified using 2 × 2 multimode interference couplers (MMI).
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