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A second-order distributed feedback interband cascade laser emitting at 3.25 µm was designed, grown, and fabricated. By coherent epitaxy of a GaSb cap layer instead of the conventional thin InAs cap on top of the laser structure, a high-quality surface grating was made of GaSb and gold. Enough coupling strength and a significant inter-modal loss difference were predicted according to the simulation within the framework of couple-wave theory. Lasers having 2-mm-long cavities and 4.5-µm-wide ridges with high-/anti-reflection coatings were fabricated. The continuous-wave threshold current and maximum single-mode output power were 60 mA and 24 mW at 20°C, respectively. The output power of 5 mW was still kept at 55°C. Continuous tuning free from mode hopping and high single-mode suppression ratios (>20 dB) were realized at all injection currents and heat-sink temperatures, covering a spectral range of over 20 cm-1.

Through soliton excitation in a fiber integrated nematic liquid crystals cell, we demonstrated an all-optical response and electrical tunable structure for light coupling and mode conversion in few mode fibers. The light is guided and controlled from the transmitting to the receiving end, making use of the soliton induced waveguide channel, the so called self-guided effect. Both a near-infrared laser, i.e., signal light, and a visible laser, i.e., the probe light, are introduced to demonstrate the self-guided effect and mode conversion, which results match well theoretically and experimentally. Our results show that, the transmitting light can be guided and selectively coupled into lower or higher order modes of the receiving fiber by steering its ‘walk-off’ through voltage control. Besides, the proposed mode converting operation can work in both the polarization-mixed and polarization-separated regimes, and is realizable in a remarkably wide wavelength band.

We investigate a strain compensation method for the growth of complex interband cascade laser structures. For thick InAs/AlSb superlattice clad layers, the sublayer thicknesses were adjusted so that the tensile strain energy in the InAs sublayer was equal to the compressive strain energy in the AlSb sublayer. For the four-constituent active region, as the compressive strain in the Ga0.65In0.35Sb alloy layer was large, a tensile strain was incorporated in the chirped InAs/AlSb superlattice region for strain compensation to the Ga0.65In0.35Sb alloy. A laser structure of thickness 6 μm was grown on the GaSb substrate by molecular beam epitaxy. The wafer exhibited good surface morphology and high crystalline quality.

Whispering gallery mode (WGM) microcavities can efficiently store and manipulate light with strong light confinement and long photon lifetime, while coupling light into and from WGMs is intrinsically hindered by their unique feature of rotational symmetry. Here, a scattering-assisted liquid crystal (LC) micropillar WGM laser is proposed. WGM lasing at the surface of the micropillar is obviously enhanced by fluorescence scattering in the core of the micropillar. Besides, weak scattering of LC molecules also builds efficient coupling channels between the laser modes and the axial transmission modes of the micropillar-based waveguide, providing an all-in-one liquid WGM laser with functions of self-seeding and self-guiding. Furthermore, based on the hysteresis characteristics of the electrically anchored LC molecules under the interaction of thermal force, an erasable read-write liquid memory device is proposed, paving the way for the application of logic-controllable WGM lasers in optical storage and optical control.

We present optical frequency combs with a spectral emission of 48 cm−1 and an output power of 420 mW based on a single-core quantum cascade laser at λ ∼ 8.7 μm. A flat top spectrum sustains up to 130 comb modes delivering ∼ 3.2 mW of optical power per mode, making it a valuable tool for dual comb spectroscopy. The homogeneous gain medium, relying on a slightly diagonal bound-to-continuum structure, promises to provide a broad and stable gain for comb operating. Remarkably, the dispersion of this device is measured within 300 fs2/mm to ensure stable comb operation over 90% of the total current range. The comb is observed with a narrow beatnote linewidth around 2 kHz and has weak dependence on the applied current for stable comb operation.

In this article, we report a high power quantum cascade laser (QCL) at λ ∼ 7.4 µm with a broad tuning range. By carefully designing and optimizing the active region and waveguide structure, a continuous-wave (CW) output power up to 1.36 W and 0.5 W is achieved at 293 K and 373 K which shows the excellent temperature stability. A high wall-plug efficiency (WPE) of 8% and 13.6% in CW and pulsed mode at 293 K are demonstrated. The laser shows a characteristic temperature T0 of 224 K and T1 of 381 K over a temperature range from 283 K to 373 K. In addition, a far field of pure zero order transverse mode and a fairly wide external cavity (EC) tuning range (280 cm-1) from 6.54 µm to 8 µm are achieved in pulsed operation. In addition, an EC single mode output power of 226 mW is obtained under CW operation at 293K.

Dynamic states in mutual-coupled mid-infrared quantum cascade lasers (QCLs) were numerically investigated in the parameter space of injection strength and detuning frequency based on the Lang–Kobayashi equations model. Three types of period-one states were found, with different periods of injection time delay τ inj, 2τ inj, and reciprocal of the detuning frequency. Besides, square-wave, quasi-period, pulse-burst and chaotic oscillations were also observed. It is concluded that external-cavity periodic dynamics and optical modes beating are the mainly periodic dynamics. The interaction of the two periodic dynamics and the high-frequency dynamics stimulated by strong injection induces the dynamic states evolution. This work helps to understand the dynamic behaviors in QCLs and shows a new way to mid-infrared wide-band chaotic laser.

We report a very long wave (14 μm) infrared quantum cascade detector based on a twin-well coupled absorption region operating at temperatures up to 130 K. By introducing two coupled absorption quantum wells that have the same width, the absorption strength and responsivity of the detector are increased relative to the single-well design. At 77 K, we observe a responsivity of 4.06 mA/W at zero bias, which is 4.27 times that of the single-well counterpart. The responsivity is further optimized for reverse bias operation, so that the obstruction of space charge field to electron transport is compensated. The photocurrent reaches a maximum value at 77 K for an applied bias of −1.3 V, and responsivity as high as 23.76 mA/W, which is 5.85 times that under zero bias, is obtained.

Quantum cascade lasers (QCLs) suffer from catastrophic failure caused by serious self-heating, thus limiting their output power and working stability. In this study, we observed a distinctive failure morphology on the back facet of watt-level power QCL emitting at λ ∼ 7.7 µm. The failure was caused by a massive localized current and the channel of the massive current can be observed in the cavity. Because the massive current significantly increased temperature nearby, two burned holes were formed around the channel. A 3D thermal model shows that the back facet is a vulnerable location for failure because light absorption by the high-reflectance metal coating increases the facet temperature significantly. However, the starting point of the massive current has a certain distance from the facet which is the hottest location in the cavity. Therefore, we conduct a hypothesis that the cause of the massive current is thermal strain relaxations induced by temperature gradient. We calculated the positions of the relaxation points and one of them correspond with the failure starting point found experimentally. The strain relaxation damaged the active region, thus leading to the formation of the massive current.

Monolithic integration of III–V materials and devices on CMOS compatible on‐axis Si (001) substrates enables a route of low‐cost and high‐density Si‐based photonic integrated circuits. Inversion boundaries (IBs) are defects that arise from the interface between III–V materials and Si, which makes it almost impossible to produce high‐quality III–V devices on Si. In this paper, a novel technique to achieve IB‐free GaAs monolithically grown on on‐axis Si (001) substrates by realizing the alternating straight and meandering single atomic steps on Si surface has been demonstrated without the use of double Si atomic steps, which was previously believed to be the key for IB‐free III–V growth on Si. The periodic straight and meandering single atomic steps on Si surface are results of high‐temperature annealing of Si buffer layer. Furthermore, an electronically pumped quantum‐dot laser has been demonstrated on this IB‐free GaAs/Si platform with a maximum operating temperature of 120 °C. These results can be a major step towards monolithic integration of III–V materials and devices with the mature CMOS technology.

We demonstrate a quantum cascade detector with two coupled double-well structures exhibiting a high peak responsivity of 166 mA W−1 for 8.2 μm detection at 80 K. The coupled double-absorption-well design offers enhanced absorption efficiency. Meanwhile, incorporating another coupled double-well structure in the extractor increases the extraction efficiency. Both factors contribute to the high performance of our device.

We investigate the influences of ridge-waveguide shape and width on performances of InP-based coupled ridge waveguide laser arrays emitting at $2.1~\mu \text{m}$ . Four devices with different shapes and widths of ridge elements are fabricated. The trapezoid ridges reduce the optical losses at regions between ridge elements in the trapezoid devices, thus enhances the optical coupling between ridge elements and lead to larger coherent output powers compared with the rectangular ones. Meanwhile, narrower ridges with the same shape give a stronger optical confinement to the lateral modes in every single ridge and improve the overall modal and far-field characteristics of the device. The results show that the trapezoid and narrower ridges can lead to a comprehensive improvement in the performances of the coupled ridge waveguide laser arrays emitting at $2.1~\mu \text{m}$ .

A high-performance III–V quantum-dot (QD) laser monolithically grown on Si is one of the most promising candidates for commercially viable Si-based lasers. Great efforts have been made to overcome the challenges due to the heteroepitaxial growth, including threading dislocations and anti-phase boundaries, by growing a more than 2 µm thick III–V buffer layer. However, this relatively thick III–V buffer layer causes the formation of thermal cracks in III–V epi-layers, and hence a low yield of Si-based optoelectronic devices. In this paper, we demonstrate a usage of thin Ge buffer layer to replace the initial part of GaAs buffer layer on Si to reduce the overall thickness of the structure, while maintaining a low density of defects in III–V layers and hence the performance of the InAs/GaAs QD laser. A very high operating temperature of 130 °C has been demonstrated for an InAs/GaAs QD laser by this approach.

Jimusaer tight oil reservoir is characterized by complex lithology, low permeability and high total organic carbon (TOC) content. These features make conventional logging responses very complicated and bring big troubles to reservoir identification. Horizontal well drilling is extremely difficult due to high heterogeneity and uncertain faulting. To maximize oil production with low cost, an integrated solution is provided. First, accurate reservoir characteristics of the pilot well was got using an unconventional evaluation approach by combining capture spectroscopy log, micro-resistivity imager log, nuclear magnetic resonance log, et al. Second, structure analysis for sidetracking well and well correlation between the sidetracking well and the pilot well were done to guide the horizontal section drilling. Third, reservoir quality and completion quality were evaluated for horizontal well, and a 3D structural model was built to optimize the stimulation design by combining reservoir quality, completion quality and natural fractures.

Fracture effectiveness, extension and connectivity from borehole surface into deep formation are the key factors to control producibility of volcanic formations. A systematic and integrated fracture delineation approach was set up which integrated available measurements with multi-scale depth of investigation to cover borehole surface, near wellbore and deep formation. High resolution micro-resistivity image was used to identify fractures on the borehole surface; shear anisotropy enhanced by dispersion analysis was used to evaluate fractures away from the borehole; Borehole acoustic reflection survey technique was applied in vertical wells to assess probable fracture networks deep into formation up to maximal 10 meters. This multi-scale approach had been implemented in multiple wells drilled in volcanic formations in Junggar basin, which helped a lot on fracture evaluation and productivity estimation.

We demonstrate high-bitrate coherent optical OFDM transmission utilizing low-noise Kerr frequency comb as multi-channel laser source. 4QAM-OFDM data with total bitrate of 136.0 Gb/s are successfully transmitted over a 100 km fiber link.

The Lower Silurian marine shale is widely distributed in Northwestern Hunan and features in a large thickness of dark shale showed at outcrops. However, the accumulation conditions and gas content is unknown. The sedimentary facies, thickness and distribution, organic matter types and content, maturity, reservoir properties and gas content of the Lower Silurian black shale in Northwestern Hunan were investigated by field observation, sampling and experimental analysis. The results show that the black shales sedimentary environment is deep water continental shelf, with featured in abundant fossil. The burial depth of the Lower Silurian black shale is 0-3000 m, and its thickness is 10-40m while the average TOC is 1.0% and average Ro is 2.9%. For the disadvantaged sedimentary facies and shallow depth, the maximum gas content of the Lower Silurian black shale from well site desorption test is 0.59m3/t only, but the result of isothermal adsorption simulate test show that the Lower Silurian black shale have a good adsorption capacity, and can generate a large number of shale gas in Northwestern Hunan where better deposition conditions and suitable depth exist in.

China has huge Shale gas resources potential. The exploitation of shale gas can effectively reduce atmosphere pollution and relieve the energy shortage in China. The thickness, burial depth, organic richness and thermal maturity of Paleozoic shales in the different regions are studied and the favorable areas of shale gas are depicted. The most favorable formation for shale gas accumulations in Lower Paleozoic are Longmaxi and Niutitang shale and the favored regions mainly distributed in Yangtze area in southern China, the Tarim Basin, etc. The distribution of Upper Paleozoic shale gas mainly developed in Taiyuan and Shanxi formations in the Ordos Basin and North China. Through the comprehensive comparison, it is summarized that Yangtze area, especially in the northeast and southeast of Sichuan Basin, the west of Hubei province and the east of Chongqing province are the preferred choices for shale gas exploration.

The Guangyuan area is located in the northern section of the Longmenshan fault zone, with strong tectonic activity, complex and changeable strata, low level of exploration and complex development status of shale. Through such means as field sample collections, section measurements and indoor organic geochemical experiments, gas content tests and physical characteristics test of Shale, critical data, such as the depth (1000-2000m), thickness (30-50m), organic geochemical indicators and gas content (1.55 m3/t) of shale in the study area, have been determined. Based on the study of tectonic movements and depositional environment in the region, combined with the rule of shale gas reservoirs formed by rich aggregation, favorable area for shale development in the study area has been identified with the method of multi-factors superposition.The favorable area is located in southeast of Guangyuan area and the area is approximate 300km2 .

Gas chromatograms of saturated hydrocarbons of shale rock extracts show three patterns of n-alkanets in the second member of Funning formation (E1f2) in Jinhu Sag of Subei basin, eastern China. Three patterns of n-alkanets are the odd-to-even carbon predominance, the even-to-odd carbon predominance, and the even and odd carbon predominance coexisting, respectively. In this paper, the characteristics of n-alkanet coexisting even and odd carbon predominance and its origin and sedimentary environment are investigated only. The short-chain n-alkanets and long-chain n-alkanets are characterized by pronounced odd carbon predominance, with the dominant carbon of nC15, nC17 and of nC25, nC27, nC29 and nC31. The mid-chain n-alkanets are dominated by even carbon predominance, with the dominant carbon of nC20 and nC22. The composition of biomarkers are characterized by phytane preference, high gamma cerate abundance, the presence of β-carotene and C24-tetracyclic terrapin, which indicate that the organic matter in source rocks deposited in an anoxic, hyper saline lacus trine environment. The biomarkers are no homogeneous, which shows that salinity and redo is not constant in pale-lacus trine. The n-alkanets are mainly derived from algae in the ancient lake and macro pyres on land or around the edges of the ancient lake. The n-alkanets distribution patterns of the dark shales studied are believed not to be dependent on the redo in the depositional environments or the salinity of the water body, but to be associated with original organic matter composition.

In conventional turbofan aero-engine designs, the effective way of improvement of engine efficiency is through the increasing of overall pressure ratio and improving of combustor inlet gas temperature, but the further incresement of compressor overall pressor ratio is constricted by high pressure compressor outlet allowed temperature. The improvement of combustor outlet temperature is limited by turbine allowed inlet temperature during take-off and climbing. An intercooled core can be designed with a significantly higher overall pressure ratio also with reduced cooling air requirements, providing a higher thermal efficiency compared with a conventional core. Through the basic analysis of performance of intercooler aeroengines. It indicated that the intercooled aero-engines can decrese the feul consume clearly and have a further potential in future civil aircraft application.

The finite element models of extruded sealing ring which had the same installation specifications but different structure sizes of sections were established, and the results from finite element analyses of the axial stiffness of these models were compared, then, an excellent characteristic of the shape of sealing ring on axial stiffness was found.

To reduce exposure and increase concealment, AIP (Air Independent Propulsion) power plant came into being. In a variety of AIP power devices, closed cycle diesel CCD (Closed Cycle Diesel Engine System) AIP system is the most commonly used at present. Drawing on the principle of existing CCDAIP closed cycle diesel, This paper presents a design about Zero Release Closed Cycle Diesel Engine System, which uses oxygen generation device to produce O2 for the fuel combustion by absorbing CO2，in order to realize the truely zero emissions of conventional submarines without exhaust trail. The paper also takes a preliminary exploration of the design.

The micromigration of oil-drive-water and gas-drive-water in oil and gas fields was studied, by using core slices and micro-experimental technology, and the migration processes and characteristics of oil and gas in pores and throats were observed, as well as entry pressures of oil/gas migration. Research shows that entry pressures of both oil-drive-water and gas-drive-water increase obviously as porosity decreases, and the statistical regularity observes the power function variation. However, there is a complex changing relationship between porosity and different entry pressure values of the two replacement processes, forming three curve sections, each representing a different accumulation significance. When the porosity is over 10%–12%, the difference between oil-drive-water and gas-drive-water entry pressures is small. Both oil and gas can migrate and accumulate in this kind of reservoir. The probabilities of oil and gas reservoir formation are nearly equal, forming conventional oil/gas pools. When porosity is between 5% and 10%–12%, the difference between the two is obvious, which indicates that this kind of reservoir can seal oil, but can also be a reservoir for gas, easily forming unconventional hydrocarbon pools (deep-basin gas pools). When porosity is less than 5%, the difference is indistinct and the entry capillary pressures show the same sealing function for oil and gas. In this condition, both oil and gas pools are difficult to form. Experimental results give a rational explanation for the difference of accumulation probability between deep-basin gas and deep-basin oil, and also for the mechanism of tight sand acting as cap rock.

A multi-wavelength sampled Bragg grating (SBG) quantum cascade laser array operating between 7.32 and 7.85 μm is reported. The sampling grating structure, which can be analyzed as a conventional grating multiplied by a sampling function, is fabricated by holographic exposure combined with optical photolithography. The sampling grating period was varied from 8 to 32 μm, and different sampling order (−1st, −2nd, and −3rd order) modes were achieved. We propose that higher-order modes with optimized duty cycles can be used to take full advantage of the gain curve and improve the wavelength coverage of the SBG array, which will be beneficial to many applications.

We demonstrated an unambiguous quantum dot cascade laser based on InGaAs/GaAs/InAs/InAlAs heterostructure by making use of self-assembled quantum dots in the Stranski-Krastanow growth mode and two-step strain compensation active region design. The prototype generates stimulated emission at λ ~ 6.15 μm and a broad electroluminescence band with full width at half maximum over 3 μm. The characteristic temperature for the threshold current density within the temperature range of 82 to 162 K is up to 400 K. Moreover, our materials show the strong perpendicular mid-infrared response at about 1,900 cm-1. These results are very promising for extending the present laser concept to terahertz quantum cascade laser, which would lead to room temperature operation. PACS 42.55.Px; 78.55.Cr; 78.67.Hc

There have been considerable interests in methane detection based on infrared absorption spectroscopy for industrial and environment monitoring. The authors report on the realization of photoacoustic detection of methane (CH4) using mid-infrared distributed-feedback quantum cascade laser (DFB-QCL). The absorption line at 1316.83 cm(-1) was selected for CH4 detection, which can be reached by the self-manufactured DFB-QCL source operating in pulsed mode near 7.6 microm at room-temperature. The CH4 gas is filled to a Helmholtz resonant photoacoustic cell, which was equipped with a commercial electret microphone. The DFB-QCL was operated at 234 Hz with an 80 mW optical peak power. A detection limit of 189 parts per billion in volume was derived when the signal-to-noise ratio equaled 1.

To describe the treatment with caspofungin of pneumocystis Carinii pneumonia (PCP) in elderly patients.A 93 year old male patient with chronic obstructive pulmonary disease (COPD) and in mechanical ventilation for 25 months. PCP was diagnosed and treated with trimethoprim-sulphamethoxazole compound (SMZ/TMP) and caspofungin.The diagnosis of PCP was confirmed by clinical features, radiographic abnormalities and sputum smear Giemsa stain PC (+) or PCR (+). SMZ/TMP was the first choice in treatment of PCP but caspofungin can be used in patients. SMZ/TMP had to be discontinued because of side effect or treatment failure. Caspofungin was effective and without any side effects in this patient.PCP is one of opportunistic infections in elderly patient admitted for long term mechanical ventilation. SMZ/TMP is the first choice for treatment but caspofungin may be an alternative.

To investigate the effects of interleukin-10 (IL-10) on expression of inflammatory mediators and anti-inflammatory mediators during acute lung injury (ALI).Rat model of ALI was reproduced by intratracheal instillation of lipopolysaccharide (LPS) in a dose of 10 mg/kg. Fifty-four male SD rats were randomly divided into control group, LPS group and LPS+IL-10 group, with 18 rats in each group (6 rats at 2, 6 and 24 hours respectively). Arterial gas analysis, the total protein concentration in bronchoalveolar lavage fluid (BALF), the total cell counts and classification in BALF, the lung coefficient, lung pathology were examined. Reverse transcription-polymerase chain reaction (RT-PCR) method was used to determine the expression of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and IL-1ra mRNA in lung tissue.(1)In LPS group the partial pressure of oxygen in artery (PaO(2)) was progressively decreased, while the lung coefficient, the total protein concentration, the total cell counts in BALF were greatly increased, and lung pathology showed severe polymorphonuclear leukocytes infiltration with bleeding and hyaline membranes formation. In LPS+IL-10 group the values of all above parameters were alleviated. (2)In LPS group TNF-alpha mRNA expression peaked at 2 hours, then decreased sharply; IL-1beta mRNA expression greatly increased at 2 hours, peaked at 6 hours, then decreased; IL-1ra mRNA expression increased and peaked at 6 hours, remaining higher than control group at 24 hours. IL-10 inhibited TNF-alpha mRNA and IL-1beta mRNA expression but showed no effect on IL-1ra mRNA expression.(1)ALI is characterized by overwhelming expression of TNF-alpha mRNA, IL-1beta mRNA, while the expression of IL-1ra mRNA is much delayed than TNF-alpha mRNA and IL-1beta mRNA. It suggests that there is an imbalance between inflammatory/anti-inflammatory mediators in the early phase of ALI. (2)IL-10 can inhibit the expression of inflammatory mediators and has no effect on the expression of anti-inflammatory mediators, thus it contributes to the balance between them, ameliorating ALI in rats.

To evaluate the diagnostic value of blinded protected specimen brush and quantitative culture (BPSB-QC) in the pathogenic diagnosis of ventilator-associated pneumonia (VAP).A prospective, self-controlled clinical trial was conducted during a 36-month period. QC of paired samples of BPSB and PSB via a fiberoptic bronchoscopy (FOB- PSB) in a total of 54 patients during 125 suspected episodes of VAP was compared. The sensitivity and accuracy, as well as the concordance between BPSB-QC and FOB-PSB-QC result in 48 patients with 106 episodes of VAP were assessed. Both BPSB-QC and FOB-PSB-QC greater than 103 cfu/ml (positive cutoff) was considered diagnostic of VAP.Forty-eight patients with 106 episodes were considered to have VAP (84.8%). The accuracy of BPSB-QC and FOB-PSB-QC were 80.8% (101/125) and 83.2% (104/125), respectively. The rate of complete concordant results was high (75.2%) for BPSB-QC and FOB-PSB-QC. The pathogenic diagnostic agreement between the two techniques was 84.8% (106/125). There were no significant differences with regard to site of pneumonia and positive diagnostic rate between the two techniques.BPSB-QC has similar accuracy and same feasibility compared with FOB-PSB-QC which was commonly primarily used in the pathogenic diagnosis of VAP, and that its use is substantially simpler, safe and cost saving, especially when FOB technique is not available.