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Sandstone-hosted roll-type U deposits has recently been found in the Middle Jurassic Zhiluo Formation in the Dongsheng area, north of the Ordos Basin. In order to assess the origin of the uranium mineralization, the host sandstone has been investigated, with emphasis on δ34S values of ore-stage pyrite, δ13C of calcite, fluid inclusion oil biomarkers, X-ray diffraction, ICP-MS, as well as studies by electron microprobe and scanning electron microscope. The mineralization consists mainly of coffinite. Some of the coffinite is intimately intergrown with ore-stage pyrite, indicating co-precipitation. Ore-stage pyrite has δ34S values from − 34 to + 17‰, suggesting the pyrite sulfur originated from bacterial sulfate reduction. In the host sandstone, calcite cement exhibits δ13C values from − 27.6 to − 2.1‰ and fluid inclusion oils show evidence of biodegradation. These lines of evidence indicate petroleum was likely oxidized by sulfate-reducing bacteria (SRB) and thus supplied a source of some of the carbon in the calcite. Microbial degradation of petroleum is partially supported by the low-temperature diagenetic environment (

The thermal stability of Paleozoic oil in eastern Tarim Basin, NW China was investigated through laboratory kinetic simulation experiments. Laboratory cracking of a selected marine oil sample from Ordovician strata in well LG-1 of Tarim Basin was performed by confined, dry pyrolysis system at T = 300–650 °C, P = 50 MPa. Results indicated the oil required higher temperature for cracking. At laboratory heating rates, oil cracking started at 390–400 °C and the laboratory cracking was completed at around 650 °C. At geological heating rates, the onset temperature is about 148–162 °C for cracking start and was completed at 245–276 °C. The oil-cracking history was recovered using the acquired kinetic parameters and the geothermal history of TD-2, and the threshold temperature for oil cracking under geological conditions was calculated. The oil cracking started at 165 °C ( R o = 1.45%) and stopped in early Devonian (390 Ma), and the oil-cracking rates in the strata of -O 1 reached 60–70% at the end of Silurian. The calculated oil generation and oil cracking windows overlapped to some extent and were completed rapidly. The possible geological controls for the occurrence of residual oil reservoirs in Eastern Tarim basin have been discussed, including the high stability of the Paleozoic oil in Tarim Basin, the fast heating rate and longer duration time for oil cracking, the slight biodegradation in later uplift, the good preservation of the paleo-reservoirs and the moderate structural adjustment, which were critical for the exploration of residual oil and gases in this area.

To evaluate the feasibility and effectiveness of transcatheter aortic valve implantation assisted with snare to fix the delivery system.This study was made in 5 healthy goats. After the abdomen was opened and the abdominal aorta was exposed, a stiff guide wire was advanced into the apex of the left ventricle through abdominal arterial puncture points. The delivery catheter equipped with valved stent was inserted into the descending aorta under fluoroscopy along the stiff guide wire. A minimal thoracic surgery approach was used to access the apex of the heart. A J-type guidewire and 5 F multifunction catheter were placed transapically and across the aortic valve down to the descending aorta. The snare was introduced through the 5 F catheter into the ascending aorta and was controlled to seize the head of stent delivery catheter. Then the delivery catheter was advanced into the left ventricle. The valved stent was positioned in the desired position under aortography and then the balloon was dilated and the valved stent was deployed into the aortic annulus assisted with snare to fix the catheter to prevent stent dispositions. Aortic angiography and echocardiography were performed to evaluate of valve performance post procedure.The interventional procedure was completed successfully in all 5 goats. The mean aortic annulus diameter was (23.8 ± 2.6) mm, two valved stent of 23 mm diameter and three valved stent of 26 mm in diameter were implanted. The operation duration and X-ray exposure time were (112.3 ± 19.5) min and (16.8 ± 5.2) min, respectively. Immediate observation after procedure showed that the valved stents were in the desired position after implantation by angiography and echocardiography. No moderate to severe aortic regurgitation was observed. All goats were alive at 1 month post procedure.The procedure of transcatheter implantation of a balloon-expandable valved stent into the aortic valve position of goats assisted with snare to fix the delivery catheter is feasible and effective. This procedure might be suitable also for patients with noncalcified aortic stenosis.

Six petroleum source beds have been developed in the Kuche Depression (also known as “Kuqa Depression”) of the Tarim Basin, including three lacustrine source rocks (Middle and Upper Triassic Kelamayi and Huangshanjie formations, and Middle Jurassic Qiakemake Formation) and three coal measures (Upper Triassic Taliqike Formation, Lower Jurassic Yangxia Formation, and Middle Jurassic Kezilenuer Formation). While type I–II organic matter occurs in the Middle Jurassic Qiakemake Formation (J2q), other source beds contain dominantly type III organic matter. Gas generation rates and stable carbon isotopic kinetics of methane generation from representative source rocks collected in the Kuche Depression were measured and calculated using an on-line dry and open pyrolysis system. Combined with hydrocarbon generation history modelling, the formation and evolution processes of the Jurassic–Triassic highly efficient gas kitchens were established. High sedimentation rate in the Neogene and the fast deposition of the Kuche Formation within the Pliocene (5 Ma) in particular have led to the rapid increase in Mesozoic source rock maturity, resulting in significant dry gas generation. The extremely high gas generation rates from source kitchens have apparently expedited the formation of highly efficient gas accumulations in the Kuche Depression. Because different Mesozoic source rocks occur in different structural belts, the presence of both lacustrine and coaly gas kitchens during the Cenozoic time can be identified in the Kuche Depression. As shown by the chemical and stable carbon isotope compositions of the discovered gases, the formation of the giant gas pools in the Kela 2, Dina 2, Yaha and Wucan 1 have involved very different geological processes due to the difference in their gas source kitchens.

Oil and gas exploration in eastern Tarim Basin, NW China has been successful in recent years, with several commercial gas accumulations being discovered in a thermally mature to over-mature region. The Yingnan2 (YN2) gas field, situated in the Yingnan structure of the Yingjisu Depression, produces gases that are relatively enriched in nitrogen and C2+ alkanes. The δ13C1 (−38.6‰ to −36.2‰) and δ13C2 values (−30.9‰ to −34.7‰) of these gases are characteristic of marine sourced gases with relatively high maturity levels. The distributions of biomarkers in the associated condensates suggest close affinities with the Cambrian–Lower Ordovician source rocks which, in the Yingjisu Sag, are currently over-mature (with 3–4%Ro). Burial and thermal maturity modeling results indicate that paleo-temperatures of the Cambrian–Lower Ordovician source rocks had increased from 90 to 210 °C during the late Caledonian orogeny (458–438 Ma), due to rapid subsidence and sediment loading. By the end of Ordovician, hydrocarbon potential in these source rocks had been largely exhausted. The homogenization temperatures of hydrocarbon fluid inclusions identified from the Jurassic reservoirs of the YN2 gas field suggest a hydrocarbon emplacement time as recent as about 10 Ma, when the maturity levels of Middle–Lower Jurassic source rocks in the study area were too low (

The molecular compositions and molecular carbon isotopic compositions of gas hydrocarbons produced in the hydrocarbon generation of oil asphaltene from Lunnnan area were investigated by pyrolysis of asphaltene sealed in gold tube in a limited system. The experimental results indicated that oil asphaltene from Lunnan area had relatively high generation potential of methane. However, the molecular compositions and molecular carbon isotopic compositions of gas hydrocarbons in the hydrocarbon generation of oil asphaltene exhibited different characteristics from that of gas hydrocarbons by primary cracking of kerogen and secondary cracking of oil. Based on kinetic simulation with paleo-geothermal data of oil reservoir, the methane produced by cracking of oil asphatene was characterized by relatively light carbon isotopic compositions. This result could not explain relatively heavy carbon isotopic compositions of natural gas from Lunnan area. Pyrolysis of kerogen from source rocks under very high temperature probably made remarkable contributions to natural gas from Lunnan area.

The Kuqa depression in the Tarim Basin, NW China contains significant natural gas and condensate resources, with only small amounts of black oil. This study demonstrates that the primary reason for the accumulation of large natural gas reserves in the Kuqa depression is the high maturity level of the Jurassic coal-bearing sequence that is currently at the peak stage of dry gas generation. From the combined stable carbon isotopes and molecular biomarker data it is possible to identify two separate source rocks for the discovered hydrocarbon fluids: the gases were primarily from the Middle-Lower Jurassic coals and associated clastic rocks, and the oils were from the Upper Triassic lacustrine mudstones. Peak oil generation from the Triassic source rocks occurred during the early Miocene (23–12 Ma b.p.). These oils migrated laterally over relatively long distances (∼20–50 km) reaching the outer periphery of the depression. Peak gas generation took place more recently, perhaps during the past 5 Ma. The gases migrated mainly along faults over relatively short lateral distances, resulting in accumulations adjacent to the over-matured source kitchens. Different timings for the trap formation along the north and south margins and a late injection of gas into early oil accumulations provided favorable conditions for the formation of evaporative condensates and the preservation of gas pools in the more down-dip reservoirs and oil pools in the more up-dip locations.

Kuqa depression bears not only plenty of natural gas, but also a large amount of condensate and small quantity of crude oil. Based on the geochemical correlation between the Jurassic and Triassic terrestrial hydrocarbon source rock, this paper confirms that the natural gas in Kuqa depression belongs to coal-type gas and the main gas source rock is attributed to the middle to lower Jurassic coal series formation, while the main oil source rock is the upper Triassic lacustrine mudstone. The authors indicated that Kuqa depression was slowly subsided in Mesozoic, but rapidly went down in Late Tertiary, which made the Jurassic and Triassic source rock suddenly deep-buried and rapidly evolved to high and over-mature phase since 5 Ma. The Triassic source rock is postponed to the Early Miocene during 23−12 Ma when entering the oil-generating peak, while the Jurassic is suspended to the latest 5 Ma, especially since 2.5 Ma to the dry gas-generating period, which is one of the characteristics of the source rock thermal evolution in Kuqa depression. This paper presents a two-stage trapping and late gas trapping model in Kuqa depression whose characteristics are: The main oil and gas reservoirs have different sources. The oil reservoir is formed early while the gas reservoir is formed lately. During the early stage, it, mainly as oil, takes long distance lateral migration, while in the later stage, it, mainly as gas, takes the vertical migration and also has lateral migration. The trap formed in different time on the south and north sides of the depression and evolved into a distributional pattern with oil in the south part and gas in the north, also oil on the outer ring and gas on the inner ring. This paper points out that the late trapping of the natural gas in Kuqa depression is favorable for the preservation of large gas fields.

Dinosteranes and 4-methyl-24-ethylcholestanes are usually to be thought of as biomarkers for dinoflagellates, and 24-norcholestanes and C28steranes for diatom. Therefore, the highest concentrations of these compounds are typically found in strata deposited since the beginning of the Mesozoic. However these compounds appeared widely and abundantly in extracts from organic-rich sediments in the Sinian and Cambrian of the Tarim Basin. This suggests that some of the planktonic algae such as dinoflagellates and diatoms have an earlier origin than the Mesozoic. Some of the remarkable algal fossils observed in the Cambrian, in both well He 4 and the outcrop section of Xiao-Er-Bulak, Tarim Basin, provide possible biological evidence for this kind of inference.

Memory T cells are a significant barrier to the induction of transplant tolerance. Our previous study demonstrated that multiple applications of anti-CD44 monoclonal antibody (mAb) could significantly inhibit CD4(+) memory T cells from mediating rejection of cardiac allografts. Now, we sought to explore the effect and mechanism of anti-CD44 mAb on the rejection of islet allografts and xenografts mediated by CD4(+) memory T cells.In this study, we first engrafted skin grafts of C57BL/6 (B6) mice or Dark Agouti (DA) rats onto BALB/c mice to induce donor-reactive memory T cells. We adoptively transferred purified CD4(+) memory T cells to BALB/c origin nude mice and then transplanted islet allografts and xenografts to produce the Allo-Tx and Xeno-Tx models, respectively. We subsequently administered multiple anti-CD44 mAb and observed changes in the survival times of the islet grafts.In the Allo-Tx model, the mean survival time (MST) of the grafts was 7.7 days in the isotype group, and 20.3 days in the anti-CD44 group. In the Xeno-Tx model, the MST of the grafts was 7.2 days in the isotype group and 8.2 days in the anti-CD44 group. Compared with the isotype group, CD4(+) T cells on the grafts in the anti-CD44 group were significantly decreased in both the Allo-Tx and Xeno-Tx models, but the proportion of CD4(+) memory T cells in the spleens and draining lymph nodes of the recipient nude mice in the anti-CD44 group was significantly decreased in the Allo-Tx model, while it was increased in the Xeno-Tx model. The production of donor-specific IgG antibody in the anti-CD44 group did not vary in the Allo-Tx model, while it was markedly elevated in the Xeno-Tx model. Furthermore, the expression of interferon gamma in the anti-CD44 group was markedly decreased in both the Allo-Tx and Xeno-Tx models, while the expression of IL-4 in the anti-CD44 group was significantly increased only in the Xeno-Tx model.Multiple applications of the anti-CD44 mAb could significantly inhibit donor-reactive CD4(+) memory T cells from rejecting grafts via a Th1-dependent pathway, but xenoreactive CD4(+) memory T cells can avoid the effects of anti-CD44 mAb to reject islet xenografts via a Th2-dependent pathway.

Donor-reactive memory T cells are known to accelerate allograft rejection; in our previous study, we reported that combined monoclonal antibodies (mAbs) could prolong islet allograft survival in alloantigen-primed mice. In this study, we examine the effects of donor-reactive memory T cells on the xenograft survival and methods to prolong the islet graft survival.To collect donor-reactive T cells, we performed full-thickness rat skin xenografting on BALB/c mice and isolated the T cells from the mice after 6-8 weeks. These cells were then adoptively transferred to syngenic mice 1 day before rat-to-mouse islet transplantation. Three experimental groups were established in the adoptive transfer model: recipient mice treated with isotype mAbs (isotype group); mice treated with anti-CD40L mAb (anti-CD40L group); and mice treated with anti-CD40L, anti-OX40L, and anti-CD122 mAbs (3-combined group).Lewis rat islet xenografts transplanted in naïve mice showed a mean survival time (MST) of 12.8 days, while the graft rejection was accelerated if the recipient mice were treated with adoptively transferred donor-reactive T cells (MST, 8.67 days). Treatment with anti-CD40L mb could not reverse the accelerated rejection (MST, 9.3 days). However, when anti-CD40L mb was combined with anti-OX40L and anti-CD122 mAbs, there was a considerable increase in the MST, which was 72.2 days. Compared to the isotype group, the 3-combined group had significantly lesser proportion of memory T cells and greater proportion of regulatory T cells (Tregs) in the spleen. Meanwhile, in the 3-combined group, the production of anti-rat antibodies was markedly inhibited. Treatment with a combination of antibodies could significantly reverse the accelerated rejection mediated by donor-reactive memory T cells by inhibiting cellular and humoral immune responses.

We study the evolution of dark spatial solitons by chi((2)): chi((2)) cascaded nonlinearity. The generation and evolution of solitons pairs by the optical branching effect is investigated. It is shown that the number of solitons pairs and the transverse velocity of a given pair depend on the parameters of the input beam. We also investigate the hollows generated in a beam with a uniform background when the two sides of the input beam have various phase difference. It is concluded that dark spatial solitons by chi((2)): chi((2)) cascaded nonlinearity have analog performance compared with that in chi((3)) defocusing Kerr media.

Classical PID controller is difficult to meet the requirement of both static and dynamic performance efficiency in practice. By analyzing the actions of PID parameters separately, for reducing or eliminating their conflict one another in different step, the concepts of backward and forward integration are introduced, and a human-simulating intelligent control (HSIC) PID controller with different modes of one dimension just for deviation and two dimensions for deviation and deviation rate is presented. The non-synchronous phenomenon is noted that control input and plant output approach their top points at different time. Simulation verifies the algorithm is reasonable. The proposed controller has been used successfully to industry boiler for pressure control object

In this letter, the global stability analysis of an L-band push-pull power amplifier is presented. The analysis is carried out for the amplifier operating in different modes, such as Class AB, Class B, and Class E/F, considering variations in the bias voltages, the input power and the input frequency. After determination of the oscillation mode, three different stabilization techniques are applied and compared: feedback resistors, neutralization capacitors, and odd-mode stabilization resistor. The element values of each stabilization network, ensuring a stable behavior for all the operating conditions, are calculated with a bifurcation-analysis technique. Good agreement is found between measured and simulated results.

We theoretically investigate the evolvement of dark spatial soliton with cascading quadratic nonlinearity in quasi-phase-matched second harmonic generation. It is shown that the dark solitary wave can propagate stably when background intensity is large enough, in which diffraction of beam can be balanced by the cascading quadratic nonlinearity. We also analyze the influence of phase-mismatch on the stability of dark soliton propagation.

Space-based radar places significant demands on the spacecraft resources (mass, power, data rate) and is therefore very expensive to implement. These systems typically require active phased-array antennas with hundreds or thousands of transmit/receive (T/R) modules distributed on the array. High-efficiency is a vitally important figure of merit for the radar T/R module because it reduces the power consumption and therefore makes best possible use of the limited power available. High efficiency also improves the thermal design and reliability. In this paper, we describe the design and preliminary results of a novel L-band (1250 MHz) T/R module technology to achieve ultra-high efficiencies. We will show that a dramatic improvement in overall T/R module efficiency is possible using high-efficiency class-E/F amplifiers. The T/R module performance goals are to achieve an overall module efficiency greater than 70% with a minimum of 30-W output power at L-band frequencies.

This work demonstrates the prediction of asymmetry in intermodulation distortion of HBT power amplifiers under two-tone excitation. While previous predictions were based on Volterra series in conjunction with a simple device model, the present approach is based on harmonic-balance simulation in conjunction with a nonlinear large-signal device model. The present approach is validated by the agreement between simulations and measurements under different bias, matching and input conditions as well as tone separations. The present result is consistent with the Volterra-series analysis of the effect of baseband termination impedance on the intermodulation asymmetry.

Laser shock forming LSF of sheet metal is a new technique realized by applying an impulsive pressure generated by a laser-induced shock wave on the surface of metal sheet. Our objective is to examine the deformation and the surface quality of LSF. LSF of a brass metal sheet is investigated using a Q-switched Nd:YAG laser with an energy per pulse of 15 to 50 J. The microhardness, roughness, and microstruc- ture of the processed brass specimen are examined. ABAQUS software is employed to simulate the LSF process. The central displacement of the shocked region is measured and compared with the simulation. The results reveal that the microhardness of the brass specimen increases by about 20% because of the LSP treatment, and the surface quality and the microstructure has no visible change: LSF is a mechanical process, not a thermal process, and no remarkable ablation is observed. The higher the pulse energy, the higher is the central displacement of the shocked region obtained. The deformation of the simulation matches the experiment quite well. © 2008 Society of Photo-Optical Instrumentation

Due to the importance of the Gloeocapsomorpha Prisca (G. prisca)-enriched source rocks, which belong to Kukersite-type source rocks in the Lower Paleozoic Ordovician strata, it has received great attentions during the petroleum exploration as to whether there are the Kukersite-type source rocks developed in the major hydrocarbon source strata of the Upper and Middle Ordovician in the Tarim Basin. Using pyrolysis-gas chromatography-mass spectrography to analyse kerogens from source rocks in the lime- mud mound with moderate maturity, study reveals that there are the Kukersite-type source rocks in the Ordovician strata of the Tarim Basin. The pyrolysis products showed a low content of >n-C19 normal alkanes with a significant odd-even predominance between n-C13 and n-C17, long-chain alky substituted alkylbenzene and alkylthiophene isomers and distinctive distribution of 5-N-alkyl-1, 3-Benzenediol and its homologous. Based on the geographic environment characteristics of G. Prisca, the molecular distributions of crude oil from the Lower Paleozoic petroleum systems in the Tarim Basin and characteristics of kerogen pyrolysis products from the Middle and Upper Ordovician source rocks, the results suggested that it is less possible to develop the G. Prisca-enriched Kukersite-type source rocks in the major hydrocarbon source rocks in the Middle and Upper Ordovician strata in the Tarim Basin. However, the benthic macroalga and planktonic algae-enriched source rocks are the main contributors.

As the number of applications of quantum dots (QDs) grows, the likelihood of exposure increases. Because these metals have the potential for detrimental environmental and health effects, concerns have been raised over our lack of understanding about the fate of these products. Among various types of QDs, cadmium-based quantum dots attract the greatest attention due to their wide applications. To properly assess the potential risk of cadmium-containing QDs, we summarize the current state of academic knowledge on the toxicity of cadmium-based QDs.