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排序方式: 共有171条查询结果,搜索用时 15 毫秒
1.
R. S. Cline W. E. Heitmann D. Bhattacharya 《JOM Journal of the Minerals, Metals and Materials Society》1986,38(5):26-30
This paper examines microalloyed steels—steels which develop their properties in the as-received condition without requiring further heat treatment, such as quenching and tempering. Microalloyed steel bars and forgings offer a clear cut potential for cost reduction and energy savings. The metallurgy for producing high strength microalloyed bars and forgings is in place. However, significant improvement in the notch toughness of these materials is necessary, and the metallurgy required to achieve this toughness improvement exists. With application of the necessary metallurgical techniques in rolling mills and forge shops, the utilization of high strength microalloyed steel bars and forgings will increase greatly. 相似文献
2.
A simple and rapid procedure was developed to isolate and purify preparative quantities (up to 200 mg) of reduced myoglobin (98% oxy) of high purity (>96%) from beef and pork muscles. This method involved fractional precipitation of a crude myoglobin extract with ammonium sulfate and purification with a single Chromatographic step on a Sephadex G-100 column. The metmyoglobin level of the myoglobin preparation was minimised by using muscle from freshly slaughtered animals (<48h post-mortem), trimming the muscle immediately before use to remove any oxidised myoglobin on the surface and carrying out all procedures at low temperature (0-5 °C) and alkaline pH (8.0-8.5). The purity of the myoglobin preparations was confirmed by ion exchange HPLC and SDS-polyacrylamide gel electrophoresis. The method was effective for skeletal muscle of both low myoglobin content (pork) and high myoglobin content (beef). The resulting purified myoglobin was very stable and there was little change in metmyoglobin level or autoxidation rate during 3 months' storage at 0 °C. 相似文献
3.
目前存在3个关键因素导致环锭纺产量无法进一步提高。介绍了一些有利于未来环锭纺技术进一步发展的基本情况。详细分析了环锭纺工序中的能耗问题,这是性能能否提高的基础。环锭纺产量的提高,不仅是技术上是否可行的问题,更重要的是能够获得良好的经济效益。 相似文献
4.
Clement Appiah Christine Arndt Katharina Siemsen Anne Heitmann Anne Staubitz Christine Selhuber‐Unkel 《Advanced materials (Deerfield Beach, Fla.)》2019,31(36)
Living beings have an unsurpassed range of ways to manipulate objects and interact with them. They can make autonomous decisions and can heal themselves. So far, a conventional robot cannot mimic this complexity even remotely. Classical robots are often used to help with lifting and gripping and thus to alleviate the effects of menial tasks. Sensors can render robots responsive, and artificial intelligence aims at enabling autonomous responses. Inanimate soft robots are a step in this direction, but it will only be in combination with living systems that full complexity will be achievable. The field of biohybrid soft robotics provides entirely new concepts to address current challenges, for example the ability to self‐heal, enable a soft touch, or to show situational versatility. Therefore, “living materials” are at the heart of this review. Similarly to biological taxonomy, there is a recent effort for taxonomy of biohybrid soft robotics. Here, an expansion is proposed to take into account not only function and origin of biohybrid soft robotic components, but also the materials. This materials taxonomy key demonstrates visually that materials science will drive the development of the field of soft biohybrid robotics. 相似文献
5.
Telle-Hansen VH Larsen LN Høstmark AT Molin M Dahl L Almendingen K Ulven SM 《Lipids》2012,47(2):151-160
Intake of fish and omega-3 (n-3) fatty acids is associated with a reduced concentration of plasma triacylglycerols (TAG) but
the mechanisms are not fully clarified. Stearoyl-CoA desaturase-1 (SCD1) activity, governing TAG synthesis, is affected by
n-3 fatty acids. Peripheral blood mononuclear cells (PBMC) display expression of genes involved in lipid metabolism. The aim
of the present study was to estimate whether intake of lean and fatty fish would influence n-3 fatty acids composition in
plasma phospholipids (PL), serum TAG, 18:1n-9/18:0 ratio in plasma PL, as well as PBMC gene expression of SCD1 and fatty acid
synthase (FAS). Healthy males and females (n = 30), aged 20–40, consumed either 150 g of cod, salmon, or potato (control) daily for 15 days. During intervention docosahexaenoic
acid (DHA, 22:6n-3) increased in the cod group (P < 0.05), while TAG concentration decreased (P < 0.05). In the salmon group both eicosapentaenoic acid (EPA, 20:5n-3) and DHA increased (P < 0.05) whereas TAG concentration and the 18:1n-9/18:0 ratio decreased (P < 0.05). Reduction of the 18:1n-9/18:0 ratio was associated with a corresponding lowering of TAG (P < 0.05) and an increase in EPA and DHA (P < 0.05). The mRNA levels of SCD1 and FAS in PBMC were not significantly altered after intake of cod or salmon when compared
with the control group. In conclusion, both lean and fatty fish may lower TAG, possibly by reducing the 18:1n-9/18:0 ratio
related to allosteric inhibition of SCD1 activity, rather than by influencing the synthesis of enzyme protein. 相似文献
6.
Information about electron-transfer reactions of dissolved organic matter (DOM) is lacking. We determined electron acceptor and donor capacities (EAC and EDC) of a peat humic acid and an untreated peat DOM by electrochemical reduction and reduction with metallic Zn and H2S (EAC), and by oxidation with complexed ferric iron (EDC) at pH 6.5. DOC concentrations (10-100 mg L(-1)) and pH values (4.5-8) were varied in selected experiments. EAC reached up to 6.2 mequiv x (g C)(-1) and EDC reached up to 1.52 mequiv-(g C)(-1). EDC decreased with pH and conversion of chelated to colloidal iron, and the electron-transfer capacity (ETC) was controlled by the redox potential Eh of the reactant (ETC = 1.016x Eh - 0.138; R(2) = 0.87; p = 0.05). The kinetics could be adequately described by pseudo first-order rate laws, one or two DOM pools, and time constants ranging from 2.1 x 10(-3) d-1 to 1.9 x 10(-2) d(-1) for the fast pool. Reactions were completed after 24-160 h depending on the redox couple applied. The results indicate that DOM may act as a redox buffer over electrochemical potentials ranging from -0.9 to +1.0 V. 相似文献
7.
精细粗梳工艺生产高档纱 总被引:3,自引:0,他引:3
AIF-Nr.14827N是德国联邦工业合作研究会(AIF)的一项研究课题,旨在研发出一种既能提高短纤维排除率又能减少棉结的粗梳工艺,可在生产线密度20tex以上的纱线时省去精梳工艺。 相似文献
8.
We consider the problem of rescheduling trains in the case where one track of a railway section consisting of two tracks
in opposing directions is closed due to construction activities. After presenting an appropriate model for this situation
we derive a polynomial algorithm for the subproblem of finding an optimal schedule with minimal latenesss if the subsequences
of trains for both directions outside the construction site are fixed. Based on this algorithm we propose a local search procedure
for the general problem of finding good schedules and report test results for some real world instances.
Received: December 8, 1999 / Accepted: May 2, 2001 相似文献
9.
Erik Berg Schmidt Jeppe Hagstrup Christensen Inge Aardestrup Trine Madsen Sam Riahi Vibeke Ellegaard Hansen Helle Aarup Skou 《Lipids》2001,36(1):S65-S68
There is some evidence from epidemiology that intake of n-3 polyunsaturated fatty acids (PUFA) from seafood may protect against coronary artery disease (CAD). This hypothesis is further supported from animal data showing a beneficial effect of n-3 PUFA on thrombosis and atherosclerosis in animals fed fish oils in most, but not all, studies. There are several mechanisms by which an increased intake of marine n-3 PUFA may protect against CAD; the most universal finding is a reduction of plasma triglycerides. It is puzzling, however, that a very low amount of n-3 PUFA, with no known beneficial biochemical effects, seems to be cardioprotective. It has therefore been of paramount interest to perform clinical trials. Such evidence and trials are discussed in later chapters, and the results have been very encouraging. 相似文献
10.
C. Notthoff A. Lorke K. Rachor D. Heitmann D. Reuter 《Journal of Low Temperature Physics》2010,159(1-2):193-196
The THz-photoresponse (PR) between two separately contacted edge-channels of a two-dimensional electron gas in the quantum Hall regime is investigated. We use a not-simply-connected sample geometry, which is topologically equivalent to a ring shape (Corbino-geometry). At filling factors ν<2, spectrally resolved PR-measurements show a Lorentzian resonance, centered at the cyclotron-frequency, whereas above the integer filling factor, an asymmetric broadening is observed. Two independent contributions to the PR-signal can be resolved. One contribution clearly results from bolometric heating inside the bulk and the other one is caused by a non-bolometric mechanism. 相似文献