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The microstructure and mechanical properties of the 7085 ingot casting was tested by OM, SEM and EDS, the fatigue damage was observed in the driving test process, the temperature gradient distribution was adjusted observably by using the FEM simulation analysis. By adjusting the pouring temperature, many micro shrinkage metallurgical defects were eliminated, the tensile strength, yield strength and elongation were raised to 498MPa, 362MPa and 7.4% at the T6 heat treatment state.

The Hechuan gas field is one of the tight gas reservoirs with the highest formation water salinity in China. The content of metal ions, such as calcium, magnesium, iron, and barium, is as high as 20 g/L. Severe scales in near-wellbore reservoir blocks the gas and liquid flow paths, affecting the normal production of gas wells. The analysis of scale samples shows that the scale compositions in the Hechuan gas field are complex, which are composed of calcium carbonate, calcium sulfate, barium sulfate, iron salt, silicate, and other inorganic scales. To dissolve these scales, 14 kinds of laboratory self-made chelating acids named AST-01 to AST-14, sequentially, were evaluated by the descaling rate, in which the chelating acid AST-01 was selected with a dissolution rate of 77.7%. Meanwhile, the optimal concentration and reaction time of AST-01 were investigated, and the concentrations of the corrosion inhibitor, the iron ion stabilizer, and surfactants were also optimized. Then, a chelating acid descaling formula was obtained, which was 15~20% of AST-01 chelating acid + 1.5~2.0% of corrosion inhibitor + 2.5% of iron ion stabilizer + 0.3% of drainage aid. A pilot field trial of this descaling formula was applied in a Hechuan X1 well. A remarkable result was obtained in that the shut-in tubing pressure recovery rate was increased by 14 times, the gas production was increased by 10 times, and the gas well resumed to produce continuously again.

Due to the severe winter climate conditions in northern China, gas wells and pipelines are at high risk of gas hydrate blockage. In order to ensure stable gas supply in winter, the required Methanol injection concentrations are as high as 30–60 wt% of water rates in Daqing gas wells. As increasing in the water-gas ratio, large quantities of Methanol are injected into wells through Methanol injection lines. However, there are some drawbacks in the current Methanol injection process, including huge Methanol consumptions, high operating costs, large loads of the pumping system, and long residence time of Methanol in injection pipelines. In addition, large amounts of Methanol injected into well bottom will inevitably affect the liquid entrainment capacity of gas wells. Therefore, to reduce Methanol injection quantities and improve the inhibitor injection efficiency, this paper carries out a research and field test on the intelligent injection technology of mixed natural gas hydrate inhibitors. The Kinetic Hydrate Inhibitor PVCap and Methanol are mixed to study methane hydrate formation temperature under the operating pressure of 5 MPa and rotating speed of 20 r/min. The results show that the critical temperature of hydrate formation can be reduced to 0.89 ℃ and induction time can be extended to 6330 s when 1 wt% PVCap and 5 wt% Methanol were mixed, which meets the safety transportation requirements between gas wells and gathering stations. Meanwhile, an intelligent inhibitor injection device has been developed, which can inject low dose mixed inhibitors continuously and can automatically adjust the injection rates by real-time monitoring and analyzing wellhead temperatures, pressures, and water productions. The technology has been tested in a hydrate-plugged gas well X. Before the test, the well cannot be opened, the opening time was 0 in 2018, which affected the annual production capacity of 450 × 104 m3. In the field test, the injection rates of the mixed inhibitors are 0–15 L/h, gas well X resumes production successfully. Compared with the traditional process, Methanol consumption is reduced by more than 80%. The manual replenishment cycle of inhibitors can be up to 15 days, and the maintenance workload is reduced by 93.3%, which is of great significance to the construction of the digital gas field in Daqing Oilfield.

Methacrylated hyperbranched polyglycerol (HPG-MA) is successfully synthesized through transesterification by controlling the ratio of HPG to glycidyl methacrylate (GMA). The concentration of the dye or phase transporter, temperature, contact time, and molecular weight of phase transporter were taken into consideration to evaluate the removal ratio and transfer capability. With malachite green optimized as a model dye, HPG-MA could reach a maximum adsorption of 990 mg/g at the feed concentration of 1 g/L, and the removal ratio is 99% compared with ~20 h for other reported phase transporters, which indicates that HPG-MA is a novel phase transporter. HPG-MA can absorb dyes in aqueous solutions, which can be ascribed to the existence of a cavity structure and abundant ether groups. We believe that HPG-MA can have potential applications in the removal of dyes from aqueous solutions due to its high adsorption capacity and eco-friendly nature.

With the decline of pouring temperature in the range of 750°C~675°C, solidification curve was shifted to left primitively, and then gradually turned to right. Temperature of concretion nucleation and binary eutectic reaction was increased after a reduction, whereas the time was presented dynamically, both the minimum value which were obtained at 715 °Care 23.48s and 89.24s respectively. Growth time of crystal nucleation was extended after a slight decrease, the lowest point which was appeared at 715°C is 607.25s, time of binary eutectic reaction was varied as the cubic polynomial, the minimum value that emerged at 715°C is 228.39s. Solidification curve was changed as the exponential function, cooling rates ascended initially and then dropped andante, the peak point that achieved at 715°C is 5.93°C/min. The test results of microstructure shows that the content of primary and eutectic silicon with the plate-like and needle morphology, was increased primarily and then decreased with the decline of pouring temperature, however, the changing trend of grain size was shown as opposite, the minimum value which was obtained at 715°C is 534μm. It was also found from the results of grain size that with lower pouring and binary eutectic temperature, along with higher cooling rate and nucleation temperature, grain size was refined properly.

The carbon dioxide corrosion inhibitor IMC-1 was composed by caprylic acid amide polyoxyethylene ethers (n=4-5) and a small amount of the TX-10(5%). When the concentration was 200 mg/L, N80 steel corrosion rate was less than 0.125mm/a. With the CO2 partial pressure and temperature increased, N80 steel corrosion rate was decreased. From the electrochemical polarization curve, the adding corrosion inhibitor prevented the electrode reaction. The corrosion inhibitor IMC-1 was anodic inhibitor.

Through the Suizhong 36-1 oilfield core acidification experiments, we studied the different acid systems on the dissolution rate of rock samples and determine the preferred suitable for different circumstances Suizhong 36-1 oilfield cuttings acid system[1].

The carbon dioxide corrosion on N80 steel was evaluated under the gas phase and the liquid phase. With the test temperature improved, the corrosion rate increases. Under the condition of gas phase, the corrosion peak is 0.2942mm/a when the temperature is 110°C and pressure is 24 MPa. Under the condition of liquid phase, the corrosion peak is 26.5325mm/a when the temperature is 50°C and pressure is 24 MPa. With the increase of CO2 partial pressure, the corrosion rate of N80 steel was falling. Microscopic analysis shows that the corrosion products of CO2 on N80 steel have a large white flocculent compounds and the corrosion surface have a lot of cracks and holes.

For the unique geological features in Haita area, we optimized the synthesis conditions of slurry fluid loss additive ZJK103 and evaluated its performance. The experimental results showed that under different water conditions, water quality had no effect on fluid loss of ZJK103; The fluid loss additive had no adverse impact on compressive strength of cement stone; With same mixing water and different conserving water, the compressive strength did not change much. ZJK103 had better thickening effect than other average fluid loss additives. According to the performance of slurry system, the indoor synthetic slurry filtrate reducer could meet the quality requirements of Haita region cementing.

Low temperature early strength cement slurry is a slurry in order to meet the well cementation in low-temperature conditions. Daqing weather is characterized by the silica fume, solid alcohols, amines and anionic polymers prepared a certain proportion, got a new low temperature early strength agent, It can greatly accelerate the hydration rate of cement and promote the formation of the cement paste early strength; and no chlorine ions, able to overcome the problem caused by traditional chlorine early strength agent casing corrosion.

The solid free completion fluid is the KCl-polymer system, it has the good inhibitory and stabilize the clay. The corrosion rate is 0.0775 g/m2·h, for different permeability core, the degree of injury is less than 20%.Use completion fluid to reduce oil layer damage of main mechanism for the effect of k+, inhibition of polymer and the synergy of K + and polymer.

Aimed at the cement slurry leak problem in the leakiness area cementing of Jilin oilfield, the fiber cement slurry system was developed. The general performance of fiber cement slurry, such as the pressure strength, thickness time, filter loss, flowing ability and water separate rate, etc was analysis in the room condition. The preventing and block leak ability was evaluated. The room and field tests prove that the ability of the fiber cement slurry is best. It can make the field cementing requirement in the leakiness formation and has the best effect of preventing and block leak ability.

In order to better protect the Daqing Oilfield Sanan oil field development, make experimental analysis and field applications of Sanan's core.Through the relationship between rheology and fluid loss ,achieve JGN best dosage of the entire completion fluid system, completion rheological law and evaluated regular patten.The effect of field application is obvious, improve strength of the oil production , the skin factor and injection pressure is reduced, and made better protect the reservoir effect.

The basic prescription of the potassium sulfate drilling fluid is: 5% bentonite+0.4%Na2CO3+5.0%K2SO4+1000ppmDCL+200ppmDesco+100ppmAlcome+500ppmSAP+1000ppmLT+1000ppmKEL. The content of K+ is 50000mg/L. The drilling fluid has appropriate viscosity, gel and filter loss. The shale rolling recovery rate is bigger than 85%. The static swelling rate is smaller than 2%. The corn damage is less than 20%. The mechanism of protect formation is the K+ ability of preventing the clay from hydrating and swelling, the adsorption ability of formation protecting agent and the cooperating role of K+ and formation protecting agent. The potassium sulfate drilling fluid was used in fang-3 outer section of the Song-fang-tun oilfield. It was shown that the drilling fluid could meet the drilling demand in this oilfield.

Acid sludge is one of the major oil field acidification increased production ineffective. Therefore, the acid sludge formation of influencing factors on improving acidification effect is of great importance. The Suizhong 36-1 oilfield is selected as the research object , a more in-depth study of the acid sludge formed in the acidification process influencing factors . The results show that: With the increase of crude oil in the colloid and asphaltene content , the amount of oleic acid mixture to form acid sludge also increases . Strong acid ionizing out of the higher concentration of H+ , the faster of the speed, the forming acid slag trend is obvious. The residual acid pH value increased , the amount of acid sludge also will continue to rise.

An acid self-diverting agent compound by betaine type surfactant and quaternary ammonium salt type surfactant was synthesized and evaluated. Found that when the pH value was higher than 1, acid viscosity rose rapidly, and the pH value up to 3, acid viscosity reached its maximum value (300mPa s), and can effectively made the acid diverse.When the pH value was 6, the system completely gelouted, easy to flowback; When added the self-diverting additives, acid system had better temperature resistance; With the elevated of concentration of the self-diverting agent, the apparent viscosity of acid increased, when the concentration of the self-diverting agent was more than 5%, the acid apparent viscosity increased little, gradually stabilized, but all above 300mPas, meet the industry standard requirements.

In this paper,we used the heavy oil of Du 84,53-55 well in Liaohe oil field,analyzed of the impact factors of the heavy oil emulsion viscosity.When the droplet size of the emulsion is reduced,the viscosity of the heavy oil emulsion increases,and the non-Newtonian obvious.Heavy oil emulsions exhibit Newtonian fluid properties at low shear rate,exhibits shear-thinning properties in the heavy oil emulsion under high shear rate.Heavy oil emulsion viscosity decreases with the increasing concentration of viscosity reducer,when the viscosity reducer concentration of more than 0.25%,heavy oil emulsion viscosity declines slowed.

A long period of development in Haituozi exploration area, downhole conditions are constantly changing, increasingly complex, and the original cementing technology is difficult to solve the region's low pressure leakage problems. For the special circumstances of the region, we set up a special research team, focus on starting from the the preferred cement slurry system, and improve stability, toughness, plugging, leak-proof ability of the slurry system performance; Another optimization cementing design and perfect cementing supporting measures effectively solve the region's dropout problem.

In-depth development of a block of Sudan, effectively develop the rich reserves of the major reservoirs, increase crude oil production, and reduce the cost of drilling.This horizon has a high penetration, high formation temperature, easy to collapse, gas channeling and complex problem, there is a great test of this case to horizontal wells cementing.Therefore, develop a new expansion slurry system,which has the feature of high-strength, low water loss, gas channeling effect, solves the region problems of cementing technical. A block of Sudan formation pressure coefficient is low, fracture pressure is small, strata is sulfur loose sandstone, and stratigraphic diagenetic is poor, easy to collapse and necking.With the deepening of the development ,these issues are more and more obvious.In order to achieve the best results in the horizontal well cementing operations, we research from geological data, well structure, cementing formulations and process in-depth and meticulous. Solve the high permeability formation temperature, easy to collapse, gas channeling technical problems, develope a new type of high-strength, low water loss, micro-expansion slurry system, and effectively solve the block problem of horizontal wells cementing .

Adsorption isotherms of new type cationic Gemini surfactant named CGS on quartz sand has been got by using solution concentration difference method. The effect of different factors on adsorption, such as temperature, pH value and salinity, are studied too. The adsorption isotherm of CGS on quartz sand accorded with Langmuir shape. The adsorption quantity increased with the increasing of surfactant concentration at an adagio rate, then the adsorption quantity increased fast, and it reached adsorption saturation when mass concentration was 150 mg/L, and saturated absorption was 6.3 mg/g. The adsorption quantity of CGS increased with the increasing of salt concentration. When heighten temperature and pH value, the adsorption quantity of CGS decreased.

In this paper, aiming at the Fuyu high angle holes cementing technical issues, in-depth study the quick-setting, high early strength and micro-expansion anti-channeling slurry system. Use this system in Fuyu region high angle holes cementing engineering, the completion of 10 high angle holes were all qualified, 8 of which were quality well, the pass rate of 100% and quality rate of 80%.Solve the difficult problem of the cementation quality and packer formation of the cement sheath, ensure the cementing Quality of Fuyu city high angle wells, which has an important guide and reference on Jilin Oilfield in the future development of the deep horizontal and cementing technology.

Cationic Gemini surfactant concentration, the inorganic salts added and the pH value of surface tension obtained cationic gemini surfactant critical micelle concentration is 0.4mmol / L;by adding three kinds of inorganic salts NaCl, MgCl2, and Na2SO4 ,which Na2SO4 has the greatest impact on surface tension, followed by MgCl2.The surface minimum tension of the pH ranged from 9 to 11 , indicating that the surface activity of cationic gemini surfactants achieved the highest.

This paper describes study of temperature variation in the gelling and hardening, thermal baking and pouring stage of foaming gypsum mold. The temperature difference curve in the gelling and hardening process shows an rapid decline, tending to the placid downward eventually after a clipping rise. During the thermal baking stage, owing to the low heat conduction coefficient of the foaming gypsum mold, the actual temperature of each thermocouple lags behind the craft temperature, lag degree increases gradually with the extension of baking temperature and holding time. At the initial period of pouring process for molten aluminum, the temperature of center position in the mold increases fast by absorbing lots of heat in the solidification process, whereas, slower temperature rising curve occurs in the edge and intersection position. Coupled with the ongoing of air convection heat transfer, resulting in a continuous falling of temperature, therefore the temperature difference curve of each point inside the mold shows a successive upward trend with the solidification process of molten aluminum alloy.

A cationic Gemini surfactant ethane-1, 2-bis (Cetyl dimethyl brominated ammonium), denoted 16-2-16 was synthesized from ethane and Hexadecyl dimethyl amine. The properties of the product were characterized, and the physical and chemical properties were determined. The results showed that the synthetic product was the target product, and its surface tension was 3.4×10-4N/m, and the CMC was 2.2×10-4mol/L at 25°C. At the same time, its synergistic effect with common surfactants was studied; the results showed that the synthetic product had good synergic effect.

Liaohe oil field block 58 for Huancai, the efficiency of production of thickened oil is low, and the efficiency of displacement is worse, likely to cause other issues. Researching and developing an type of Heavy Oil Viscosity Reducer for exploiting. The high viscosity of W/O emulsion changed into low viscosity O/W emulsion to facilitate recovery, enhanced oil recovery. Through the experiment determine the viscosity properties of Heavy Oil Viscosity Reducer. The oil/water interfacial tension is lower than 0.0031mN•m-1, salt-resisting is good. The efficiency of viscosity reduction is higher than 90%, and also good at 180°C.

MFR high temperature profile control agent consisted of 6.5% wood Fortunately sulfonic acid calcium (Ca-LS) and 6.5% crosslinker modified furfural resin (MFR),and the gel solution formed a stable performance gel in the 150~300°C.The higher the temperature, the shorter the gelation time; and the longer the heating time, the higher the gel strength. The gel is very stable at 300°C, and is well in acid and salt resistance. The core experiments showed that the blocking agent's blockage ratio is more than 99% ; the units of the breakthrough pressure was greater than 100 kPa / cm,which the gel solution is a good performance of high-temperature profile control agent.

The main problem dehydration system of XinMu Oil Field at present is high dehydration temperatures,high the amount of demulsifier, increase output moisture content year by year and more and more frequent fluctuations.Through the reform to establish a dehydration subsystems,and composite demulsifier alone to deal with special oil to eliminate the influence of special crude oil to dehydration system.Filter out Daqing produced 169＃ demulsifier 150mg·L-1, when add oxalic acid 200mg·L-1 and fungicide 100mg·L-1 the demulsifier of good dehydration effect.After processing crude oil water content of less than 5%,sewage oil content of less than 20mg·L-1, which has solved the dehydration problems of troubled XinMu for many years.

Take the lauric acid, the ethylene diamine, the chloroacetic acid, the soda ash as raw material synthesized a new type of Anionic Gemini surfactants-N, N'-double lauroyl ethylene diamine two sodium acetate, The properties of the product were characterized, and the physical and chemical properties were determined. The experimental results can be seen that the anionic Gemini surfactants can greatly reduce the oil/water interface tension, and it has good viscosity properties, Thus deduced that the Gemini surfactants is better than the ordinary surfactant better table (world) surface activity, Can be used in the tertiary oil recovery field.

The overall distribution of mechanical properties of A357 aluminum alloy connection beam casting after solidification and T6 heat treatment was researched in this paper, through the mechanics performance test, metallographic microstructure observation, SEM and EDS scanning analysis of the fracture surface, the ensemble mechanical properties of connection beam casting was characterized. The results show that owing to the low cooling rate nearby the arc thick-walled department and the trasition region between the thick and thin-walled of the connection beam casting, leading to the morphology of the crystalline grains and silicon particles in this vicinity are thick. Some casting defects such as oxide inclusions located in the lateral stud district were caused by the strong erosion of high temperature melting liquid during the pouring process, resulting in the mechanical properties decreased significantly, casting defects were not eliminated in the T6 heat treatment process. Due to both the high cooling rate and the smooth pouring process among the thin-wall, forward stud and square box region of A357 aluminum connection beam casting, after the solid solution and limitation strengthening of T6 heat treatment, resulting in the overall mechanical properties were higher than other areas. The tensile strength has reached 360.96MPa, also with the yield strength and elongation respectively attained 297.95MPa and 8.82 %.

This paper describes the cast structure study of A357 aluminum alloy stress frame casting under consecutive solidification and simultaneous solidification by test and numerical simulation methods, with the conclusions of tensile tests by using of SEM and EDS analysis, the mechanical properties and fracture morphology were observed both under the cast and T6 heat-treatment state. Intergranular fracture cracks were observed to be the main failure mode in the casting state condition, cracks originated from the tissue defects and continued to proliferate until the tensile specimens were ruptured. Simultaneous solidification can decrease the casting shrinkage and micro-cavity and improve the mechanical properties of the castings. Dimple fracture was the dominated failure mode after T6 heat treatment state, the distribution of some intergranular cracks staggered with dimple fracture can surveyed under the fractography analysis. The superiority of simultaneous solidification was demonstrated by the numerical simulation of China casting CAE.

In this paper, we introduced the method of preparing cationic copolymer clay stabilizer PDA and something about its laboratory study. Dimethyl diallyl ammonium chloride (DMDAAC) and acrylamide (AM) were the reaction materials, and potassium persulfate was the initiating agent, which was used to synthesize the cationic copolymer clay stabilizer PDA. Through laboratory experiments, the performance of clay stabilizer PDA was evaluated, and the results were as follows: the anti-swelling performance of PDA was better than that of KCl solution and another cationic copolymer clay stabilizer PTE. The swelling ratio of 1.0% PDA clay stabilizer was only 15.3% and anti-swelling ratio was more than 72.0%. Under the temperature of 25°C to 150°C, the anti-swelling performance was still stable. Furthermore, clay stabilizer PDA performed well in resisting salt and calcium at normal temperature, and the average damage ratio of natural cores was less than 17.5%.

With the rapid development of modern nondestructive testing technologies, ultrasonic phased array and Ultrasonic array testing technology has been used widely, at the same time the propagation process of ultrasonic in the material becomes more and more complex. In order to make the ultrasonic propagation path become visible and researchers can observe the acoustic field directly, considering the properties of the ultrasonic as a stress wave, according to the theory of polarized light interference, a multi-channel dynamic photoelastic imaging system is developed successfully. The system can generate many kinds of focusing ultrasonic fields in optical specimen by controlling the ultrasonic transmission delay time of each equipment channel, and the system has the ability to simulate the acoustic field’s focusing process of the ultrasonic phased array. The image shot by CCD camera reflects the propagation process of the acoustic field in the specimen, and the dynamic video is formed under control of the timing circuit, and the system has the ability to save the captured image in the computer.

To study the effects of the 50 Hz-filter circuit in a microelectrode amplifier on cardiac action potential waveform and parameters.Cardiac action potential signals were fed into a microcomputer through a glass microelectrode, a microelectrode amplifier, a differentiator and A/D converter. The cardiac action potential signals were recorded and analyzed with 50 Hz-filter circuit and without it, and the frequency spectrum in the signals was analyzed with the fast Fourier transformation.When the 50 Hz-filter circuit was used, the phase 0 of the potential waveform was seriously distorted and prolonged. The maximal rate of depolarization at the phase 0 was cut down, while the other parameters were not effected.There has already been much 50 Hz element in the action potential waveform. During amplifying the cardiac action potential signal, the 50 Hz-filter circuit should not be turned on. Otherwise, the experiment results will be effected.

To introduce the manufacture and use of a simple, new type of drop recorder of frog heart.To improve the perfusion device of (see text for symbol) and Straub method. Two electrodes of drop recorder were fixed in an injector of 20 ml. The input tube, output tube and resistance tube were all made of plastic material.This device could be used to observe effects of preload, after-load, hormone and electrolyte on the cardiac output in isolated frog heart.The new type of drop recorder was economical and could be easily operated, it could be also connected to computer. Using the new type of drop recorder, effects of various physical and chemical factors on cardiac function could be observed directly, accurately.

In the title compound, {[Cu(C(6)H(2)N(2)O(4))(C(3)H(7)NO)]·H(2)O}(n), the Cu(II) atom is coordinated by an N,O-bidentate pyrazine-2,3-dicarboxyl-ate (pzdc) dianion, two O atoms from two other pzdc anions and one O atom from the dimethlyformamide ligand, forming a distorted square-pyramidal CuNO(4) geometry. The polymeric character of the structure is established by the formation of layers parallel to (100) via bridging pzdc ligands. O-H⋯O hydrogen bonding between water mol-ecules and uncoordinated carboxyl-ate O atoms leads to additional stabilization of the structure.

To study the electrophysiological effects of genistein (GST) on pacemaker cells in sinoatrial (SA) nodes of rabbits.Parameters of action potential (AP) in SA node were recorded using intracellular microelectrode technique.GST (10 - 150 micromol/L) not only decreased the amplitude of action potential (APA), maximal rate of depolarization (Vmax) [from (6.2 +/- 2.8) to (2.8 +/- 1.4) V/s, P0.01], velocity of diastolic (phase 4) depolarization (VDD) [from (55 +/- 14) to (38 +/- 8) mV/s, P0.01], and rate of pacemaker firing (RPF) [from (154 +/- 23) to (107 +/- 25) beat/min, P0.01], but also prolonged duration of 90 % repolarization of action potential (APD90) in a concentration-dependent manner. Both elevation of calcium concentration (5 mmol/L) in superfusate and application of L-type Ca2+ channel agonist Bay K8644 (0.5 micromol/L) reversed the inhibitory effects of GST on pacemaker cells, while pretreatment with NG-nitro-L-arginine methyl ester (L-NAME, 1 mmol/L), an NO synthase inhibitor, failed to block the electrophysiological effects of GST.GST exerted a negative chronotropic action and induced a delayed repolarization of pacemaker cells in SA nodes of rabbits. These effects were likely due to reduction in calcium influx and potassium efflux, but had no association with NO release.

The cardiac electrophysiological effects of genistein (GST) were examined in guinea pig papillary muscle using intracellular microelectrode technique. The results obtained are as follows. (1) Duration of action potential (APD) in normal papillary muscles was decreased by GST (10 100 micromol/L) in a concentration-dependent manner. (2) In partially depolarized papillary muscles, 50 micromol/L GST not only reduced APD, but also decreased the amplitude of action potential, overshoot and maximal velocity of phase 0 depolarization. (3) Pretreatment with N( )-nitro-L-arginine (L-NNA, 5 mmol/L) failed to affect the above effects of GST (50 micromol/L)on papillary muscles. (4) 17beta-estradiol (E(2), 5 micromol/L) or GST (10 micromol/L) alone did not affect action potential, while GST combined with E(2) at the same doses shortened APD significantly. All these results indicate that the effects of GST on papillary muscles are likely due to a decrease of calcium inflow which is not mediated by NO and that GST has a facilitative or synergetic action with E(2).

In the title compound, {[Cu(C6H2N2O4)(C3H7NO)]·H2O}n, the Cu(II) atom is coordinated by an N,O-bidentate pyrazine-2,3-dicarboxyl­ate (pzdc) dianion, two O atoms from two other pzdc anions and one O atom from the dimethlyformamide ligand, forming a distorted square-pyramidal CuNO4 geometry. The polymeric character of the structure is established by the formation of layers parallel to (100) via bridging pzdc ligands. O—H⋯O hydrogen bonding between water mol­ecules and uncoordinated carboxyl­ate O atoms leads to additional stabilization of the structure.

In the title compound, [Ni(C(8)H(3)NO(6))(C(12)H(10)N(2))(H(2)O)](n), the Ni(II) atom is octa-hedrally coordinated by two cis N atoms from two different 1,2-bis-(4-pyrid-yl)ethyl-ene (bpe) ligands, two O atoms from one chelating carboxyl group of the 5-nitro-isophthalic acid (nip) ligand, one O atom from another monodentate nip ligand and one O atom from a water mol-ecule, forming a three-dimensional network structure. Inter-molecular O-H⋯O hydrogen bonding stabilizes this arrangement. The asymmetric unit of the structure contains one Ni(II) atom, one water mol-ecule, one nip ligand and two half-mol-ecules of the bpe ligand with an inversion centre at the mid-point of the central C=C bond.